Apollo 5

Apollo 5

Lunar Module 1 being mated to the Spacecraft–LM adapter (SLA) in preparation for launch as Apollo 5
Mission type	Uncrewed Earth orbital LM flight (B)
Operator	NASA
COSPAR ID	Ascent stage: 1968-007A Descent stage: 1968-007B S-IVB: 1968-007C
SATCAT no.	3106
Mission duration	11 hours, 10 minutes
Orbits completed	7
Spacecraft properties
Spacecraft	Apollo Lunar Module-1
Manufacturer	Grumman
Launch mass	14,360 kilograms (31,660 lb)[1]
Start of mission
Launch date	January 22, 1968, 22:48:09 (1968-01-22UTC22:48:09Z) UTC
Rocket	LC-37B
End of mission
Disposal	Uncontrolled reentry
Deactivated	January 23, 1968 9:58 (1968-01-23UTC09:59Z) UTC
Decay date	Ascent stage: January 24, 1968 (1968-01-25) Descent stage: February 12, 1968 (1968-02-13)
Orbital parameters
Reference system	Geocentric
Regime	Low Earth orbit
Perigee altitude	167 kilometers (90 nmi)[1]
Apogee altitude	222 kilometers (120 nmi)[1]
Inclination	31.63 degrees[1]
Period	88.4 minutes[1]
Epoch	January 22, 1968[2]
Apollo program ← Apollo 4 Apollo 6 →

Apollo 5 (launched January 22, 1968), also known as AS-204, was the uncrewed first flight of the Apollo Lunar Module (LM) that would later carry astronauts to the surface of the Moon. The Saturn IB rocket bearing the LM lifted off from Cape Kennedy on January 22, 1968. The mission was successful, though due to programming problems an alternate mission to that originally planned was executed.

Like Apollo 4, this flight was long delayed, due in part to setbacks in development of the LM, manufactured by Grumman Aircraft. The original Saturn IB rocket that was to take the first LM (LM-1) to space was taken down during the delays and replaced with the one that would have launched Apollo 1 if the spacecraft fire that killed three astronauts had not occurred. LM-1 arrived at the Kennedy Space Center in June 1967; the following months were occupied in testing and placing the LM atop the Saturn IB. After final delays due to equipment trouble, the countdown began on January 21, 1968, and the space vehicle was launched the following day.

Once the craft reached orbit and the LM separated from the

As of September 6, 1967, Apollo 5 was running about 39 days behind the plan established on July 18, but all known issues were being dealt with, with the exception of some leaks from the propulsion system.[12] Most mission documents were ready by late 1967; Mission Director William C. Schneider issued mission rules on November 18, 1967. The following day, LM-1 was mated to its launch vehicle, and the space vehicle readiness test was completed in December. In early January 1968, the office of NASA Administrator James E. Webb announced that Apollo 5 would be launched no earlier than January 18, 1968. Minor faults such as clogged filters led to some additional delays. The countdown demonstration test concluded on January 19 and an abbreviated 22-hour countdown began on January 21.^[13][14]

Objectives

Apollo 5 was intended to verify the operation of the subsystems of the LM. During the flight, the ascent and descent engines would be fired. A "fire in the hole" test would be conducted to verify that the ascent stage could still fire while attached to the descent stage, a procedure that would be used on the lunar surface and in the event of an aborted lunar landing. It involved shutting down the descent stage, switching control and power to the ascent stage, and starting the ascent engine while the two stages were still mated. The term "fire in the hole" derived from a term used in mining when explosives are about to be used.^[13][15][16] Additional testing was to check that the LM engines could be restarted after initial use.^[17] In addition to testing LM systems, Apollo 5 was to test the Instrument Unit in its Saturn V configuration.^[9]

It was expected that the ascent stage of LM-1 would remain in orbit for about two years before re-entering the atmosphere and disintegrating, and the descent stage for about three weeks.^[18]

Equipment

Apollo 5 was launched into orbit by the Saturn IB, designated SA-204R, which had been assigned to Apollo 1. Originally brought to Cape Kennedy in August 1966, it had survived the fire unscathed, having been inspected after the fire for corrosion or other damage.^[9][11][19] Ignition weight for the launch vehicle, including the spacecraft and propellant, was 589,413 kilograms (1,299,434 lb).^[20]

The space vehicle for this mission was 55 meters (180 ft) tall but had a stubby appearance since it had neither a CSM nor a launch escape system. Instead, the LM was housed within the spacecraft-lunar module adapter (SLA) at the top of the vehicle stack.^[11] The SLA, numbered as SLA-7,^[21] was just below the nose cap in the stack, and had four panels that would open once the nose cap was jettisoned in orbit, allowing the LM room to separate and move away.^[22]

The LM, designated as LM-1, was the first flight-ready Apollo lunar module. To save weight, and because they would not be necessary during the test mission, LM-1 had no landing legs.^[23]

After one of the windows of LM-5 (which would fly on Apollo 11) broke during testing in December 1967, NASA officials decided to replace the windows of LM-1 with aluminum plates out of concern a window might fail in flight.^[24] Since there would be no astronauts aboard, LM-1 had a mission programmer installed, which could control the craft remotely.^[25] Not all LM-1 systems were fully activated nor was it given a full load of consumables: for example, its primary batteries were partially discharged to avoid over-voltage complications, and the oxygen tanks for the environmental control systems were only partially full.^[26]

Flight

On January 22, 1968, Apollo 5 lifted off from Launch Complex 37B at Cape Kennedy Air Force Station^[23] at 17:48:08 Eastern Standard Time (22:48:08 UTC).^[9] The Saturn IB worked perfectly, inserting the second stage and LM into an 88-by-120-nautical-mile (163 by 222 km) orbit.^[1][b] The nose cone was jettisoned, and after a coast of 43 minutes 52 seconds, the LM separated from its adapter, in a 90-by-120-nautical-mile (167 by 222 km) orbit.^[1]

After two orbits, the first planned 39-second descent-engine burn was started, but this was aborted after only four seconds by the Apollo Guidance Computer, which detected that the spacecraft was not going as fast as expected. This happened because one of the engine's valves was suspected of being leaky and was not armed until it was time to ignite the engine, in orbit, which meant that the propellant took longer to reach the engine, leading to the lag. Programmers could have adjusted the software to account for this, but were not told. In addition, the tanks were only half full, and this contributed to the slowness of the ship. Had this occurred on a crewed mission, the astronauts would have been able to analyze the situation and decide whether the engine should be restarted.^[13][27]

Gene Kranz was the flight director for Apollo 5.^[16] Mission Control, under Kranz's command, decided on a plan to conduct the engine and "fire-in-the-hole" tests under manual control. There were communication problems with the spacecraft, and omitting these tests would have meant the mission was a failure. Despite this, Kranz's team accomplished every burn.^[28] The ascent stage spun out of control eight hours into the mission, after completion of the engine burns, due to a problem with the guidance system.^[29]

The stages were left in a low enough orbit that atmospheric drag would soon cause their orbits to decay and re-enter the atmosphere. The ascent stage re-entered on January 24 and burned up; the descent stage re-entered on February 12, falling into the Pacific several hundred miles southwest of Guam.^[30][31] Simulations showed that the S-IVB stage of the launch vehicle (1968-007B) re-entered about 15.5 hours into the flight.^[32]

Apollo Spacecraft Program Manager

References

1. ^ ^{a b c d e f g} "Apollo 5". NASA Space Science Data Coordinated Archive. Retrieved September 26, 2016.
2. ^ McDowell, Jonathan. "SATCAT". Jonathan's Space Pages. Retrieved March 23, 2014.
3. ^ "Apollo 11 Mission Overview". NASA. December 21, 2017. Retrieved February 14, 2019.
4. ^ Orloff & Harland 2006, pp. 25–26.
5. ^ Orloff & Harland 2006, p. 26.
6. ^ Benson & Faherty 1978, p. 435.
7. ^ Astronautics 1967, p. 81.
8. ^ LaPage, Andrew (May 25, 2018). "SA-206: The Odyssey of a Saturn IB". Drew ex Machina. Retrieved September 12, 2021.
9. ^ ^{a b c d e f} Orloff & Harland 2006, p. 139.
10. ^ Ertel et al, p. 132.
11. ^ ^{a b c d} Brooks 1979, p. 241.
12. ^ Ertel et al, pp. 153–154.
13. ^ ^{a b c} Brooks 1979, p. 242.
14. ^ Orloff & Harland 2006, p. 140.
15. ^ Press Kit, pp. 2–4.
16. ^ ^{a b} Kranz 2000, p. 215.
17. ^ Press Kit, p. 2.
18. ^ Press Kit, p. 5.
19. ^ Press Kit, p. 20.
20. ^ Press Kit, p. 19.
21. ^ "Apollo/Skylab ASTP and Shuttle Orbiter Major End Items" (PDF). NASA. March 1978. p. 10.
22. ^ Press Kit, pp. 9–10.
23. ^ ^{a b c} "50 Years Ago: The Apollo Lunar Module". NASA. January 24, 2018. Retrieved September 11, 2021.
24. ^ Ertel et al, pp. 185, 190.
25. ^ Press Kit, p. 6.
26. ^ Press Kit, pp. 10–11.
27. ^ Eyles, Don (February 6, 2004). Tales From The Lunar Module Guidance Computer. 27th annual Guidance and Control Conference. Breckenridge, Colorado: American Astronautical Society.
28. ^ Kranz 2000, pp. 218–220.
29. ^ Orloff & Harland 2006, pp. 142–143, 150.
30. ^ Orloff & Harland 2006, pp. 142–144.
31. ISBN 9780387790930
    .
32. ^ ^{a b} Orloff & Harland 2006, p. 143.
33. ^ Orloff & Harland 2006, p. 223.

Sources

• Apollo 5 Press Kit. Washington, D.C.: NASA. 1968. Archived from the original on January 25, 2022. Retrieved September 12, 2021.
• Astronautics and Aeronautics, 1967 (PDF). Washington, D.C.: NASA. 1968.
• Benson, Charles D.; Faherty, William Barnaby (1978). Moonport: A History of Apollo Launch Facilities and Operations. NASA. NASA SP-4204.
• Brooks, Courtney G.; Grimwood, James M.; Swenson, Loyd S. Jr. (1979). Chariots for Apollo: A History of Manned Lunar Spacecraft (PDF). NASA History Series. Washington, D.C.: Scientific and Technical Information Office, NASA.
  LCCN 79001042
  . NASA SP-4205.
• Ertel, Ivan D.; Newkirk, Roland W.; et al. (1969–1978). The Apollo Spacecraft: A Chronology. Vol. IV. Washington, D.C.: NASA.
  OCLC 23818. NASA SP-4009. Archived from the original
  on February 5, 2008. Retrieved September 11, 2021.
• ISBN 978-0-7432-0079-0
  .
• Orloff, Richard W.;
  ISBN 978-0-387-30043-6
  .

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