In space in a damaged rocket - 13 Minutes Presents: The Space Shuttle, BBC World Service

Key Concepts

• STS-1: The first space shuttle mission.
• Orbiter Columbia: The space shuttle used for the STS-1 mission.
• Payload Bay Doors: Large doors on the shuttle that house the cooling mechanism.
• Thermal Protection System (TPS): The heatshield composed of over 30,000 tiles that protects the shuttle during re-entry.
• Heatshield Tiles: Individual tiles made of silica fibers and glass coating that make up the TPS.
• Re-entry: The process of returning to Earth's atmosphere.
• Blackout: The period of radio silence during re-entry caused by ionization of the air around the orbiter.
• Roll Reversals: S-shaped turns performed during landing to bleed off speed.

Opening the Payload Bay and Discovering Missing Tiles

• During the STS-1 mission, about two hours in, astronaut Bob Crippen opened the payload bay doors to expose the shuttle’s cooling mechanism, vital for regulating temperature in space.
• Upon opening the doors, Crippen noticed missing heatshield tiles on the tail section, specifically on the starboard and port Orbital Maneuvering System (OMS) pods. He reported that the starboard pod had three missing tiles and some smaller pieces and the port pod had one full tile and a few triangular shapes missing.
• Marianne Dyson, a flight controller, described the missing tiles as resembling a "gap tooth smile".

The Arrival of Columbia at Kennedy Space Center

• Two years before the STS-1 mission, in March 1979, Columbia arrived at Kennedy Space Center mounted on a 747 aircraft.
• Bill Carr, a technician, and John Tribe, a shuttle processing engineer, were present and saw the shuttle up close for the first time. They noted the poor condition of the shuttle, with many placeholder tiles missing.
• These placeholder tiles were temporary and were intended to be replaced by permanent tiles capable of withstanding the heat of re-entry.

The Development of Heatshield Tiles

• Tom Moser, a materials engineer, was tasked with creating a reusable and lightweight heatshield.
• The tiles are made of silica fibres with a glass coating, making them fragile. Each tile is uniquely shaped to fit a specific location on the orbiter, like a jigsaw puzzle.
• The tiles needed to fit perfectly within an eighth of an inch of each other, and a material was needed to prevent hot gases from seeping between them.

The "Puzzle People" and the Tile Bonding Issues

• In 1979, an "army of workers" known as the "puzzle people" were responsible for replacing the placeholder tiles with the permanent ones.
• A pull test was developed to ensure the tiles were properly bonded, but the initial tests failed, with the tiles easily coming off due to the sandy texture of the back of the tiles.
• A solution was developed to strengthen and densify the back of the tiles, but it required removing and reattaching all the tiles, causing delays and morale issues. The original launch date was scheduled for 1979 but was delayed to April 1981.

Concerns About Missing Tiles and Public Statements

• During the STS-1 mission, after discovering the missing tiles, the media questioned NASA officials, including Gene Kranz and Neil Hutchinson, about the potential risks.
• NASA stated that nine tiles were missing from the starboard pod and four to six from the port pod.
• Tom Moser assured the public that the missing tiles, located on the top side of the orbiter, would not affect the safety during re-entry.

Lack of Underside Photos and Classified Information

• The media questioned whether photos of the underside of the orbiter had been taken to assess damage.
• Gene Kranz stated that officially, no usable photos were obtained from ground stations.
• He neither confirmed nor denied reports of surveillance by the Air Force or spy satellites, citing classified information.

Re-entry and Landing

• During re-entry, the orbiter faced temperatures of up to 2750 degrees Fahrenheit on the wing leading edge.
• The blackout period occurred due to ionization of the air around the orbiter, causing radio signal loss.
• John Young and Bob Crippen successfully navigated the orbiter through the atmosphere and landed at Edwards Air Force Base.

Post-Landing Euphoria and Discovery of Damage

• The successful landing was met with euphoria in Mission Control. Chris Kraft wrote ”We just got infinitely smarter”.
• John Young was excited and ran to inspect the orbiter.
• Post-landing inspection revealed damage to a landing gear door caused by heat exposure due to a failed tile material, but the vehicle landed safely.

Conclusion

The STS-1 mission was a significant achievement, demonstrating the viability of reusable spacecraft. Despite challenges with the heatshield tiles and concerns about potential damage, the mission was ultimately successful. The safe return of Columbia marked a major milestone in space exploration, underscoring the importance of rigorous testing, problem-solving, and the dedication of the teams involved. The mission also highlighted the risks inherent in spaceflight and the need for continuous improvement in safety measures.