Since this series of articles began, the National Aeronautics and Space Administration and the Russian Space Agency have taken what NASA administrator Daniel S. Goldin calls "the next crucial step" in building a spaceflight partnership.

They have formally agreed to the following joint efforts:

1. NASA will fly two instruments to the Martian surface on the Russian "Mars '94" mission landing craft.

2. Russian cosmonauts Vladimir G. Titov and Sergei K. Krikalev begin astronaut training at the Johnson Space Center in Houston this month. One of them will fly on a space shuttle mission in November 1993. Colonel Titov holds the space flight endurance record for a Mir space station mission that lasted 365 days, 23 hours, 29 minutes, from Dec. 21, 1987 to Dec. 21, 1988.

3. A NASA astronaut - yet to be named - will fly a mission lasting more than 90 days on the Russian Mir space station. He or she will begin cosmonaut training at the Russian Star City cosmonaut center near Moscow about a year before the mission. A Russian Soyuz spacecraft will ferry the astronaut to Mir.

During this mission, a NASA space shuttle will ferry a replacement crew of two Russian cosmonauts to Mir. It will return the two Russian cosmonauts and American astronaut, who were serving on Mir, to the United States. There, they will carry out post-flight work on life-sciences experiments they conducted on board Mir.

Johnson Space Center information officer Barbara Schwartz says people at the center are "excited" at the opportunity to work with the Russian cosmonauts. She explains that "we really have good feelings for them because of the Apollo-Soyuz [1975 joint spaceflight] experience." She adds that "there are still some people here from that period."

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