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Hyperphosphatemia

Hyperphosphatemia is an electrolyte disorder in which there is an elevated level of phosphate in the blood. Most people have no symptoms while others develop calcium deposits in the soft tissue. The disorder is often accompanied by low calcium blood levels, which can result in muscle spasms.

Causes include kidney failure, pseudohypoparathyroidism, hypoparathyroidism, diabetic ketoacidosis, tumor lysis syndrome, and rhabdomyolysis. Diagnosis is generally based on a blood phosphate level exceeding 1.46 mmol/L (4.5 mg/dL). Levels may appear falsely elevated with high blood lipid levels, high blood protein levels, or high blood bilirubin levels.

Treatment may include a phosphate low diet and antacids like calcium carbonate that bind phosphate. Occasionally, intravenous normal saline or kidney dialysis may be used. How commonly it occurs is unclear.

Signs and symptoms
Signs and symptoms include ectopic calcification, secondary hyperparathyroidism, and renal osteodystrophy. Abnormalities in phosphate metabolism such as hyperphosphatemia are included in the definition of the new chronic kidney disease–mineral and bone disorder (CKD–MBD).

Causes
Hypoparathyroidism: In this situation, there are low levels of parathyroid hormone (PTH). PTH normally inhibits reabsorption of phosphate by the kidney. Therefore, without enough PTH there is more reabsorption of the phosphate leading to a high phosphate level in the blood.

Chronic kidney failure: When the kidneys are not working well, there will be increased phosphate retention.

Drugs: hyperphosphatemia can also be caused by taking oral sodium phosphate solutions prescribed for bowel preparation for colonoscopy in children.

Diagnosis
The diagnosis of hyperphosphatemia is made through measuring the concentration of phosphate in the blood. A phosphate concentration greater than 1.46 mmol/L (4.5 mg/dL) is indicative of hyperphosphatemia, though further tests may be needed to identify the underlying cause of the elevated phosphate levels. It is considered significant when levels are greater than 1.6 mmol/L (5 mg/dL).

Units
Phosphates in blood exist in a chemical equilibrium of hydrogen phosphate (HPO42–) and dihydrogen phosphate (H2PO4–), which have different masses. Phosphate (PO43–) and phosphoric acid (H3PO4) are not present in significant amounts. Thus millimoles per liter (mmol/L) are often used to denote the phosphate concententration. If milligrams per decililiter (mg/dL) is used, it often denotes the mass of phosphorus bound to phosphates, but not the mass of some individual phosphate.

Treatment
High phosphate levels can be avoided with phosphate binders and dietary restriction of phosphate. If the kidneys are operating normally, a saline diuresis can be induced to renally eliminate the excess phosphate. In extreme cases, the blood can be filtered in a process called hemodialysis, removing the excess phosphate. Phosphate-binding medications include sevelamer, lanthanum carbonate, calcium carbonate, and calcium acetate. Previously aluminum hydroxide was the medication of choice, but its use has been largely abandoned due to the increased risk of aluminum toxicity.

title: Hyperphosphatemia


text:
User:Kelly Makin

Kelly Makin is a director. One of his works was Mickey Blue Eyes.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: User:Kelly Makin


text:
Hypophosphatemia

Hypophosphatemia is an electrolyte disorder in which there is a low level of phosphate in the blood. Symptoms may include weakness, trouble breathing, and loss of appetite. Complications may include seizures, coma, rhabdomyolysis, or softening of the bones.

Causes include alcohol use disorder, refeeding in those with malnutrition, recovery from diabetic ketoacidosis, burns, hyperventilation, and certain medications. It may also occur in the setting of hyperparathyroidism, hypothyroidism, and Cushing syndrome. It is diagnosed based on a blood phosphate concentration of less than 0.81 mmol/L (2.5 mg/dL). When levels are below 0.32 mmol/L (1.0 mg/dL) it is deemed to be severe.

Treatment depends on the underlying cause. Phosphate may be given by mouth or by injection into a vein. Hypophosphatemia occurs in about 2% of people within hospital and 70% of people in the intensive care unit (ICU).

Signs and symptoms

 * Muscle dysfunction and weakness – This occurs in major muscles, but also may manifest as: diplopia, low cardiac output, dysphagia, and respiratory depression due to respiratory muscle weakness.
 * Mental status changes – This may range from irritability to gross confusion, delirium, and coma.
 * White blood cell dysfunction, causing worsening of infections.
 * Instability of cell membranes due to low adenosine triphosphate (ATP) levels – This may cause rhabdomyolysis with increased serum levels of creatine phosphokinase, and also hemolytic anemia.
 * Increased affinity for oxygen in the blood caused by decreased production of 2,3-bisphosphoglyceric acid.
 * If hypophosphatemia is chronic; rickets in children or osteomalacia in adults may develop.

Causes

 * Refeeding syndrome – This causes a demand for phosphate in cells due to the action of hexokinase, an enzyme that attaches phosphate to glucose to begin metabolism of glucose. Also, production of ATP when cells are fed and recharge their energy supplies requires phosphate. A similar mechanism is seen in the treatment of diabetic ketoacidosis, which can be complicated by respiratory failure in these cases due to respiratory muscle weakness.
 * Respiratory alkalosis – Any alkalemic condition moves phosphate out of the blood into cells. This includes most common respiratory alkalemia (a higher than normal blood pH from low carbon dioxide levels in the blood), which in turn is caused by any hyperventilation (such as may result from sepsis, fever, pain, anxiety, drug withdrawal, and many other causes). This phenomenon is seen because in respiratory alkalosis carbon dioxide (CO2) decreases in the extracellular space, causing intracellular CO2 to freely diffuse out of the cell.  This drop in intracellular CO2 causes a rise in cellular pH which has a stimulating effect on glycolysis.  Since the process of glycolysis requires phosphate (the end product is adenosine triphosphate), the result is a massive uptake of phosphate into metabolically active tissue (such as muscle) from the serum.  However, that this effect is not seen in metabolic alkalosis, for in such cases the cause of the alkalosis is increased bicarbonate rather than decreased CO2.  Bicarbonate, unlike CO2, has poor diffusion across the cellular membrane and therefore there is little change in intracellular pH.
 * Alcohol use disorder – Alcohol impairs phosphate absorption. People who excessively consume alcohol are usually also malnourished with regard to minerals. In addition, alcohol treatment is associated with refeeding, which further depletes phosphate, and the stress of alcohol withdrawal may create respiratory alkalosis, which exacerbates hypophosphatemia (see above).
 * Malabsorption – This includes gastrointestinal damage, and also failure to absorb phosphate due to lack of vitamin D, or chronic use of phosphate binders such as sucralfate, aluminum-containing antacids, and (more rarely) calcium-containing antacids.
 * Intravenous iron (usually for anemia) may cause hypophosphatemia. The loss of phosphate is predominantly the result of renal wasting.

Primary hypophosphatemia is the most common cause of non-nutritional rickets. Laboratory findings include low-normal serum calcium, moderately low serum phosphate, elevated serum alkaline phosphatase, and low serum 1,25 dihydroxy-vitamin D levels, hyperphosphaturia, and no evidence of hyperparathyroidism.

Hypophosphatemia decreases 2,3-bisphosphoglycerate (2,3-BPG) causing a left shift in the oxyhemoglobin curve.

Other rarer causes include:
 * Certain blood cancers such as lymphoma or leukemia
 * Hereditary causes
 * Liver failure
 * Tumor-induced osteomalacia

Pathophysiology
Hypophosphatemia is caused by the following three mechanisms:
 * Inadequate intake (often unmasked in refeeding after long-term low phosphate intake)
 * Increased excretion (e.g. in hyperparathyroidism, hypophosphatemic rickets)
 * Shift of phosphorus from the extracellular to the intracellular space. This can be seen in treatment of diabetic ketoacidosis, refeeding, short-term increases in cellular demand (e.g. hungry bone syndrome) and acute respiratory alkalosis.

Diagnosis
Hypophosphatemia is diagnosed by measuring the concentration of phosphate in the blood. Concentrations of phosphate less than 0.81 mmol/L (2.5 mg/dL) are considered diagnostic of hypophosphatemia, though additional tests may be needed to identify the underlying cause of the disorder.

Treatment
Standard intravenous preparations of potassium phosphate are available and are routinely used in malnourished people and people who consume excessive amounts of alcohol. Supplementation by mouth is also useful where no intravenous treatment are available. Historically one of the first demonstrations of this was in people in concentration camp who died soon after being re-fed: it was observed that those given milk (high in phosphate) had a higher survival rate than those who did not get milk.

Monitoring parameters during correction with IV phosphate
 * Phosphorus levels should be monitored after 2 to 4 hours after each dose, also monitor serum potassium, calcium and magnesium. Cardiac monitoring is also advised.

title: Hypophosphatemia


text:
The Burning Bed

The Burning Bed is both a 1980 non-fiction book by Faith McNulty about battered housewife Francine Hughes, and a 1984 TV-movie adaptation written by Rose Leiman Goldemberg. The plot follows Hughes' trial for the murder of her husband, James Berlin "Mickey" Hughes, following her setting fire to the bed he was sleeping in at their Dansville, Michigan home on March 9, 1977 after thirteen years of physical domestic abuse at his hands.

Plot
On March 9, 1977, Francine Hughes and her three children arrive at the Dansville, MI, police station, where she turns herself in, after setting her husband, James Berlin “Mickey” Hughes, on fire in their home. Public defender Aryon Greydanus is appointed as Francine’s attorney and tries to gain insight into her motive. Initially reluctant, Francine recounts her life and the events leading up to the murder.

In 1964, sixteen-year-old Francine meets Mickey Hughes, and the two marry shortly after. Mickey begins displaying signs of jealousy and anger and physically abuses Francine, often in the presence of his parents. The abuse escalates over the years, and circumstances worsen with Mickey’s alcoholism. Francine divorces Mickey and takes their three young children. Mickey tries to convince Francine to get back together with him, promising he has changed his ways, but Francine refuses. After learning Mickey has been involved in a serious car accident, rendering him severely injured, Francine agrees to care for him temporarily in his parents’ home; however, the situation eventually traps Francine into a domestic partnership with him. As the children get older, Francine takes business courses at a community college, much to Mickey’s disapproval. Mickey’s abuse becomes relentless, and Francine tries to leave numerous times, only for Mickey to follow her and threaten her into returning. She also seeks help from the police, family courts, and Mickey’s family, but to no avail.

As the case goes to trial, Francine testifies about the horrifying instances of abuse she suffered from Mickey over the years and what happened the day of the murder:

Francine returns home late from school, after giving a classmate a ride home, enraging a drunken Mickey. He refuses to allow her to cook TV dinners for the family and beats her. He then orders her to quit school, and when Francine refuses, he destroys her school books and forces her to burn them. Later that night, at dinner, Mickey beats her again and knocks the food on the floor. He rubs Francine’s face in the mess and orders her to quit school again. A defeated Francine agrees. Afterward, Mickey rapes her and falls asleep in a drunken stupor. Francine goes to the garage and obtains a can of gasoline, which she pours over Mickey’s body. She takes her children to the car and drives away as the house becomes engulfed in flames. As the jury returns from deliberation, Francine is found not guilty by reason of temporary insanity, and Francine is embraced by her children.

Film adaptation
Having adapted the book into a made-for-television movie, Goldemberg's screenplay, The Burning Bed, premiered on NBC on October 8, 1984. Directed by Robert Greenwald, the film starred Farrah Fawcett as Francine Hughes and Paul Le Mat as Mickey Hughes.

The house was in Rosharon, Texas.

The movie was filmed in El Monte, California.

Cast

 * Farrah Fawcett as Francine Hughes
 * Paul Le Mat as James Berlin "Mickey" Hughes
 * Richard Masur as Aryon (Arjen) Greydanus
 * Grace Zabriskie as Flossie Hughes
 * Penelope Milford as Gaby
 * Christa Denton as Christy Hughes, age 12
 * James T. Callahan as Berlin Hughes
 * Gary Grubbs as District Attorney
 * David Friedman as Jimmy Hughes, age 10
 * David Andrews as Wimpy Hughes
 * James Hampton as Police Witness
 * Virgil Frye as Virg
 * Dixie K. Wade as Hazel Moran
 * Heather Rich as Christy age 6
 * Justin Gocke as Jimmy age 4
 * Elizabeth Lyn Fraser as Nicole Hughes
 * Jeremy Ross as Judge Hotchkiss

Ratings
The movie premiered with a household share of 36.2 ranking it the 17th highest rated movie to air on network television and NBC's highest rated television movie.

Critical response
Television critic Matt Zoller Seitz in his 2016 book co-written with Alan Sepinwall titled TV (The Book) named The Burning Bed as the 7th greatest American TV-movie of all time, writing that "The film was a landmark in terms of content, depicting domestic violence as an unambiguous horror and a human rights violation". Seitz also praised the performance of Fawcett as "one of the finest in the history of TV-movies".

title: The Burning Bed


text:
USS Spruance

Two ships of the United States Navy have been named USS Spruance, in honor of Admiral Raymond A. Spruance (1886–1969):

 * USS Spruance (DD-963) was the lead ship of Spruance-class destroyers, launched in 1973 and struck in 2005
 * USS Spruance (DDG-111) is an Arleigh Burke-class destroyer, launched in 2010 and commissioned in 2011

title: USS Spruance


text:
Space capsule

A space capsule is a spacecraft designed to transport cargo, scientific experiments, and/or astronauts to and from space. Capsules are distinguished from other spacecraft by the ability to survive reentry and return a payload to the Earth's surface from orbit or sub-orbit, and are distinguished from other types of recoverable spacecraft by their blunt shape, not having wings and often containing little fuel other than what is necessary for a safe return. Capsule-based crewed spacecraft such as Soyuz or Orion are often supported by a service or adapter module, and sometimes augmented with an extra module for extended space operations. Capsules make up the majority of crewed spacecraft designs, although one crewed spaceplane, the Space Shuttle, has flown in orbit.

Current examples of crewed space capsules include Soyuz, Shenzhou, and Dragon 2. Examples of new crew capsules currently in development include NASA's Orion, Boeing's Starliner, Russia's Orel, India's Gaganyaan, and China's Mengzhou. Historic examples of crewed capsules include Vostok, Mercury, Voskhod, Gemini, and Apollo, and active programs include the New Shepard launches. A crewed space capsule must be able to sustain life in an often demanding thermal and radiation environment in the vacuum of space. It may be expendable (used once, like Soyuz) or reusable (like Crew Dragon).

Vostok

The Vostok was the Soviet Union's first crewed space capsule. The first human spaceflight was Vostok 1, accomplished on April 12, 1961 by cosmonaut Yuri Gagarin.

The capsule was originally designed for use both as a camera platform for the Soviet Union's first spy satellite program, Zenit and as a crewed spacecraft. This dual-use design was crucial in gaining Communist Party support for the program. The design used a spherical reentry module, with a biconic descent module containing attitude control thrusters, on-orbit consumables, and the retro rocket for orbit termination. The basic design has remained in use for some 40 years, gradually adapted for a range of other uncrewed satellites.

It was a single-seat capsule that was 4.4 meters long and 2.4 meters in diameter, weighing 4.73 tonnes at launch. The reentry module was completely covered in ablative heat shield material, 2.3 m in diameter, weighing 2460 kg. The capsule was covered with a nose cone to maintain a low-drag profile for launch, with a cylindrical interior cabin approximately 1 m in diameter nearly perpendicular to the capsule's longitudinal axis. The cosmonaut sat in an ejection seat with a separate parachute for escape during a launch emergency and landing during a normal flight. The capsule had its own parachute for landing on the ground. Although official sources stated that Gagarin had landed inside his capsule, a requirement for qualifying as a first crewed spaceflight under International Aeronautical Federation (IAF) rules, it was later revealed that all Vostok cosmonauts ejected and landed separately from the capsule. The capsule was serviced by an aft-facing conical equipment module 2.25 m long by 2.43 m, weighing 2270 kg containing nitrogen and oxygen breathing gasses, batteries, fuel, attitude control thrusters, and the retrorocket. It could support flights as long as ten days. Six Vostok launches were successfully conducted, the last two pairs in concurrent flights. The longest flight was just short of five days, on Vostok 5 on June 14–19, 1963.

Since the attitude control thrusters were located in the instrument module which was discarded immediately prior to reentry, the reentry module's path and orientation could not be actively controlled. This meant that the capsule had to be protected from reentry heat on all sides, determining the spherical design (as opposed to Project Mercury's conical design, which allowed for maximum volume while minimizing the heat shield diameter). During reentry, the heat of atmospheric friction is so great that air molecules around the capsule are ionized, creating a layer of plasma around the capsule which blocks radio communication with the ground. However, ionized gases in the plasma layer can also be used to create an artificial radio window, allowing communication signals to be transmitted and received despite the interference. Some control of the capsule's reentry orientation was possible by offsetting its center of gravity. Proper orientation with the cosmonaut's back to the direction of flight was necessary in order to best sustain the which also maximized the 8 to 9 g-force.

Voskhod
The Vostok design was modified to permit carrying multi-cosmonaut crews, and flown as two flights of the Voskhod programme. The cylindrical interior cabin was replaced with a wider, rectangular cabin which could hold either three cosmonauts seated abreast (Voskhod 1), or two cosmonauts with an inflatable airlock in between them, to permit extravehicular activity (Voskhod 2). A backup solid-fuel retro rocket was added to the top of the descent module. Vostok's ejection seat was removed to save space (thus there was no provision for crew escape in the event of a launch or landing emergency). The complete Voskhod spacecraft weighed 5682 kg.

Lack of space meant that the crew members of Voskhod 1 did not wear space suits. Both Voskhod 2 crew members wore spacesuits, as it involved an EVA by cosmonaut Alexei Leonov. An airlock was needed because the vehicle's electrical and environmental systems were air-cooled, and complete capsule depressurization would lead to overheating. The airlock weighed 250 kg, was 700 mm in diameter, 770 mm high when collapsed for launch. When extended in orbit, it was 2.5 m long, had an internal diameter of 1 m and an external diameter of 1.2 m. The second crew member wore a spacesuit as a precaution against accidental descent module depressurization. The airlock was jettisoned after use.

The lack of ejection seats meant that the Voskhod crew would return to Earth inside their spacecraft unlike the Vostok cosmonauts who ejected and parachuted down separately. Because of this, a new landing system was developed, which added a small solid-fuel rocket to the parachute lines. It fired as the descent module neared touchdown, providing a softer landing.

Mercury

The Mercury program was the United States' first crewed space program. It ran from 1958 through 1963, with the goal of putting a human in orbit around the Earth and returning him safely. The program used a small capsule attached to a booster rocket to achieve orbit. The development of the Mercury capsule began in earnest after NASA selected the McDonnell Aircraft Corporation as its contractor in 1959. The Mercury spacecraft's principal designer was Maxime Faget, who started research for human spaceflight during the time of the NACA. It was 10.8 ft long and 6.0 ft wide; with the launch escape system added, the overall length was 25.9 ft. With 100 ft3 of habitable volume, the capsule was just large enough for a single crew member. Inside were 120 controls: 55 electrical switches, 30 fuses and 35 mechanical levers. The heaviest spacecraft, Mercury-Atlas 9, weighed 3000 lb fully loaded. Its outer skin was made of René 41, a nickel alloy able to withstand high temperatures.

The spacecraft was cone shaped, with a neck at the narrow end. It had a convex base, which carried a heat shield (Item 2 in the diagram below) consisting of an aluminum honeycomb covered with multiple layers of fiberglass. Strapped to it was a retropack (1) consisting of three rockets deployed to brake the spacecraft during reentry. Between these were three minor rockets for separating the spacecraft from the launch vehicle at orbital insertion. The straps that held the package could be severed when it was no longer needed. Next to the heat shield was the pressurized crew compartment (3). Inside, an astronaut would be strapped to a form-fitting seat with instruments in front of him and with his back to the heat shield. Underneath the seat was the environmental control system supplying oxygen and heat, scrubbing the air of CO2, vapor and odors, and (on orbital flights) collecting urine. The recovery compartment (4) at the narrow end of the spacecraft contained three parachutes: a drogue to stabilize free fall and two main chutes, a primary and reserve. Between the heat shield and inner wall of the crew compartment was a landing skirt, deployed by letting down the heat shield before landing. On top of the recovery compartment was the antenna section (5) containing both antennas for communication and scanners for guiding spacecraft orientation. Attached was a flap used to ensure the spacecraft was faced heat shield first during reentry. A launch escape system (6) was mounted to the narrow end of the spacecraft containing three small solid-fueled rockets which could be fired briefly in a launch failure to separate the capsule safely from its booster. It would deploy the capsule's parachute for a landing nearby at sea. (See also Mission profile for details.)

The Mercury spacecraft did not have an on-board computer, instead relying on all computation for reentry to be calculated by computers on the ground, with their results (retrofire times and firing attitude) then transmitted to the spacecraft by radio while in flight. All computer systems used in the Mercury space program were housed in NASA facilities on Earth. The computer systems were IBM 701 computers.

The US launched its first Mercury astronaut Alan Shepard on a suborbital flight almost a month after the first crewed orbital spaceflight. The Soviets were able to launch a second Vostok on a one-day flight on August 6, before the US finally orbited the first American, John Glenn, on February 20, 1962. The United States launched a total of two crewed suborbital Mercury capsules and four crewed orbital capsules, with the longest flight, Mercury-Atlas 9, making 22 orbits and lasting 32 and one-half hours.

Gemini
Many components in the capsule itself were reachable through their own small access doors. Unlike Mercury, Gemini used completely solid-state electronics, and its modular design made it easy to repair. The Gemini spacecraft was the precursor to the Apollo program which aimed to land humans on the Moon. It was designed to test new techniques for orbital rendezvous and docking, but it also featured improvements in life support systems, spacecraft reentry, and other critical areas. Gemini's emergency launch escape system did not use an escape tower powered by a solid-fuel rocket, but instead used aircraft-style ejection seats. The tower was heavy and complicated, and NASA engineers reasoned that they could do away with it as the Titan II's hypergolic propellants would burn immediately on contact. A Titan II booster explosion had a smaller blast effect and flame than on the cryogenically fueled Atlas and Saturn. Ejection seats were sufficient to separate the astronauts from a malfunctioning launch vehicle. At higher altitudes, where the ejection seats could not be used, the astronauts would return to Earth inside the spacecraft, which would separate from the launch vehicle.

The main proponent of using ejection seats was Chamberlin, who had never liked the Mercury escape tower and wished to use a simpler alternative that would also reduce weight. He reviewed several films of Atlas and Titan II ICBM failures, which he used to estimate the approximate size of a fireball produced by an exploding launch vehicle and from this he gauged that the Titan II would produce a much smaller explosion, thus the spacecraft could get away with ejection seats.

Maxime Faget, the designer of the Mercury LES, was on the other hand less-than-enthusiastic about this setup. Aside from the possibility of the ejection seats seriously injuring the astronauts, they would also only be usable for about 40 seconds after liftoff, by which point the booster would be attaining Mach 1 speed and ejection would no longer be possible. He was also concerned about the astronauts being launched through the Titan's exhaust plume if they ejected in-flight and later added, "The best thing about Gemini was that they never had to make an escape."

The Gemini ejection system was never tested with the Gemini cabin pressurized with pure oxygen, as it was prior to launch. In January 1967, the fatal Apollo 1 fire demonstrated that pressurizing a spacecraft with pure oxygen created an extremely dangerous fire hazard. In a 1997 oral history, astronaut Thomas P. Stafford commented on the Gemini 6 launch abort in December 1965, when he and command pilot Wally Schirra nearly ejected from the spacecraft:

"So it turns out what we would have seen, had we had to do that, would have been two Roman candles going out, because we were 15 or 16 psi, pure oxygen, soaking in that for an hour and a half. You remember the tragic fire we had at the Cape. (...) Jesus, with that fire going off and that, it would have burned the suits. Everything was soaked in oxygen. So thank God. That was another thing: NASA never tested it under the conditions that they would have had if they would have had to eject. They did have some tests at China Lake where they had a simulated mock-up of Gemini capsule, but what they did is fill it full of nitrogen. They didn't have it filled full of oxygen in the sled test they had."

Gemini was the first astronaut-carrying spacecraft to include an onboard computer, the Gemini Guidance Computer, to facilitate management and control of mission maneuvers. This computer, sometimes called the Gemini Spacecraft On-Board Computer (OBC), was very similar to the Saturn Launch Vehicle Digital Computer. The Gemini Guidance Computer weighed 58.98 lb. Its core memory had 4096 addresses, each containing a 39-bit word composed of three 13-bit "syllables". All numeric data was 26-bit two's-complement integers (sometimes used as fixed-point numbers), either stored in the first two syllables of a word or in the accumulator. Instructions (always with a 4-bit opcode and 9 bits of operand) could go in any syllable.

Apollo
The Apollo spacecraft was first conceived in 1960 as a three-man craft to follow Project Mercury, to accomplish several types of mission: ferrying astronauts to an Earth-orbiting space station, circumlunar flight, or a Moon landing. NASA solicited feasibility study designs from several companies in 1960 and 1961, while Faget and the Space Task Group worked on their own design using a conical/blunt-body capsule (Command Module) supported by a cylindrical Service Module providing electrical power and propulsion. NASA reviewed the entrants' designs in May 1961, but when President John F. Kennedy proposed a national effort to land a man on the Moon during the 1960s, NASA decided to reject the feasibility studies and proceed with Faget's design, focused on the lunar landing mission. The contract to build Apollo was awarded to North American Aviation.

The main Apollo spacecraft was built in two segments: a Command Module (CM) and a Service Module (SM). The CM was 3.91 m in diameter and 3.48 m high, with a mass of 5560 kg at launch. The Service Module was 13 ft long, with a total Command/Service Module (CSM) vehicle length of 36 ft including the engine bell. The hypergolic propellant service propulsion engine was sized at 20500 lbf to lift the CSM off the lunar surface and send it back to Earth using a direct ascent mission profile. This required a single-launch vehicle much larger than the Saturn V, or else multiple Saturn V launches to assemble it in Earth orbit before sending it to the Moon.

Early on, the direct ascent mission profile was replaced with lunar orbit rendezvous, augmenting the CSM with the Lunar Excursion Module (LM) to ferry two astronauts to the lunar surface. This reduced the net spacecraft mass, allowing the mission to be launched with a single Saturn V. Since significant development work had started on the design, it was decided to continue with the existing design as Block I, while a Block II version capable of rendezvous with the LEM would be developed in parallel. Besides addition of a docking tunnel and probe, Block II would employ equipment improvements based on lessons learned from the Block I design. Block I would be used for uncrewed test flights and a limited number of Earth orbit crewed flights. Though the service propulsion engine was now bigger than required, its design was not changed since significant development was already in progress; however, the propellant tanks were downsized slightly to reflect the modified fuel requirement. Based on astronaut preference, the Block II CM would replace the two-piece plug door hatch cover, chosen to avoid an accidental hatch opening such as had happened on Gus Grissom's Mercury-Redstone 4 flight, with a one-piece, outward-opening hatch to make egress easier at the end of the mission.

The Mercury-Gemini practice of using a prelaunch atmosphere of 16.7 psi pure oxygen proved to be disastrous in combination with the plug-door hatch design. While participating in a pre-launch test on the pad on January 27, 1967, in preparation for the first crewed launch in February, the entire crew of Apollo 1—Grissom, Edward H. White, and Roger Chaffee—were killed in a fire that swept through the cabin. The plug door made it impossible for the astronauts to escape or be removed before their deaths. An investigation revealed the fire was probably started by a spark from a frayed wire, and fed by combustible materials that should not have been in the cabin. The crewed flight program was delayed while design changes were made to the Block II spacecraft to replace the pure oxygen pre-launch atmosphere with an air-like nitrogen/oxygen mixture, eliminate combustible materials from the cabin and the astronauts' space suits, and seal all electrical wiring and corrosive coolant lines.

The Block II spacecraft weighed 63500 lb fully fueled, and was used in four crewed Earth and lunar orbital test flights, and seven crewed lunar landing missions. A modified version of the spacecraft was also used to ferry three crews to the Skylab space station, and the Apollo-Soyuz Test Project mission which docked with a Soviet Soyuz spacecraft. The Apollo spacecraft was retired after 1974.

Retired robotic space capsules

 * Corona
 * Dragon
 * FSW
 * Foton
 * Raduga
 * Atmospheric Reentry Demonstrator
 * SRE
 * Zond/L1
 * L3
 * TKS
 * Yantar
 * OREX
 * Xiaofei
 * HSRC

Soyuz
In 1963, Korolev first proposed the three-man Soyuz spacecraft for use in Earth orbit assembly of a lunar exploration mission. He was pressured by Soviet premier Nikita Khrushchev to postpone development of Soyuz to work on Voskhod, and later allowed to develop Soyuz for space station and lunar exploration missions. He employed a small, lightweight bell-shaped reentry capsule, with an orbital crew module attached to its nose, containing the bulk of the mission living space. The service module would use two panels of electric solar cells for power generation, and contained a propulsion system engine. The 7K-OK model designed for Earth orbit used a 2810 kg reentry module measuring 2.17 m in diameter by 2.24 m long, with an interior volume of 4.00 m3. The 1100 kg spheroidal orbital module measured 2.25 m in diameter by 3.45 m long with a docking probe, with an interior volume of 5.00 m3. The total spacecraft mass was 6560 kg.

Ten of these craft flew crewed after Korolev's death, from 1967 to 1971. The first (Soyuz 1) and last (Soyuz 11) resulted in the first in-space fatalities. Korolev had developed a 9850 kg 7K-LOK variant for use in the lunar mission, but this was never flown crewed.

The Russians continued to develop and fly the Soyuz to this day.

Shenzhou

Space capsules have also been used for scientific research and experimentation in space. For example, the Chinese Shenzhou spacecraft has carried out experiments in life sciences, material sciences, fluid dynamics, and space environment monitoring. The PRC developed its Shenzhou spacecraft in the 1990s based on the same concept (orbital, reentry and service modules) as Soyuz. Its first uncrewed test flight was in 1999, and the first crewed flight in October 2003 carried Yang Liwei for 14 Earth orbits.

Dragon 2
The seven-seat SpaceX Dragon 2 capsule first launched crew to the International Space Station on 30 May 2020 on the Demo-2 mission for NASA. Although originally envisaged as a development of SpaceX's uncrewed Dragon capsule which was used for the NASA Commercial Resupply Services contract, the demands of crewed spaceflight resulted in a significantly redesigned vehicle with limited commonality. The Dragon capsule was designed to be reusable. In fact, SpaceX has flown the same Dragon capsule to the International Space Station multiple times, with the first successful reuse occurring in June 2017.

New Shepard Crew Capsule
The six-seat Blue Origin developed New Shepard crew capsule is a suborbital crewed spacecraft designed for human tended research and space tourism. The capsule can also fly uncrewed, carrying a larger number of payloads and experiments.

Russia

 * Orel

United States

 * Orion
 * Starliner

India

 * Gaganyaan

China

 * Mengzhou

Iran

 * Kavoshgar E

title: Space capsule


text: Category:Pre-Raphaelite Brotherhood

title: Category:Pre-Raphaelite Brotherhood


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Old-growth forest

An old-growth forest (also referred to as primary forest) is a forest that has developed over a long period of time without disturbance. Due to this, old-growth forests exhibit unique ecological features. The Food and Agriculture Organization of the United Nations defines primary forests as naturally regenerated forests of native tree species where there are no clearly visible indications of human activity and the ecological processes are not significantly disturbed. One-third (34 percent) of the world's forests are primary forests. Old-growth features include diverse tree-related structures that provide diverse wildlife habitats that increases the biodiversity of the forested ecosystem. Virgin or first-growth forests are old-growth forests that have never been logged. The concept of diverse tree structure includes multi-layered canopies and canopy gaps, greatly varying tree heights and diameters, and diverse tree species and classes and sizes of woody debris.

, the world has 1.11 billion ha of primary forest remaining. Combined, three countries (Brazil, Canada, and Russia) host more than half (61 percent) of the world's primary forest. The area of primary forest has decreased by 81 million ha since 1990, but the rate of loss more than halved in 2010–2020 compared with the previous decade.

Old-growth forests are valuable for economic reasons and for the ecosystem services they provide. This can be a point of contention when some in the logging industry desire to harvest valuable timber from the forests, destroying the forests in the process, to generate short-term profits, while environmentalists seek to preserve the forests in their pristine state for benefits such as water purification, flood control, weather stability, maintenance of biodiversity, and nutrient cycling. Moreover, old-growth forests are more efficient at sequestering carbon than newly planted forests and fast-growing timber plantations, thus preserving the forests is vital to climate change mitigation.

Characteristics

Old-growth forests tend to have large trees and standing dead trees, multilayered canopies with gaps that result from the deaths of individual trees, and coarse woody debris on the forest floor. The trees of old-growth forests develop distinctive attributes not seen in younger trees, such as more complex structures and deeply fissured bark that can harbor rare lichens and mosses.

A forest regenerated after a severe disturbance, such as wildfire, insect infestation, or harvesting, is often called second-growth or 'regeneration' until enough time passes for the effects of the disturbance to be no longer evident. Depending on the forest, this may take from a century to several millennia. Hardwood forests of the eastern United States can develop old-growth characteristics in 150–500 years. In British Columbia, Canada, old growth is defined as 120 to 140 years of age in the interior of the province where fire is a frequent and natural occurrence. In British Columbia's coastal rainforests, old growth is defined as trees more than 250 years, with some trees reaching more than 1,000 years of age. In Australia, eucalypt trees rarely exceed 350 years of age due to frequent fire disturbance.

Forest types have very different development patterns, natural disturbances and appearances. A Douglas-fir stand may grow for centuries without disturbance while an old-growth ponderosa pine forest requires frequent surface fires to reduce the shade-tolerant species and regenerate the canopy species. In the boreal forest of Canada, catastrophic disturbances like wildfires minimize opportunities for major accumulations of dead and downed woody material and other structural legacies associated with old growth conditions. Typical characteristics of old-growth forest include the presence of older trees, minimal signs of human disturbance, mixed-age stands, presence of canopy openings due to tree falls, pit-and-mound topography, down wood in various stages of decay, standing snags (dead trees), multilayered canopies, intact soils, a healthy fungal ecosystem, and presence of indicator species.

Biodiversity

Old-growth forests are often biologically diverse, and home to many rare species, threatened species, and endangered species of plants and animals, such as the northern spotted owl, marbled murrelet and fisher, making them ecologically significant. Levels of biodiversity may be higher or lower in old-growth forests compared to that in second-growth forests, depending on specific circumstances, environmental variables, and geographic variables. Logging in old-growth forests is a contentious issue in many parts of the world. Excessive logging reduces biodiversity, affecting not only the old-growth forest itself, but also indigenous species that rely upon old-growth forest habitat.

Mixed age
Some forests in the old-growth stage have a mix of tree ages, due to a distinct regeneration pattern for this stage. New trees regenerate at different times from each other, because each of them has a different spatial location relative to the main canopy, hence each one receives a different amount of light. The mixed age of the forest is an important criterion in ensuring that the forest is a relatively stable ecosystem in the long term. A climax stand that is uniformly aged becomes senescent and degrades within a relatively short time to result in a new cycle of forest succession. Thus, uniformly aged stands are less stable ecosystems. Boreal forests are more uniformly aged, as they are normally subject to frequent stand-replacing wildfires.

Canopy openings
Forest canopy gaps are essential in creating and maintaining mixed-age stands. Also, some herbaceous plants only become established in canopy openings, but persist beneath an understory. Openings are a result of tree death due to small impact disturbances such as wind, low-intensity fires, and tree diseases.

Old-growth forests are unique, usually having multiple horizontal layers of vegetation representing a variety of tree species, age classes, and sizes, as well as "pit and mound" soil shape with well-established fungal nets. Because old-growth forest is structurally diverse, it provides higher-diversity habitat than forests in other stages. Thus, sometimes higher biological diversity can be sustained in old-growth forests, or at least a biodiversity that is different from other forest stages.

Topography
The characteristic topography of much old-growth forest consists of pits and mounds. Mounds are caused by decaying fallen trees, and pits (tree throws) by the roots pulled out of the ground when trees fall due to natural causes, including being pushed over by animals. Pits expose humus-poor, mineral-rich soil and often collect moisture and fallen leaves, forming a thick organic layer that is able to nurture certain types of organisms. Mounds provide a place free of leaf inundation and saturation, where other types of organisms thrive.

Standing snags
Standing snags provide food sources and habitat for many types of organisms. In particular, many species of dead-wood predators such as woodpeckers must have standing snags available for feeding. In North America, the spotted owl is well known for needing standing snags for nesting habitat.

Decaying ground layer

Fallen timber, or coarse woody debris, contributes carbon-rich organic matter directly to the soil, providing a substrate for mosses, fungi, and seedlings, and creating microhabitats by creating relief on the forest floor. In some ecosystems such as the temperate rain forest of the North American Pacific coast, fallen timber may become nurse logs, providing a substrate for seedling trees.

Soil
Intact soils harbor many life forms that rely on them. Intact soils generally have very well-defined horizons, or soil profiles. Different organisms may need certain well-defined soil horizons to live, while many trees need well-structured soils free of disturbance to thrive. Some herbaceous plants in northern hardwood forests must have thick duff layers (which are part of the soil profile). Fungal ecosystems are essential for efficient in-situ recycling of nutrients back into the entire ecosystem.

Stand age definition
Stand age can also be used to categorize a forest as old-growth. For any given geographical area, the average time since disturbance until a forest reaches the old growth stage can be determined. This method is useful, because it allows quick and objective determination of forest stage. However, this definition does not provide an explanation of forest function. It just gives a useful number to measure. So, some forests may be excluded from being categorized as old-growth even if they have old-growth attributes just because they are too young. Also, older forests can lack some old-growth attributes and be categorized as old-growth just because they are so old. The idea of using age is also problematic, because human activities can influence the forest in varied ways. For example, after the logging of 30% of the trees, less time is needed for old-growth to come back than after removal of 80% of the trees. Although depending on the species logged, the forest that comes back after a 30% harvest may consist of proportionately fewer hardwood trees than a forest logged at 80% in which the light competition by less important tree species does not inhibit the regrowth of vital hardwoods.

Forest dynamics definition
From a forest dynamics perspective, old-growth forest is in a stage that follows understory reinitiation stage. Those stages are:

 * 1) Stand-replacing: Disturbance hits the forest and kills most of the living trees.
 * 2) Stand-initiation: A population of new trees becomes established.
 * 3) Stem-exclusion: Trees grow higher and enlarge their canopy, thus competing for the light with neighbors; light competition mortality kills slow-growing trees and reduces forest density, which allows surviving trees to increase in size. Eventually, the canopies of neighboring trees touch each other and drastically lower the amount of light that reaches lower layers. Due to that, the understory dies and only very shade-tolerant species survive.
 * 4) Understory reinitiation: Trees die from low-level mortality, such as windthrow and diseases. Individual canopy gaps start to appear and more light can reach the forest floor. Hence, shade-tolerant species can establish in the understory.
 * 5) Old-growth: Main canopy trees become older and more of them die, creating even more gaps. Since the gaps appear at different times, the understory trees are at different growth stages. Furthermore, the amount of light that reaches each understory tree depends on its position relative to the gap. Thus, each understory tree grows at a different rate. The differences in establishment timing and in growth rate create a population of understory trees that is variable in size. Eventually, some understory trees grow to become as tall as the main canopy trees, thereby filling the gap. This perpetuation process is typical for the old-growth stage. This, however, does not mean that the forest will be old-growth forever. Generally, three futures for old-growth stage forest are possible: 1) The forest will be hit by a disturbance and most of the trees will die, 2) Unfavorable conditions for new trees to regenerate will occur. In this case, the old trees will die and smaller plants will create woodland, and 3) The regenerating understory trees are different species from the main canopy trees. In this case, the forest will switch back to stem-exclusion stage, but with shade-tolerant tree species. 4) The forest in an old-growth stage can be stable for centuries, but the length of this stage depends on the forest's tree composition and the climate of the area. For example, frequent natural fires do not allow boreal forests to be as old as coastal forests of western North America.

Of importance is that while the stand switches from one tree community to another, the stand will not necessarily go through old-growth stage between those stages. Some tree species have a relatively open canopy. That allows more shade-tolerant tree species to establish below even before the understory reinitiation stage. The shade-tolerant trees eventually outcompete the main canopy trees in stem-exclusion stage. Therefore, the dominant tree species will change, but the forest will still be in stem-exclusion stage until the shade-tolerant species reach old-growth stage.

Tree species succession may change tree species' composition once the old-growth stage has been achieved. For example, an old boreal forest may contain some large aspen trees, which may die and be replaced by smaller balsam fir or black spruce. Consequently, the forest will switch back to understory reinitiation stage. Using the stand dynamics definition, old-growth can be easily evaluated using structural attributes. However, in some forest ecosystems, this can lead to decisions regarding the preservation of unique stands or attributes that will disappear over the next few decades because of natural succession processes. Consequently, using stand dynamics to define old-growth forests is more accurate in forests where the species that constitute old-growth have long lifespans and succession is slow.

Social and cultural definitions

Common cultural definitions and common denominators regarding what comprises old-growth forest, and the variables that define, constitute and embody old-growth forests include:
 * The forest habitat possesses relatively mature, old trees;
 * The tree species present have long continuity on the same site;
 * The forest itself is a remnant natural area that has not been subjected to significant disturbance by mankind, altering the appearance of the landscape and its ecosystems, has not been subjected to logging (or other types of development such as road networks or housing), and has inherently progressed per natural tendencies.

Additionally, in mountainous, temperate landscapes (such as Western North America), and specifically in areas of high-quality soil and a moist, relatively mild climate, some old-growth trees have attained notable height and girth (DBH: diameter at breast height), accompanied by notable biodiversity in terms of the species supported. Therefore, for most people, the physical size of the trees is the most recognized hallmark of old-growth forests, even though the ecologically productive areas that support such large trees often comprise only a very small portion of the total area that has been mapped as old-growth forest. (In high-altitude, harsh climates, trees grow very slowly and thus remain at a small size. Such trees also qualify as old growth in terms of how they are mapped, but are rarely recognized by the general public as such.)

The debate over old-growth definitions has been inextricably linked with a complex range of social perceptions about wilderness preservation, biodiversity, aesthetics, and spirituality, as well as economic or industrial values.

Economic definitions
In logging terms, old-growth stands are past the economic optimum for harvestingusually between 80 and 150 years, depending on the species. Old-growth forests were often given harvesting priority because they had the most commercially valuable timber, they were considered to be at greater risk of deterioration through root rot or insect infestation, and they occupied land that could be used for more productive second-growth stands. In some regions, old growth is not the most commercially viable timberin British Columbia, Canada, harvesting in the coastal region is moving to younger second-growth stands.

Other definitions
A 2001 scientific symposium in Canada found that defining old growth in a scientifically meaningful, yet policy-relevant, manner presents some basic difficulties, especially if a simple, unambiguous, and rigorous scientific definition is sought. Symposium participants identified some attributes of late-successional, temperate-zone, old-growth forest types that could be considered in developing an index of "old-growthness" and for defining old-growth forests:

Structural features:
 * Uneven or multi-aged stand structure, or several identifiable age cohorts
 * Average age of dominant species approaching half the maximum longevity for species (about 150+ years for most shade-tolerant trees)
 * Some old trees at close to their maximum longevity (ages of 300+ years)
 * Presence of standing dead and dying trees in various stages of decay
 * Fallen, coarse woody debris
 * Natural regeneration of dominant tree species within canopy gaps or on decaying logs

Compositional features:
 * Long-lived, shade-tolerant tree species associations (e.g., sugar maple, American beech, yellow birch, red spruce, eastern hemlock, white pine)

Process features:
 * Characterized by small-scale disturbances creating gaps in the forest canopy
 * A long natural rotation for catastrophic or stand-replacing disturbance (e.g., a period greater than the maximum longevity of the dominant tree species)
 * Minimal evidence of human disturbance
 * Final stages of stand development before a relatively steady state is reached

Importance

 * Old-growth forests often contain rich communities of plants and animals within the habitat due to the long period of forest stability. These varied and sometimes rare species may depend on the unique environmental conditions created by these forests.
 * Old-growth forests serve as a reservoir for species, which cannot thrive or easily regenerate in younger forests, so they can be used as a baseline for research.
 * Plant species that are native to old-growth forests may someday prove to be invaluable towards curing various human ailments, as has been realized in numerous plants in tropical rainforests.
 * Old-growth forests also store large amounts of carbon above and below the ground (either as humus, or in wet soils as peat). They collectively represent a very significant store of carbon. Destruction of these forests releases this carbon as greenhouse gases, and may increase the risk of global climate change. Although old-growth forests serve as a global carbon dioxide sink, they are not protected by international treaties, because it is generally thought that aging forests cease to accumulate carbon. However, in forests between 15 and 800 years of age, net ecosystem productivity (the net carbon balance of the forest including soils) is usually positive; old-growth forests accumulate carbon for centuries and contain large quantities of it.

Ecosystem services
Old-growth forests provide ecosystem services that may be far more important to society than their use as a source of raw materials. These services include making breathable air, making pure water, carbon storage, regeneration of nutrients, maintenance of soils, pest control by insectivorous bats and insects, micro- and macro-climate control, and the storage of a wide variety of genes.

Climatic impacts
The effects of old-growth forests in relation to global warming have been addressed in various studies and journals.

The Intergovernmental Panel on Climate Change said in its 2007 report: "In the long term, a sustainable forest management strategy aimed at maintaining or increasing forest carbon stocks, while producing an annual sustained yield of timber, fibre, or energy from the forest, will generate the largest sustained mitigation benefit."

Old-growth forests are often perceived to be in equilibrium or in a state of decay. However, evidence from analysis of carbon stored above ground and in the soil has shown old-growth forests are more productive at storing carbon than younger forests. Forest harvesting has little or no effect on the amount of carbon stored in the soil, but other research suggests older forests that have trees of many ages, multiple layers, and little disturbance have the highest capacities for carbon storage. As trees grow, they remove carbon from the atmosphere, and protecting these pools of carbon prevents emissions into the atmosphere. Proponents of harvesting the forest argue the carbon stored in wood is available for use as biomass energy (displacing fossil fuel use), although using biomass as a fuel produces air pollution in the form of carbon monoxide, nitrogen oxides, volatile organic compounds, particulates, and other pollutants, in some cases at levels above those from traditional fuel sources such as coal or natural gas.

Each forest has a different potential to store carbon. For example, this potential is particularly high in the Pacific Northwest where forests are relatively productive, trees live a long time, decomposition is relatively slow, and fires are infrequent. The differences between forests must, therefore, be taken into consideration when determining how they should be managed to store carbon. A 2019 study projected that old-growth forests in Southeast Asia, the majority of which are in Indonesia and Malaysia, are able to sequester carbon or be a net emitter of greenhouse gases based on deforestation scenarios over the subsequent decades.

Old-growth forests have the potential to impact climate change, but climate change is also impacting old-growth forests. As the effects of global warming grow more substantial, the ability of old-growth forests to sequester carbon is affected. Climate change showed an impact on the mortality of some dominant tree species, as observed in the Korean pine. Climate change also showed an effect on the composition of species when forests were surveyed over a 10- and 20-year period, which may disrupt the overall productivity of the forest.

Logging

According to the World Resources Institute, as of January 2009, only 21% of the original old-growth forests that once existed on Earth are remaining. An estimated one-half of Western Europe's forests were cleared before the Middle Ages, and 90% of the old-growth forests that existed in the contiguous United States in the 1600s have been cleared.

The large trees in old-growth forests are economically valuable, and have been subject to aggressive logging throughout the world. This has led to many conflicts between logging companies and environmental groups. From certain forestry perspectives, fully maintaining an old-growth forest is seen as extremely economically unproductive, as timber can only be collected from falling trees, and also potentially damaging to nearby managed groves by creating environments conducive to root rot. It may be more productive to cut the old growth down and replace the forest with a younger one.

The island of Tasmania, just off the southeast coast of Australia, has the largest amount of temperate old-growth rainforest reserves in Australia with around 1,239,000 hectares in total. While the local Regional Forest Agreement (RFA) was originally designed to protect much of this natural wealth, many of the RFA old-growth forests protected in Tasmania consist of trees of little use to the timber industry. RFA old-growth and high conservation value forests that contain species highly desirable to the forestry industry have been poorly preserved. Only 22% of Tasmania's original tall-eucalypt forests managed by Forestry Tasmania have been reserved. Ten thousand hectares of tall-eucalypt RFA old-growth forest have been lost since 1996, predominantly as a result of industrial logging operations. In 2006, about 61,000 hectares of tall-eucalypt RFA old-growth forests remained unprotected. Recent logging attempts in the Upper Florentine Valley have sparked a series of protests and media attention over the arrests that have taken place in this area. Additionally, Gunns Limited, the primary forestry contractor in Tasmania, has been under recent criticism by political and environmental groups over its practice of woodchipping timber harvested from old-growth forests.

Management

Increased understanding of forest dynamics in the late 20th century led the scientific community to identify a need to inventory, understand, manage, and conserve representative examples of old-growth forests with their associated characteristics and values. Literature around old growth and its management is inconclusive about the best way to characterize the true essence of an old-growth stand.

A better understanding of natural systems has resulted in new ideas about forest management, such as managed natural disturbances should be designed to achieve the landscape patterns and habitat conditions that are normally maintained in nature. This coarse filter approach to biodiversity conservation recognizes ecological processes and provides for a dynamic distribution of old growth across the landscape. And all seral stagesyoung, medium and, oldsupport forest biodiversity. Plants and animals rely on different forest ecosystem stages to meet their habitat needs.

In Australia, the Regional Forest Agreement (RFA) attempted to prevent the clearfelling of defined "old-growth forests". This led to struggles over what constitutes "old growth". For example, in Western Australia, the timber industry tried to limit the area of old growth in the karri forests of the Southern Forests Region; this led to the creation of the Western Australian Forests Alliance, the splitting of the Liberal Government of Western Australia and the election of the Gallop Labor Government. Old-growth forests in this region have now been placed inside national parks. A small proportion of old-growth forest also exists in South-West Australia, and is protected by federal laws from logging, which has not occurred there for more than 20 years.

In British Columbia, Canada, old-growth forests must be maintained in each of the province's ecological units to meet biodiversity needs.

In the United States, from 2001, around a quarter of the federal forests is protected from logging. In December 2023, Biden's administration introduced a rule, according to which, logging is strongly limited in old growth forests, but permitted in "mature forests" what represent a compromise between the logging industry and environmental activists.

Locations of remaining tracts
In 2006, Greenpeace identified that the world's remaining intact forest landscapes are distributed among the continents as follows:
 * 35% in South America: The Amazon rainforest is mainly located in Brazil, which clears a larger area of forest annually than any other country in the world.
 * 28% in North America, which harvests 10,000 km2 of ancient forests every year. Many of the fragmented forests of southern Canada and the United States lack adequate animal travel corridors and functioning ecosystems for large mammals. Most of the remaining old-growth forests in the contiguous United States and Alaska are on public land.
 * 19% in northern Asia, home to the largest boreal forest in the world
 * 8% in Africa, which has lost most of its intact forest landscapes in the last 30 years. The timber industry and local governments are responsible for destroying huge areas of intact forest landscapes and continue to be the single largest threat to these areas.
 * 7% in South Asia Pacific, where the Paradise Forests are being destroyed faster than any other forest on Earth. Much of the large, intact forest landscapes have already been cut down, 72% in Indonesia, and 60% in Papua New Guinea.
 * Less than 3% in Europe, where more than 150 km2 of intact forest landscapes are cleared every year and the last areas of the region's intact forest landscapes in European Russia are shrinking rapidly. In the United Kingdom, they are known as ancient woodlands.

title: Old-growth forest


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Honda Legend

The Honda Legend (ホンダ・レジェンド) is a series of V6-engined executive cars that was produced by Honda between 1985 and 2021, and served as its flagship vehicle. The Legend has also been sold under the Acura Legend, RL and RLX nameplates — the successive flagship vehicles of Honda's luxury Acura division in North America from 1986 until 2020.

First generation (KA1–6; 1985)

The first-generation Legend, introduced to Japan on October 22, 1985, was the first production Honda vehicle to offer only a SOHC V6 engine worldwide. The introduction of the Legend also coincided with the launch of a new dealership sales channel in Japan, called Honda Clio. The Legend was the result of a joint venture with Britain's Austin Rover Group called Project XX that started in November 1981 with the Austin Rover-Honda XX letter of intent signed by the two companies to replace the Rover SD1 and to provide a luxury vehicle for Honda, and was codenamed as HX. The Rover Company had a long-established reputation as a luxury car maker in the United Kingdom and Europe, demonstrated by the Rover P5 and Rover P6, and Honda wanted to introduce a luxury car for the Japanese, European and North American markets. Rover also wanted to return to the American market when previously they had reportedly sold only 1,500 cars in 1971, and a brief return in 1980, selling 800 Rover SD1s by offering the Sterling which was also a result of the ARG-Honda partnership. The development work was carried out at Rover's Canley, Coventry plant and Honda's Tochigi Prefecture development centre. Design work concluded on the Legend in 1982, with a design patent being filed on September 27, 1982, at the Japan Patent Office under application number 1982-043493 and registered on September 19, 1984, under patent number 0640105.

Honda and British Leyland/Rover agreed that Legends would be built at Cowley for the British market. However, few UK built Legends passed Honda's quality control standards, and many simply ended up being used as in-plant transport. In the end, only 4,409 Legends were built in the UK, from 1986 until 1988. All US-market Legends were built in Japan.

Japanese market
Honda wanted to expand its model range above the Honda Accord, and offer a premium level sedan that would appeal to wealthy middle-aged customers who were the traditional buyers of the Toyota Crown, Mazda Luce and Nissan Cedric/Gloria. In 1981, Honda had introduced a luxury level version of the Accord, called the Honda Vigor, but realized that they needed to manufacture a larger, more exclusive sedan with similar dimensions to the Crown, Luce, Cedric and Gloria. When the Legend was introduced worldwide, the optional equipment list was minimal as commonly identified equipment regarded as luxury in nature was included as standard equipment, leaving the only option the choice between a manual or automatic transmission.

The major mechanical difference between the Legend and the Toyota, Mazda and Nissan sedans was that the Legend was front-wheel drive, which Honda stated was "quite simply the most logical means to the ends the engineers desired: a true luxury car with a low, aerodynamic hood; a spacious interior with a nearly flat floor, and the superior traction that results from placing the engine and drivetrain transversely over the drive wheels." This provided the Legend with a front-end heavy 63/37 front to rear weight distribution ratio, similar to the NSU Ro 80. The ride was engineered to appeal towards the luxury car market and not necessarily towards the performance market, and the front to rear weight distribution ratio reflected this goal. Efforts to minimize torque steer were achieved by the half shafts and the angles of the joints at the ends of those shafts being equalized, helping the Legend to accelerate in a straight line.

The Japanese-spec Legend was offered in three trim levels; the V6Xi with the 2.5 L C25A V6 engine, with the slightly shorter and narrower V6Gi and V6Zi using the 2.0 L C20A V6. The V6Gi had the same level of equipment and luxury features as the V6Xi, whereas the V6Zi had reduced content and a lower price. The V6 engines were available with electronic, multi-port sequential fuel injection Honda called Programmed Fuel Injection, or PGM-FI and a variable length intake manifold on the smaller 2.0-liter V6. The larger 2.5 engine was upgraded to the C27A 2.7 liters of displacement for model year 1988 and added a variable length intake manifold. The engine benefited from Honda's successes with its endeavors in Formula One racing in 1964, and Honda's F1 racing car, the Honda RA271. Transmission selections were either a four-speed automatic transaxle with a computer controlled lockup torque converter, or a five-speed manual transaxle.

In order for the sedan to comply with Japanese vehicle size requirements and reduced tax liability, the car with the 2.0 L V6 was slightly shorter and narrower for Japanese buyers by reducing the extension of the front and rear bumper covers, and reducing the overall width to 1695 mm. This also offered an alternative to the traditional Crown and Cedric/Gloria customer base due to the sedan being in the smaller size classification and reduced tax liability but with a comparable level of luxury equipment found in the larger cars, and the same amount of interior space due to the front-wheel drive powertrain, with a wheelbase advantage of 30 mm over the Cedric/Gloria and Crown. To address the issue of durability, the Legend was manufactured as a pillared sedan instead of a four-door hardtop, a body style still offered at the time by Toyota and Nissan on the Crown and Cedric/Gloria. The slightly smaller body style also allowed the Legend to compete with the upscale Toyota Cresta and Chaser and the Nissan Laurel.

The Legend offered many Honda "firsts", such as a driver side airbag, vehicle speed sensitive power assist rack and pinon steering, anti-lock brakes, seat belt pre-tensioners with Emergency Locking Retractors (called E.L.R.), a choice of 100% wool or cloth moquette upholstery, and "TCS" Traction control, the first car to use traction control on a front-wheel drive vehicle. Attention was given to make sure the Legend was quiet, so Honda used computer simulation using NASTRAN, a stress analysis program created by NASA, helping the car achieve a drag coefficient of 0.32 and an interior noise level of 63 dB (measured while the vehicle was travelling at 100 km/h using a manual transmission in 5th gear), and by using triple seals around the tops of door openings.

The Legend was introduced with a double wishbone suspension for the front wheels, and a modified Chapman strut with trailing arm rear suspension Honda called "RF (Reduced Friction) Strut Rear Suspension" with progressive rate rear coil springs that stiffen as they compress to combine smooth ride and good handling. The rear coil spring was separate from the strut and positioned so that vertical pressure was supported by the lower control arm. The term Reduced Friction referred to the minimizing of forces that create friction in the shock absorbers, providing more efficient damping for the full suspension stroke. The rear suspension was upgraded to double wishbone starting with the 1988 model year worldwide.

Notable owners of the first generation Legend were Soichiro Honda the founder of Honda, Satoru Nakajima, Tyrrell Racing F1 driver in 1990, and Ayrton Senna. The Legend V6Xi was used as the pace car for the Suzuka Circuit for 1986.

"Wing Turbo" version
In October 1988, Honda upgraded the C20A V6 engine used exclusively in the KA5 series Legend with a variable geometry turbocharger, calling it the "Wing Turbo" in a Japanese TV commercial to address the modest power available from the previous engine with variable length intake manifold used in earlier models. The turbocharger compressor housing had four vanes made from heat resistant Inconel alloy surrounding the turbine wheel (on the inlet side of it) that would fluctuate based on engine load and transmission gearing above 2,000 rpm to allow for increased airflow into the engine as needed. The turbo compressor could generate as much as 450 mmHg of boost, and was paired with a water cooled intercooler installed inside the intake plenum between the cylinder banks to produce 140 kW net at 6000 rpm and a maximum torque of 24.6 kgm at 3,500 rpm. The turbo was installed not necessarily to make the engine more powerful, but rather to increase fuel efficiency and reduce emissions, as the Japanese pay a tax on the amount of emissions the car produces.

According to an excerpt of Automotive Engineering in January 1989, "The movable wings are positive pressure- and vacuum-operated, their angle changes are controlled by an eight-bit 36-kilobyte computer that also manages fuel injection. Positive pressure to the wing actuator is supplied by the turbo's supercharge pressure, controlled by a frequency solenoid valve, and negative pressure is generated by intake vacuum and accumulated in a reservoir which is also solenoid controlled. The CPU is fed signals including boost pressure, intake temperature, coolant temperature, throttle opening, engine rpm, and vehicle speed. The Wing Turbo is not fitted with a conventional wastegate.

On idling and steady-state cruising that do not require supercharging, the movable flags—or wings—which are fully opened, allow exhaust gas to enter the enlarged nozzle area and pass through the turbine smoothly with little resistance. At the beginning of full acceleration, the wings close fully, reducing the nozzle area through which accelerated gas enters and strikes the turbine blades forcefully, gaining boost quickly. When maximum boost is obtained, the movable wings begin to close gradually, until the vehicle reaches a desired cruising velocity whereby the wings open fully. The nozzle area varies continuously according to operating and load conditions."

The turbo was installed just above the automatic transmission unit; a manual transmission was not offered. This engine was only offered in Japan using the more compact sedan body style, labeled as "2.0 Ti Exclusive" and "2.0 Ti". The engine was used for just two years, due to the introduction of the second generation Legend in 1990 with the much larger C32A V6, and as such Wing Turbo sedans are extremely rare. Much of the research on this engine contributed to the VTEC C30A V6 engine used in the 1990 Honda NSX. The Legend Turbo can be identified as by a "TURBO" badge attached to the front grille on the bottom right hand side and a "V6Ti" rear badge.

European market
The Honda Legend was introduced for the 1987 model year and was virtually identical in equipment offered and vehicle dimensions to the North American model, with one trim designation called the V6-2.5i. This means very few options were available other than the choice of transmission, and an air conditioning system identical to the North American version. The Europeans were offered an optional "Special Equipment Pack" that offered cruise control, aluminium alloy wheels, a driver's seat with power lumbar support, height, fore/aft and reclining adjusters, adjustable rear headrests, a 4-speaker stereo system provided by Philips and headlight wipers. Front and rear mud flaps were standard in undisclosed countries but not all. The radio volume control rocker switch and preset radio scan button installed on the instrument binnacle was not offered.

Legend coupe and other changes

The Legend Coupe was introduced February 6, 1987, with a larger displacement 2.7-liter V6 engine featuring a variable intake system for increased torque and a rear double wishbone suspension which wasn't available on the sedan until 1989 model year. Incidentally, the Japanese coupe was both longer and wider, which increased its tax liability, yet it had a shorter wheelbase by 2.2 in.

Starting with the introduction of model year 1988, the trim level "Exclusive" was introduced, offering genuine wood trim provided by Tendo Mokko on the dashboard and center console with a very large selection of available wood type and hues to choose from, automatic headlights, headlight washer/wipers, separate rear passenger climate control, and chrome-plated power folding mirrors and door handles with infrared remote keyless entry. October 14, 1988 saw a minor restyle offered for the interior and dashboard, to provide a more luxurious appearance in comparison to the Nissan and Toyota uplevel sedans the Legend was competing with. Due to the success Honda had with the Legend, it served as an inspiration for many vehicles from multiple manufacturers, including the Subaru Legacy with which it shares many visual resemblances and dimensions both inside and out.

Second generation (KA7/8; 1990)
The second generation model was introduced on October 24, 1990, and continued to offer both a sedan and coupé. The Rover 800 was not updated to the new platform, and instead continued with the old XX platform. In Japan, this Legend was also known as the "Super Legend" due to the much larger 3.2 C32A engine, which was now the only engine offered in the Legend. The Type I engine was rated at 215 PS, and the Type II was rated at 235 PS and was included with the Touring system. This Legend benefited from much of the research and testing done for Honda's new mid-engined high performance sports car, the Honda NSX, and the Legend was used as a test platform for new NSX technologies and research. Honda mounted the engine behind the front axle, for what they called a "front-wheel-drive midship" layout. Nonetheless, the 60/40 weight distribution was still heavily biased towards the front wheels. Honda introduced a passenger side airbag on this model, and used off-set collision testing to improve collision performance and safety.

Trim level designations were changed to α ("Alpha") for the top level vehicle, and β ("Beta") for the lower grade. No other trim levels were offered. The "Alpha" was very well equipped, offering ABS, leather or 100% wool moquette upholstery, projector beam headlights, and dual-zone air conditioning.

The customer base served by the slightly smaller first generation Legend was now offered the completely revised CB5 series Honda Vigor and Honda Inspire sold at different Japanese Honda retail sales locations Honda Clio and Honda Verno. The business practice of offering the previous generation Legend in two sizes so that it could comply with Japanese dimension and engine displacement regulations was ceded to the Inspire and Vigor, where both vehicles were offered in two versions so as to comply with the regulations, while offering Japanese buyers more choices. The installation of the larger 3.2-litre engine obligated Japanese buyers for higher amounts of annual road tax over the smaller engines in the previous generation.

The Japanese Domestic Market version of the 1990 Legend (second generation) was the second vehicle offered with a navigation system called the Electro Gyrocator (first being the 1981 Honda Accord and Vigor), although it was not satellite-based and instead relied on a gas gyroscope (Inertial navigation system). September 29, 1992 saw an upgrade to the "Alpha" trim level, called the Touring Series, which added the Honda Progressive Damper suspension system, and included upgraded calipers for the front and rear disc brakes, and increased the wheel size to 16 inches. A Luxman premium sound system was added to the options list. The prefectural police department of Aomori used "Beta" sedans with the Type II engine for traffic monitoring.

Daewoo Arcadia
The second-generation Legend was also manufactured by Daewoo in South Korea from 1994 to 1999 under the name of Daewoo Arcadia (ko:대우 아카디아 ), for the Korean market, replacing the Daewoo Imperial.

It was named for the region in Greece called Arcadia, a region regarded in Greek mythology as a utopian garden.

During this period, Honda had a loose alliance with Daewoo, and the Arcadia was larger than Hyundai Grandeur and Kia Potentia competitors. Daewoo Motors (GM Korea's predecessor) sold more than 800 vehicles. The Arcadia was essentially the base level Legend. At the time of the Arcadia's introduction, it had a large engine for a car in Korea, with a 220-horsepower V6 3.2 C32A, and the starting price was a high 41.9 million won. ABS, dual airbags, safety belt pre-tensioners, and the most advanced car safety features at the time, commensurate with a focus on protecting the passengers. Some of the features included driver's seat position memory function and front heated seats, push-button door opening and closing devices, automatic climate control air conditioning. After the acquisition of SsangYong by Daewoo, the Arcadia was succeeded by the somewhat larger Chairman (a rebadged SsangYong). Remaining stock of Arcadia sedans were reduced in price, and the Arcadia ended production in December of that year.

Third generation (KA9; 1995)
The third generation Legend appeared on October 26, 1995, continuing the Honda tradition of front-wheel drive, and increasing the engine displacement to 3.5 L with the horsepower remaining at 215 PS. The actual Honda internal platform code for this vehicle is E-KA9.

In an attempt by Honda to dispute the call for the Legend to be offered with a V8 to be considered an international premium level luxury car, this generation had a wheelbase that compared to the Infiniti Q45 at 2830 mm with a length at 5056 mm, and the Lexus LS at 2850 mm wheelbase and 4996 mm length. The Legend also had very similar dimensions to the front-wheel drive, V8 sedan Mitsubishi Proudia which was sold only in Japan. In Japan, the Legend continued to compete with the Toyota Crown, the Mitsubishi Debonair, the Mazda Luce, and the Nissan Cedric and Gloria at the executive sedan segment.

The trim level "Exclusive" returned as the upper level car, with the standard grade vehicle known as "Euro", with the more performance tuned suspension.The wood trim used was more upscale for the "Exclusive" vehicle with a lower grade wood used on the "Euro". Both vehicles were very well equipped. The instruments used were simplified from previous versions, but 100% wool moquette upholstery was still offered, along with optional leather. Honda's internet-based navigation system Internavi was introduced with this generation on Japanese domestic vehicles. The Luxman premium sound system was still available. The styling was said to more closely resemble the Mercedes-Benz E-Class and a transponder key security system was offered. Starting with this generation, cabin air filters (also known as pollen filters) were installed as standard equipment and are located behind the glove compartment internationally.

September 21, 1998 saw a minor styling change, with the front grille cutting into the front bumper, providing a more prominent front grille. Emphasis was increased on providing a luxurious sense of style, both inside and out. Side impact airbags now complemented the dual front airbags as standard equipment. The steering wheel can be automatically adjusted based on the position of the driver's seat, thereby optimizing a safe distance between the driver and the airbag installed in the steering wheel.

September 24, 1999 saw the engine meet emission regulations to comply with California LEV requirements.

June 19, 2003 saw the interior updated, and maple wood was offered for interior decoration. Electro-luminescent instruments were offered, as well as a higher grade of leather interior.

The third-generation model was offered as a sedan only. A mid-term facelift came in 1999. The Legend went on sale in Australia starting with the 1997 model year.

In the U.S. market, when the Legend coupe was discontinued, they were offered the Acura CL two-door coupé that was based on the American market Honda Accord coupé, so as to continue offering a premium vehicle in this niche.

Fourth generation (KB1/2; 2004)
The swoopier, shorter fourth-generation Honda Legend was launched on October 7, 2004, and became Japan's Car of the Year for 2004–2005, marking the fourth time in five years that Honda has taken the award. Its reduced dimensions over the third generation model seem to suggest a return to what made the Legend so popular with the first generation, being a top level sedan that offered something different from its competitors. The 2011 model marks the 25th anniversary of Honda Legend production.

In an attempt to address market driven requests that the Legend needed to be a rear-wheel drive sedan with a V8 engine, Honda introduced four-wheel drive technology on the Legend, called "Super Handling All-Wheel Drive" (SH-AWD), which earned Honda the Japan Car of the Year, and Mosuto 2005 Annual RJC technology of the Year award. This generation Legend is only available with the Super Handling All-Wheel Drive powertrain. Due to continuous product improvement efforts over past generations, the series CP3 North American Honda Accord (Honda Inspire in some markets) shares wheelbase, length, width and engine displacement almost exactly with this generation Legend, with a reduced price in many international markets. The Legend does have a higher level of standard features and optional equipment but not by much.

Select-Shift was introduced on the 5-speed automatic transmission. The newly designed J35A 3.5-liter V6 was changed from a 90 degree "V", in use since the first 1986 C25A V6 engine, to a 60 degree layout, while VTEC was added to improve efficiency (M-TEC was added by the MUGEN division, called the "M1 package"). In a move echoing the many "firsts" introduced by the first generation Legend, the horsepower no longer complied with the self-imposed horsepower restrictions of the Japanese auto industry. The engine is capable of 300 PS.

Perhaps to accommodate the all-wheel drive setup, the engine was reoriented from a longitudinal installation used since 1990, to a transverse installation, which was the original orientation of the first generation model. Honda began to expand the Acura division into Mexico, Hong Kong and China. Plans to introduce the Acura brand in Japan haven't been formally announced, relying on speculation. This generation Legend shares large sedan duties with the Honda Inspire, known in North America as the Honda Accord starting with model year 2003 (series UC1) and continuing with the series CP3 sedan. September 15, 2005 saw a mild body restyle, which included a rear backup camera. The Akita and Kumamoto Prefectures adopted this Legend as the official car for local senior government officials.

In the UK, the Legend is only offered in one trim, the EX. Buyers can also choose to pay extra for the ADAS (Advanced Driver Assist System) package. The ADAS package includes Honda's CMBS (Collison Mitigation Braking System), and LKAS (Lane Keeping Assist System).

The Legend received a Mid-Model Change (MMC) for the 2009 model year. Among the usual upgrades, the Honda Legend offered some additional optional safety features, including Lane Keeping Assistance System (LKAS). The LKAS could actually make small steering adjustments to keep a car in lane so long as the radius of the turn was more than 220 meters, which was the legal minimum in Japan. The LKAS would relinquish control at the slightest steering input so the driver had control at all times. Intelligent Night Vision with the world's first pedestrian detection feature, and a standard pop-up hood for pedestrian safety. The night vision system uses a separate heads up type display projected on the center bottom of the windshield. The infrared cameras do not require a light source, and the software is able to detect human like figures, surround the image with a red box and give audible caution tones. The pop-up hood uses a series of sensors that can detect a pedestrian-like object being thrown onto the hood. An actuator will pop the hood up at the rear, close to the base of the windshield, 10 cm (4 inches) to help minimize pedestrian injuries, especially head trauma. All markets feature energy absorbing hood and fender supports and deformable windshield wiper pivots to minimize pedestrian injury. Honda's internet-based navigation system Internavi is standard equipment on Japanese domestic vehicles.

In October 2010, it is reported that Brake Defect from Honda Legend were delivered to customers before the problem is discovered. Honda says that it doesn't know how many of its vehicles have suffered a faulty brake system. The U.S. Honda outfit says it will replace the faulty seal and, if leaking has occurred, the brake booster will be replaced as well. At least some owners in the UAE, Saudi Arabia and other GCC countries are likely affected. Honda told that no stop-sale is issued.

In June 2012, Honda Japan announced the Legend and Inspire were to stop being produced at the Sayama, Saitama, Japan plant.

Reception
The second-generation 2005 Acura RL appeared on Car and Driver's Ten Best list for 2005. The car also garnered a CNET.com "Editor's Choice" Award for Top Tech Car.

The SH-AWD all-wheel drive system was lauded by Popular Science as one of the best automotive innovations of 2004, and earned the 2005 "Tech Car of the Year" from CNET.com. Subsequent moves by both Audi and BMW to design and market their own versions of torque vectoring all-wheel drive systems bear out the innovative nature of the SH-AWD design.

While critically acclaimed, sales have not met expectations. Regarding sales of Japanese luxury flagships during the first six months of 2010, Acura has sold only 872 RLs, compared to 5,650 Lexus LS and 6,602 Infiniti M sedans. Enthusiasts and dealers said that the RL was not competitive because it is smaller, uses front-wheel drive, and lacks a V8 option, compared to its larger rivals in the mid-luxury segment that are rear-wheel drive and have a V8 available.

Some have suggested that the initial price of the RL is perceived to be out of its bracket. As the new RL offered more features and performance than the base version of its luxury competitors (i.e., the base six-cylinder BMW 5 Series), Honda Japan suggested that it could charge more, though Honda Canada disagreed. The RL's initial MRSP was $69,500 CAD, more than the six-cylinder BMW 525i and close to that of the V8-powered BMW 545i. At the RL's price point, most consumers expected a V8, furthermore they did not perceive Acura as being on par with its German rivals and expected more value from the Japanese marque. The damage from Honda Japan's alleged hubris was done, perhaps giving the RL an unfavorable impression that could not be removed, even though Honda Canada has since reduced the RL's price. The UK magazine `Car` ran a Honda Legend on its long term fleet and rated the car for its performance, handling and acceleration but felt the styling was too anonymous. In 2009, the new generation of the Acura TL was released and it is expected to offer tough competition to the RL, as the TL has essentially the same engine (but with 5 more horsepower), the SH-AWD system, similar dimensions, and many of the RL's features for only $44,900 CAD.

In October 2010, the Acura RL has been named as one of Consumer Reports most reliable cars, one of among 5 Honda models (Acura TL with front-wheel drive; Acura RL luxury car; Honda CR-V small SUV; Acura RDX small upscale SUV, and Honda Ridgeline compact pickup truck) named as most reliable in various categories.

Fifth generation (KC2; 2014)

The fifth generation Legend was unveiled in Japan on November 10, 2014, and went on sale on February 20, 2015, it is near identical to the Acura RLX and only available in Sport Hybrid. The facelifted model was unveiled in Japan on October 2, 2017, and launched at the Tokyo Motor Show on October 27, 2017.

Facelift
The front fascia of the facelifted model is based from the facelifted RLX. It is equipped with HONDA Sensing which now includes Traffic Jam Assist (Congestion Driving Support Function) which support steering, acceleration, braking, and camera/sensor harmony when congested in traffic jams. The length grew to 5,032 mm, making it the longest Honda/Acura sedan to date, with length exceeding 5,000 mm.

Discontinued sales of RLX
2020 was the final model year for the North American Acura RLX due to low sales, with no direct successor planned.

Hybrid EX
On March 5, 2021, Honda began lease sales in Japan of the all-new Legend equipped with "Honda SENSING Elite", which is a variation of Honda SENSING, a suite of advanced safety and driver-assistive technologies currently available for Honda vehicles around the world. One of the “elite” technologies is the “Traffic Jam Pilot” function, an advanced technology qualifying for Level 3 automated driving (conditional automated driving in limited area).

Discontinuation
In June 2021, it was announced that the Sayama plant that produces the Legend would be closed at the end of 2021 and the current car would not have a successor.

title: Honda Legend