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CSM Electrical


CSM Electrical Development Diary

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CSM Electrical Chronology


1962 November 13 - .
  • Westinghouse to build power conversion units for the Apollo command module - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Electrical. North American Aviation, Inc., selected the Aerospace Electrical Division of Westinghouse Electric Corporation to build the power conversion units for the command module (CM) electrical system. The units would convert direct current from the fuel cells to alternating current.

1962 November 17 - .
  • Four injured when an electrical spark ignited a fire in a Navy altitude chamber - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Electrical. Four Navy officers were injured when an electrical spark ignited a fire in an altitude chamber, near the end of a 14-day experiment at the U.S. Navy Air Crew Equipment Laboratory, Philadelphia, Pa. The men were participating in a NASA experiment to determine the effect on humans of breathing pure oxygen for 14 days at simulated altitudes.

1963 February 25 - .
  • Batteries independent of the main electrical system in the Apollo CM to fire all pyrotechnics - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Electrical. Summary: MSC ordered North American to provide batteries, wholly independent of the main electrical system in the CM, to fire all pyrotechnics aboard the spacecraft..

1963 March 25 - . LV Family: Little Joe II. Launch Vehicle: Little Joe II.
  • First Little Joe II completed - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Electrical. General Dynamics Convair completed structural assembly of the first launcher for the Little Joe II test program. During the next few weeks, electrical equipment installation, vehicle mating, and checkout were completed. The launcher was then disassembled and delivered to WSMR on April 25, 1963.

1963 May 20 - .
  • Contract to Westinghouse for study of potential physiological damage by cosmic radiation - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Electrical. Summary: In support of NASA's manned space flight programs, Ames Research Center awarded a $150,000 contract to Westinghouse Electric Corporation for a one-year study of potential physiological damage in space caused by cosmic radiation..

1963 June 3 - .
  • ITT to provide battery chargers for the Apollo CSM - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Electrical. Summary: North American announced that it had selected ITT's Industrial Products Division to provide battery chargers for the CSM, designed for an operational lifetime of 40,000 hours..

1963 June 26 - .
  • First full-scale firing of the Apollo SM engine - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Electrical. The first full-scale firing of the SM engine was conducted at the Arnold Engineering Development Center. At the start of the shutdown sequence, the engine thrust chamber valve remained open because of an electrical wiring error in the test facility. Consequently the engine ran at a reduced chamber pressure while the propellant in the fuel line was exhausted. During this shutdown transient, the engine's nozzle extension collapsed as a result of excessive pressure differential across the nozzle skin.

1964 March 16-April 15 - .
  • First prototype of the Apollo CM reentry battery was delivered - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Electrical. Summary: The first prototype of the CM battery for use during reentry was delivered to North American by Eagle-Picher Industries, Inc..

1964 March 26-April 1 - .
  • Because of pure oxygen atmosphere specified, Apollo requirements for component testing reviewed - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Electrical. Because of the pure oxygen atmosphere specified for the spacecraft, North American reviewed its requirements for component testing. Recent evaluation of the CM circuit breakers had indicated a high probability that they would cause a fire. The company's reliability office recommended more flammability testing, not only on circuit breakers but on the control and display components as well. The reliability people recommended also that procurement specifications be amended to include such testing.

1964 November 5 - .
  • Battery charger for Apollo LEM - . Nation: USA. Program: Apollo. Spacecraft: Apollo LM; CSM Electrical; LM Electrical. Summary: MSC authorized Grumman to proceed with procurement of a battery charger for the LEM, to replenish the portable life support system's power source. On the following day, Houston informed North American such a device was no longer needed in the CSM..

1964 November 17-18 - .
  • Apollo-Saturn Emergency Detection System Design Sub-Panel - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Electrical. The Emergency Detection System (EDS) Design Sub-Panel of the Apollo-Saturn Electrical Systems Integration Panel held its first meeting at North American's Systems and Information Division facility at Downey, Calif. A. Dennett of MSC and W. G. Shields of MSFC co-chaired the meeting.

    Personnel from MSC, MSFC, KSC, OMSF, and North American attended the meeting. Included in the discussions were a review of the EDS design for both the launch vehicle and spacecraft along with related ground support equipment; a review of the differences of design and checkout concepts; and a review of EDS status lights in the spacecraft.


1965 January 23 - . LV Family: Saturn V. Launch Vehicle: Saturn V.
  • Technique for Apollo LEM / S-IVB separation during manned mission approved - . Nation: USA. Program: Apollo. Spacecraft: Apollo LM; CSM Electrical; LM Electrical. ASPO approved the technique for LEM S-IVB separation during manned missions, a method recommended jointly by North American and Grumman. After the CSM docked with the LEM, the necessary electrical circuit between the two spacecraft would be closed manually. Explosive charges would then free the LEM from the adapter on the S-IVB.

1965 April 26-May 2 - .
  • Apollo boilerplate 14 simulated the mission for spacecraft 009 - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Electrical. Summary: Using boilerplate 14, North American simulated the mission for spacecraft 009. The test was conducted in two phases, with the vehicle on external and then internal power. All data showed satisfactory performance..

1965 July 21 - .
  • Qualification testing completed on Apollo CSM batteries - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Electrical. Summary: North American reported that qualification testing had been completed on two items of electrical hardware, the CSM battery charger and the pyrotechnic battery..

1965 November 24 - .
  • Electrically actuated explosive devices on the LEM would be fired by the Apollo standard initiator - . Nation: USA. Program: Apollo. Spacecraft: Apollo LM; CSM Electrical; LM Electrical. MSC notified Grumman that all electrically actuated explosive devices on the LEM would be fired by the Apollo standard initiator. This would be a common usage item with the CSM and would be the single wire configuration developed by NASA and provided as Government-furnished equipment.

1966 January 13-27 - .
  • Single Apollo battery for all flight hardware studied - . Nation: USA. Program: Apollo. Spacecraft: Apollo LM; CSM Electrical; LM Electrical. Hamilton Standard Division was directed by Crew Systems Division to use a 2.27-kg (5-lbs) battery for all flight hardware if the power inputs indicated that it would meet the four-hr mission. The battery on order currently weighed 2.44 kg (5.4 lbs). This resulted in an inert weight saving of l.45 kg (3.2 lbs) and a total saving on the LEM and CSM of 5.44 kg (12 lbs).

1966 February 6-8 - .
  • First test of Apollo cryogenic gas storage system - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Electrical. The first test of the cryogenic gas storage system was successfully conducted from 12:30p.m. February 6 through 8:50 p.m. February 8 at the White Sands Test Facility (WSTF), N. Mex. Primary objectives were to demonstrate the compatibility between the ground support equipment and cryogenic subsystem with respect to mechanical, thermodynamic, and electrical interfaces during checkout, servicing, monitoring, and ground control. All objectives were attained.

1966 March 9-10 - .
  • First integrated test of major Apollo service module systems - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Electrical. Summary: The first integrated test of the service propulsion system, electrical power system, and cryogenic gas storage system was successfully conducted at the White Sands Test Facility..

1967 January 27 - . Launch Site: Cape Canaveral. LV Family: Saturn I. Launch Vehicle: Saturn IB.
1967 January 29 - .
  • Astronaut Borman briefed the Apollo 204 Review Board after inspection of the damaged CSM 012 - . Nation: USA. Program: Apollo. Flight: Apollo 204. Spacecraft: Apollo CSM; CSM Electrical. Summary: Astronaut Frank Borman briefed the Apollo 204 Review Board after his inspection of the damaged command and service modules. . Additional Details: here....

1967 March 14 - .
  • Apollo 204 Review Board test results failed to show any SM anomalies - . Nation: USA. Program: Apollo. Flight: Apollo 204. Spacecraft: Apollo LM; CSM Electrical; LM Electrical. The Service Module Disposition Panel (No. 21) report accepted by the Apollo 204 Review Board said test results had failed to show any SM anomalies due to SM systems and there was no indication that SM systems were responsible for initiating the January 27 fire. Additional Details: here....

1967 April 10 - .
  • Two task teams to investigate Apollo CSM electrical systems and flammable materials - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Electrical. George Low requested William M. Bland, MSC, to take action on two recommendations made by MSC Director Robert R. Gilruth:

    1. Take stereo color photos of all spacecraft areas before they were closed out. This procedure had been invaluable during the Apollo Review Board's activities at KSC, and the same technique, applied during the manufacturing process of current spacecraft, might help answer questions raised subsequent to the closeout of an area and thereby save time.
    2. Make additional requirements for the use of cover plates over spacecraft wire bundles. Greater use of cover plates during manufacturing, test, and perhaps even flight would prevent damage during subsequent activities.

1967 April 18 - .
  • No NASA accountability for Apollo wiring - . Nation: USA. Related Persons: Faget. Program: Apollo. Spacecraft: Apollo CSM; CSM Electrical. ASPO Manager George M. Low pointed out to MSC Director of Engineering and Development Maxime A. Faget that apparently no single person at MSC was responsible for spacecraft wiring. Low said he would like to discuss naming a subsystem manager to follow this general area, including not only the wiring schematics, circuitry, circuit-breaker protection, etc., but also the detailed design, engineering, fabrication, and installation of wiring harnesses.

1967 May 5 - .
  • Circuit breakers in Apollo were flammable - . Nation: USA. Related Persons: Faget. Program: Apollo. Spacecraft: Apollo LM; CSM Electrical; LM Electrical. Circuit breakers being used in both CSM and LM were flammable, MSC ASPO Manager George Low told Engineering and Development Director Maxime A. Faget. Low said that although Structures and Mechanics Division was developing a coating to be applied to the circuit breakers, such a solution was not the best for the long run. He requested that the Instrumentation and Electronics Systems Division find replacement circuit breakers for Apollo - ideally, circuit breakers that would not bum and that would fit within the same volume as the existing ones, permitting replacement in panels already built. On July 12 Low wrote Faget again: "In light of the work that has gone on since my May 5, 1967, memo, are you now prepared to propose the use of metal-jacketed circuit breakers for Apollo spacecraft? If the answer is affirmative, then we should get specific direction to our contractors immediately. Also, have you surveyed the industry to see whether a replacement circuit breaker is available or will be available in the future?" Low requested an early reply.

1967 May 31 - .
  • Wiring harnesses for the Apollo lunar module acceptable - . Nation: USA. Program: Apollo. Spacecraft: Apollo LM; CSM Electrical; LM Electrical. Grumman Aircraft Engineering Corp.'s method of building wiring harness for the lunar module was acceptable, George Low, MSC Apollo Spacecraft Program Office Manager, wrote Apollo Program Manager Samuel C. Phillips at NASA Hq. Low had noted on a visit to Grumman on May 9 that many of the harnesses were being built on two-dimensional boards. In view of recent discussions of the command module wiring, Low requested Grumman to reexamine their practice and to reaffirm their position on two-versus three-dimensional wiring harnesses.

    In his May 31 letter to Phillips, Low enclosed Grumman's reply and said that, in his opinion, Grumman's practice was acceptable because

    1. most wire bundles on the LM were much thinner than the CSM wiring bundles and were much more flexible;
    2. portions of the LM harness were often fabricated on a three dimensional segment of the harness board; and
    3. connectors were usually mounted on metal brackets with the proper direction and clocking.

1967 July 24 - .
  • Changes resulting from AS-204 investigation - . Nation: USA. Program: Apollo. Flight: Apollo 204. Spacecraft: Apollo CSM; CSM ECS; CSM Electrical; CSM Hatch. ASPO Manager George M. Low issued instructions that the changes and actions to be carried out by MSC as a result of the AS-204 accident investigation were the responsibility of CSM Manager Kenneth S. Kleinknecht. The changes and actions were summarized in Apollo Program Directive No. 29, dated July 6, 1967.

1967 September 15 - .
  • Short circuit on Apollo CSM 020 - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Electrical. Summary: A short circuit occurred during checkout of CSM 020 at North American, Downey, Calif. . Additional Details: here....

1967 December 16 - .
  • Decisions on flammability problems related to coax cables in Apollo CMs - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Electrical. Top NASA and North American Rockwell management personnel discussed flammability problems associated with coax cables installed in CMs. It was determined that approximately 23 meters of flammable coax cable was in CM 101 and, when ignited with a nichrome wire, the cable would burn in oxygen at both 4.3 and 11.4 newtons per square centimeter (6.2 and 16.5 pounds per square inch). Burning rates varied from 30 to 305 centimeters per minute, depending upon the oxygen pressure and the direction of the flame front propagation. The cable was behind master display panels, along the top of the right-hand side of the cabin, vertically in the rear right-hand corner of the cabin, in the cabin feed-through area, and in the lower equipment bay. The group reviewed the detailed location of the cable, viewed movies of flammability tests, examined movies of the results of testing with fire breaks, discussed possible alternatives, and inspected cable installations in CMs 101 and 104.

    The following alternatives were considered:

    1. Replace all coax cable.
    2. Wrap all coax cable with aluminum tape.
    3. Partially wrap the cable to provide fire breaks. Tests at North American indicated that a 102-millimeter segment of wrapped cable with four layers of aluminum foil would provide a fire break. MSC tests indicated such a fire break was not adequate for multiple cables.
    4. Leave the installation as it was.

    The following factors were considered in reaching a decision for spacecraft 101:

    1. The wiring in that spacecraft had been completed for several months. All subsystems had been installed and protective covers had been installed. Complete replacement or complete wrapping of all coax cables would be time consuming; it might take as long as three months, when taking retest into consideration. Additionally, in spite of extreme care, complete replacement or wrapping might do considerable damage to the installed wiring, and even partial wrapping might cause damage in many areas.
    2. The coax cable could not self-ignite under any conditions.
    3. In most installations, the coax cable was a separate bundle and not part of other wire bundles. An exception was the feed-through area in the lower right-hand corner of the cabin, where the coax cable was intertwined with other wires. Although power cables existed in this area, these were not high-current-carrying cables.
    4. A minimum number of possible ignition sources existed in the vicinity of the coax cables, and a complex series of events would be required to ignite the cable.

    In view of these factors, decisions for spacecraft 101 were:

    1. The cable would be flown essentially as installed. The only exception was that the vertical cable bundle in the right-hand corner of the spacecraft would be wrapped with layers of aluminum tape. Each cable in this bundle would be individually wrapped.
    2. An analysis by North American would document all other wiring near the coax cable, including the wire size, functions, maximum currents carried, and degree of circuit-breaker protection.
    3. All possible ignition sources near the coax cable would be documented.
    4. Tests would be made in boilerplate (BP) 1250 to determine the effects of fire breaks inherent in the installation.
    In making these decisions, NASA and North American recognized that they were contrary to existing criteria and guidelines. Those present agreed that the decisions were an exception and in no way should be construed as a change or relaxation of the criteria and guidelines. The basic reason for the exception was summarized as follows: "As a result of the clean installation of the coax cables, the lack of external ignition sources, and the complete job done in cleaning up the spacecraft from the flammability viewpoint, the risk of igniting the coax cables is exceedingly small. This risk is believed to be less than would likely be incurred through possible damage to existing installations had a decision been made to replace or wrap the cables."

    The installation in spacecraft 2TV-1 would not be changed. This decision was made fully recognizing that more flammable material remained in 2TV-1 than in 101. However, the burning rate of coax cable had been demonstrated as very slow, and it was reasoned that the crew would have sufficient time to make an emergency exit in the vacuum chamber from 2TV-1 long before any dangerous situations would be encountered.

    Officials also agreed that coax cable in boilerplate 1224 would not be ignited until after the results of the BP 1250 tests had been reviewed.


1967 December 27 - .
  • NAA Apollo solder joint fixes rejected - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Electrical. CSM Manager Kenneth S. Kleinknecht asked the Manager of the Resident Apollo Spacecraft Program Office (RASPO) at Downey to inform North American Rockwell that MSC had found the suggestion that aluminum replace teflon for solder joint inserts and outer armor sleeves in Apollo spacecraft plumbing unacceptable because

    1. the teflon insert was designed to give an interference fit to prevent the passage of solder balls into the plumbing;
    2. an aluminum insert could not be designed with an interference fit for obvious reasons;
    3. the aluminum insert was tested at the beginning of the program and found to be inferior to the teflon insert; and
    4. the aluminum armor seal could not be used as a replacement for the outer armor sleeves because it did not eliminate the creep problem of solder.

1968 April 22 - .
  • 100 percent oxygen in the cabin of the Apollo LM at launch - . Nation: USA. Program: Apollo. Spacecraft: Apollo LM; CSM Electrical; LM ECS. ASPO Manager George M. Low advised top officials in Headquarters, MSFC, and KSC that he was recommending the use of 100 percent oxygen in the cabin of the LM at launch. MSC had reached this decision, Low said, after thorough evaluation of system capabilities, requirements, safety, and crew procedures. The selection of pure oxygen was based on several important factors: reduced demand on the CSM's oxygen supply by some 2.7 kilograms; simplified crew procedures; the capability for immediate return to earth during earth-orbital missions in which docking was performed; and safe physiological characteristics. All of these factors, the ASPO Chief stated, outweighed the flammability question. Because the LM was unmanned on the pad, there was little electrical power in the vehicle at launch and therefore few ignition sources. Further, the adapter was filled with inert nitrogen and the danger of a hazardous condition was therefore minimal. Also, temperature and pressure sensors inside the LM could be used for fire detection, and fire could be fought while the mobile service structure was in place. As a result, Low stated, use of oxygen in the LM on the pad posed no more of a hazard than did hypergolics and liquid hydrogen and oxygen.

1968 September 28 - .
  • Review of functional interfaces between launch vehicle and spacecraft for Apollo 7 - . Nation: USA. Program: Apollo. Flight: Apollo 7. Spacecraft: Apollo CSM; CSM Electrical. Summary: Results of a joint MSFC-MSC review of functional interfaces between the launch vehicle and spacecraft for Apollo 7 were forwarded to NASA Hq. . Additional Details: here....

1968 November 8 - . LV Family: Saturn V. Launch Vehicle: Saturn V.
  • Proper spacecraft deployment during the Apollo 8 flight - . Nation: USA. Related Persons: Petrone. Program: Apollo. Flight: Apollo 7; Apollo 8. Spacecraft: ; CSM Electrical. Summary: ASPO Manager George M. Low asked Rocco A. Petrone, Launch Operations Director at KSC, to set up a special task team to review all paperwork and to inspect visually all hardware, to ensure proper spacecraft deployment during the Apollo 8 flight. . Additional Details: here....

1969 March 12 - .
  • Status of a fire detection system for Apollo - . Nation: USA. Related Persons: Faget. Program: Apollo. Spacecraft: Apollo CSM; CSM Electrical. George M. Low discussed the status of a fire detection system for Apollo in a memorandum to Martin L. Raines, reminding him that such a system had been under consideration since the accident in January 1967. Low said: "Yesterday, Dr. (Maxime A.) Faget, you, and I participated in a meeting to review the current status of a flight fire detection system. It became quite clear that our state of knowledge about the physics and chemistry of fire in zero gravity is insufficient to permit the design and development of a flightworthy fire detection system at this time. For this reason, we agreed that we would not be able to incorporate a fire detection system in any of the Apollo spacecraft. We also agreed that it would be most worthwhile to continue the development of a detection system for future spacecraft."

1970 April 13-June 15 - .
  • Apollo 13 - "Hey - we've got a problem here" - . Nation: USA. Program: Apollo. Flight: Apollo 13. Spacecraft: Apollo CSM; CSM Electrical. "Hey, we've got a problem here." The message from the Apollo 13 spacecraft to Houston ground controllers at 10:08 p.m. EDT on April 13, initiated an investigation to determine the cause of an oxygen tank failure that aborted the Apollo 13 mission. Additional Details: here....

1970 April 19 - .
1970 November 24 - .
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