January 3

The Aerospace Safety Advisory Panel, at the request of the NASA Administrator, undertook an extensive review of the Skylab Program. Priorities in the review were given to the activities and systems deemed to he most critical to crew safety [291] and mission success:

• Contractor development and manufacture of Skylab modules and associated NASA management activities. (This included factfinding trips to principal contractor and NASA management Centers.)
• NASA management activities for the evaluation of design and hardware maturity and mission operations planning and preparation.

The Panel was satisfied with the technical management system for development and fabrication of the modules, spacecraft, and launch vehicles; the design and hardware acceptance reviews; and preparations for and execution of mission operations. They felt that the NASA/industry team was mature and that it was applying careful planning and responsible management to the hardware, software, and checkout operations. However, some mission operational areas, cluster change control, and integrated testing would require continued future emphasis. Some of these specific areas were contractor policies for joint operational activities; fire extinguishment and toxicity controls; and flammability of materials. Following the presentation of the written report, the Panel, by letter of 26 January 1973, was requested by George M. Low (NASA Hq) to continue the review and provide comments before each Skylab flight. This would include consideration of prelaunch activities, test, and checkout activities, mission preparations, and the areas identified in the study as warranting continued emphasis. The Panel would also review mission operations for each flight to assess the basis for confidence in mission operation for the next flight. In this area, the Panel conducted a comprehensive review of MSC operations activities on 12 and 13 March 1973.

Panel personnel were Carroll H. Dunn, chairman; Frank C. DiLuzio, Henry Reining, Jr., Bruce T. Lundin, John A. Hornbeck, and Harold M. Agnew, members; William A. Mrazek, consultant; and Gilbert L. Roth, Carl R. Praktish, V. Eileen Evans, staff.

Volume I, Summary Report to the Administrator by the NASA Aerospace Safety Advisory Panel on the Skylab Program, January 1973; letters, C. H. Dunn to J. C. Fletcher, NASA Hq, 4 January 1973; C. A. Berry, NASA Hq, to Director, Skylab Program, NASA Hq, "Skylab Between Mission Durations," 14 February 1973; memoranda, D. D. Myers, NASA Hq, to the Administrator, "Third Annual Report of the Aerospace Safety Advisory Panel," 27 June 1972; W C. Schneider, NASA Hq, to Associate Administrator for Manned Space Flight, "Comments on Third Report of the Aerospace Safety Advisory Panel," 26 June 1972; G. L. Roth to Manager, Skylab Program, MSC, "MSC Review," 14 February 1973; JSC (formerly MSC), "Skylab Program Office Weekly Activity Report," 16 March 1973.

January 10

At a Manned Space Flight Management Council meeting, William C. Schneider (NASA Hq) emphasized the mounting pressures from open work at KSC and the demanding schedule for integrated systems testing during February and March. As examples he cited the following areas:

February	ATM system verification
	AM/MDA/OWS end-to-end system test
	SL-2 (first manned Skylab launch) vehicle roll
[292] March	Stowage and crew compartment fit and function review
	SL-1 and SL-2 flight readiness test

Summary of Action Items, Manned Space Flight Management Council, 10 January 1973.

January 15

At a NASA general management review, Dale D. Myers summarized Skylab problems which were aggravated by a requirement to replace a control and display panel in the multiple docking adapter-one of the pacing program items. He told the general management review group that confidence in the ability to maintain an April launch date was slipping. Following the review, a decision was made to delay the launch of SL-1 and SL-2 until May 1973, with tentative launch dates of 14 and 15 May. An evaluation of launch intervals between SL-2 and SL-3 and between SL-3 and SL-4 was being made to determine if an approximate recovery date of 21 December 1973 could be maintained.

TWX, William C. Schneider, NASA Hq, to MSC, MSFC, KSC, and GSFC, "Skylab Planning," 22 January 1973; OMSF, "Summary of January Action Items " 10 February 1973; memorandum, Dale D. Myers, .NASA Hq, to the Administrator, "Rescheduling of Skylab I Workshop Launch," 24 January 1973.

January 17-19

A three-day mission planning simulation was conducted at MSC. Work was underway to resolve the problems identified during the simulation. Consideration was also being given to replacing the planned two-day on-orbit simulations with three-day simulations. A decision on this change would be reflected in a revised mission planning simulation schedule.

MSC, "Skylab Program Office Weekly Activity Report," 26 January 1973.

January 19

MSFC began implementation of a plan for preparation and storage of unassigned Saturn hardware, phaseout of the Saturn V production capability, and amendment of the facility operations contract at the Michoud Assembly Facility for minimum surveillance of stored hardware.

Letter, E. F. M. Rees, MSFC, to Dale D. Myers, NASA Hq, "January Management Council Meeting," 19 January 1973.

January 19

A design certification review was held at KSC. Primary and supporting Center responsibility was assigned for certain action items. Input from the supporting Center would be utilized by the Center having primary responsibility in generating the closeout information for the action. In the majority of the action items, KSC was assigned primary responsibility, with MSFC providing support.

Letters, William C. Schneider, NASA Hq, to MSFC, MSC, and KSC, "Launch Complex 39 Delta DCR and Integrated SWS and Launch Vehicle GSE/ESE DCR Action Items," 30 January 1973; William C. Schneider to Dist., same title, 22 February 1973; William C. Schneider to Associate Administrator for Manned Space Flight, "DCR Action Items," 22 March 1973.

January 19 - February 2

[293] KSC processing of SL-1 and SL-2 was progressing as planned. The Workshop and its associated modules were successfully stacked 29-31 January. No major problems were encountered in the SL-2 processing. Propellant loading and unloading, facilities, and ground support equipment tests were conducted on the Saturn IB launch vehicle at Pad B. Following tests, the vehicle was rolled back to the Vehicle Assembly Building. Prime and backup crews completed manned altitude chamber tests of the SL-2 command and service modules on 19 January, following which the spacecraft was moved to the Vehicle Assembly Building where it would be erected on the S-IB.

"Skylab Engineering Weekly Highlight Reports," 1, 8, and 16 February 1973; Manned Space Flight Management Council, "Summary of Proceedings," 14 February 1973.

January 22

An ATM calibration rocket systems launch was accomplished at the White Sands Test Facility in New Mexico. The launch was one of a series to qualify the calibration rocket program before the Skylab missions.

MSFC, "Skylab Weekly Activity Report," 23 January 1973.

January 24

An evaluation to determine the impact of changing the Skylab 1 and 2 launch dates indicated that the greatest impact was on the crew training activities. The evaluation indicated that the star charts aboard the Orbital Workshop were launch-date dependent. Changeout packages were being prepared for the star charts which would be carried in the command module. Changeout packages were also being prepared for the rendezvous book, the ATM systems checklist and data book, the flight plan, and the flight plan sequence for the activation and deactivation checklist.

MSC, "Skylab Program Office Weekly Activity Report," 2 February 1973; JSC, "Skylab Program Office Weekly Activity Report," 23 February 1973.

January 26

MSFC Director Eberhard F. M. Rees retired. He had served as Director since 1 March 1970. Rocco A. Petrone, NASA Apollo Program Director, became the new MSFC Director.

MSFC PAO; Marshall Star, 17 January 1973.

January 29-30

Checkout of the AM/MDA and ATM flight units was completed at KSC, and the units were mated to the launch vehicle.

MSFC, "Weekly Activity Report," 30 January 1973.

February 5

A customer acceptance readiness review for the Skylab television system was completed at Westinghouse Electric Corporation, Baltimore. The unit was being assigned to the qualification test program for testing.

MSC, "Skylab Program Office Weekly Activity Report," 9 February 1973.

February 12

The Manned Space Flight Management Council acting in the capacity of a design certification review board completed the following Skylab Program reviews:

Saturn launch vehicles	7-8 June 1972
Command and service modules and MSC experiments	10-11 Aug. 1972
Mission operations	15 Sept. 1972
MSFC modules and experiments	2-3 Oct. 1972
Cluster systems	19 Oct. 1972
Launch Complex 39 and integrated ground and electrical support equipment	19 Jan. 1973

The adequacy of the design performance requirements and verification programs for Skylab vehicles, spacecraft, modules, experiments, cluster systems, launch complex and ground support equipment, and mission operations planning were examined to certify that equipment and operational elements could safely accomplish the planned Skylab mission.

Memorandum, Dale D. Myers, NASA Hq, to the Administrator, "Skylab Design Certification Reviews," 12 February 1973.

February 14

At a Manned Space Flight Management Council meeting, William C. Schneider (NASA Hq) summarized the results of a Skylab study on launch interval options. The purpose of the study had been to assess the potential effect of reducing the interval between SL-2 and SL-3 by 5 days and between SL-3 and SL-4 by 10 days. The study indicated concern about launch abort lighting, night recovery, and circadian rhythm on SL-4 and about a reduction in the mission planning cycle between SL-3 recovery and SL-4 launch to 27 days. The Council accepted [295] Schneider's recommendation to retain the previously scheduled launch intervals shown below. Planning would proceed on that basis.

Mission	Launch	Recovery*
.
Skylab Workshop (SL-1)	May 14, 1973	-
First manned mission (SL-2)	May 15,1973	June 12, 1973
Second manned mission (SL-3)	Aug. 8, 1973	Oct. 3, 1973
Third manned mission (SL-4)	Nov. 9,1973	Jan. 4, 1974
------------------------------------
*No nighttime recoveries were planned.

Manned Space Flight Management Council, "Summary of Proceedings," 14 February 1973; TWX, William C. Schneider to MSC, MSFC, KSC, and GSFC, "Skylab Planning," 16 February 1973.

February 15

The North American Rockwell Corporation and Rockwell Manufacturing Corporation merged to become Rockwell International Corporation.

Telecon, R. Newkirk, Historical Services and Consultants Co., to Lyle Burt, Rockwell International, 15 October 1974.

February 17

The Manned Spacecraft Center at Houston, Texas, was officially redesignated the Lyndon B. Johnson Space Center in honor of the late President.

MSC Announcement 73-34, 17 February 1973.

February 19

Astronaut Robert A. R. Parker was designated Skylab Program Scientist and would be responsible for ensuring that the inflight Skylab science requirements to be implemented by flight operations elements were compatible with NASA and Skylab program requirements. John R. Sevier served as Assistant Program Scientist. Parker was assigned to Skylab Program Manager Kenneth S. Kleinknecht and during actual mission operations would respond to the directions of the Skylab Program Director and the MSC and MSFC Skylab Program Managers.

MSC Announcement No. 73-32, "Key Personnel Assignment," 2 March 1973.

February 20

The OWS high-fidelity mockup arrived at MSFC from McDonnell Douglas, Huntington Beach. It was updated for use as a systems engineering mockup along with an AM/MDA and the ATM dynamic test articles, which were modified at MSFC for this use.

MSFC, "Weekly Activity Report," 27 February 1973.

February 22-23

A customer acceptance readiness review for Skylab flight food was held at Whirlpool Corporation in St. Joseph, Michigan. Items of OWS were accepted. However, the CSM flight and backup food were not accepted because of lack of [296] stowage definition and the required stowage drawings in the data pack. This food would be accepted when the stowage arrangement in the CSM was defined.

JSC, "Skylab Program Office Weekly Activity Report," 2 March 1973.

February 27 - May 25

The Skylab 2 spacecraft, mated to its launch vehicle, was transferred 27 February from the KSC Vehicle Assembly- Building to Launch Complex 39B in preparation for launch. The SL-2 space vehicle consisted of the following major components: an S-IB (the first stage); an S-IVB (the second stage, which comprised the propulsion stages); an IU; a CSM; and an SLA. The next five paragraphs trace the SL-2 from the arrival of the component parts at KSC through liftoff.

The S-IVB stage had arrived at KSC' on 24 June 1971 and was placed in storage until 17 April 1972. The CSM arrived on 19 July 1972 and was immediately moved into the Operations and Checkout Building for systems testing. The S IB and the IU both arrived on 22 August 1972. On 5 September 1972 the S-IVB was mated to the S-IB. Three days later, 8 September 1972, the IU was mated to the S-IVB.

Since SL-2 was the first Saturn IB space vehicle to be launched from LC-39, it was necessary to verify the modified facilities and systems. Therefore, the SL-2,....

[297] ...with a boilerplate spacecraft, was moved to LC-39B on 9 January 1973. The mobile service structure was positioned on 12 January 1973, and the fit, function, and facility systems tests required in support of the SL-2 launch were performed. The Propellant Loading All Systems Test was performed on 29 and 30 January, 1973. The SL- 2 was then returned to the Vehicle Assembly Building.

On 9 February 1973 the SLA was mated to the CSM. The CSM/SLA was then moved to the Vehicle Assembly Building on 20 February 1973 and mated to the launch vehicle the following day. Transfer of the SL-2 to LC-39B was completed 27 February

The space vehicle Flight Readiness Test was completed on 5 April 1973. The Countdown Demonstration Test began on 25 April 1973. At 0:00 a.m. EDT 9 May 1973, the launch countdown for SL-2 was started.

Because of the meteoroid shield anomaly and failure of the solar wings to deploy on the Workshop, the SL-2 launch was scrubbed on 14 May 1973 at T minus 14 hours 35 minutes (9:10 p.m. EDT 14 May), and scrub turnaround procedures started. The countdown clock was then held at T minus 59 hours until countdown resumed at 10:30 p.m. EDT 22 May 1973. SL-2 was successfully launched at 9:00 a.m. EDT on 25 May 1973 (see 25 May 1973 entry).

KSC, "Skylab 2 Post-Launch Report," 21 June 1973, pp. 7-1, 7-2.

February 28

During a news conference in Washington, Charles "Pete" Conrad, first manned Skylab mission commander, reviewed activities that would be conducted during the SL-2 mission.

NASA News Release, "Press Conference with Pete Conrad," 28 February 1973.

March 1

MSFC Director Rocco A. Petrone initiated an MSFC flight hardware integrity review at MSFC and contractors' facilities. The purpose of the review was to ensure integrity of MSFC-developed hardware by examining in-depth specifications, design and design changes, failures, and test results of critical hardware components and systems associated with the activation sequences. The review was scheduled to be completed before the MSFC preflight readiness review meeting in mid-April.

MSFC, "Weekly Activity Report," 20 March 1973.

March 8

Following two lightning strikes on Apollo 12 while in flight and a strike on the launch umbilical tower while Apollo 15 was on the launch pad, an intra-Center telecon with participation from NASA Hq, KSC, JSC, and MSFC was held to discuss previous studies on lightning. It was determined that analyses and corrective actions accomplished since the strikes on Apollo 12 had reduced to a very low probability the chance of system damage to Skylab vehicles from lightning strikes.

[298] Memorandum for record, H. Wong, NASA Hq, "Lightning Strikes," 8 March 1973.

March 8

During a meeting of the Manned Space Flight Management Council, R. C. Hock (KSC) summarized the major test milestones completed and those remaining to be completed on SL-1 and SL-2 in order to meet the launch planning dates of 14 and 15 May 1973.

KSC Presentation Outline for MSF Management Council, 8 March 1973; Manned Space Flight Council, "Summary of Agreements and Action Items," 8-9 March 1973.

March 19

Consideration was being given to the feasibility of a second set of Skylab missions (designated Skylab-B) during the interval between the Apollo-Soyuz Test Project in 1975 and the start of Space Shuttle operations late in 1979. The inherent worth of a Skylab-B was recognized, but officials were reluctant to recommend it, on the premise that it would be unwise to allow it to delay or displace the development of the Space Shuttle and other programs already included in the FY 1974 budget.

Letter, James P. Fletcher, NASA Hq, to Lowell P. Weicker, Jr., U.S. Senate, 19 March 1973; note, William C. Schneider, NASA Hq, to Dale D. Myers, NASA Hq, "Skylab-B Planning," 15 March 1973; memorandum, William C. Schneider to Deputy Director, Budget and Program Analysis, "Request for Answer Regarding Skylab-B," 19 March 1973.

March 20

To reduce the possibility of fire hazards onboard spacecraft, NASA adopted a rigid materials selection and control program based on elimination of flammable materials and substitution of nonflammable or self-extinguishing materials wherever possible. Where this was not possible, flame propagation paths were eliminated. In addition, a two-gas system was adopted, fire sensors were added to the caution and warning system, fire extinguishers were installed in all elements of the Skylab cluster, and crews were trained in fire-fighting and evacuation methods.

Memorandum, Dale D. Myers, NASA Hq, to the Administrator, "Full-Scale Flammability Testing on Skylab," 20 March 1973.

March 25-30

The Skylab flight hardware successfully completed the first total mission operations sequence during the mission simulation and flight readiness test at KSC. The test included the SL 2 astronaut crew participation in the simulated launches of SL-1 and SL-2, mission activation and operation, deactivation, data dump, and powerdown.

KSC Skylab Spacecraft Integrated Daily Schedule, 30 March 1973.

March 28

The USNS Vanguard, a part of NASA's Space Flight Tracking and Data Network, departed Port Canaveral, Florida, for temporary duty at Mar del Plata, Argentina. The ship would provide a two- way flow of information and communication....

[300] ...between Skylab and Mission Control Center in Houston via Goddard Space Flight Center. Upon completion of the Skylab Program, it would return to Port Canaveral. The Vanguard was originally designed to provide tracking and data acquisition for the Apollo flights. It played an important role in the Apollo Program.

GSFC News Release, "Vanguard Tracking Ship to Argentina for Skylab Support," 28 March 1973; Cocoa, Florida, Today, 28 March 1973, pp. 1B, 2B.

March 29

An agreement was published which provided for the optimum utilization of resources in programs and projects in which both JSC and MSFC had development roles. It would permit the direct application of each Center's institutional resources for the benefit of visiting members from the other Center.

"MSC (sic)/MSFC Inter-Center Agreement on Institutional Resources," 29 March 1973.

April 3

An ATM Naval Research Laboratory rocket calibration launch was unsuccessful due to two major discrepancies. l he guidance system failed to work properly and the recovery system failed. The launch was a qualification test flight of the rocket vehicle, science package, and support equipment which would he flown during the manned Skylab mission to calibrate the Naval Research Laboratory instrument in the ATM. This calibration would establish the amount of misalignment or degradation of the optics, if any, in the ATM instrument due to the launch environment or contamination. Investigations were initiated to determine the causes of the failures.

Memorandum, William C. Schneider, NASA Hq, to Associate Administrator for Manned Space Flight, "Skylab/ATM Calibration Rocket NRL Qualification Launch," 9 April 1973.

April 3

Studies were conducted to determine the feasibility of conducting a controlled deorbit of the Orbital Workshop. Three methods were considered: (l) using the CSM service propulsion system; (2) using the CSM reaction control system; and (3) implementing an S-II (Saturn V second stage) deorbit. The service propulsion system deorbit was assessed as not feasible; the reaction control system deorbit was considered technically feasible but, like the service propulsion system, it had an inherent program and crew safety risk associated with it. Implementation of an S-II deorbit would have serious time and cost impacts on the program. A 1970 study, which indicated that the probability of damage from the deorbiting Skylab was so small that changes which caused major impact in cost and schedule were not worth pursuing, was confirmed.

TWXs, William C. Schneider, NASA Hq, to MSFC and JSC, "OWS Deorbit," 2 March 1973; William C. Schneider to MSFC, JSC, and KSC, "SWS Deorbit," 30 March 1973; letter, Leland F. Belew and R. G. Smith, MSFC, to Director, Skylab Program, "SWS Deorbit," 12 March 1973; memoranda, William C. Schneider to Associate Administrator for Manned Space Flight, "SWS and S-II Deorbit," 3 April [301] 1973; Dale D. Myers, NASA Hq, to Administrator, "Deorbit of Skylab Elements," 2 May 1973; Dale D. Myers to Administrator, "Workshop Deorbit," 23 June 1973.

April 4-5

Reporters and commentators from the United States and several foreign countries attended a series of Skylab news briefings at MSFC. MSFC Director Rocco A. Petrone and MSFC Skylab Program Manager Leland F. Belew gave a general presentation on the program. They were followed by a series of presentations by specialists on the various systems, experiments, and research efforts connected with the Skylab missions. Tours of the high-fidelity mockup and the neutral buoyancy simulator were included during the two days.

MSFC PAO, Marshall Star, 11 April 1973.

April 5

The planning dates of 14 and 15 May 1973 were officially confirmed as the launch dates for SL-1 and SL-2, respectively. The launch planning date for SL-3 continued to be 8 August 1973; for SL-4, 9 November 1973.

TWX, William C. Schneider, NASA Hq, to JSC, MSFC, KSC, and GSFC, "Firm Launch Dates for SL-1 and SL-2," 5 April 1973.

April 13

A miniature, fast, analytical clinical laboratory developed by the Atomic Energy Commission's Oak Ridge National Laboratory for use on manned space stations was undergoing laboratory tests at JSC. It was expected that the new system would subsequently be used in clinical situations. The analyzer would provide a pediatrician with the capability of rapidly completing 12 simultaneous analyses of an infant through the use of only a drop of blood compared to as much as five cc's required by single analyzers. Tests would be performed in the doctor's office, with the results available within minutes. The same would apply for geriatric patients, emergency room patients, and accident victims where rapid multiple diagnoses with minimum blood samples were vital.

JSC News Release 73-37, "Analyzer Has Spinoff Potential," 13 April 1973.

April 16-19

Loading of the Apollo spacecraft's hypergolic propellants for a scheduled 15 May launch was completed at KSC. The next major milestone in preparing the Saturn IB/Apollo for launch would occur 23 April when the kerosene to fuel the Saturn IB booster's eight engines would be pumped aboard the first stage.

KSC News Release 75-73.

April 16 - May 13

The Skylab 1 spacecraft on its launch vehicle was moved to Launch Complex 39, Pad A, on 16 April. The SL-1 space vehicle consisted of two launch vehicle stages, an instrument unit, and the three major payload modules of the Saturn Workshop (SWS). The two launch vehicle stages and IU (S-IC, S-II, and S-IU) were identical to the first and second launch vehicle stages of the Apollo Saturn V space vehicle. The SL-1 payload consisted of the Orbital Workshop [302] (a converted S-IVB stage), airlock module/multiple docking adapter, Apollo telescope mount, payload shroud, nose cone, and experiments.

The S-II stage had been the first to arrive at KSC, on 1 April 1971, and was placed in storage. The stage underwent modifications for approximately one year. On 16 July 1972, the S-IC stage had arrived and was erected on Mobile Launcher 2 on 2 August. The S-II stage was mated to the S-IC stage on 20 September.

Both the ATM and the OWS arrived at KSC on 22 September 1972. The ATM was moved into the Operations and Checkout Building cleanroom, checked out, and moved to the Vertical Assembly Building. The OWS was moved to the Vertical Assembly Building and stacked on 29 September. On 26 October, the IU stage arrived at KSC; it was mated to the OWS on 1 November. The AM/MDA arrived at KSC on 6 October and was moved into the Operations and Checkout Building. Docking tests between the SL 2 CSM and the AM/ MDA were conducted. The AM/MDA was flight-mated to the fixed airlock shroud (FAS) and docking adapter (DA), and on the following day the AM/ MDA/FAS/DA was mated with the payload shroud. This section of the payload was then moved to the VAB and was mated to the OWS. The ATM was mated to the DA on 30 January 1973.

System testing began on the payload modules and the launch vehicle stages. Testing included both intra- and intermodule/stage testing, including SWS mission simulation flight readiness test and launch vehicle flight readiness test. The nose cone was installed on 8 April, and SL-1 transfer to Pad A was completed on 16 April.

High winds delayed the connection of environmental control system air and prevented internal access to the spacecraft until late on 17 April.

Skylab 1 countdown demonstration test started at T minus 123 hours at 7:00 p.m. EDT, 26 April. Final stowage of the ATM cameras and film in the MDA stowage locker and flight closeout of the MDA was completed on 27 April. Final closeout of the AM/MDA was completed on 1 May, and the EVA hatch was secured for flight.

Launch countdown began at 2:00 a.m. EDT, 9 May. A small amount of rain fell into the ATM area during a thunderstorm that day, but affected areas were temporarily covered. High winds prevented further weatherproofing of the payload shroud nose cap until 10 May. The Mobile Launcher 2 lightning mast was struck by lightning at 12:57 p.m. EDT on 9 May. Lightning retest operations on the launch vehicle and spacecraft were successfully completed. No anomalies attributed to the lightning were noted.

KSC, "Skylab 1 Post-Launch Report," 8 June 1973, pp. 7-1, 7-2.

April 17

[303] NASA Hq issued a policy instruction on accountability for experiment materials returned from the Skylab missions. The purposes of the instruction were to ensure the integrity of the experimental data in the returned material and to prevent loss, theft, or unauthorized use or disposition of such material.

Skylab Program Directive No. 61, "Skylab Policy on Accountability for Experiment Materiel Returned from the Skylab Missions," 17 April 1973.

April 17-20

The final NASA top management review and approval of the launch and mission readiness was completed in a flight readiness review at KSC. Items covered in the review ranged from modules and launch vehicles readiness to missions and operations support. Following the review, NASA Skylab Program Director William C. Schneider said, "We still have a few things to be closed out, but we have assured ourselves that the systems are all working with one or two minor open items and we're still ready to go for a 14 May launch of Skylab 1 and a 15 May launch of Skylab 2."

Transcript.

April 18

KSC and MSFC were directed by NASA Hq to implement a reduction in force of contractor personnel immediately following the launches of SL-1 and SL-2, but to maintain a sufficient complement for a backup launch capability through 30 September 1973.

TWX, William C. Schneider, NASA Hq, to KSC, MSFC, and JSC, "Post SL-1/2 Launch Manpower Planning," 18 April 1973.

April 25

Since the adjustment of the Skylab launch dates, KSC updated rescue response times. The new SL-R rescue response times are shown in the following table:

Letter, R. C. Hock, KSC, to Dist., "Skylab Rescue," 25 April 1973.

May 1

Individual and group behavioral evaluations, which were discontinued following the 14-day flight of Gemini VII , were being reinstituted for the Skylab flights because of the longer duration of the SL-2, 3, and 4 missions. Information obtained from these evaluations would provide additional data useful in future diversified crew selection and expected performance in future long-duration flights.

Letter, Dale D. Myers, NASA Hq, to Christopher C. Kraft, Jr., MSC, "Behavioral Evaluation of Skylab Crews," 1 May 1973.

May 3

Three types of private conversations were authorized for Skylab missions by the NASA Administrator: private phone calls from astronauts to their families once a week, conversations required by extreme operational emergency, and routine medical conversations. In the cases of operational emergency and medical conversations, bulletins would be issued to the news media. Bulletins or public announcements of crew member conversations with their families would not be made.

Memorandum, James C. Fletcher, NASA Hq, to the Associate Administrator for Manned Space Flight and the Assistant Administrator for Public Affairs, "Private Communications for Skylab," 3 May 1973; NASA News Release 73-110, "Fletcher Statement on Skylab Private Communications," 1 June 1973.

May 8

A fund of unsolicited cash contributions, which started in 1959 and contained $5548, would be used to defray the cost of equipment for student scientific experiments on Skylab. NASA was authorized by the Space Act of 1958 to accept unrestricted gifts.

NASA Hq News Release 73-98, "NASA Gift Fund Used for Skylab Student Experiments Program," 14 May 1973.

May 9

Lightning struck the Skylab 1 launch umbilical tower near swing arm eight at 1:00 p.m. Lightning retest plans were satisfactorily completed on the AM, MDA, and ATM. No significant anomalies due to the lightning static were revealed.

"Skylab Engineering Weekly Status Report," 9 May 1973.

May 14

Skylab 1, the unmanned Orbital Workshop (OWS) was launched from KSC Launch Complex 39A at 1:30 p.m. EDT. (See item for 16 April 13 May for countdown detail.)

An unexpected telemetry indication of meteoroid shield deployment and solar array wing 2 beam fairing separation was received 1 minute and 3 seconds after liftoff. However, all other systems of the OWS appeared normal, and the OWS was inserted into a near-circular Earth orbit of approximately 435 km altitude.

The payload shroud was jettisoned, and the ATM with its solar array was deployed as planned during the first orbit. Deployment of the Workshop solar [306] array and the meteoroid shield was not successful. Evaluation of the available data indicated that the following sequence of events and failures occurred:

Time from Liftoff (hr:min:sec)	Event
.
0:01:02.9	Meteoroid shield tension strap 2 separated.
0:01:03	Meteoroid shield tension strap 1 and 3 separated.
0:01:03	Solar array system wing 2 beam fairing separated.
0:01:30	Meteoroid shield temperatures went off-scale.
0:01:30	Partial deployment of meteoroid shield was indicated.
0:10:00	Thermal measurements on wing 2 solar array panels ranged from 345 K (161°F) to 389 K (240°F), rather than the expected temperature of about 300 K (80°F). Wing 1 temperatures remained normal.
0:55:55.9	Wing 1 beam fairing separated.

Solar array wing 1 was released, but there were indications that the wing had not fully deployed. Wing 2 was inoperative or had encountered structural failure. Temperature excursions in the OWS showed that the meteoroid shield was not affecting the temperatures as intended. The remainder of the planned Workshop system activation and deployment functions occurred as scheduled with transfer of attitude control from the instrument unit to the OWS approximately 41/2 hours after liftoff.

The OWS was maneuvered into a solar inertial attitude, with the plane of the solar arrays normal to the Sun for maximum electric power generation. The OWS area temperature then rose above operating limits. The Workshop was subsequently pitched up toward the Sun at 13 hours into the flight to reduce the solar incidence angle on the OWS area. This attitude further reduced the power generation capability which had already been severely limited by the loss of the Workshop solar array wing 2 and the failure of wing 1 to deploy. A continuing adjustment of attitude was necessary to keep the power and temperature within acceptable limits. Constraints to maintain adequate heat in other critical areas of the Workshop and to optimize the operation of the attitude control system in an off-nominal mode added further complications. This delicate balance continued for approximately 10 days.

The electrical power available from the ATM solar array was further reduced by the requirement to cycle certain power regulator modules on and off to [307] prevent the overheating caused by unplanned vehicle attitudes. Although considerably below the total design capability of approximately 8500 watts, the power was sufficient for the critical loads. Many components and systems were turned off or were cycled as required to remain within the power generation capability.

The high internal temperatures that were reached in the Workshop could have caused outgassing of some materials which would have been hazardous to the crew. Therefore, before crew arrival, the habitation area was depressurized and repressurized four times with nitrogen to purge the outgassing products. The final repressurization was with the proper oxygen/nitrogen mixture for the crew.

Maneuvering into and out of the various thermal control attitudes and maintaining attitude hold and control during several docking attempts caused a much larger use of the Workshop thruster propellant than predicted. Sufficient propellant remained, however, for the three manned missions.

JSC, Skylab Mission Report First Visit, JSC-08414, August 1973, pp. 2 and 4; JSC, "Skylab Program Office Weekly Activity Report," 18 May 1973.

May 22

A Skylab 1 Board of Investigation was established to investigate the anomalies that occurred during the launch and Earth orbit of SL-1. Bruce T. Lundin (Lewis Research Center) was named chairman of the Board.

Letter, James C. Fletcher, NASA Hq, to Bruce T. Lundin, "Skylab 1 Investigation Board," 22 May 1973; memorandum, James C. Fletcher to Associate Administrator for Manned Space Flight, "Investigation of Skylab 1 Anomalies," 22 May 1973; NASA Notice 1154, "Skylab 1 Investigation Board," 22 May 1973.

May 23

NASA Administrator James C. Fletcher briefed members of the Senate on the anomalies that occurred during liftoff and orbit of Skylab 1. Fletcher summarized as follows:

1. We encountered unexpected problems with the micrometeroid shield and the workshop solar arrays.

2. These problems led to overheating and reduced power.

3. We believe we can control the heating by one of several fixes executed by the crew of Skylab 2.

4. We will try to improve the power situation, but even if we can't, there is enough for nearly normal execution of the 28- and 56-day missions.

They are going to look at the condition of the solar panels. They are not going to spend too much time on that because we have enough power. If it looks like an easy thing to do, if one of the panels, which is missing here, is partially deployed and is hung Up on something and all it needs is a little tug, we will put a loop of twine around the end of it, play it out 50 that we are well away from the panel in case it starts to deploy, and give a little tug on the twine. If it deploys, fine; but if it does not, we will go on without it.

[308] But we are not going to spend too much time on that fix. There are too many uncertainties and we do not really need the power.

5. We will be unable to carry out some 3 out of the planned 87 experiments. This is normal for almost any test of this complexity. Usually we aren't able to complete the large number of experiments that are planned. In this particular case we estimate that three of them will not be able to be carried out. Those are primarily the ones that would have come out of the airlock. If there is a sunshade over the airlock you can't do very many experiments from it.

The remaining experiments, in our judgment, fully warrant going ahead with the repair activity and then executing as much of the fully planned program as possible.

6. There will be no relaxation of safety considerations in the conduct of the replanned Skylab missions.

7. We have established a Skylab I investigation board whose findings will be reported to the committee as soon as available.

In closing, let us say that the crew, the Skylab team, and NASA management are cautiously confident-some more than others, hut all are optimistic-that the Skylab 2 mission will be a historic one and that it will permit us to meet almost all of the major objectives of the Skylab program.

U.S. Congress, Senate, Committee on Aeronautical and Space Sciences, Skylab: Hearing on Status of Skylab Mission, 93d Cong., 1st sess., 23 May 1973, pp. 4-17.

May 23-24

A design certification review was held for the revised Skylab 2 mission. The review board determined that a "Skylab parasol," with a strengthened ultraviolet resistant material, deployed through the scientific airlock would be the prime method for the deployment of a thermal shield on the Orbital Workshop. A "twin pole" thermal shield and a standup extravehicular thermal sail would be flown as backup methods. Following final assessment of mission readiness with favorable recommendations, a certification of flight worthiness for the new hardware was executed.

Letters, William C. Schneider, NASA Hq, to SL-1 and -2 Flight Readiness Review Board, "Confirmation of Flight Readiness for SL-2 Launch," 31 May 1973; William C. Schneider to Dist., "Skylab Design Certification Review of New or Changed Equipment and Procedures for Revised SL-1/SL-2 Mission," 11 June 1973.

May 25

At 9:00 a.m. EDT, Skylab 2 lifted off from Pad B, Launch Complex 39 at KSC. The vehicle was manned by astronauts Charles "Pete" Conrad, Jr., Joseph P. Kerwin, and Paul J. Weitz.

Skylab 2 , consisting of a modified Apollo CSM payload and a Saturn IB launch vehicle, was inserted into Earth orbit approximately 10 minutes after liftoff. The orbit achieved was 357 by 156 km and, during a six-hour period following insertion, four maneuvers placed the CSM into a 424 by 415 km orbit for...

...rendezvous with the Orbital Workshop. Normal rendezvous sequencing led to stationkeeping during the fifth revolution followed by a flyaround inspection of the damage to the OWS.

The crew provided a verbal description of the damage in conjunction with 15 minutes of television coverage. The solar array system wing (beam) 2 was completely missing. The solar array system wing (beam) 1 was slightly deployed and was restrained by a fragment of the meteoroid shield. Large sections of the meteoroid shield were missing. Following the flyaround inspection, the CSM soft-docked with the OWS at 5:56 p.m. EDT to plan the next activities. At 6:45 p.m. EDT the CSM undocked and extravehicular activity was initiated to deploy the beam 1 solar array. The attempt failed. Frustration of the crew was compounded when eight attempts were required to achieve hard docking [310] with the OWS. The hard dock was made at 11:50 p.m. EDT, terminating a Skylab 2 first-day crew work period of 22 hours.

JSC, "Skylab Mission Report First Visit," JSC-08414, August 1973, p. 2-1; R. V. Gordon, JSC Skylab News Center, "Skylab 1/2 Quick Look Reference," 2 July 1973, p. 3.

May 26

The second manned day of the Skylab mission was focused on entry into the OWS and deployment of the Skylab parasol. The crew removed and inspected the docking probe and drogue. They then entered the MDA to activate the airlock module and MDA systems. The crew entered the OWS at 3:30 p.m. EDT. The atmosphere, although hot, was habitable, and the crew was able to work in the environment for 10- to 15-minute intervals. At 5:00 p.m. the crew began deployment of the parasol; the task was completed at 7:30 p.m.

The parasol provided thermal shielding for the area of the Workshop exposed to the Sun because of the missing meteoroid shield. The parasol concept, design, development, construction, and delivery to KSC was completed in seven days by JSC. Two other thermal protection devices were also devised and delivered during this same time period. One was a sail, produced by JSC and designed to be deployed by an extravehicular crewman standing in the command module hatch while the spacecraft was being flown in close to the OWS. The other, called a twin-boom sunshade and produced by MSFC, was designed to be deployed by extravehicular crewmen from the ATM station.

The parasol provided a thermal protective device which was simple, and deployment could be accomplished from within the OWS in a shirt-sleeve environment. The system was capable of being jettisoned.

The parasol concept made use of a spare experiment T027 (ATM contamination measurement) canister which was designed to interface with the solar scientific airlock. The seal design used in the back plate of the experiment canister was incorporated into a new back plate required for the parasol. This allowed the use of deployment rods which were of the same type used for experiment deployment, and also allowed use of the experiment T027 photometer ejection rod, if jettisoning became necessary.

Major components of the parasol, other than the modified canister, were a 6.7 by 7.3-m aluminized Mylar/nylon laminate canopy that was partially opaque to solar thermal energy, a canopy mast, a mast hub with deployment springs, four telescoping deployment rods, seven extension rods, and the experiment T027 canister support tripod.

Deployment was accomplished through the solar scientific airlock by attaching the extension rods to the mast and pushing the rod assembly outward. As the mast hub was extended to 4.9 m above the opening of the airlock, the telescoping deployment rods became fully extended and locked and the tip retainers....

....for the telescoping rods were released. The mast hub was then extended to 6.4 m above the outer surface of the OWS, allowing the rod tips to swing free of the solar scientific airlock opening and deploy the canopy. The parasol was then retracted to its final position a few centimeters above the OWS outer surface During the retraction process, the long extension rods were removed, and the short extension rod was left in place.

OWS temperatures started dropping immediately upon parasol deployment. The initial temperature drop for the outer wall exceeded 36 K (65°F) per hour. Temperatures within the OWS, though dropping at a much slower rate, were below 311 K (100°F) within a day of deployment. The inside temperature continued a steady decline until stabilization was reached somewhat below 297 K (75°F). At the end of the first visit, the temperatures increased because of the increase of daytime exposure for the orbital plane at that time of the year.

R. V. Gordon, JSC Skylab News Center, "Skylab 1/2 Quick Look Reference," 2 July 1973, p. 3; JSC, "Skylab Mission Report First Visit," JSC-08414, August 1973, pp. 2-2, 3-1, and 3-6; abstract, J. A. Kinzler, JSC, "The Skylab Parasol," ca. January 1974.

May 27

A Skylab Program Director's meeting was held to identify further actions required for the SL 2 mission and actions required for the SL-3 mission. The following agreements were reached:

• The parasol installed on the OWS would not be jettisoned until a replacement thermal shield was on board, if a twin-boom thermal shield had not been deployed during the SL-2 mission.
• The twin-boom sunshade and the JSC sail would be retained in the OWS at the end of the SL-2 mission.

"Minutes of Skylab Program Director's Meeting," 27 May 1973.

May 27 - June 22

[312] Following the successful deployment of the parasol, the Skylab-2 crew began to transfer and store equipment and activate experiments. On 29 May, everything in the OWS was turned on for the first time. The crew checked out the EREP and the ATM.

On 7 June astronauts Conrad and Kerwin performed an EVA to free the undeployed OWS solar array. EVA began at 11:15 a.m. EDT. At 2:01 p.m., the strap restraining the solar wing was severed, the beam was fully deployed, and the three panels had begun to deploy. The 3-hour 25-minute EVA was completed at 2:40 p.m. By 8:55 p.m., all the solar array system solar power sections were deployed, and the OWS power crisis had abated.

At 3:22 a.m. EDT, 18 June, the crew of SL-2 broke the space flight record of 570 hours 23 minutes set by the Soviet Soyuz 11 flight in June 1971.

During the SL-1/SL-2 mission, the following experiments were conducted:

• Medical-all medical experiments were successfully conducted with a completion range of 80 to 100 percent.
• Apollo telescope mount-82 hours of manned viewing time and 154 hours of ground commanded data gathering were accomplished.
• EREP-11 passes with a full range of instrument operation and task site assignments were completed. (Prelaunch planning called for 14 passes.)
• Corollary-56 hours of crew time were devoted to these experiments. (Prelaunch planning called for 64 hours.)

A breakdown of the actual crew time allocation for experiments as opposed to the preflight plan is shown in the following chart.

[313] TWX, G. S. Lunney, JSC, to American Embassy Science Attache, Moscow, U.S.S.R., 22 June 1973; R. V. Gordon, JSC Skylab News Center, "Skylab 1/2 Quick Look Reference," 2 July 1973; NASA Hq Post Launch Mission Operations Report No. M 960-SL-1/SL-2, 14 July 1973.

May 30

The following editorials were typical of those evoked by the launch of Skylab I with its attendant anomalies. The first editorial quoted is from the Los Angeles Times.

The men of NASA at Cape Kennedy and Houston were getting ready to pass another miracle, but there had been so many-the first men on the moon followed by a succession on moon landings-that the success of the latest adventure in space was taken for granted. Even the crowd of spectators on the cape was less than a quarter of the million persons who watched the last of the Apollo moon missions Dec. 7.

The launch went smoothly, as Skylab, an 85-ton vehicle perched atop a Saturn 5 rocket, ascended majestically May 14 from a roaring flame and disappeared into the heavens on its journey into orbit 270 miles above the earth. "Everything looks super-good so far," Mission Control in Houston reported, and Skylab, the largest weight ever thrust into space, began to respond to radio signals.

Minutes later, the $2.6 billion project was in trouble. Two solar panels failed to deploy. The launching of three astronauts, scheduled to dock in space with Skylab the next day, had to be postponed. Skylab 2 was recycled for five days until May 20 and again for May 25, last Friday. What was needed was a simple little plan to shield the space laboratory from the sun-something like an umbrella.

An umbrella. Why, of course, Jack Kinzler, a NASA technician with a reputation as a fix-it man, started thumbing through the Yellow Pages. He found what he was looking for-fishing poles that would telescope down to 18 inches. Using the poles as ribs, he and other technicians constructed an umbrella with a 24-by-28 foot expanse of coated nylon, designed so that the collapsed umbrella could be projected through an 8-by-8 inch airlock passage and deployed over the laboratory.

It was packed, handy-like, in a small metal box and placed in Skylab 2 when the three astronauts were launched into space for their delayed rendezvous with Skylab 1. The astronauts poked the umbrella through the airlock in careful stages. The gadget worked. [A more sophisticated version of Kinzler's idea was produced and flown.]

It wasn't much, really. Just a few fishing poles and a spread of nylon. In all, a modest little miracle, but enough. Enough to save Skylab and enough to give a lift to the spirit of all who followed the latest human drama enacted in space.

The following editorial is taken from Test magazine.

IN OUR PRESENT pre-occupation with consumer products and problems, it is easy to forget the miracles of our great space projects. Skylab's failures tend to bring space and space testing back into focus.

It is possible to speculate, as some authorities are doing already, that the damage done to Skylab on its way into orbit was due either to (a) the unanticipated [314] effects of vibration in the Saturn rocket or (b) the under-design of the failed Skylab components or (c) a combination of both.

In any event, it would seem likely that insufficient testing was done in the effort to live within what is generally considered to be a too-tight budget. After the vast achievements of Project Apollo, one would think that the accumulated knowledge of NASA as to how to achieve the essential near 100% reliability in a space flight would have caused NASA managers to throw out enough stern warnings to Congress and to the public about underfinancing and possible failures. In a project running to two and one-half billion dollars, perhaps another $250 million (10%), for example, for more testing and redesign might have made the difference. At this writing, three highly intelligent, highly trained, highly motivated men are out there trying with all their ingenuity and that of NASA to salvage some part of this all-important basic Skylab mission. Of course, their success in this attempt is fervently prayed for by everyone.

"A Modest Little Miracle," Los Angeles Times , 30 May 1973; R. H. Mattingley, Editor's Page, Test Magazine, June 1973.

May 31

During a Manned Space Flight Management Council telecon, four agenda items were discussed: an early launch date for SL-3; plans for an EVA solar array system repair; deorbiting of the Skylab cluster; and lengthening the SL-2 mission.

The Council decided to go for a 27 July launch date, with the possibility of a further acceleration on a crash effort basis to 22 July if possible degradation of hardware because of unexpected thermal stresses required an earlier launch. Decisions on the other three agenda items were deferred pending further study.

"Minutes of Management Council Telecon," 31 May 1973; memorandum, Dale D. Myers, NASA Hq, to Associate Administrator through Deputy Administrator, "Launch Date for SL-3," 8 June 1973.

June 1

William C. Schneider, NASA Hq, expressed regret that certain experiments would be deleted from the Skylab Program because of loss of the micrometeoroid thermal control shield and the subsequent deployment of the parasol. Schneider also requested that Principal Investigators wishing to make changes in their experiments' protocol submit proposed changes by 5 June 1973, in order that the changes might be reviewed by the Skylab advisory group for experiments.

TWX, William C. Schneider to JSC, MSFC, Dudley Observatory, Naval Research Laboratory, Martin Marietta Corporation, Denver Div., and Westinghouse Electric Corporation, Pittsburgh, "Deletion of Change in Protocol for Certain Experiments on Skylab Missions," 1 June 1973; memorandum, William C. Schneider to Associate Administrator for Manned Space Flight, "Experiments Deleted from Skylab SL-1/ SL-2 Mission-Costs, and Alternate Approaches for Operation on SL-3/SL-4 Missions," 22 June 1973.

June 4

Testing began on 1200 OWS flight food samples and 5 cu m of ground test analytical food samples. They would be exposed to a thermal profile simulating that on the OWS, to verify that the food safety and quality had not been [315] compromised by the 17 days of high temperature to which the OWS had been subjected.

JSC, "Skylab Program Office Weekly Activity Report," 15 June 1973.

June 11 - July 28

The Skylab 3 space vehicle was moved to KSC Launch Complex 39, Pad B, on 11 June in preparation for launch. The space vehicle consisted of a Saturn IB launch vehicle S-IB-207 first stage, S-IVB-207 second stage, and a S-IU-208 instrument unit; a CSM; and a spacecraft lunar module adapter. The SL-3 crew consisted of commander Alan L. Bean, science pilot Owen K. Garriott, and pilot Jack R. Lousma.

On 6 June, the SL-3 launch date had been changed from 8 August to 27 July; the launch date was subsequently changed to 28 July to optimize the rendezvous conditions. The prelaunch checkout was accelerated accordingly.

The S-IVB stage had arrived at KSC on 26 August 1971 and was placed in storage until 28 November 1972. The CSM arrived on 1 December 1972 and was moved into the Operations and Checkout Building for systems testing. The S-IB stage arrived 30 March 1973 and was erected on Mobile Launcher 1 on 28 May. The IU arrived at KSC 9 May.

The S-IVB and IU were mated to the S IB 29 May. On 7 June the CSM/ spacecraft lunar module adapter was moved to the Vehicle Assembly Building and mated to the launch vehicle the following day. SL-3 transfer to LC-39B was completed on 11 June.

On 17 June, the mobile launcher and mobile service structure sustained several lightning strikes. The damaged parts for the CSM, mostly instrumentation, were replaced and retested or waived. The damaged ground support equipment parts were replaced and retested. The launch vehicle lightning retest revealed no related failures or effects on the launch vehicle or ground support equipment.

The flight readiness test was completed on 29 June. The final countdown began at 7:00 a.m. EDT 25 July in preparation for a 28 July launch (see 28 July entry).

KSC, "Skylab 3 Post-Launch Report," 20 August 1973, pp. 7-1, 7-2.

June 15

A review was conducted at NASA Hq to determine whether the astronaut maneuvering unit and foot controller maneuvering unit could be safely used within the confines of the OWS. It was concluded that the units could be safely operated, and approval was given for scheduling their use. Previously, a decision to operate the units had been deferred until a more thorough briefing could be provided. Concern over their use had been based on the Aerospace Safety Advisory Panel Report on Skylab.

Memorandum for record, R. A. Aller, NASA Hq, "Deputy Administrator Briefing on Skylab Experiments M509/T020," 21 June 1973.

June 20

A recommendation to jettison the docking ring and probe assembly on SL-2 while the crew was unsuited was reaffirmed. Major considerations in arriving at the recommendations were that a suited landing was unacceptable, the additional risk of performing the operation unsuited was extremely low, and the crew had trained premission and in flight using the proposed timeline for an unsuited jettison of the docking ring and probe assembly.

Memorandum, Dale D. Myers, NASA Hq, to the Deputy Administrator, "Separation of Docking Ring and Probe Assembly," 20 June 1973.

June 22

At 9:49 a.m. EDT, Skylab 2 splashed down in the Pacific Ocean 9.6 km from the recovery ship, U.S.S. Ticonderoga , and 1320 km southwest of San Diego. At 10:28 a.m., the crew and spacecraft were aboard the Ticonderoga.

The objectives of the SL-1/SL-2 mission were to establish the Orbital Workshop in Earth orbit, obtain medical data on the crew for use in extending the duration of manned space flight, and perform inflight experiments. A summary...

The photograph above, left, shows central Florida and was taken from an altitude of 432 km by the Skylab 2 crew on 13 June 1973. The outlines of the Green Swamp area are (1) Zenith Acres; (2) Groveland Ranch Estates; and (3) Groveland Ranch Acres. The city of Orlando is at center right. Above right is an overhead view of the Skylab space station as photographed from the Skylab 2 CSM during its final flyaround inspection.
Above is a photo of a significant solar flare reproduced from a frame of flight film recovered from the Hydrogen Alpha telescope No.1 and returned on Skylab 2. The solar flare occurred on 15 June 1973.

....assessment of the mission objectives indicated a very high degree of completion, particularly when the reduction in experiment time due to parasol deployment, solar array wing deployment, and OWS system anomalies were considered. Primary mission objectives were accomplished, and a majority of the assigned experiment-detailed objectives were completed.

The following conclusions were drawn from the SL-1/SL-2 mission:

• Resolution of the seemingly insurmountable system difficulties that occurred on the flight demonstrated the advantage of having man on board space vehicles.
• The flight demonstrated that for long-term manned and unmanned space flight, provisions needed to be made for unforeseen inflight repair and [320] maintenance in the form of accessibility, handholds, tools, facilities, materials, and hardware appropriate for interior and exterior operation.
• There were no operationally significant physical or psychological health problems associated with the space vehicle environment for the 28-day visit. There were no findings that would preclude longer duration visits.
• The habitability provisions were satisfactory and contributed to the ability of the crew to work effectively for a visit of this duration. No factors were identified to preclude longer duration visits.
• Operation of the command and service module systems in a semiquiescent state was demonstrated for the 28-day period. No factors were identified which precluded operation for longer periods.
• Extensive scientific data were returned in all planned experiment disciplines
• The methods and techniques employed in the daily flight planning provided the flexibility to react to major departures from preflight plans and constraints. This ability was an important factor in optimizing the scientific return.
• The various experiment groups were organized effectively within each discipline and functioned well as a unit. In addition, with the excellent cooperation between the various experiment groups, flight planning techniques were effective in resolving interdisciplinary conflicts and integrating the diverse experiments program.
• Long-duration flight with sophisticated multidiscipline experiments generated large amounts of data requiring ground data handling and processing capabilities.
• Overall objectives of the visit were accomplished.

Memorandum, Dale D. Myers, NASA Hq, to Administrator, "Skylab Mission SL-1/ SL-2," 10 July 1973; Post-Launch SL l/SL-2 Mission Operation Report No. M-960-73-01102, 14 July 1973; TWX, G. S. Lunney, JSC, to Science Attache, American Embassy, Moscow, 22 June 1973; JSC, Skylab Mission Report First Visit, JSC-08414, August 1973, pp. 14-7 and 18-1.

July 2

NASA Hq issued guidelines for the preparation of a Skylab mission evaluation report that would consist of a unified set of individual reports or sections. The report, which would be prepared by NASA Hq and the three manned spacecraft Centers, would cover such areas as summary and objective assessment, Skylab vehicle description, Orbital Workshop, command and service modules, crew equipment and activities, experiments, pilots' report, and operations.

Letter, William C. Schneider, NASA Hq, to Dist., "Guidelines for Preparation of Unified Skylab Mission Evaluation Report," 2 July 1973; JSC, "Skylab Program Office Weekly Activity Report," 13 July 1973; Skylab Program Directive No. 35, "Skylab Mission Evaluation Requirements," 22 April 1971.

July 3

The launch date for Skylab 3 was officially established as 28 July 1973. The launch window would open at 7:08 a.m. EDT for 10 minutes and would provide for a rendezvous in five revolutions. Recovery of SL-3 was planned for 22 September 1973.

TWX, William C. Schneider, NASA Hq, to JSC, KSC, and MSFC, "SL-3 Launch Date," 3 July 1973; memorandum, Dale D. Myers, NASA Hq, to the Administrator, "SL-3 Launch Date," 5 July 1973.

July 5

William H. Rock was appointed Acting Manager of the Apollo-Skylab Programs at KSC. He succeeded Robert C. Hock, who was named Acting Director of Executive Staff. Rock would also continue to serve in his previous position as Manager, Science and Applications Project Office.

KSC Announcement, "Mr. William H. Rock Named Acting Manager, Apollo-Skylab Programs," 5 July 1973.

July 12

Joint Skylab 3 flight readiness reviews and thermal shield design certification reviews were held at KSC. A comprehensive series of center reviews were completed before, and in preparation for, the flight readiness reviews.

"Minutes of the Skylab SL-3 Flight Readiness Review and the Thermal Shields Delta DCR," 12 July 1973.

July 13

Premature deployment of the meteoroid shield during the Skylab 1 launch interjected additional factors in the consideration of the OWS deorbit. (Reference entry of 3 April 1973.) Because of the additional uncertainties and complications....

....deriving from these factors and the inherent crew and mission risks involved in the OWS deorbit even under expected conditions, the decision was taken to terminate all OWS deorbit efforts.

Letter, William C. Schneider, NASA Hq, to JSC and MSFC, "SWS Deorbit," 13 July 1973

July 17

Testifying before a joint Congressional Committee hearing, astronaut Charles "Pete" Conrad, Jr., stated:

....I like to think of it as the Pete Conrad private citizen approach-as an overall systems design, tie all of these things we talk about with different satellites into a big picture.

Through something like the shuttle vehicle you maintain a space orientation that allows you to do communications, weather, Earth resources. And there are many other things I can conjecture about such as typing computers and telemetry from airplanes for air traffic control. There are all kinds of things you can get into. But I feel that these little niches we are making with the data we brought back from the Moon gave us a system that allowed us to, in a relatively inexpensive manner, fly a space station for the flight that we flew. And it will fly several more flights. And the future says that we have a tremendous capability to help mankind, if it is developed. And I feel it has to be developed in a profitable nature. And that is something this country can do under the free enterprise system. It is the payloads of the future and how they are integrated into the system that will give us all of these benefits, Earth resources, solar technology and many of the other things that are being done by the unmanned satellites. I think man is a necessary link in this system because he has to repair it, maintain it and operate it. That means not only on the ground but also in the air. I could go on forever with what I think....

 

 

....some of the systems could be. But I think we are giving enough data to the citizens of this country that they should appreciate that there is a place for using this system that we have developed that will really bring benefits to many, many people....

U.S. Congress, Senate Committee on Aeronautical and Space Sciences and House Committee on Science and Astronautics, Testimony from Skylab Astronauts: Joint Hearing, 93d Cong., 1st sess., 17 July 1973, p. 10.

July 25

Twice-weekly experiment planning meetings were being instituted for the 59-day Skylab 3 mission. The purpose of the meetings was to formulate a balanced set of experiment requirements for each upcoming week based on a consideration of plans for the remainder of the mission.

Letter, William C. Schneider, NASA Hq, to Principal Investigators, "Second Skylab Mission," 25 July 1973.

July 28

[324] Skylab 3 lifted off from Pad B, Launch Complex 39, KSC, at 7:10:50.5 a.m. EDT. The vehicle was manned by astronauts Alan L. Bean, Owen K. Garriott, and Jack R. Lousma.

The space vehicle, consisting of a modified Apollo command and service module payload on a Saturn IB launch vehicle, was inserted into a 231.3 by 154.7 km orbit. Rendezvous maneuvers were performed during the first five orbits as planned. During the rendezvous, the CSM reaction control system forward firing engine oxidizer valve leaked. The quad was isolated. Station-keeping with the Saturn Workshop began approximately 8 hours after liftoff, with docking being performed about 30 minutes later.

JSC, Skylab Mission Report Second Visit, JSC-08662, January 1974, p. 2-1.

July 28 - September 25

The Skylab 3 crewmen experienced motion sickness during the first three visit days. Consequently, the Orbital Workshop activation and experiment implementation activities were curtailed. By adjusting the crew's diet and maintaining a low workload, the crew was able to complete the adjustment to space flight in five days, after which flight activities returned to normal.

On 2 August the service module reaction control system engines were inhibited, and the isolation valves closed because of another leak. Acceptable control modes and deorbit and entry procedures were defined, consistent with the constraints imposed by the two reaction control system problems.

The first extravehicular activity was delayed until 6 August because of the crew's motion sickness. The EVA lasted almost six and one-half hours during which time the crew changed the Apollo telescope mount film, deployed the twin-pole sun shield (see 6 August entry), inspected and performed repair work on the S055 (ultraviolet spectrometer) experiment, deployed the S149 (particle collection) experiment, and installed the calibration shield from experiment S230 (magnetospheric particle composition).

A second EVA was performed on 24 August. It lasted 4 hours 30 minutes. The tasks accomplished included installation of a rate gyro package, deployment of a thermal shield material sample, retrieval and replacement of the ATM work station film, temporary stowage of the experiment S149 in the fixed airlock shroud and redeployment at the Sun end, and removal of the aperture door/ramp latch from two ATM experiments.

A third EVA was accomplished in 2 hours and 45 minutes on 22 September. Its purpose was to retrieve the expended film on the ATM solar experiments and experiments S230 and S149.

Earth resources experiment package activities included 39 passes with a total of 930 minutes of data. All experiment coverage was normal with the exception [325] of the loss of experiment S193 (microwave radiometer/scatterometer and altimeter) when the antenna failed to operate during data pass 29.

A series of medical experiments was accomplished which assessed the effect of a 59-day space mission on the crewmen. Included were a hematology and immunology program, a mineral balance assessment, an evaluation of the changes in hormonal and associated fluid and electrolyte parameters, the extent of bone mineral loss, the cardiovascular effects utilizing the lower body negative pressure experiment and the vector-cardiogram, and an assessment of metabolic activity.

Four astrophysics experiments were successfully performed: experiment S019 (ultraviolet stellar astronomy); experiment S063 (ultraviolet and visible Earth photography); experiment S149 (particle collection); and experiment S230 (magnetospheric particle composition). Data were obtained for studies of the habitability and crew quarters and crew activities and maintenance. In addition, several experiment M509 (astronaut maneuvering unit) sequences were performed. The chart below gives a comparison of the actual crew time devoted to experiments as opposed to that allocated in the preflight plan.

On 25 September, the command module was reactivated and the crew performed the final OWS closeout. Following undocking and separation, the command module entered the atmosphere and landed in the Pacific Ocean approximately 300 km southwest of San Diego. Splashdown was at 6:20 p.m. EDT. The recovery ship, U.S.S. New Orleans, retrieved the command module and crew 42 minutes after landing. The total flight time was 1427 hours 9 minutes 4 seconds.

R. V. Gordon, "JSC PAO Skylab Activities Summary," September 1973; JSC, Skylab Mission Report Second Visit, JSC-08662, January 1974, pp. 2-1, 2-2, and 15-2.

July 30

[326] Lewis Research Center Director Bruce T. Lundin, who served as chairman of the Skylab 1 Investigation Board, presented the findings of the board and the recommended corrective actions in congressional testimony:

'.. . the Board developed 14 findings, quoted directly herein as contained in o~ report to the Administrator of NASA.

 

1. The launch anomaly that occurred at approximately 63 seconds after liftoff was a failure of the meteoroid shield of the OWS.

2. The SAS-2 wing tie downs were broken by the action of the meteoroid shield at 63 seconds. Subsequent loss of the SAS-2 wing was caused by retrorocket plume impingement on the partially deployed wing at 593 seconds.

3. The failure of the S-II interstage adapter to separate in flight was probably due to damage to the ordnance separation device by falling debris from the meteoroid shield.

4. The most probable cause of the failure of the meteoroid shield was internal pressurization of its auxiliary tunnel. This internal pressurization acted to force the forward end of the tunnel and meteoroid shield away from the OWS and into the supersonic air stream. The resulting forces tore the meteoroid shield from the OWS.

5. The pressurization of the auxiliary tunnel resulted from the admission of high pressure air into the tunnel through several openings in the aft end. These openings were: (1) An imperfect fit of the tunnel with the aft fairing; (2) an open boot seal between the tunnel and the tank surface; and (3) open stringers on the aft skirt under the tunnel.

6. The venting analysis for the tunnel was predicated on a completely sealed aft end. The openings in the aft end of the tunnel thus resulted from a failure to communicate this critical design feature among aerodynamics, structural design, and manufacturing personnel.

7. Other marginal aspects of the design of the meteoroid shield which, when taken together, could also result in failure during launch are:

a. The proximity of the MS [meteoroid shield] forward reinforcing angle to the air stream.

b. The existence of gaps between the OWS and the forward ends of the MS.

c. The light spring force of the auxiliary tunnel frames.

d. The aerodynamic crushing loads on the auxiliary tunnel frames in flight.

e. The action of the torsion-bar actuated swing links applying an outward radial force to the MS.

f. The inherent longitudinal flexibility of the shield assembly.

g. The nonuniform expansion of the OWS tank when pressurized.

h. The inherent difficulty in rigging for flight and associated uncertain tension loads in the shield.

8. The failure to recognize many of these marginal design features through 6 years of analysis, design and test was due, in part, to a presumption that the meteoroid shield would be "tight to the tank" and "structurally integral with the S-IVB tank" as set forth in the design criteria.

9). Organizationally, the meteoroid shield was treated as a structural subsystem. The absence of a designated 'project engineer" for the shield contributed to the lack of effective integration of the various structural, aerodynamic, aeroelastic, test, fabrication, and assembly aspects of the MS system.

10. The overall management system used for Skylab was essentially the same as that developed in the Apollo program. This system was fully operational for [327] Skylab; no conflicts or inconsistencies were found in the records of the management reviews. Nonetheless, the significance of the aerodynamic loads on the MS during launch was not revealed by the extensive review process.

11. No evidence was found to indicate that the design, development, and testing of the meteoroid shield were compromised by limitations of funds or time. The quality of workmanship applied to the MS was adequate for its intended purpose.

12. Given the basic view that the meteoroid shield was to be completely in contact with and perform as structurally integral with the S-IVB tank, the testing emphasis on ordnance performance and shield deployment was appropriate.

13. Engineering and management personnel on Skylab, on the part of both contractor and Government, were available from the prior Saturn deployment and were highly experienced and adequate in number.

14. The failure to recognize these design deficiencies of the meteoroid shield, as well as to communicate within the project the critical nature of its proper venting, must therefore be attributed to an absence of sound engineering judgment and alert engineering Ieadership concerning this particular system over a considerable period of time.

'These findings led the Board to offer the following four corrective actions, again quoted directly from our report to the Administrator.

1. If the backup OWS or a similar spacecraft is to be flown in the future, a possible course of action is to omit the meteoroid shield, suitably coat the OWS for thermal control, and accept the meteoroid protection afforded by the OWS tank walls. If, on the other hand, additional protection should be necessary, the Board is attracted to the concept of a fixed, nondeployable shield.

2. To reduce the probability of separation failures such as occurred at the S 11 interstage second separation plane, linear shaped charges should be detonated simultaneously from both ends. In addition, all other similar ordnance applications should be reviewed for a similar failure mode.

3. Structural systems that have to move or deploy, or that involve other mechanisms, equipment or components for their operation should not be considered solely as a piece of structure nor be the exclusive responsibility of a structures organization.

4. Complex, multidisciplinary systems such as the meteoroid shield should have a designated project engineer who is responsible for all aspects of analysis, design, fabrication, test, and assembly."

U.S. Congress, Senate, Committee on Aeronautical and S