Shuttle to Mir: Let's Rendezvous in Space
FOR the American space-shuttle program, this is the year of Mir. For Russia's manned space-flight program, it's the year of the shuttle.
As agreements signed in 1993 and 1994 kick in, the long-held dream of Russian-US space-flight cooperation should become a reality.
The prelude to the main action is due to start Feb. 2 with dispatch of US shuttle Discovery to rendezvous with Russian space station Mir. The two spacecraft are to pass within 35 feet of each other as practice for a launch in June of shuttle Atlantis, which will dock with Mir.
In March, ``Phase One'' of the cooperative program should begin. That's when United States astronaut Norman Thagard plans to ride a Russian Soyuz spacecraft up to Mir for a three-month duty tour.
From March on, US astronauts will visit Mir regularly until construction of the international space station starts in 1997. At least seven shuttle flights are to ferry crews and supplies between our planet and the Russian station.
What the pacts don't specify is how this new togetherness in space is to survive political stress on Earth. One congressional analyst says manned space flight has always been tied to politics.
The new joint program could be vulnerable if the Clinton administration or the Congress decided to ``make a statement'' protesting Russia's handling of the Chechen rebellion.
It also could be jeopardized if economic damage from the war hurts Russia's ability to fund its obligations.
But the two countries have a far stronger public commitment to manned-flight cooperation than ever before. Suspending or curtailing this highly visible cooperation - to which Canada, Europe, and Japan are also committed - would be a far more serious step than such measures have ever been.
Therefore, the analyst said, he doesn't think it will actually happen. But it is a caveat to bear in mind.
The Mir-shuttle program is designed to test hardware and gain experience that that will lead directly to cooperation in the international space-station program. It is to be the laboratory in which two different cultures with different space-flight styles learn to work together.
The two countries have already been honing their cooperative skills in preparatory work. Cosmonauts have repositioned solar arrays and made other changes to prepare for shuttle visits.
Earlier this month, Alexander Viktorenko, Yelena Kondakova, and Valery Polyakov tested the Mir automatic docking mechanism that failed twice last year. Their Soyuz TM-20 space ship drifted away from Mir and redocked.
Russian mission control reported that the operation ``went smoothly.'' Both the Russian Space Agency (RSA) and the US National Aeronautics and Space Administration (NASA) want to ensure the mechanism will work when the shuttle Atlantis tries to dock in June.
Meanwhile, NASA has sent 90 solar-panel modules to Russia to be fitted into mounting frames. Atlantis is scheduled to deliver these to Mir in October to boost the station's power supply. The two countries also are testing a new docking module for the space station.
But the most important preparation has gone on in space and in space-flight simulators. The shuttle is bigger and more massive than any spacecraft that has yet docked with the station. It must be guided to the docking port as carefully as a pilot docks an ocean liner. The usual technique of firing rocket thrusters to slow the shuttle's approach won't work. Thruster plumes could damage Mir. Instead, mission commander Robert Gibson and pilot Charles Precourt will use what NASA calls a new ``inherently fail-safe'' technique to dock Atlantis in June. They will approach Mir from directly below. Astronauts will use thrusters to push the shuttle toward the docking port, but thruster plumes will be pointed away from Mir. Gravity will slow the shuttle's approach. Should the spacecraft lose power, it will just drift away from Mir. Scientists say it will not bump into the station.
The piloting requirements are tight. Atlantis must approach the docking port within two angular degrees of perfect alignment. It must ease itself in at a closing rate of only 1.2 inches a second.
That's four times slower than the smaller Soyuz spacecraft docks. Also, Atlantis must arrive within a four-minute time window when it and Mir are in contact with a specific Russian ground station.
So far, this technique has worked in space-flight simulators. An Atlantis crew also successfully demonstrated it last November while recovering the German Cristo-Spas satellite. Discovery's crew will practice it again when they approach to within 10 meters (33 feet) of Mir's docking port.
The shuttle's commitment to service Mir starts when Atlantis delivers supplies and cosmonauts Anatoll Solovyov and Nikolai Budarin.
It will bring back Norman Thagard and his Russian colleagues Vladimir Dezhurov and Gennadi Strekalov. Other Mir-shuttle missions currently are targeted for October 1995; March, July , and December. 1996; and May and September. 1997.
In the mission this week, NASA is planning a spacewalk by two astronauts and wants to release and retrieve a science satellite as well.