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Space Station Slowdown
May 18, 2000
A model of what ISS will look like, some day. image: NASA
With its launch early Friday morning, the space shuttle Atlantis is heading for a critical maintenance mission to the International Space Station. But even if the launch goes off without a hitch, there’s no guarantee that the construction of the ISS won’t be delayed. Again.
If the Russians put off the next phase of the project—the launching of the Zvezda Service Module this summer—relations between NASA and its Russian counterpart could be strained. "It’s a very crucial period in the construction of the International Space Station," says John Schumacher, a NASA spokesman.
The Atlantis mission—or STS-101, as NASA calls it—is just one of the more than 90 U.S. and Russian space flights needed to construct the ISS over a period of several years. When it’s completed, the ISS will measure the length of a football field and will have involved the efforts of 16 countries.
ISS assembly animation.
If you prefer to view it with Real Player, click here. clip courtesy NASA
Eventually, the ISS will be a permanent orbiting research laboratory where scientists will conduct experiments in the fields of medicine, engineering and biology. It will house up to seven astronauts at a time, allowing them to spend extended periods of time in orbit so that we can learn the long-term effects of microgravity, or weightlessness, on the human body.
But because it is such an enormous project, undertaken in space no less, setbacks and delays are inevitable. The latest of these is the Atlantis mission. Originally it was supposed to follow the Zvezda mission, but when that was delayed more than two years ago, NASA agreed to fly two separate Atlantis flights this year. STS-101 will replace components and refurbish the Zarya and Unity modules already in orbit. The update is necessary because the computers aboard Zarya were only supposed to control function for about 18 months. Then, after Zvezda is launched in mid-July, ST-106 will unload supplies onto it in August.
Zvezda image: NASA
The Zvezda launch is so important because it will serve as the early station living quarters, allowing astronauts to live on the ISS for the first time. It will also serve as a docking port for Russian resupply missions. But the most recent launch attempt failed last fall when the proton rockets that were supposed to deliver Zvezda didn’t work. Since then the Russians have been working to fix the problem.
"Our understanding, and we have people in Russia who are tracking that, is that it [the [proton rocket] is ready and it is being prepared for launch in the July time frame," says Schumacher. The service module itself is ready and waiting, he adds.
But the problems plaguing the Russians may be more than technical. Funding difficulties are to blame, Schumacher says. Unable to afford the maintenance costs of Mir, its aging and troubled space station, Russia abandoned the project last summer and was expected to let the 14-year-old station crash into the atmosphere and burn up. Last month, however, the Russians sent a crew to Mir.
The Mir Problem
Mir, still floating.
Even though the mission was financed by a private consortium, there is widespread concern that resuscitating Mir will siphon off already scarce Russian resources from the ISS, causing further delays. "We have had very detailed conversations with the Russian space agency as you can imagine," says Schumacher. "Our concern remains that Russia fully meet its International Space Station obligation. But what they do once they meet debt obligations is the commercial contractor’s business."
Should delays in the program continue, NASA says it has backup plans, as well as a backup module, which could involve changing the final appearance of the station. Those decisions could be made as early as July.
Scientists have already learned much about the feasibility of living in space from Mir. For example, they discovered that bone loss does not lessen over time spent in orbit and that seeds from plants grown in space can be planted and harvested there as well. So there are high hopes that the ISS will help them expand this knowledge—provided there are no further delays, technical or otherwise.
Elsewhere on the web:
Information about ISS orbit trajectories
NASAs Skywatch to find out when and where to see the ISS in the night sky
Living in the space shuttle
ISS Virtual Tour
Shuttle countdown and information about human spaceflight