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Thursday, 22 September 2016

Disasters in Space and spce race

Disaster strikes both sides

In 1967, both nations faced serious challenges that brought their programs to temporary halts. Both had been rushing at full-speed toward the first piloted flights of Apollo and Soyuz, without paying due diligence to growing design and manufacturing problems. The results proved fatal to both pioneering crews.

Charred interior of the Apollo 1 spacecraft after the fire that killed the first crew

On January 27, 1967, the same day the US and USSR signed the Outer Space Treaty, the crew of the first manned Apollo mission, Command Pilot Virgil "Gus" Grissom, Senior Pilot Edward H. White, and Pilot Roger Chaffee, were killed in a fire that swept through their spacecraft cabin during a ground test, less than a month before the planned February 21 launch. An investigative board determined the fire was probably caused by an electrical spark, and quickly grew out of control, fed by the spacecraft's pure oxygen atmosphere. Crew escape was made impossible by inability to open the plug door hatch cover against the greater-than-atmospheric internal pressure. The board also found design and construction flaws in the spacecraft, and procedural failings, including failure to appreciate the hazard of the pure-oxygen atmosphere, as well as inadequate safety procedures. All these flaws had to be corrected over the next twenty-two months until the first piloted flight could be made. Mercury and Gemini veteran Grissom had been a favored choice of Deke Slayton, NASA's Director of Flight Crew Operations, to make the first piloted landing.

Commemorative plaque and the "Fallen Astronaut" sculpture left on the Moon in 1971 by the crew of Apollo 15 in memory of 14 deceased NASA astronauts and USSR cosmonauts

On April 24, 1967, the single pilot of Soyuz 1, Vladimir Komarov, became the first in-flight spaceflight fatality. The mission was planned to be a three-day test, to include the first Soviet docking with an unpiloted Soyuz 2, but the mission was plagued with problems. Early on, Komarov's craft lacked sufficient electrical power because only one of two solar panels had deployed. Then the automatic attitude control system began malfunctioning and eventually failed completely, resulting in the craft spinning wildly. Komarov was able to stop the spin with the manual system, which was only partially effective. The flight controllers aborted his mission after only one day. During the emergency re-entry, a fault in the landing parachute system caused the primary chute to fail, and the reserve chute became tangled with the drogue chute; Komarov was killed on impact. Fixing the spacecraft faults caused an eighteen-month delay before piloted Soyuz flights could resume.

Onward to the Moon

The United States recovered from the Apollo 1 fire, fixing the fatal flaws in an improved version of the Block II command module. The US proceeded with unpiloted test launches of the Saturn V launch vehicle (Apollo 4 and Apollo 6) and the Lunar Module (Apollo 5) during the latter half of 1967 and early 1968. Apollo 1's mission to check out the Apollo Command/Service Module in Earth orbit was accomplished by Grissom's backup crew commanded by Walter Schirra on Apollo 7, launched on October 11, 1968. The eleven-day mission was a total success, as the spacecraft performed a virtually flawless mission, paving the way for the United States to continue with its lunar mission schedule.

Artist view of Soyuz 4 and Soyuz 5 after docking

The Soviet Union also fixed the parachute and control problems with Soyuz, and the next piloted mission Soyuz 3 was launched on October 26, 1968. The goal was to complete Komarov's rendezvous and docking mission with the un-piloted Soyuz 2. Ground controllers brought the two craft to within 200 meters (660 ft) of each other, then cosmonaut Georgy Beregovoy took control. He got within 40 meters (130 ft) of his target, but was unable to dock before expending 90 percent of his maneuvering fuel, due to a piloting error that put his spacecraft into the wrong orientation and forced Soyuz 2 to automatically turn away from his approaching craft. The first docking of Soviet spacecraft was finally realized in January 1969 by the Soyuz 4 and Soyuz 5 missions. It was the first-ever docking of two manned spacecraft, and the first transfer of crew from one space vehicle to another.

Soyuz 7K-L1 Zond spacecraft. Artist view

The Soviet Zond spacecraft was not yet ready for piloted circumlunar missions in 1968, after five unsuccessful and partially successful automated test launches: Cosmos 146 on March 10, 1967; Cosmos 154 on April 8, 1967; Zond 1967A September 27, 1967; Zond 1967B on November 22, 1967. Zond 4 was launched on March 2, 1968, and successfully made a circumlunar flight. After its successful flight around the Moon, Zond 4 encountered problems with its Earth reentry on March 9, and was ordered destroyed by an explosive charge 15,000 meters (49,000 ft) over the Gulf of Guinea. The Soviet official announcement said that Zond 4 was an automated test flight which ended with its intentional destruction, due to its recovery trajectory positioning it over the Atlantic Ocean instead of over the USSR.

Earthrise as seen from Apollo 8, December 24, 1968 (NASA)

During the summer of 1968, the Apollo program hit another snag: the first pilot-rated Lunar Module (LM) was not ready for orbital tests in time for a December 1968 launch. NASA planners overcame this challenge by changing the mission flight order, delaying the first LM flight until March 1969, and sending Apollo 8 into lunar orbit without the LM in December. This mission was in part motivated by intelligence rumors the Soviet Union might be ready for a piloted Zond flight during late 1968. In September 1968, Zond 5 made a circumlunar flight with tortoises on board and returned to Earth, accomplishing the first successful water landing of the Soviet space program in the Indian Ocean. It also scared NASA planners, as it took them several days to figure out that it was only an automated flight, not piloted, because voice recordings were transmitted from the craft en route to the Moon. On November 10, 1968 another automated test flight, Zond 6 was launched, but this time encountered difficulties in its Earth reentry, and depressurized and deployed its parachute too early, causing it to crash-land only 16 kilometers (9.9 mi) from where it had been launched six days earlier. It turned out there was no chance of a piloted Soviet circumlunar flight during 1968, due to the unreliability of the Zonds.

The Lunar Module flew in lunar orbit on Apollo 10, May 22–23, 1969

On December 21, 1968, Frank Borman, James Lovell, and William Anders became the first humans to ride the Saturn V rocket into space on Apollo 8. They also became the first to leave low-Earth orbit and go to another celestial body, and entered lunar orbit on December 24. They made ten orbits in twenty hours, and transmitted one of the most watched TV broadcasts in history, with their Christmas Eve program from lunar orbit, that concluded with a reading from the biblical Book of Genesis. Two and a half hours after the broadcast, they fired their engine to perform the first trans-Earth injection to leave lunar orbit and return to the Earth. Apollo 8 safely landed in the Pacific ocean on December 27, in NASA's first dawn splashdown and recovery.

The American Lunar Module was finally ready for a successful piloted test flight in low Earth orbit on Apollo 9 in March 1969. The next mission, Apollo 10, conducted a "dress rehearsal" for the first landing in May 1969, flying the LM in lunar orbit as close as 47,400 feet (14.4 km) above the surface, the point where the powered descent to the surface would begin. With the LM proven to work well, the next step was to attempt the landing.

Unknown to the Americans, the Soviet Moon program was in deep trouble. After two successive launch failures of the N1 rocket in 1969, Soviet plans for a piloted landing suffered delay. The launch pad explosion of the N-1 on July 3, 1969 was a significant setback. The rocket hit the pad after an engine shutdown, destroying itself and the launch facility. Without the N-1 rocket, the USSR could not send a large enough payload to the Moon to land a human and return him safely.

Apollo 11

American Buzz Aldrin during the first Moon walk in 1969

Apollo 11 was prepared with the goal of a July landing in the Sea of Tranquility. The crew, selected in January 1969, consisted of commander (CDR) Neil Armstrong, Command Module Pilot (CMP) Michael Collins, and Lunar Module Pilot (LMP) Edwin "Buzz" Aldrin. They trained for the mission until just before the launch day. On July 16, 1969, at exactly 9:32 am EDT, the Saturn V rocket, AS-506, lifted off from Kennedy Space Center Launch Complex 39 in Florida.

The trip to the Moon took just over three days. After achieving orbit, Armstrong and Aldrin transferred into the Lunar Module, named Eagle, and after a landing gear inspection by Collins remaining in the Command/Service Module Columbia, began their descent. After overcoming several computer overload alarms caused by an antenna switch left in the wrong position, and a slight downrange error, Armstrong took over manual flight control at about 180 meters (590 ft), and guided the Lunar Module to a safe landing spot at 20:18:04 UTC, July 20, 1969 (3:17:04 pm CDT). The first humans on the Moon waited six hours before they left their craft. At 02:56 UTC, July 21 (9:56 pm CDT July 20), Armstrong became the first human to set foot on the Moon.

The first step was witnessed by at least one-fifth of the population of Earth, or about 723 million people. His first words when he stepped off the LM's landing footpad were, "That's one small step for [a] man, one giant leap for mankind." Aldrin joined him on the surface almost 20 minutes later. Altogether, they spent just under two and one-quarter hours outside their craft. The next day, they performed the first launch from another celestial body, and rendezvoused back with Columbia.
Apollo 11 left lunar orbit and returned to Earth, landing safely in the Pacific Ocean on July 24, 1969. When the spacecraft splashed down, 2,982 days had passed since Kennedy's commitment to landing a man on the Moon and returning him safely to the Earth before the end of the decade; the mission was completed with 161 days to spare With the safe completion of the Apollo 11 mission, the Americans won the race to the Moon.

The race winds down

Apollo 17's Saturn V in 1972

Moonwalk, December 13, 1972

NASA had ambitious follow-on human spaceflight plans as it reached its lunar goal, but soon discovered it had expended most of its political capital to do so.

The first landing was followed by another, precision landing on Apollo 12 in November 1969. NASA had achieved its first landing goal with enough Apollo spacecraft and Saturn V launchers left for eight follow-on lunar landings through Apollo 20, conducting extended-endurance missions and transporting the landing crews in Lunar Roving Vehicles on the last five. They also planned an Apollo Applications Program to develop a longer-duration Earth orbital workshop (later named Skylab) to be constructed in orbit from a spent S-IVB upper stage, using several launches of the smaller Saturn IB launch vehicle. But planners soon decided this could be done more efficiently by using the two live stages of a Saturn V to launch the workshop pre-fabricated from an S-IVB (which was also the Saturn V third stage), which immediately removed Apollo 20. Belt-tightening budget cuts soon led NASA to cut Apollo 18 and 19 as well, but keep three extended/Lunar Rover missions. Apollo 13 encountered an in-flight spacecraft failure and had to abort its lunar landing in April 1970, returning its crew safely but temporarily grounding the program again. It resumed with four successful landings on Apollo 14 (February 1971), Apollo 15 (July 1971), Apollo 16 (April 1972), and Apollo 17 (December 1972).

In February 1969, President Richard M. Nixon convened a Space Task Group to set recommendations for the future US civilian space program, headed by his Vice President Spiro T. Agnew. Agnew was an enthusiastic proponent of NASA's follow-on plans, and the STG recommended plans to develop a reusable Space Transportation System including a Space Shuttle, which would facilitate development of permanent space stations in Earth and lunar orbit, perhaps a base on the lunar surface, and the first human flight to Mars as early as 1986 or as late as 2000. Nixon had a better sense of the declining political support in Congress for a new Apollo-style program, which had disappeared with the achievement of the landing, and he intended to pursue detente with the USSR and China, which he hoped might ease Cold War tensions. He cut the spending proposal he sent to Congress to include funding for only the Space Shuttle, with perhaps an option to pursue the Earth orbital space station for the foreseeable future.

The USSR continued trying to perfect their N1 rocket, finally canceling it in 1976, after two more launch failures in 1971 and 1972.

Salyuts and Skylab

The Soyuz 11 crew with the Salyut station in the background, in a Soviet commemorative stamp

Having lost the race to the Moon, the USSR decided to concentrate on orbital space stations. During 1969 and 1970, they launched six more Soyuz flights after Soyuz 3, then launched the first space station, the Salyut 1 laboratory designed by Kerim Kerimov, on April 19, 1971. Three days later, the Soyuz 10 crew attempted to dock with it, but failed to achieve a secure enough connection to safely enter the station. The Soyuz 11 crew of Vladislav Volkov, Georgi Dobrovolski and Viktor Patsayev successfully docked on June 7, and completed a record 22-day stay. The crew became the second in-flight space fatality during their reentry on June 30. They were asphyxiated when their spacecraft's cabin lost all pressure, shortly after undocking. The disaster was blamed on a faulty cabin pressure valve, that allowed all the air to vent into space. The crew was not wearing pressure suits and had no chance of survival once the leak occurred.

Salyut 1's orbit was increased to prevent premature reentry, but further piloted flights were delayed while the Soyuz was redesigned to fix the new safety problem. The station re-entered the Earth's atmosphere on October 11, after 175 days in orbit. The USSR attempted to launch a second Salyut-class station designated Durable Orbital Station-2 (DOS-2) on July 29, 1972, but a rocket failure caused it to fail to achieve orbit. After the DOS-2 failure, the USSR attempted to launch four more Salyut-class stations up to 1975, with another failure due to an explosion of the final rocket stage, which punctured the station with shrapnel so that it would not hold pressure. All of the Salyuts were presented to the public as non-military scientific laboratories, but some of them were covers for the military Almaz reconnaissance stations.

The United States launched the orbital workstation Skylab 1 on May 14, 1973. It weighed 169,950 pounds (77,090 kg), was 58 feet (18 m) long by 21.7 feet (6.6 m) in diameter, with a habitable volume of 10,000 cubic feet (280 m3). Skylab was damaged during the ascent to orbit, losing one of its solar panels and a meteoroid thermal shield. Subsequent manned missions repaired the station, and the final mission's crew, Skylab 4, set the Space Race endurance record with 84 days in orbit when the mission ended on February 8, 1974. Skylab stayed in orbit another five years before reentering the Earth's atmosphere over the Indian Ocean and Western Australia on July 11, 1979.

Apollo–Soyuz Test Project

 the five crew members of ASTP sitting around a miniature model of their spacecraft

Apollo-Soyuz crew: From left to right: Donald "Deke" Slayton, Thomas Patten Stafford, Vance Brand, Alexey Leonov, and Valeri Kubasov

In May 1972, President Richard M. Nixon and Soviet Premier Leonid Brezhnev negotiated an easing of relations known as detente, creating a temporary "thaw" in the Cold War. In the spirit of good sportsmanship, the time seemed right for cooperation rather than competition, and the notion of a continuing "race" began to subside.

The two nations planned a joint mission to dock the last US Apollo craft with a Soyuz, known as the Apollo-Soyuz Test Project (ASTP). To prepare, the US designed a docking module for the Apollo that was compatible with the Soviet docking system, which allowed any of their craft to dock with any other (e.g. Soyuz/Soyuz as well as Soyuz/Salyut). The module was also necessary as an airlock to allow the men to visit each other's craft, which had incompatible cabin atmospheres. The USSR used the Soyuz 16 mission in December 1974 to prepare for ASTP.

The joint mission began when Soyuz 19 was first launched on July 15, 1975 at 12:20 UTC, and the Apollo craft was launched with the docking module six and a half hours later. The two craft rendezvoused and docked on July 17 at 16:19 UTC. The three astronauts conducted joint experiments with the two cosmonauts, and the crew shook hands, exchanged gifts, and visited each other's craft.

Legacy

Human spaceflight after Apollo

International Space Station in 2010

In the 1970s, the United States began developing a new generation of reusable orbital spacecraft known as the Space Shuttle, and launched a range of unmanned probes. The USSR continued to develop space station technology with the Salyut program and Mir ('Peace' or 'World', depending on the context) space station, supported by Soyuz spacecraft. They developed their own large space shuttle under the Buran program. The USSR dissolved in 1991 and the remains of its space program mainly passed to Russia. The United States and Russia worked together in space with the Shuttle–Mir Program, and again with the International Space Station.

The Russian R-7 rocket family, which launched the first Sputnik at the beginning of the space race, is still in use today. It services the International Space Station (ISS) as the launcher for both the Soyuz and Progress spacecraft. It also ferries both Russian and American crews to and from the station.

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