To preserve an option to fly an additional Space Shuttle mission this year to perform maintenance on the
International Space Station, Shuttle and Station managers today decided to formally plan a revision to the
content of Shuttle mission STS-101. The planning will allow the orbiter Atlantis to visit the Station in April
if needed, ahead of the arrival of the Russian Zvezda service module, to perform maintenance. However,
managers could decide as late as March to return to the original planned content for STS-101 and eliminate
the added mission based on the launch date selected for the Russian Zvezda service module by the Station

The option including a Station maintenance flight would distribute the original content of STS-101 between
two Shuttle missions. The first mission, now targeted for launch no earlier than April 13 aboard Atlantis, will
retain the STS-101 designation but be a 10-day long flight to perform maintenance on the International
Space Station’s Zarya and Unity modules. The second mission, which would be designated STS-106 and
remains under review by managers, would be a Zvezda module outfitting mission that would dock with the
Station about one month after Zvezda’s launch.

The plan for near-term Shuttle and International Space Station launches now includes:

Date Mission/Vehicle Payload
1/31/00 STS-99/Endeavour Space Radar Topography Mission
NET 4/13/00 STS-101/Atlantis ISS maintenance/Assembly Flt
TBD ISS-1R/Proton Zvezda service module/Assembly Flt
TBD Possible STS-106/TBD ISS Zvezda outfitting/Assembly Flt

Whether or not STS-106 will be required and any necessary adjustments to the target launch dates for
subsequent Shuttle flights will be dependent on the launch date scheduled for Zvezda. A launch date for
Zvezda is expected to be selected following an International Space Station Joint Program Review to be held
next month. The composition of crews for a revised STS-101 and STS-106 is under review.