Meet the Orbiters
A fleet of winged spacecraft, the likes of which we'll never see again.
- By Michael Klesius
- AirSpaceMag.com, March 01, 2011
(Page 3 of 5)
Starting in 1998 with Atlantis, each orbiter received a major upgrade, the Multi-function Electronic Display System, a so-called glass cockpit that replaced dozens of dials and gauges with 11 flat-panel, liquid-crystal color displays. The new cockpit weighed less, used less power, and reduced glare in bright sunlight, all while offering better views of data from a wide range of angles.
Ross was the first person to be launched into space seven times, all on the shuttle. He flew five missions on Atlantis. “The thing about Atlantis is that to me it seemed to have a little bit stronger buffeting [than the other orbiters] during the transonic Mach, right around Mach 1, coming back in to land,” he says. “It felt like you had run off the tracks and were riding on the railroad ties. It was just a real rough ride for just a little bit.” He felt some of this on Columbia and Endeavour, but it was more pronounced on Atlantis, he says. The crew brought it up in debriefings, but it always remained a mystery.
Franklin Chang-Dìaz, the only other seven-time shuttle flier, flew on every orbiter but Challenger. “Columbia tended to rattle a bit more on liftoff,” he recalls. “Structural integrity was always on my mind, particularly on ascent and reentry.” After years of training as a mechanical engineer with a Ph.D. in applied plasma physics, he couldn’t help thinking about the extreme heating and cooling the orbiter tolerated as it passed every 90 minutes from day to night and back to day. “It reminded me of the way one makes a steel wire break by twisting it until it fatigues away,” he says. “But at the end of the day, I would walk away in awe at the machine that kept me warm and cozy and safe so many times in such an inhospitable place.” After all, each orbiter was designed to operate for 100 missions.
Was there anything he would have changed about the orbiter? “The idea of sending crew and cargo together has never been my favorite,” says Chang-Dìaz. “I would have concentrated on a solely human vehicle and sent the cargo in a robotic craft. But this is all 20/20 hindsight, and considering the compromises that every major space program has had to accommodate, the end result was a technological achievement of the first order.”
Standardization was key to the shuttle’s purpose. “All the vehicles look basically the same,” says Ross. “There are some relatively minor differences. Obviously, Columbia being the first and the heaviest was probably the most significant difference.” Engineers erred on the side of caution, reinforcing Columbia’s airframe more than needed; it ended up 7,000 pounds heavier than the other orbiters. The extra weight disqualified it for later flights to the International Space Station. Because of the station’s high inclination—51.6 degrees from the equator—NASA had to sacrifice the launch boost provided by the spin of Earth. For each degree north in a launch trajectory, an orbiter had to leave about 500 pounds of payload at home. Columbia could have reached the ISS, but it wouldn’t have been able to bring much. Instead, it traveled to lower-inclination destinations, such as the Hubble Space Telescope, orbiting at 28.5 degrees.
Story Musgrave is the only astronaut to have flown aboard all five orbiters. “Columbia, I always viewed her as sort of the queen of the fleet,” he says. “Columbia was the first of the five to climb into space and the one that could orbit Earth the longest. It had more oxygen and hydrogen tanks. And so for every long-duration mission, it was Columbia that flew it. Because it turns out the limiting factor on all the flights was electricity.” On Musgrave’s sixth and final mission, STS-80, which launched in November 1996, the crew set a record for the longest shuttle mission: 17 days, 15 hours, 53 minutes, and 18 seconds.
Few astronauts have ever complained about the shuttle’s close quarters. And “close” is a relative term. Discovery, for example, offered 2,325 cubic feet of habitable volume, versus 316 for the Orion capsule that NASA proposed as the spacecraft after the shuttle, or 36 cubic feet inside the Mercury capsule.
“I loved to sleep on the flight deck,” recalls Ross. “But some commanders would not allow it, or some missions were 24-hour operations.” He would try to sleep during the night pass, he says, and wake for the day pass “to see parts of the Earth we would not have seen otherwise because of the orbit we were in.” It was also cooler on the flight deck, which had strong flows of fan air, he recalls.