Lasting legacy

Twenty-five years ago this week, the first Space Shuttle – Orbiter Vehicle (OV) 102 Columbia – blasted off the pad at Kennedy Space Center. Almost a decade after man’s final footsteps on the Moon, the test flight mission launched the USA’s latest adventure in spaceflight.

In the spirit of optimism that surrounded the 12 April 1981 first flight – STS or Space Transportation System 1 – those exchanging handshakes, backslaps and hugs in mission control and contractor officers around the country could have little imagined that 112 successful missions later, plus two that ended in disaster, NASA would be managing the demise of the world’s only reusable spacecraft and planning a return to a capsule-style vehicle for human spaceflight.

Four years ago, the Shuttle was planned to last until 2020, with programmed upgrades for the remaining four orbiters: OV-103 Discovery, OV-104 Atlantis, Columbia and OV-099 Challenger’s replacement, OV-105 Endeavour. When Columbia disintegrated on re-entry over California in February 2003, with the death of seven astronauts, the programme’s future was thrown into doubt.

Back in 1981, on that same Shuttle, the crew restarting US human spaceflight after a hiatus of five years since the 1975 Apollo-Soyuz test project were a Gemini veteran and moonwalker John Young, and astronaut candidate Robert Crippen. Young and Crippen orbited Earth 36 times during their two-day, 6h 20min flight. Its objective was to check out the overall Shuttle system, accomplish a safe ascent into orbit and to return to Earth. Columbia landed on 14 April at 17:20 GMT on runway 23 of Edwards AFB, California.

In a premonition of the problems the Shuttle would suffer in later years, STS 1 had been delayed from its originally scheduled first flight in 1979 due to issues with its thermal protection system (TPS) tiles. During tests before the 1981 flight the thermal tiles were breaking. Only the application of a thin plate of cement on the bottom of each tile to enable it to spread stress loads solved the problem.Unfortunately about two-thirds of the tiles for Columbia had been installed with the old method and it took a year to change them.

Once Columbia was rolled out to the launch pad at the beginning of 1981, the problems with the Shuttle’s external propellant tank (ET) insulation began. The insulation was designed to keep ice from forming on the tank’s skin because lumps could break off and damage the TPS tiles during launch. But after the ET was filled with the cryogenic liquid hydrogen and liquid oxygen, NASA discovered that 32 panels of tank insulation had peeled off. Twenty-two years later, on 16 January 2003, it was a piece of insulation that would damage Columbia’s wing leading edge during launch, resulting in the vehicle’s break-up during re-entry on 1 February.

In 1981, a post-STS 1 flight inspection revealed that ice falling from the ET had chipped and scored more than 300 of the orbiter’s 24,300 heat-shield tiles.

Former McDonnell Douglas engineer Hoa Vu was troubleshooting the TPS problems before the first launch and he is amazed the Shuttle is still flying after 25 years. “I think we were designing it for only 15 years. After more than 100 launches I still get goose bumps watching it on TV. I think pretty much every flight is a test flight and you learn something new every day.”

The Shuttle programme was announced on 5 January 1972 by then US President Richard Nixon. NASA admini­strator at the time James Fletcher said the Shuttle “will change the nature of what Man could be in space. By the end of the decade the nation will have the means of getting men and equipment to and from space routinely.”

In 1972 Rockwell Inter­national was awarded the contract to design and build the orbiters. On 8 March 1979, Columbia was rolled out of Air Force plant 42 at the Palmdale, California assembly facility. UK-born John Tribe, who had moved to the USA in 1961 to work on the space programme and had become Rockwell’s manager for design of the orbiter’s subsystems, recalls: “They were hectic days and as I’d been working on the Shuttle since 1972 we were wondering if we’d ever get it off the ground as the months slipped by,” he says.

When the Shuttle finally did launch, the 11 April 1981 edition of Flight International announced: “The lives of commander John Young and pilot Robert Crippen, as well as the future of American spaceflight, depend on it. Space Shuttle is the first re-useable rocket and none of it has flown unmanned tests in space as happened with Mercury, Gemini and Apollo.”

Tribe shared those feelings at the time and remembers being nervous. “After a lifetime of launches that had had some spectacular failures I was very concerned that we were launching two people on a new vehicle.”

Despite the insulation and tile problems and the concerns of Shuttle engineers, Columbia successfully completed the first five flights, including the first satellite deployment on mission STS 5. The sixth mission would see Challenger make its maiden flight on 30 August 1982.

The number of flights increased from two in 1981, to three in 1982, four in 1983, five in 1984 and then to an all-time high of nine in 1985. During that time the first satellite repair mission was carried out by Challenger/STS 41C. Earlier Challenger missions, STS 7 and STS 8, both in 1983, saw the first woman and first African American to go into space.

Challenger/STS 8, launched on 30 August 1983 carrying the Indian Space Research Organisation’s India Satellite-1A, was also the first night launch and the first night landing. On 13 October the following year, Challenger, after the eight-day-mission STS 41G, landed at KSC’s 15,000ft long runway instead of Edwards AFB or White Sands for the first time. The following flight saw another first: satellite retrieval.

But tragedy struck on the second flight of 1986 with the Challenger accident on 28 January. The subsequent investigation found that a solid rocket booster (SRB) O-ring failure had led to the catastrophic explosion that destroyed Challenger. Shuttle flights ceased until 1988.

In 1990 Discovery would deploy the Hubble Space Telescope on STS 31 and the first Hubble servicing mission would take place three years later. While space telescopes were one possible use for the Shuttle when it was proposed, ultimately it would not be until 1995 that it would finally begin the job it was originally designed to do: service a space station.

On 27 June, Atlantis lifted off from KSC to make the first Shuttle docking with Russian space station Mir. There would be 10 missions to Mir in all, although the first was simply a rendezvous, not a docking.

Since 1998, the Shuttle has been assembling the International Space Station (ISS). STS 88 saw the US-built Unity node attached to Russia’s Zarya module.

However, today’s ISS assembly sequence is much changed from that planned in 1998. The loss of Columbia on 1 February 2003 has altered the ISS’s final configuration because US President Bush decided to retire the Shuttle in 2010.

But what if Columbia had not broken up? Edward “Mack” Henderson is NASA’s deputy office manager in strategic planning for the Shuttle programme and was working on Shuttle upgrades at the time. “We were planning to upgrade the main engine with advanced health management to control engine performance in flight. We were also working on an electric auxiliary power unit to replace the hydrazine-driven turbines currently used. There was also a new fuel cell that would last twice as long at 5,000h. The cockpit upgrade was going to be very difficult and would have been ready in 2009. Now that technology is going into the Crew Exploration Vehicle,” says Henderson.

Looking back at the early days, Tribe, who retired in 1997 as orbiter chief engineer, says: “I was very pleasantly surprised by the wonderful performance of the orbiter on its maiden flight and vividly remember John Young literally gambolling around the nose of the vehicle after landing – he was so excited and pleased with the flight.”

In the words of NASA administrator Michael Griffin, the Shuttle is “the most amazing machine humans have ever built, and it has been the recipient of the most brilliant engineering that America can provide”. Despite two disasters and the loss of 14 astronauts, the Space Shuttle remains the world’s only reusable orbital spaceplane and that is a claim that is likely to remain for decades to come after the fleet’s retirement.

ROB COPPINGER / COLORADO SPRINGS

Source: Flight International