Discovery is back, praise the Lord!
We are relieved, but we want more.
|DID WE JUST RUSH TO SPACE THIS TIME?
1. Is the 20-year old space flight technology viable?
2. Why did the external tank fuel sensors conk out several times?
3. How come the external tank throw up foam again?
4. Why did a piece of fabric stick out of the shuttle body, prompting a third repair
5. How come there have been so many launch postponements, and several landing deferments?
10 August, 2005: After its 14 days in space, Shuttle Discovery hurtled down from space, plunging through superheated plasma at hypersonic speeds, to enter the Earth's atmosphere. "I can see the runway", said STS-114 Commander Eileen Collins, as cheers went up at the control room at Nasa's Kennedy Space Centre. As Discovery touched down, the heartburn of the last fortnight became a mere memory, with smiling orange-suits stepping out of the spacecraft, seeing the ground beneath from close quarters again.
"It's going to be hard to top this mission," NASA Administrator Michael Griffin said. "Everywhere you look, there's nothing but outstanding success."
It has been really tough on Nasa this time - cautious optimism ruled as the Shuttle was returning to flight after two and a half years. The last shuttle - before Space Shuttle Discovery - flew in 2003, which broke up mid-air as it was re-entering Earth's atmosphere. Later, an inquiry committee found that when Columbia left for space, a small piece of foam had fallen off the shuttle's external fuel tank, blowing a hole in
the shuttle's belly. During its re-entry to
atmosphere, superheated gases entered Columbia's belly, blowing it to pieces. Nasa deferred shuttle flights indefinitely till the reasons for the shuttle collapse were found and rectified.
So, it was with much hope that the world awaited the lauch of Space Shuttle Discovery's STS-114 mission. After two delays, caused by a fuel sensor malfunction, the Shuttle finally left for space, even as furrows appeared on Nasa eyebrows - another piece of foam had fallen off Discovery's external fuel tank - the type of which had caused the Columbia disaster. Fortunately, the piece did not hit the shuttle. Yet, the worries were very real - this was exactly what Nasa engineers had wanted to prevent.
The space sojourn was more eventful than ever. STS-114 delivered supplies to the International Space Station, collected station material, repaired the station gyroscopes and did several experiments in space, besides repairing the shuttle itself. US president George Bush and Japanese prime minister Junichiro Koizumi congratulated the crew members and residents of the station.
Half the work in space must have been about safely returning the shuttle to Earth. Even as it approached the space station, Space Shuttle Discovery did a back flip to expose the thermal tiles to the cameras on the space station. The high-resolution pictures were sent back to Nasa's control room for analysis. The study found that there was a piece of fabric protruding from between the thermal tiles in Discovery's underbelly. Either it had to be fixed back into the tiles or had to be cut off, to prevent any chance of air friction overheating the errant piece on the shuttle's return to Earth. So, in an unscheduled third spacewalk, astronauts fixed the problem in a first-of-its kind repair on space.
After its scheduled 12 days in space, it was finally time for Discovery to come home. After all clearances from Nasa's ground control, the shuttle undocked from the space station and started drifting away. In a series of manouevres, the shuttle positioned itself in a pre-designated angle in the orbit, and started its deorbiting engine burns, taking it closer to the atmosphere. The engine burn started when the spacecraft was above the Indian Ocean, to bring the shuttle in a steep descent to ground at the California Edwards Air Force runway. It takes a total of about 30 minutes of free fall to reach the Earth Entry Interface.
As gravity drew the shuttle in like a magnet, the shuttle, already flying in orbit at high speeds, started feeling the effects of the atmosphere. At hypersonic speeds of 17,000 miles an hour, Space Shuttle Discovery entered the atmosphere in a series of manourvres to help dissipate the spacecraft speed as it zoomed down. The spacecraft,
on its atmosphere entry, turns into an aircraft. The Shuttle finally kissed the Edwards runway, before the first rays of Sun were up in the horizon.
The success of the mission notwithstanding, the fate of the shuttle itself remains under a cloud. Is the 20-year old space flight technology viable for the future? Why did the external tank fuel sensors conk out several times, despite Nasa spending enormours man-hours to make shuttle flights error-proof? How come the external tank disgorge the foam again, despite such a happening identified as the prime culprit for the Columbia disaster? Why did a piece of fabric stick out of the shuttle body, prompting a third repair spacewalk? Most importantly, how come there have been several launch postponements, and several landing deferments? Did Nasa send the shuttle up with adequate preparation?
Nasa does not have all the answers. Which is whey they immediately deferred further space flights, till the new questions are answered. Till now, Nasa's major responsibility was to make sure all recommendations of the Columbia Accident Investigation Board (CAIB) were met, before Return to Flight. Now, it has more questions to answer. How come the problems crop up again, if everything was fool-proofed?
"We have had a fantastic mission," Eileen Collins said shortly after the Discovery crew disembarked from the Shuttle. "We brought Discovery back in great shape. This is a wonderful moment for us all to experience."
The so-called marvel of modern technology, the Space Shuttle surely has a long, long way to go. Our children should be marvelling the space flights, not just relieved at seeing the shuttle back on ground. May be a new space shuttle, may be an entirely different wonder of technology is called for. Spacewatchers and astronauts surely wouldn't like to live with their hearts in their mouths whenever the shuttle goes to space, would they?