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SHUTTLE COMPLETES FIRST RENDEZVOUS WITH ISS

On 27 May the Space Shuttle Discovery took off on its Mission STS-96 headed for the International Space Station (ISS). It was the first Shuttle flight this year. Even this flight got delayed by a week at the last minute because the external tank was damaged during a hailstorm. Most of the 648 holes in the foam insulation had to be filled with new insulation material.

The spacecraft's take off went without a hitch. Two days later, on 29 May, Discovery's commander Kent Rominger docked the Shuttle with the seven-story space station at an altitude of 380 km. The first task of the seven STS-96 crew was the eight hour spacewalk of the two US Mission Specialists Tamara Jernigan and Dan Barry. The two astronauts were asked to attach about 1.8 tonnes of hardware to the outside of the two station modules, which are used during later ISS assembly flights.

During this activity Jernigan worked primarily on a platform, which is fitted to the Shuttle's robotic arm. In the meantime Barry moved freely along the 23meter long station. During this spacewalk both astronauts were linked with Discovery by a double safety line. They were also carrying emergency jetpacks on their backs.

Jernigan and Barry's first task was to attach the American Crane OTD (Orbital Transfer Device) with a mass of about 90kg to the linking adapter (Pressurised Mating Adapter), which connects the US Module Unity to the Russian function block. The crane can be extended telescopically to a length of six meters.

After that the two astronauts fitted the Russian crane Strela to the PMA-2, which connected the Unity Module with the docking mechanism during the visit of Discovery. The positions of both cranes are only temporary and will be changed during the continuing ISS outfitting.

As well as the two cranes the two astronauts made secure three bags containing tools, handles and two portable foot rests, into which both American and Russian spacesuit boots fit. All this work was done to the outside of the module. This outside activity of the STS-96 crew was the second longest during a Shuttle mission and is only surpassed by the Intersat-Repair-Mission, which took place in 1992 and lasted 8:29hrs.

To transport the crew to the ISS the double Spacehab-Logistics-Module and for the first time the Integrated Cargo Carrier, the ICC, were used. The latter was especially designed by the Dasa Spaceflight Infrastructure department and the Russian RSC Energija for ISS logistics flights of the US spacecraft.

The cargo carrier is installed in the front part of the shuttle payload bay and is said to allow a much better use of the available space. The ICC Platform, which measures 4.37 by 2.4 meters, is able to carry pieces of equipment weighing up to four tons. It is connected with the cargo bay via specially shaped keel carriers. These act as buffers during the shuttle's take off.

After having completed their activities outside the space station, the STS-96 crew entered the Space Station, which had orbited Earth for five and a half months unmanned. During the next four days the Shuttle crew loaded 580 kg of American and 775 kg of Russian supply goods into the station. These will be needed by the station's first permanent crew. They include clothing, water, sleeping bags, spares and medical equipment. The cargo was stored in 123 cargo sacks. 71 of these remained unopened in the Russian module and 15 in the US part. The remaining sacks were opened by the crew and stored on board the station.

After entering the ISS, one of the most important tasks was the repair of a faulty communications system inside the American module. It had failed a few weeks before Discovery docked. Data connection with the Unity Module had to be done via the Russian system until the repair could be carried out. Apart from this the Discovery crew replaced 18 battery chargers which are important for charging the six critical nickel cadmium batteries inside the Russian module. In order to carry out this repair, the crew had to lift up floor plates of the module.

In all the Discovery Crew spent 79:30 hrs onboard the Space Station. The last hatch was closed in the early hours of 3 June. One hour later Shuttle commander Rominger and pilot Rick Husband fired the spacecraft's thrusters 17 times, in order to lift the station's orbit by ten km and thus transport ISS into the correct position for the arrival of the Russian service module. After a re-boost lasting 37 min, the International Space Station is now in an orbit at a height of 396 x 388km.

Before Discovery started its journey home, the crew launched the mirror satellite Starshine, which will be used by students to calculate atmospheric density.

According to the station management's latest plans, the long awaited third station module will be launched in November 1999 by a Russian launcher and will dock with the ISS via remote control. In December of this year, only a short time later, the next manned supply mission will take off for the ISS with the Shuttle Atlantis.

From page 42 of FLUG REVUE 8/99