6.4 POSSIBILITY OF RESCUE OR REPAIR

¶To put the decisions made during the flight of STS-107 into perspective, the Board asked NASA to determine if there were options for the safe return of the STS-107 crew. In this study, NASA was to assume that the extent of damage to the leading edge of the left wing was determined by national imaging assets or by a spacewalk. NASA was then asked to evaluate the possibility of:

Rescuing the STS-107 crew by launching Atlantis.

Atlantis would be hurried to the pad, launched, rendezvous with Columbia, and take on Columbiaʼs crew for a return. It was assumed that NASA would be willing to expose Atlantis and its crew to the same possibility of External Tank bipod foam loss that damaged Columbia.

Repairing damage to Columbiaʼs wing on orbit. In the

repair scenario, astronauts would use onboard materials to rig a temporary fix. Some of Columbiaʼs cargo might be jettisoned and a different re-entry profile would be flown to lessen heating on the left wing leading edge. The crew would be prepared to bail out if the wing structure was predicted to fail on landing.

¶In its study of these two options, NASA assumed the following timeline. Following the debris strike discovery on Flight Day Two, Mission Managers requested imagery by Flight Day Three. That imagery was inconclusive, leading to a decision on Flight Day Four to perform a spacewalk on Flight Day Five. That spacewalk revealed potentially catastrophic damage. The crew was directed to begin conserving consumables, such as oxygen and water, and Shuttle managers began around-the-clock processing of Atlantis to prepare it for launch. Shuttle managers pursued both the rescue and the repair options from Flight Day Six to Flight Day 26, and on that day (February 10) decided which one to abandon.

¶The NASA team deemed this timeline realistic for several reasons. First, the team determined that a spacewalk to inspect the left wing could be easily accomplished. The team then assessed how the crew could limit its use of consumables to determine how long Columbia could stay in orbit. The limiting consumable was the lithium hydroxide canisters, which scrub from the cabin atmosphere the carbon dioxide the crew exhales. After consulting with flight surgeons, the team concluded that by modifying crew activity and sleep time carbon dioxide could be kept to acceptable levels until Flight Day 30 (the morning of February 15). All other consumables would last longer. Oxygen, the next most critical, would require the crew to return on Flight Day 31.

¶Repairing Damage On Orbit

¶The repair option (see Figure 6.4-1), while logistically viable using existing materials onboard Columbia, relied on so many uncertainties that NASA rated this option "high risk." To complete a repair, the crew would perform a spacewalk to fill an assumed 6-inch hole in an RCC panel with heavy metal tools, small pieces of titanium, or other metal scavenged from the crew cabin. These heavy metals, which would help protect the wing structure, would be held in place during

¶Figure 6.4-1. The speculative repair option would have sent astronauts hanging over the payload bay door to reach the left wing RCC panels using a ladder scavenged from the crew module.

¶re-entry by a water-filled bag that had turned into ice in the cold of space. The ice and metal would help restore wing leading edge geometry, preventing a turbulent airflow over the wing and therefore keeping heating and burn-through levels low enough for the crew to survive re-entry and bail out before landing. Because the NASA team could not verify that the repairs would survive even a modified re-entry, the rescue option had a considerably higher chance of bringing Columbiaʼs crew back alive.

¶Rescuing the STS-107 Crew with Atlantis

¶Accelerating the processing of Atlantis for early launch and rendezvous with Columbia was by far the most complex task in the rescue scenario. On Columbiaʼs Flight Day Four, Atlantis was in the Orbiter Processing Facility at Kennedy Space Center with its main engines installed and only 41 days from its scheduled March 1 launch. The Solid Rocket Boosters were already mated with the External Tank in the Vehicle Assembly Building. By working three around-the-clock shifts seven days a week, Atlantis could be readied for launch, with no necessary testing skipped, by February 10. If launch processing and countdown proceeded smoothly, this would provide a five-day window, from February 10 to February 15, in which Atlantis could rendezvous with Columbia before Columbiaʼs consumables ran out. According to records, the weather on these days allowed a launch. Atlantis would be launched with a crew of four: a command-Figure 6.4-2. The rescue option had Atlantis (lower vehicle) rendezvousing with Columbia and the STS-107 crew transferring via ropes. Note that the payload bay of Atlantis is empty except for the external airlock/docking adapter.

174

¶er, pilot, and two astronauts trained for spacewalks. In January, seven commanders, seven pilots, and nine spacewalk- trained astronauts were available. During the rendezvous on Atlantisʼs first day in orbit, the two Orbiters would maneuver to face each other with their payload bay doors open (see Figure 6.4-2). Suited Columbia crew members would then be transferred to Atlantis via spacewalks. Atlantis would return with four crew members on the flight deck and seven in the mid-deck. Mission Control would then configure Columbia for a de-orbit burn that would ditch the Orbiter in the Pacific Ocean, or would have the Columbia crew take it to a higher orbit for a possible subsequent repair mission if more thorough repairs could be developed.

¶This rescue was considered challenging but feasible. To succeed, it required problem-free processing of Atlantis and a flawless launch countdown. If Program managers had understood the threat that the bipod foam strike posed and were able to unequivocally determine before Flight Day Seven that there was potentially catastrophic damage to the left wing, these repair and rescue plans would most likely have been developed, and a rescue would have been conceivable. For a detailed discussion of the rescue and repair options, see Appendix D.13.

¶Findings:

¶F6.4-1 The repair option, while logistically viable using

existing materials onboard Columbia, relied on so many uncertainties that NASA rated this option "high risk."

was potentially catastrophic damage to the left wing, accelerated processing of Atlantis might have provided a window in which Atlantis could rendezvous with Columbia before Columbiaʼs limited consumables ran out.

¶Recommendation:

¶R6.4-1 For missions to the International Space Station,

develop a practicable capability to inspect and effect emergency repairs to the widest possible range of damage to the Thermal Protection System, including both tile and Reinforced Carbon- Carbon, taking advantage of the additional capabilities available when near to or docked at the International Space Station.

For non-Station missions, develop a comprehensive autonomous (independent of Station) inspection and repair capability to cover the widest possible range of damage scenarios.

Accomplish an on-orbit Thermal Protection System inspection, using appropriate assets and capabilities, early in all missions.

The ultimate objective should be a fully autonomous capability for all missions to address the possibility that an International Space Station mission fails to achieve the correct orbit, fails to dock successfully, or is damaged during or after

¶F6.4-2 If Program managers were able to unequivocally undocking.

¶determine before Flight Day Seven that there

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The crew cabin access arm in position against Columbia on Launch Complex 39-A.

176

¶The citations that contain a reference to "CAIB document" with CAB or

¶CTF followed by seven to eleven digits, such as CAB001-0010, refer to a document in the Columbia Accident Investigation Board database maintained by the Department of Justice and archived at the National Archives.

"Space Shuttle Program Description and Requirements Baseline," NSTS- 07700, Volume X, Book 1. CAIB document CTF028-32643667.

¶"External Tank End Item (CEI) Specification – Part 1," CPT01M09A, contract NAS8 –30300, April 9, 1980, WBS 1.6.1.2 and 1.6.2.2.³³ See John M. Logsdon, "The Space Shuttle Program: A Policy Failure?" Report, 1985. Science, May 30, 1986 (Vol. 232), pp. 1099-1105 for an account of this 14 The quote is from page 2 of the We Deliver brochure, reproduced in decision process. Most of the information and quotes in this section are Exploring the Unknown Volume IV, p. 423. taken from this article. 15 NASA Johnson Space Center, "Technology Influences on the Space President George H. W. Bush, "Remarks on the 20th Anniversary of the Apollo 11 Moon Landing," Washington, D.C., July 20, 1989.Show full note

¶"STS-1 Orbiter Final Mission Report," JSC-17378, August 1981, p. 85.

Discussed in Craig Covault, "Investigators Studying Shuttle Tiles, Aviation Week & Space Technology, May 11, 1981, pg. 40.

Report of the Presidential Commission on the Space Shuttle Challenger Accident, Volume V, 1986, pp. 1028-9, hearing section pp. 1845-1849.

"Orbiter Vehicle End Item Specification for the Space Shuttle System, Part 1, Performance and Design Requirements," contract NAS9-20000, November 7, 2002. CAIB documents CAB006-06440645 and CAB033- 20242971.

"Problem Reporting and Corrective Action System Requirements," NSTS- 08126, Revision H, November 22, 2000, Appendix C, Definitions, In Family. CAIB document CTF044-28652894.

¶Ibid.⁹⁹ R. J. Gomex et al, "STS-107 Foam Transport Final Report," NSNS- 60506, August 2003. 84 Report Volume I August 2003

¶Ibid.¹⁰¹⁰ The civil aviation study indicates that the risk to groundlings is significantly 25 Julie Kramer, et al., "Minutes from CAIB / Engineering Meeting to higher in the vicinity of an airport. The average annual risk of fatality Discuss CAIB Action / Request for Information B1-000193," April 24, within 0.2 miles of a busy (top 100) airport is about 1 in a million. 2003. CAIB document CTF042-00930095.

¶The umbilical wells are compartments on the underside of the Orbiter

where External Tank liquid oxygen and hydrogen lines connect. After the Orbiters land, the umbilical well camera film is retrieved and developed.

NSTS-08126, Paragraph 3.4, Additional Requirements for In-Flight Anomaly (IFA) Reporting.

¶Integrated Hazard Analysis INTG 037, "Degraded Functioning of

Orbiter TPS or Damage to the Windows Caused by SRB/ET Ablatives or Debonded ET or SRB TPS."

¶Ibid. 14

¶Ibid.

During the flight of STS-112, the Intercenter Photo Working Group speculated that a second debris strike occurred at 72 seconds, possibly to the right wing. Although post-flight analysis showed that this did not

occur, the Board notes that the Intercenter Photo Working Group failed to properly inform the Mission Management Team of this strike, and that the Mission Management Team subsequently failed to aggressively address the event during flight.

"Safety and Mission Assurance Report for the STS-113 Mission, Pre- Launch Mission Management Team Edition," Enterprise Safety and Mission Assurance Division, November 7, 2002. CAIB Document

¶CTF024-00430061. 17

Orbiter TPS damage numbers come from the Shuttle Flight Data and In- Flight Anomaly List (JSC-19413).

CAIB Meeting Minutes, presentation and discussion on IFAs for STS-27 and STS-28, March 28, 2003, Houston, Texas.

"STS-27R National Space Transportation System Mission Report," NSTS- 23370, February 1989, p. 2.

CAIB Meeting Minutes, presentation and discussion on IFAs for STS-27 and STS-28, March 28, 2003, Houston, Texas.

Corrective Action Record, 27RF13, Closeout Report (no date). CAIB document CTF010-20822107.

"STS-27R OV-104 Orbiter TPS Damage Review Team Summary Report," Volume I, February 1989, TM-100355, p. 64. CAIB document CAB035- 02290303.

¶Ibid. 24

"In-Flight Anomaly: STS-35/ET-35," External Tank Flight Readiness Report 3500.2.3/91. CAIB document CAB057-51185119.

STS-36 PRCB, IFA Closure Rationale for STS-35. CAIB document CAB029- 03620433.

¶Identified by MSFC in PRACA database as "not a safety of flight"

"STS-45 Space Shuttle Mission Report," NSTS-08275, May 1992, pg. 17. CAIB document CTF003-00030006.

"STS-45 Space Shuttle Mission Report," NSTS-08275, May 1992. CAIB document CTF003-00030006.

Both STS-56 and STS-58 post mission PRCBs discussed the debris events and IFAs. Closeout rationale was based upon the events being considered "in family" and "within experience base."

"Problem Reporting and Corrective Action System Requirements," NSTS- 08126, Revision H, November 22, 2000, Appendix C, Definitions, Out of

¶Family. CAIB document CTF044-28652894. 31

¶Post STS-87 PRCBD, S 062127, 18 Dec 1997. 32