Tim Furniss/LONDON
Members of the crew of a routine Space Shuttle Discovery mission have waited a year to be launched but, during that time, their mission has taken on a higher profile, as well as an extra crewman. The wait will have been worthwhile. The Discovery is now to rendezvous with the Russian Mir 1 space station and will carry veteran Russian cosmonaut Vladimir Titov - who follows Sergei Krikalev as the second cosmonaut to fly on the Shuttle.
The Discovery is to be the pathfinder for the first joint mission by US and Russian spacecraft for 20 years. Carrying Eileen Collins as the first female Shuttle pilot, the crew of the STS63 mission will practise the rendezvous and stationkeeping manoeuvres which will have to be conducted during the first docking flight between sister ship the Atlantis and the Mir 1 in June 1995 and, subsequently, by up to six other Shuttles over the next two years, in preparations for the operation of the international Alpha space station.
On mission day 3, the Discovery will approach no closer than 10m to the Kristall module of the Mir 1 and will also be used to perform a fly-around of the space station, during joint close-proximity operations lasting about 75min. Because Russian mission managers insist that the rendezvous - as well as future dockings - takes place when the Mir is in contact with Russian ground stations, the Discovery's rendezvous will be in darkness. To make a daylight rendezvous would mean delaying the mission for at least two weeks, which cannot be tolerated within the NASA Shuttle schedule for 1995.
Although it will be used to test rendezvous procedures, the Discovery will not exactly simulate the Atlantis docking. The Discovery's approach will be a V-Bar manoeuvre to the Mir 1's Kristall module, which will be aligned backwards to the flight path of the station. For the docking mission, the Kristall will be moved 90degrees, to be perpendicular to the main axis of the station, which will be orientated so the Kristall points towards the Earth, and the Atlantis approach will be from below using an R-Bar manoeuvre.
The Discovery will also be used on a second rendezvous manoeuvre when it is moved to retrieve the Spartan astronomy and astrophysics science satellite which it is to deploy earlier in the mission. The Spartan 204 (Shuttle-pointed autonomous research tool for astronomy) will be deployed by Titov on mission day 2, using the remote-manipulator-system (RMS) robot arm. The free flier is equipped with a far-ultraviolet imaging spectrograph from the US Naval Research Laboratory. The retrieval will be made by Janice Ford, using the RMS.
Spacewalking
The Spartan will also feature in a spacewalk planned for the STS63 mission. Astronauts Bernard Harris and British-born Michael Foale will spend a maximum of 6h outside the Discovery on flight day 5, evaluating procedures that will be used during the construction and maintenance of the Alpha station. This will involve manoeuvring the Spartan satellite by hand in the payload bay.
The astronauts will also place themselves on the end of the RMS and be positioned directly above the payload bay, facing away from the Earth to assess new units in the environmental-control system which have been fitted to prevent the overheating experienced in previous spacewalks.
The other major payload aboard the Discovery is the Spacehab mid-deck extension module, being flown on its third mission. It was the need to ensure that the Spacehab 3 would carry a reasonably full complement of NASA-sponsored and commercial experiments which delayed the STS63 mission.
NASA experiments
The Spacehab is fitted with experiments from NASA, the US Department of Defense and National Institute of Health, and Canada's space agency. While the crew is not monitoring Spacehab experiments on future flights, scientists will be able to observe or interact with their experiments using the Charlotte, a robot developed by McDonnell Douglas, which will be assessed during the STS63 mission during a series of prescribed experiment-support tasks.
Other experiments being operated on the STS63 mission, mounted in the payload bay and in the Shuttle mid-deck, include the Orbital Debris Radar Calibration Spheres experiment, in which three metal "Spaceballs" and three dipoles, ranging in size from 50mm to 150mm diameter or length, will be deployed from the payload bay for calibrating ground-based radar and optical systems.
Source: Flight International
