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CSM RCS


CSM RCS Development Diary

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CSM RCS Chronology


1962 March 2 - .
  • Marquardt to build the reaction control rocket engines for the Apollo spacecraft - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM RCS. Summary: The Marquardt Corporation was selected by NAA's Space and Information Systems Division to design and build the reaction control rocket engines for the Apollo spacecraft. The contract was signed during April..

1962 April - .
  • Configuration of the Apollo command module forward compartment changed - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM RCS. Summary: The basic design configuration of the command module forward compartment was changed by the relocation of two attitude control engines from the lower to the upper compartment area, where less heat flux would be experienced during reentry..

1962 May - .
  • Apollo command module reaction control system selected - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM RCS. The command module reaction control system (RCS) selected by NAA was a dual system without interconnections. Either would be sufficient for the entire mission.

    For the service module RCS, a quadruple arrangement was chosen which was basically similar to the command module RCS except that squib valves and burst discs were eliminated.


1962 August 13-14 - .
  • Reduction in reaction control thrust for Apollo - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM RCS. Summary: NAA suggested that the pitch, roll, and yaw rates required for the Apollo guidance and navigation system would permit reduction in the reaction control thrust..

1962 August 22 - .
  • Contractor for Apollo CM reaction controls changed - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM RCS. Summary: Responsibility for the design and manufacture of the reaction controls for the Apollo command module was shifted from The Marquardt Corporation to the Rocketdyne Division of NAA, with NASA concurrence..

1962 August - .
  • Apollo CM high-altitude abort attitude orientation studies completed - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM RCS. NAA completed attitude orientation studies, including one on the control of a tumbling command module (CM) following high-altitude abort above 125,000 feet. The studies indicated that the CM stabilization and control system would be adequate during the reentry phase with the CM in either of the two possible trim configurations.

1962 October - . LV Family: Saturn V. Launch Vehicle: Saturn V.
  • Technique for separating the Apollo command and service modules during an abort - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM RCS. The technique tentatively selected by NAA for separating the command and service modules from lower stages during an abort consisted of firing four 2000-pound-thrust posigrade rockets mounted on the service module adapter. With this technique, no retrorockets would be needed on the S-IV or S-IVB stages. Normal separation from the S-IVB would be accomplished with the service module reaction control system.

1962 November - .
  • Study of Apollo CSM-LEM transposition and docking - . Nation: USA. Program: Apollo. Spacecraft: Apollo LM; CSM RCS; LM RCS; LM Weight. North American completed a study of CSM-LEM transposition and docking. During a lunar mission, after the spacecraft was fired into a trajectory toward the moon, the CSM would separate from the adapter section containing the LEM. It would then turn around, dock with the LEM, and pull the second vehicle free from the adapter. The contractor studied three methods of completing this maneuver: free fly-around, tethered fly- around, and mechanical repositioning. Of the three, the company recommended the free fly-around, based on NASA's criteria of minimum weight, simplicity of design, maximum docking reliability, minimum time of operation, and maximum visibility.

    Also investigated was crew transfer from the CM to the LEM, to determine the requirements for crew performance and, from this, to define human engineering needs. North American concluded that a separate LEM airlock was not needed but that the CSM oxygen supply system's capacity should be increased to effect LEM pressurization.

    On November 29, North American presented the results of docking simulations, which showed that the free flight docking mode was feasible and that the 45-kilogram (100-pound) service module (SM) reaction control system engines were adequate for the terminal phase of docking. The simulations also showed that overall performance of the maneuver was improved by providing the astronaut with an attitude display and some form of alignment aid, such as probe.


1962 December 28 - .
  • First test firings of the Apollo CM reaction control engines - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM RCS. Summary: North American's Rocketdyne Division completed the first test firings of the CM reaction control engines..

1963 February 18 - .
  • Bell to provide propellant tanks for the Apollo CSM reaction control system - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM RCS. North American selected Bell Aerosystems Company to provide propellant tanks for the CSM reaction control system. These tanks were to be the "positive expulsion" type (i.e., fuel and oxidizer would be contained inside flexible bladder; pressure against one side of the device would force the propellant through the RCS lines).

1963 July 10 - .
  • Prototype engine for the Apollo SM reaction control system - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM RCS. Summary: The Marquardt Corporation began testing the prototype engine for the SM reaction control system. Preliminary data showed a specific impulse slightly less than 300 seconds..

1963 October 31 - .
  • Marquardt production of reaction control engines for the SM - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM RCS. The Marquardt Corporation received a definitive $9,353,200 contract from North American for development and production of reaction control engines for the SM. Marquardt, working under a letter contract since April 1962, had delivered the first engine to North American that November.

1963 December 16-January 15 - .
  • Adequacy of the Apollo CM RCS for automatic reentry - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM RCS. Summary: North American completed a study to determine, for automatic modes of reentry, adequacy of the current CM reaction control system (RCS) and compatibility of the RCS with other reentry subsystems..

1963 December 21 - .
  • MSC defined the Apollo LEM terminal rendezvous maneuvers - . Nation: USA. Program: Apollo. Spacecraft: Apollo LM; CSM RCS; LM Ascent Propulsion; LM RCS. MSC defined the LEM terminal rendezvous maneuvers. That phase of the mission would begin at a range of 9.3 kilometers (five nautical miles) from the CSM and terminate at a range of 152.4 meters (500 feet). Before rendezvous initiation, closing velocity should be reduced to 61 meters (200 feet) per second by use of the ascent engine. The reaction control system should be used exclusively thereafter.

1964 January 17 - .
  • Design review of the Apollo CM reaction control system - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM RCS. A design review of the CM reaction control system (RCS) was held. Included was a discussion of possible exposure of the crew to hazardous fumes from propellants if the RCS ruptured at earth impact. For the time being, the RCS design would not be changed, but no manned flights would be conducted until the matter had been satisfactorily resolved. A detailed study would be made on whether to eliminate, reduce, or accept this crew safety hazard.

1964 February 14 - .
  • Apollo SM RCS to have emergency deorbit capability - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM RCS. Summary: MSC ordered North American to design the SM's reaction control system with the capability for emergency retrograde from earth orbit..

1964 October 12 - .
  • Apollo CSM-LM active docking interfaces discussed - . Nation: USA. Program: Apollo. Spacecraft: Apollo LM; CSM RCS; LM RCS. At a North American-Grumman interface meeting on September 23-24, two possible relative role alignments for CSM-active docking were agreed upon. The major item blocking final selection was the effect of the SM's reaction control system engines upon the LEM antennas. ASPO requested Grumman to investigate the problem, to analyze the design penalties of the two-attitude docking mode, and to report any other factors that would influence the final attitude selection.

1964 December 7 - .
  • Apollo LEM to be the active vehicle during lunar rendezvous - . Nation: USA. Program: Apollo. Spacecraft: Apollo LM; CSM RCS; LM RCS. Summary: MSC advised Grumman that, normally, the LEM would be the active vehicle during lunar rendezvous. This would conserve reaction control system propellants aboard the CSM..

1964 December 10-January 7 - .
  • Positive expulsion tanks for Apollo CSM RCS failed tests - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM RCS. Summary: Because of faults in both design and in testing procedures, the positive expulsion tanks for the CSM reaction control system failed their verification tests (begun during the preceding month)..

1964 December 15-16 - .
  • Thermal-demanded weight increases for the Apollo LEM's steerable antenna - . Nation: USA. Program: Apollo. Spacecraft: Apollo LM; CSM RCS; LM RCS; LM Weight. Dalmo-Victor studied thermal-demanded weight increases for the LEM's steerable antenna. Investigators reported to Grumman and RCA that, in the plume of the CSM's reaction control engines, 1.18 kg (2.5 lbs) was necessary merely for the survival of the antenna; another 1.18 kg would be required for tracking during this impingement.

1964 December 16 - .
  • Mission planning presentation for flights AS-201; AS-202 and AS-203 - . Nation: USA. Related Persons: Shea. Program: Apollo. Spacecraft: Apollo CSM; CSM RCS. A mission planning presentation was given to ASPO Manager Joseph F. Shea, Assistant Director for Flight Operations Christopher C. Kraft, Jr., and Assistant Director for Flight Crew Operations Donald K. Slayton covering missions AS-201, AS-202, and AS-203. Additional Details: here....

1965 April 5-11 - .
  • Qualification tests completed on two Apollo CM reaction control engines - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM RCS. Summary: Rocketdyne completed qualification tests on two CM reaction control engines. These were successful. One of the nozzle extensions failed to seat, however, and was rejected. Its failure was being analyzed..

1965 April 7 - .
  • A LEM/Apollo CSM interface meeting uncovered a number of design problems - . Nation: USA. Program: Apollo. Spacecraft: Apollo LM; CSM RCS; LM Communications; LM RCS. A LEM/CSM interface meeting uncovered a number of design problems and referred them to the Systems Engineering Division (SED) for evaluation: the requirement for ground verification of panel deployment prior to LEM withdrawal; the requirement for panel deployment in earth orbit during the SA-206 flight; the absence of a backup to the command sequencer for jettisoning the CSM (Flight Projects Division (FPD) urged such a backup signal); and Grumman's opposition to a communications link with the LEM during withdrawal of the spacecraft (FPD felt that such a link was needed through verification of reaction control system ignition). SED's recommendations on these issues were anticipated by April 22.

1965 April 22 - .
  • Common Apollo reaction control system propellant tanks - . Nation: USA. Program: Apollo. Spacecraft: Apollo LM; CSM RCS; LM RCS. Grumman was requested to attend a meeting at MSC and to present their reasons as to why the LEM reaction control system (RCS) propellant tanks could not be of common technology with the CSM RCS propellant tanks. Grumman was to also say why an additional development program was required for the LEM tanks.

1965 May 4 - .
  • Apollo RCS oxidizer tank failure - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM RCS. Technical personnel at MSC became concerned over an RCS oxidizer tank failure that occurred in February 1965, during propellant exposure and creep tests. The failure had previously been explained as stress corrosion caused from a fingerprint on the tank shell before heat treat. NASA requested that the test be repeated under tighter controlled procedures.

1965 May 21 - .
  • Preliminary flight rating tests on the Apollo reaction control engine - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM RCS. Summary: Marquardt Corporation completed preliminary flight rating tests on the reaction control engine for the SM..

1965 June 7-13 - .
  • Qualification testing on the Apollo CM's reaction control system engines - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM RCS. Summary: North American's Rocketdyne Division began qualification testing on the CM's reaction control system engines..

1965 June 25 - .
  • Design approved for thermal control of the valves in the Apollo CM's reaction control system - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM RCS. MSC approved North American's concept for thermal control of the valves in the CM's reaction control system (essential for long-duration missions). The crew could electrically heat the valves for about ten minutes before CSM separation and before the system was pressurized, thereby forestalling possible freezing of the oxidizer when it contacted the valve.

1965 July 11 - .
  • Apollo RCS oxidizer tank failed during test - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM RCS. An RCS oxidizer tank failed during a test to demonstrate propellant compatibility with titanium tanks. This was the first of seven tanks to fail from a group of ten tanks put into test to investigate a failure that occurred during February 1965. These results caused an intensive investigation to be undertaken.

1965 August 2 - .
  • Marquardt to build Apollo Block II SM reaction control system engines - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM RCS. NASA's office at Downey, Calif., approved the contract with the Marquardt Corporation for the procurement of Block II SM reaction control system engines. Estimated cost of the fixed price contract would be $6.5 million. Marquardt was supplying the Block I SM engines.

1965 November - .
  • Stress corrosion of the Apollo reaction control system tanks - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM RCS. A series of tests were run to determine the cause of stress corrosion of the reaction control system titanium tanks. Results showed that tanks exposed to chemically pure nitrogen tetroxide (N2O4) oxidizer suffered stress corrosion cracking, but tanks exposed to N2O4 containing small amounts of nitric oxide did not fail. The qualification testing program would soon resume.

1965 December 31 - .
  • Apollo SM reaction control system engine qualification completed - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM RCS. Summary: The SM reaction control system engine qualification was completed with no apparent failures..

1968 March 18 - .
  • Apollo CSM 020 reaction control system pressure vessel reviews - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM RCS. Summary: The MSC Structures and Mechanics Division reported to ASPO Manager George M. Low that additional verification of the spacecraft 020 reaction control system (RCS) pressure vessels would not be required. . Additional Details: here....

1970 April 19 - .
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