With the launch of STS-135 today, the US Space Shuttle program will end with a whimper. To celebrate the shuttles’ service to both our nation and the sciences, the NASA Space Shuttle Manual by David Baker discusses the launch of the very first, Columbia.
Assembly of the first Orbiter destined for space flight began on March 27, 1975, less than 14 years after Yuri Gagarin became the first human in space. Named Columbia after a sloop based in Boston, Massachusetts, famous for making the first American circumnavigation of the globe, OV-102 was finally rolled out on 8 March 1979. Columbia was also the name chosen for the Apollo spacecraft carrying the first moon landing crew to the lunar surface in July 1969. With the Shuttle programme already running a year or so late, there was pressure on NASA to begin flights but there were insidious flaws in the system that would bring about a succession of delays. Succumbing to pressure to get the Shuttle into space, Columbia arrived at the Kennedy Space centre atop its Boeing 747 SCA on 25 March 1979. Few could have foreseen that it would still be sitting there two years later.
With development problems on the main engines, NASA now encountered trouble with the worrisome thermal protection system comprising more than 30,000 separate ceramic tiles designed to protect the undersurface and sides of the Orbiter from the heat of re-entry. Manufactured for resilience and reusability, tests in 1979 revealed that the tiles had inadequate tensile strength and there were problems too with the bonding adhesive which had to keep all the tiles in place. In some areas they would protect the Orbiter’s vulnerable aluminium structure from temperatures as high as 2,300 deg F.
Various techniques were tried and all appeared resistant to solutions but gradually, over time, the problems were resolved. Columbia arrived at KSC with 24,000 tiles installed and 6000 to be added in the Orbiter Processing Facility (OPF) where it was prepared for flight. But the tile tests revealed that almost all the tiles fitted in Palmdale would have to be replaced – some had even fallen off flying it across country – and for 20 months a veritable army of recruits worked three shifts a day, six days a week, installing a total of 30,759 tiles.
The External Tank for the first Shuttle mission, STS-1 (Space Transportation System-1) arrived at the Cape on 29 June 1979, and was mated with the two SRBs destined for this historic event on 3 November 1980. Columbia was mated to the ET on 26 November after spending a record 613 days in the OPF. Finally, the stack was rolled out to the pad on 29 December 1980. Because the flight engines for Columbia had not been fired as a group within that Orbiter, NASA wanted to give them a quick firing test on the pad, so a Flight Readiness Firing (FRF) took place on 20 February 1981, when engineers ‘blipped the throttle’ for 20 seconds to see if it all held together, including the tiles. Each new Orbiter would conduct a FRF.
On 19 March 1981, the flight crew comprising veteran astronaut John W. Young and Robert L. Crippen were on the flight deck for a scheduled test when two technicians working in the main engine compartment at the rear if the Orbiter were asphyxiated by nitrogen during a purge of that chamber. Both men lost their lives. Numerous tests were conducted, including loading and unloading the vast External Tank, and all appeared ready for a flight on 10 April when a problem between timing systems in the avionics caused a scrub in the launch attempt for that day. Two days later, on 12 April 1981, exactly 20 years after the flight of the first human into space, Columbia thundered into life and the world’s first reusable Shuttle was launched.
Although every element of the Shuttle had been tested separately, this was the first time astronauts would fly in a vehicle that had not already been first tested in space. Previous manned spacecraft (Mercury, Gemini and Apollo) had all been flown unmanned several times before astronauts were allowed to fly in them. With the Shuttle that was not feasible because it was both a launch vehicle and a spacecraft and it was not designed to fly unmanned. In that regard it was like an aircraft which had to have a pilot to fly. To have fitted it out with an unmanned capability would have significantly delayed the programme and not represented the configuration capable of carrying astronauts.
The FRF had demonstrated a ‘twang’ effect, where the offset alignment of the Orbiter’s engines causes the entire vehicle to bend over about 20 inches in response to the shock of ignition. It was necessary to allow the stack to reflex back before ignition of the SRBs. The countdown reached zero at ignition of the Orbiter’s three SSMEs, followed four seconds later by ignition of the two big SRBs and lift-off. On later flights the countdown would incorporate ignition of the SSMEs within the final few seconds so that lift-off came at T-0. As a result of engineering analysis on STS-1, the duration of the burn prior to ignition of the SRBs would be extended to allow more time to null the ‘twang’ effect.
At lift-off the Shuttle weighed 2200 tons (4,457,111lb) and the two SRBs burned for 2 minutes 10 seconds carrying the stack to a height of 31 miles. Separating from the External Tank they fell back into the Atlantic Ocean supported by parachutes, impacting the water at 7 minutes 10 seconds, 161 miles downrange from the Kennedy Space centre. The SRBs were recovered by a special vessel and towed to Port Canaveral from where the booster segments would be cleaned out and used again. The remaining Orbiter and External Tank now weighed just over 700 tons (1,476,278lb) and the Shuttle arched over on its way into orbit burning cryogenic propellants from the ET. As the three main engines consumed propellant and made the stack lighter, they were gradually throttled back to contain acceleration within 3g.
The computers shut down the three SSMEs at 8 minutes 34.4 seconds. Having achieved altitude, in the final few minutes the Shuttle had been flying slightly down toward the earth, gathering speed and at separation of the ET, 24 seconds later, the Shuttle was at an altitude of 72½ miles and not quite at orbital velocity. The External Tank gradually descended into the earth’s atmosphere and broke up at an altitude of 54 miles over the Indian Ocean, most of it destroyed by the fiery heat of re-entry. Exactly two minutes after the three main engines shut down the two Orbital Manoeuvring System (OMS) engines, using propellant housed in tanks within the two blisters either side of the tail, fired for 86 seconds to put Columbia in a safe orbit. Another firing of the OMS engines for 75 seconds, 44 minutes after launch, placed Columbia in a 153 x 154 mile orbit.
After two days of orbital tests Columbia turned to place its aft end in the direction of travel, pitched the nose down slightly so that the engines at the rear were pointing upward, and fired the two OMS engines in a retro-burn that slowed the Shuttle and gradually brought it down toward the earth. Turned around now, and pitched up slightly and began to enter the atmosphere at a height of 76 miles still some 5,000 miles up-range of its landing strip at Edwards Air Force Base toward which it would fly, gradually decelerating from nearly 18,000mph to a touchdown speed of 207mph. With a weight of just under 200 tons (197,472lb) Columbia rolled to a stop in 8,893ft and was delivered back to the Kennedy Space centre atop the Boeing SCA on 28 April.
NASA Space Shuttle Manual: An Insight into the Design, Construction and Operation of the NASA Space Shuttle is available from Amazon.com