Monster Storm

Unfortunately, the landing, like the launch, did not go entirely according to plan. STS-3 was originally supposed to come home, as the previous two missions had done, to Runway 23 at Edwards, on 29 March. However, unseasonal mid-March rain showers had left Edwards under several centimetres of water and four days before Columbia's launch the backup landing strip at White Sands in New Mexico was chosen instead. Ironically, despite having 90% near-perfect weather throughout the year, on the very day Lousma and Fullerton were to come home, it suffered its worst wind and sand storm for 25 years.

Although Edwards and KSC were the official end-of-mission landing sites, White Sands had been named as a 'contingency' strip in 1979. As well as offering an enormous runway, which provided the margins of safety needed by the Shuttle, it is virtually unobstructed and can be seen from space. It lies in a mountain-ringed, salt-

and-gypsum area called Alkali Flats and was first used by the Northrop Aviation Corporation in the 1940s to test their target-drone projects. The site quickly acquired the nickname 'Northrop Strip', which later became 'Northrup' due to a typo in a press release. The new name stuck.

By 1952, the site had become part of White Sands Missile Range and soon acquired a pair of 10.6-km-long runways, crossing each other in an 'X' shape. During the first two Shuttle missions, it would have been used if an emergency had forced them to return to Earth during their first orbit. Even today, although STS-3 is the only one to have ever come home to White Sands, it remains on NASA's list of contingency sites and astronauts continue to hone their flying skills there.

One person supporting STS-3's landing at White Sands was rookie astronaut Charlie Bolden, who would later fly Columbia in January 1986. ''This dust storm was unlike anything I'd ever seen,'' he said later. ''It's gypsum and it's very fine, like talcum powder. Everything was covered with plastic; the windows were sealed [but it] didn't make any difference. That was a hint that this was not a good place to land the Shuttle.''

Blissfully unaware of the poor weather in New Mexico, on 29 March the astronauts proceeded smartly through their preparations to fire Columbia's OMS engines for the descent through the atmosphere. Then, with less than half an hour to go before the burn, Mission Control advised them that conditions were unsatisfactory and they would try again on the 30th. The reason given was based on higher-than-allowable surface gusts, but in fact high-altitude winds were also unacceptable. After seven hectic, work-packed days in space, Lousma and Fullerton were overjoyed at the chance to spend more time aloft.

''There was this realisation: 'hey, this is free time', and it was terrific,'' Fullerton said after the mission. ''We got out of our suits, and then we got something to eat and watched the world and I wouldn't have had it any other way, if it had been my choice. In fact, we flew right over White Sands with [Columbia's] nose pointing straight down, and I could see this monster storm going on there. It looked like it was headed for Texas, the dust in the valley there. It was clearly a good decision. It looked really bad down there.''

Already, astronaut John Young, flying weather reconnaissance runs over White Sands, had recommended that conditions were nowhere near acceptable for Columbia to land. ''We had drifts blow sand into the [public-affairs] area and some areas up against buildings; it was about 18 inches deep!'' said White Sands facility manager Grady McCright. ''The runway got eroded [by the] wind. So we had people driving a road grader that night [to] grade it, compact it and get it ready for landing the next morning. The wind didn't quit blowing until dark that night.''

Fortunately, by 30 March the sandstorm had subsided and the STS-3 crew repeated their preparations for re-entry without problems. One of the APUs was switched on just before the burn and the other two came online shortly after Columbia made contact with the uppermost limit of the atmosphere. Sixteen minutes into the fiery plunge back to Earth, the Kuiper Airborne Observatory successfully acquired its third set of IRIS data, photographing the Shuttle's glowing belly and sides as she hurtled home at 15 times the speed of sound.

Columbia descends towards landing at the end of STS-3.

Fullerton was clearly overwhelmed by his first flying experience where outside temperatures closely matched a blast furnace. ''The entry was pretty cool,'' he said later, ''because it was an early morning landing, meaning that the main part of the entry is at night, so we could see this glow from the ionisation really bright out there.''

As Columbia continued to fall, passing over Edwards and heading for the mountains of New Mexico, Lousma prepared for the ultimate flying challenge of his career: landing a $2-billion spacecraft first time, with no opportunity to recover from a missed approach. When the Shuttle reached 3,000 metres, he tested the 'autoland' system - which NASA expected to use operationally on future missions - but took manual control 42 metres above the runway. After so many years preparing for this moment, there was no way the seasoned test pilot would allow a computer to land his ship.

That, however, was not the only concern. ''The crews [are] very concerned that they have everything that they can at their control to make sure it goes well,'' said Arnie Aldrich, ''and what they were worried about is not that the autoland system wouldn't fly the vehicle right, what they're worried about is if there was some glitch in the autoland system right at a critical [point] of approach, and they had to take control back over: the transient of getting off the autoland and back into manual control might be something they couldn't deal with.''

Charlie Bolden, who had followed the development of the Shuttle's software during his first two years as an astronaut, was unhappy about using autoland so close to touchdown, especially on a test flight. ''We developed the procedures that we would use for autoland, how they would manually take over at the very last second, to go ahead and land the vehicle,'' he remembered later. ''We recommended [that] this was not a good thing to do. You're asking a person who's been in space to take over in this dynamic mode of flight and land the vehicle safely.

''Their physical gains, their mental gains, their balance; everything's not there. Not a smart thing to do. Everything we had seen at [NASA's] Ames [Research Center at Moffett Field in California] in the simulator, when we were in complete control of our faculties, told us you didn't want to do that. But the decision was made that 'we really need to demonstrate this, so we're going to do it and we're only going to go to 500 feet anyway.''

It was decided before the flight to use airspeed, rather than altitude, as a cue to deploy the landing gear. The wheels began to lower 30 metres above the runway, but took longer than expected to deploy; they only locked into place a mere two seconds before Columbia touched down. To observers, it was nail-biting to see a Shuttle streaking in to land at over 320 km/h with her gear still in the process of coming down. Fortunately, the landing was successful, although NASA would revert to using altitude, rather than airspeed, as a cue on future flights.

The decision to use airspeed, rather than altitude, as the landing cue resulted in Columbia touching down 1.2 km past the runway threshold and required Lousma to apply differential braking to keep the Shuttle within 24 metres of the centreline. Although the vertical impact velocity of both the main and nose gears was within the limits set by mission rules, it was still harsher than expected and caused a 46-cm scrape in one of her tyres, a cracked beryllium rotor in one of her brakes and extensive contamination by the white gypsum dust.

So fine was the dust that it quite literally saturated the entire spacecraft and caused extensive damage that was not entirely resolved in time for her next flight -nor for the remainder of Columbia's career, according to Bolden. ''That was Columbia! I flew it several flights later, on my first flight, and when we got on orbit there was still gypsum coming out of everything! They thought they had cleaned it, but I think probably some of the debris from Columbia that we gathered probably had gypsum in it. It was just unreal what it had done.''

0 0

Post a comment