Forty years ago today, the Space Shuttle Columbia successfully returned from its first earth-orbital mission. An estimated 225,000 people witnessed the historic landing on Rogers Dry Lake at Edwards Air Force Base, California.
Known officially as the Space Transportation System (STS), the Space Shuttle was unlike any manned space vehicle ever flown. A giant aircraft known as the Orbiter was side-mounted on a huge liquid-propellant stage called the External Tank (ET). Flanking opposing sides of the ET was a pair of Solid Rocket Boosters (SRB). The Orbiter, SRB’s and ET measured 122 feet, 149 feet and 154 feet in length, respectively.
The Space Shuttle system was conceived with an emphasis on reusability. Each Orbiter (Columbia, Challenger, Atlantis, Discovery, and Endeavor) was designed to fly 100 missions. Each SRB was intended for multiple mission use as well. The only single-use element was the ET since it was more cost effective to use a new one for each flight than to recover and refurbish a reusable version.
NASA called STS-1 the boldest test flight in history. Indeed, the STS-1 mission marked the first time that astronauts would fly a space vehicle on its inaugural flight! STS-1 was also the first time that a manned booster system incorporated solid rocket propulsion. Unlike liquid propellant rocket systems, once ignited, the Shuttle’s solid rockets burned until fuel exhaustion.
And then there was the Orbiter element which had its own new and flight-unproven propulsion systems. Namely, the Space Shuttle Main Engines (SSME) and Orbital Maneuvering System (OMS). Each of the three (3) SSME’s generated 375,000 pounds of thrust at sea level. Thrust would increase to 475,000 pounds in vacuum. Each OMS rocket engine produced 6,000 pounds of thrust in vacuum.
The Orbiter was also configured with a reusable thermal protection system (TPS) which consisted of silica tiles and reinforced carbon-carbon material. The TPS for all previous manned space vehicles utilized single-use ablators. Would the new TPS work? How robust would it be in flight? What post-flight care would be needed? Answers would come only through flight.
To add to the stress of first flight, the Orbiter was a winged vehicle and would therefore perform a hypersonic lifting entry. The vehicle energy state would have to be managed perfectly over the 5,000 mile reentry flight path from entry interface to runway touchdown. Since the Orbiter flew an unpowered entry, it would land dead-stick. There would only be one chance to land.
On Sunday,12 April 1981, the Space Shuttle Columbia lifted-off from Pad 39A at Cape Canaveral, Florida. Official launch time was 12:00:03 UTC. The flight crew consisted of Commander John W. Young and Pilot Robert L. Crippen. Their Columbia launch stack tipped the scales at 4.5 million pounds and thundered away from the pad on over 7 million pounds of thrust.
Columbia went through maximum dynamic pressure (606 psf) at Mach 1.06 and 26.5 KFT. SRB separation occurred 120 seconds into flight at Mach 3.88 and 174,000 feet; 10,000 feet higher than predicted. This lofting of the ascent trajectory was later attributed to unmodeled plume-induced aerodynamic effects in the Orbiter and ET base region.
Following separation, Columbia rode the ET to burnout at Mach 21 and 389.7 KFT. Following ET separation, Columbia’s OMS engines were fired minutes later to achieve a velocity of 17,500 mph and a 166-nautical mile orbit.
Young and Crippen orbited the Earth 37 times before coming home on Tuesday, 14 April 1981. In doing so, they successfully flew the first hypersonic lifting reentry from earth orbit. Though unaware of it at the time, the crew came very close to catastrophe as the Orbiter’s body flap had to be deflected 8 degrees more than predicted to maintain hypersonic pitch control.
The reason for this “hypersonic anomaly” was that ground test and aero modeling had failed to capture the effects of high temperature gas dynamics on Orbiter pitch aerodynamics. Specifically, the vehicle was more stable in hypersonic flight than had been predicted. This necessitated greater nose-down body flap deflections to trim the vehicle in pitch. It was a close-call. But Columbia and her crew lived to fly another day.
Columbia and her crew touched-down at 220 mph on Runway 23 at Edwards Air Force Base, California at 18:20:57 UTC. Young and Crippen were euphoric with the against-the-odds success of the Space Shuttle’s first mission.
NASA too reveled in the Shuttle’s marvelous accomplishment. And so did America. This was the country’s first manned space mission since 1975. At the time, this was the longest period of manned spaceflight inactivity ever in our nation’s history.
Fittingly, a well-known national news magazine celebrated Columbia’s success with a headline which read: “America is Back!”
And while Columbia flies no more, we remember with fondness that first Orbiter, her first flight, and her many subsequent accomplishments. To which we say: Hail Columbia!