For almost three decades, from November 1981 through July 2011, Canada’s Remote Manipulator System (RMS), also known as the “Canadarm,” supplied much of the muscle needed by the space shuttle fleet to complete its myriad missions in space. From the maneuvering of spacewalking astronauts to the retrieval, repair, and redeployment of scientific and commercial satellites—most notably the Hubble Space Telescope (HST)—and from delivering hardware to Russia’s Mir space station and forming the backbone for the assembly of the International Space Station (ISS), the RMS has been a critical asset. Thirty-five years ago, today, on 12 November 1981, NASA astronauts Joe Engle and Dick Truly roared into orbit aboard Shuttle Columbia to put the RMS through its paces for the first time. In doing so, they also became the first crew to fly a “used” spacecraft into Earth orbit for the second time.
As detailed in a previous AmericaSpace history article, Columbia flew her maiden voyage in April 1981, during which astronauts John Young and Bob Crippen flawlessly executed a two-day mission and returned to a textbook landing at Edwards Air Force Base, Calif. Her second flight, STS-2, was originally targeted for 30 September, but met with significant delay, firstly to No Earlier Than (NET) 9 October and eventually slipping into the first half of November. Engle and Truly were named as the prime crew on 23 April 1981, during a pilots’ meeting in the Astronaut Office when Young and Crippen handed them a ceremonial cardboard “key” for the orbiter. Yet the astronauts had been in generic shuttle training for much longer, having been announced by NASA in March 1978. Indeed, Engle and Truly had also previously flown two of Shuttle Enterprise’s Approach and Landing Test (ALT) free flights in September and October 1977.
Following her return from Edwards to the Kennedy Space Center (KSC) in Florida, at the tail end of April 1981, Columbia was subjected to extensive work in the Orbiter Processing Facility (OPF). More than 350 of her thermal protection tiles needed replacement, a further 818 had to be removed and repaired, and 2,000 others were serviced, in situ. In the meantime, the 50-foot-long (15.2-meter) RMS was delivered in April and installed aboard the shuttle’s payload bay on 20 June. During the planned five-day STS-2 flight, the arm would be utilized by Truly for a series of tests, ahead of its first significant role lifting a major payload on STS-3 in March 1982. Additionally, Engle and Truly’s mission would feature the shuttle’s first fully fledged scientific research payload, provided by NASA’s Office of Space and Terrestrial Applications and dubbed “OSTA-1.”
However, efforts to get Columbia into space on 9 October came to nothing. During the loading of nitrogen tetroxide aboard the Reaction Control System (RCS), technicians accidentally spilled 12 pounds (5.5 liters) of the highly toxic oxidizer onto the shuttle’s nose. All told, no less than 379 thermal protection tiles had to be removed, cleaned, and replaced. A revised launch date of 4 November was set, but with 48 hours to go, an unusual pressure drop was noticed in one of the oxygen tanks for Columbia’s fuel cells. A change in the loading procedure seemed to do the trick, and Engle and Truly were strapped into the seats on launch morning. Unfortunately, the fuel cell gremlins returned at T-9 minutes, when the oxygen tanks again showed up lower-than-permitted pressures. The issue was quickly cleared, but when Truly activated the Auxiliary Power Units (APUs) at T-5 minutes they exhibited higher-than-normal oil pressures. As engineers worked the problem, the countdown proceeded. Eventually, at T-31 seconds, just on the cusp of Autosequence Start, the tank pressures were still too low and the clock was recycled to T-9 minutes and eventually to T-20 minutes. Finally, as the weather began to close in, NASA opted to scrub the launch.
It turned out that the oil filters of Columbia’s APUs had become clogged with pentaerythritol, a crystal which formed when hydrazine penetrated their gearboxes. This led to the unexpected rise in temperature. Both gearboxes were flushed, their filters replaced, and launch was rescheduled for 12 November 1981. Additionally, the orbiter’s forward flight deck windows—which Engle and Truly reported provided marginal visibility—were cleaned in readiness for the next attempt.
Yet getting STS-2 off the ground was still not smooth sailing. Problems were faced when loading the No. 3 fuel cell oxygen tank and, the night before launch, one of Columbia’s four Multiplexer-Demultiplexers (MDMs) failed. A spare for this critical unit, which provided instrumentation measurements, commands, and data to the cockpit displays, was flown to the Cape from California in the small hours of 12 November. (Interestingly, the new MDM came from the second shuttle, Challenger, which was then at Rockwell’s Palmdale facility, undergoing final construction.)
STS-2 got underway with a perfect liftoff at 10:09 a.m. EST, reaching space within nine minutes. Columbia’s second launch suffered only from the need to shut down one of the APUs slightly earlier than expected, due to high oil temperatures. After dumping residual propellant into space—a process terminated 16 seconds early, due to the APU problem—Engle and Truly performed a pair of Orbital Maneuvering System (OMS) firings to circularize their orbit at approximately 120 miles (193 km) x 125 miles (201 km), inclined 38 degrees to the equator. The low orbit was needed on STS-2 to permit OSTA-1 to gather its data at the required resolution. The astronauts also opened the payload bay doors to expose the scientific platform to space for the first time.
Although only the first two OMS burns were necessary to establish Columbia in her correct orbit, two additional firings were performed to raise the altitude to 137 miles (220 km). The third burn was split into two halves in order to satisfy one of STS-2’s flight test objectives: an ability to turn off an OMS engine and restart it a few minutes later in the vacuum of space, with no ill-effects. The fourth firing then demonstrated the ability of the OMS to feed the right-hand engine with the left-hand pod and vice versa. All of the tests proved successful.
What did not turn out to operate well, only a couple of hours into the mission, was one of the fuel cells. This had damaging implications for the accomplishment of the scheduled five-day mission, during which Engle and Truly were to conduct extensive tests of the RMS in both manual and automatic modes and try out the new shuttle Extravehicular Activity (EVA) suit in the middeck. All that began to change dramatically late on the afternoon of the 12th, when ground controllers spotted a high pH indication on the No. 1 cell. Its overall performance, though, at least at this stage, remained more or less normal.
That, however, would change dramatically for the worse.
The second part of this article will appear tomorrow.