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CSM Communications


CSM Communications Development Diary

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CSM Communications Chronology


1962 October - .
  • Apollo personal communications system to have a duplex capability with a simplex backup - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Communications. The revised NAA recommendation for a personal communications system consisted of a duplex capability with a simplex backup. Simultaneous transmission of voice and biomedical data with a break-in capability would be possible. Two changes in spacecraft VHF equipment would be needed: a dual-channel in place of a single-channel receiver, and a diplexer for use during duplex operation.

1962 November - .
  • Motorola to produce the Apollo spacecraft S-band transponder - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Communications. Collins Radio Company selected Motorola, Inc., Military Electronics Division, to develop and produce the spacecraft S-band transponder. The transponder would aid in tracking the spacecraft in deep space; also, it would be used to transmit and receive telemetry signals and to communicate between ground stations and the spacecraft by FM voice and television links. The formal contract with Motorola was awarded in mid-February 1963.

    Also, Collins awarded a contract to the Leach Corporation for the development of command and service module (CSM) data storage equipment. The tape recorders must have a five-hour capacity for collection and storage of data, draw less than 20 watts of power, and be designed for in-flight reel changes.


1962 December 28 - .
  • Radiation to develop the Apollo CM telemetry system - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Communications. North American selected Radiation, Inc., to develop the CM pulse code modulation (PCM) telemetry system. The PCM telemetry would encode spacecraft data into digital signals for transmission to ground stations. The $4.3 million contract was officially announced on February 15, 1963.

1962 December - .
  • Contract for Apollo CSM C-band transponder to American Car and Foundry - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Communications. The contract for the development and production of the CSM C-band transponder was awarded to American Car and Foundry Industries, Inc., by Collins Radio Company. The C-band transponder was used for tracking the spacecraft. Operating in conjunction with conventional, earth-based, radar equipment, it transmitted response pulses to the Manned Space Flight Network,

1963 January 8 - .
  • Existing C-band tracking radars to be modified to increase range for Apollo - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Communications. After studying the present radar coverage provided by ground stations for representative Apollo trajectories, North American recommended that existing C-band radars be modified to increase ranging limits. The current capability for tracking to 920 kilometers (500 nautical miles), while satisfactory for near-earth trajectories, was wholly inadequate for later Apollo missions. Tracking capability should be extended to 59,000 kilometers (32,000 nautical miles), North American said; and to improve tracking accuracy, transmitter power and receiver sensitivity should be increased.

1963 January 17 - .
  • Digital up-data link for Gemini acceptable for Apollo - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Communications. Christopher C. Kraft, Jr., of MSC's Flight Operations Division (FOD), advised ASPO that the digital up-data link being developed for the Gemini program appeared acceptable for Apollo as well. In late October 1962, representatives of FOD and ASPO had agreed that an independent up-data link a means by which the ground could feed current information to the spacecraft's computer during a mission was essential for manned Apollo flights. Kraft proposed that the Gemini-type link be used for Apollo as well, and on June 13 MSC ordered North American to include the device in the CM.

1963 May 22 - .
  • Grumman representatives met with the Apollo ASPO Electrical Systems Panel (ESP) - . Nation: USA. Program: Apollo. Spacecraft: Apollo LM; A7L; CSM Communications; LM Communications. Grumman representatives met with the ASPO Electrical Systems Panel (ESP). From ESP, the contractor learned that the communications link would handle voice only. Transmission of physiological and space suit data from the LEM to the CM was no longer required. VHF reception of this data and S-band transmission to ground stations was still necessary. In addition, Grumman was asked to study the feasibility of a backup voice transmitter for communications with crewmen on the lunar surface should the main VHF transmitter fail.

1963 June 10 - .
  • Up-data link (UDL) to be included on the Apollo LEM - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Communications; LM Communications. Christopher C. Kraft, Jr., of the MSC Flight Operations Division, urged that an up-data link (UDL) be included on the LEM. In general, the UDL would function when a great deal of data had to be transmitted during a time-critical phase. It would also permit utilization of the ground operational support system as a relay station for the transmission of data between the CM and LEM. In case of power failure aboard the LEM, the UDL could start the computer faster and more reliably than a manual voice link, and it could be used to resume synchronization in the computer timing system.

1963 June 21-27 - .
  • Avien to develop the steerable S-band antenna for the Apollo CSM - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Communications. Summary: North American awarded a contract, valued at $2.8 million, to Avien, Inc., to develop the steerable S-band antenna for the CSM..

1963 June 28 - .
  • Apollo CSM data storage equipment modified to incorporate a fast-dump capability - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Communications. Summary: The CSM data storage equipment was modified to incorporate a fast-dump capability. Data could thus be recorded at a low speed for later playback at high speed to ground stations..

1963 Week of August 22-29 - .
  • Ad Hoc Rendezvous Working Group formed - . Nation: USA. Program: Apollo. Spacecraft: Apollo LM; CSM Communications; LM Communications; LM Guidance. Summary: An Ad Hoc Rendezvous Working Group was formed at MSC to study the possibility of substituting a unified S-band system for the rendezvous X-band radar on the LEM and CSM..

1963 November 1 - .
  • Advantages outlined of Apollo CSM's HF transceiver capability - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Communications. MSC Flight Operations Division outlined the advantages inherent in the CSM's capability to use the HF transceiver during earth orbit. The HF transceiver would allow the CSM to communicate with any one tracking station at any time during earth orbit, even when the spacecraft had line-of-sight (LOS) contact with only one or two ground stations in some orbits. It would give the astronauts an additional communications circuit. Most important, this HF capability could alert the network about any trouble in the spacecraft and give the Flight Director more time to make a decision while the spacecraft was out of LOS communication with the ground stations.

1964 January 14 - .
  • Spacecraft communications problems - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Communications. At an MSC-North American meeting, spacecraft communications problems were reviewed. Testing had indicated that considerable redesign was essential to ensure equipment operation in a high-humidity environment. Also antenna designs had created several problem areas, such as the scimitar antenna's causing the CM to roll during reentry. The amount of propellant consumed in counteracting this roll exceeded reentry allowances. Further, because the CM could float upside down, the recovery antenna might be pointed at the ocean floor. In fact, many at this meeting doubted whether the overall communications concept was satisfactory "without having detailed ground receiver characteristics." The situation derived from "one of the primary problems in the area of communications system design . . . the lack of functional requirements specifications."

1964 January 17 - .
  • LEM missed rendezvous comm problems - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Communications; CSM Docking. Grumman was studying problems of transmitting data if the LEM missed rendezvous with the CSM after lunar launch. This meant that the LEM had to orbit the moon and a data transmission blackout would occur while the LEM was on the far side of the moon. There were two possible solutions, an onboard data recorder or dual transmission to the CSM and the earth. This redundancy had not previously been planned upon, however.

1964 February 17 - .
  • Motorola proposal for the Apollo Unified S-band Test Program - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Communications. Motorola, Inc., submitted a proposal to NASA for the Apollo Unified S-band Test Program, a series of tests on the unified S-band transponder and premodulation processor. Motorola had already begun test plans, analytical studies, and fabrication of special test equipment.

1964 October 1-8 - .
  • Spring-activated pop-up antenna for the Apollo CM - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Communications. Summary: North American switched to a spring-activated pop-up antenna for the command module (CM) high-frequency recovery radio..

1964 November 3 - .
  • ITTcontract for S-band acquisition receivers for Apollo ground-based dish antennas - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Communications. Summary: International Telephone and Telegraph Corporation (ITT) Federal Laboratories' Astrionics Center received a $125,000 contract from Collins Radio for the S-band acquisition receivers that position the ground-based dish antennas toward the spacecraft..

1964 December 8 - .
  • Communications during LEM and Apollo CSM rendezvous - . Nation: USA. Program: Apollo. Spacecraft: Apollo LM; CSM Communications; LM Communications. Representatives of MSC's Information and Electronic Systems Division, Flight Operations Division, Flight Crew Operations Division, Guidance and Control Division, Astronaut Office, and ASPO, Goddard Space Flight Center, and Bellcomm, Inc., met to discuss communications during LEM and CSM rendezvous.

    Capability of the Manned Space Flight Network (MSFN) to provide data for rendezvous was studied. Aaron Cohen of ASPO stated sufficient data could be collected, processed, and transmitted via MSFN to the LEM to achieve rendezvous. Dr. F. O. Vonbun of Goddard showed that MSFN data did little to improve data already available in the LEM before launch. Although five tracking stations would communicate with the LEM during ascent and the first 10 minutes of orbit, there would be only a slight improvement in spacecraft position and motion data over the data already contained in the LEM computer. No decision was made concerning the MSFN's capability.

    Alternate rendezvous methods were discussed.


1965 January 11 - .
  • Dalmo-Victor to supply antennas for Apollo CSM's - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Communications. North American selected Dalmo-Victor to supply S-band high-gain antennas for Apollo CSM's. (The deployable antenna would be used beyond 14,816 km (8,000 nm) from the earth.) Dalmo-Victor would complete the antenna design and carry out the development work, and North American would procure production units under a supplemental contract.

1965 February 24 - .
  • Contract to Collins for Apollo S-band telemetry equipment - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Communications. NASA awarded a $2,740,000 fixed-price contract to the Collins Radio Company for S-band telemetry equipment. Collins would install the equipment at three antenna facilities that supported Apollo lunar missions (at Goldstone, Calif.; Canberra, Australia; and Madrid, Spain).

1965 March 16 - .
  • Requirement deleted for relaying transmissions from astronaut via the Apollo LEM/CSM VHF link - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Communications. MSC eliminated the requirement for relaying, via the LEM/CSM VHF link, transmissions from a moon-exploring astronaut to the earth. This change allowed the 279.0 megacycle (Mc) transmitters in both vehicles to be eliminated; cleared the way for a common VHF configuration; and permitted duplex voice communications between astronaut and spacecraft. For communicating with the LEM, MSC directed North American to provide a 259.7 Mc transmitter in the CSM.

1965 March 25-April 1 - .
  • Common personal communications equipment for Apollo - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Communications. Summary: Crew Systems Division confirmed the feasibility of commonality of personal communications equipment for the entire Apollo program..

1965 April 19-26 - .
  • Meeting resolved all interfaces between the Apollo space suit and the two blocks of spacecraft - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; A7L; CSM Communications. North American, Hamilton Standard, Grumman, David Clark, and MSC representatives, meeting in Downey, California, resolved all interfaces between the space suit and the two blocks of spacecraft. As a result of these agreements, MSC directed North American and Grumman to make some minor changes (suggested by the Crew Systems Division) in the communications cables; to remove the portable life support systems from the CM; and to add a thermal-meteoroid garment - rather than one providing merely thermal protection - to the CM.

1965 June 3-10 - .
  • Programmer timer to be used for earth reacquisition by the Apollo CSM's S-band high-gain antenna - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Communications. Summary: MSC approved North American's recommendation that a programmer timer approach be used for earth reacquisition by the CSM's S-band high-gain antenna..

1965 June 24-July 1 - .
  • Report on modifications for lunar distance operating range for the Apollo CSM high-gain antenna - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Communications. Summary: Dalmo-Victor submitted to MSC a report on modifications necessary to extend to lunar distances the operating range of the CSM's high-gain antenna. The Instrumentation and Electronic Systems Division was reviewing the report..

1968 February 5 - .
  • 40 per-cent nitrogen prelaunch atmosphere in Apollo - . Nation: USA. Related Persons: Faget; Slayton. Program: Apollo. Spacecraft: Apollo CSM; CSM Communications. A Senior Flammability Review Board meeting at MSC reached a number of decisions on the CSM. Attending were Robert R. Gilruth, chairman; George M. Low, Kenneth S. Kleinknecht, Aleck C. Bond, Maxime A. Faget, Donald K. Slayton, Charles A. Berry, and Rodney G. Rose, all of MSC; Samuel C. Phillips, NASA Hq.; William B. Bergen and Dale D. Myers, North American Rockwell; and George Stoner, Boeing (nonvoting observer).

    Several previous action assignments were reviewed:

    1. Component level Flammability Test Program - North American reviewed the results of its material identification and test program, the component test program, and the boilerplate 1,250 tests. These tests had provided the basis for design decisions on selection and application of CM nonmetallic materials.
    2. Boilerplate 1224 configuration comparison to CSMs 2TV-1 and 101 - North American presented the comparison and the Board decided that the boilerplate configuration was representative of the "worst case" configuration, considering both 2TV-l and 101.
    3. Internal ignition rationale - ignition rationale for the boilerplate 1224 tests was presented to the Board. Nichrome wire ignitors were used with the ignitor wire embedded in potting. In some locations a Ladicote cover was applied over the potting and ignitor. The Board pointed out that the ignition techniques were not really representative of actual operating conditions and were indeed overly severe.
    4. Crew communications umbilical - North American was evaluating a fluorel crew communications umbilical as well as fluorel oxygen umbilicals. A Beta sleeve over the oxygen and crew communications umbilicals would also be evaluated for its operational acceptability by the Crew.
    The Board presented a review of test results. In the tests at pressure of 4.3 newtons per square centimeter (6.2 pounds per square inch) in a 95-percent oxygen atmosphere, there were 38 ignitions in boilerplate 1224. Of these,5 produced fires large enough to require further consideration. In tests at 11.2 newtons per sq cm (16.2 psia) in a 60-percent-oxygen and 40-percent nitrogen atmosphere, there were 31 ignitions. Of these, 4 produced fires large enough to require further consideration.

    The Board concluded that the material changes made in the CM had resulted in a safe configuration in both the tested atmospheres. The Board agreed "that there will always be a degree of risk associated with manned space flight," but the risk of fire "was now substantially less than the basic risks inherent in manned space flight."

    Among decisions reached were:

    1. the CSM 2TV-1 and 101 coaxial cable configuration would be tested in the 60-percent-oxygen and 40-percent nitrogen atmosphere;
    2. material improvements and testing would be continued and changes would be phased in, pending the availability of proved materials; and
    3. action would be taken to be prepared to use a 60-percent-oxygen and 40-percent-nitrogen prelaunch atmosphere in CSM 101.
    A final decision would be made at the Design Certification Review on March 7.

1968 March 8 - .
  • Apollo S-band high-gain-antenna system problems - . Nation: USA. Related Persons: Rees. Program: Apollo. Spacecraft: Apollo CSM; CSM Communications. Apollo Special Task Team Director Eberhard F. M. Rees wrote Dale D. Myers, Apollo CSM Program Manager at North American Rockwell, to convey the concern of ASPO Manager George M. Low and others over the status of the S-band high-gain-antenna system. (Of all the subsystems in the spacecraft, that antenna seemed to face perhaps the toughest technical and schedule problems.) On December 14, 1967, Rees had visited the subcontractor's plant (Dalmo Victor) at Belmont, Calif., and had heard optimistic status reports on the entire system, including quality control and delivery schedules. Shortly thereafter, when Dalmo Victor began quality testing, the company encountered serious technical difficulties and the delivery schedule, as Rees put it, "collapsed completely." He then recounted several efforts by analytical teams to pinpoint the technical problems and to put the program back into shape (including reviews in mid-February and again on March 1, when very little progress could be seen). This record of inability to remedy technical problems, said Rees, indicated a serious weakness among Apollo contractors regarding visibility of their programs as well as their analytical engineering capability.

1968 March 21 - .
  • Continuing problems with the Apollo high-gain antenna - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Communications. In an effort to resolve the continuing technical and schedule problems with the high-gain antenna system at Dalmo Victor, Apollo CSM Program Manager Dale D. Myers named a Resident Subsystem Project Manager at the vendor's plant. This change provided a single management interface with Dalmo Victor. The representative had been given authority to call on whatever North American Rockwell resources he might need to accomplish program objectives.

1969 August 13 - .
  • Antenna for Apollo communications on the lunar surface suggested - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Communications. S. C. Phillips, NASA Hq., suggested that for communications on the lunar surface a long, deployable antenna might work. He suggested that an antenna about 30 meters long could be used. The antenna would be rolled up like a tape measure and would curl into a cylinder when deployed, somewhat like an antenna that had been used on the CSM.

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