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ISS: ZVEZDA MODULE IN POSITION

Only seldom before in the almost 40-year long history of manned spaceflight has a launch been accompanied by so much hope and anxiety as that of the Russian service module Zvezda (which means "star" in English). It is not just that chronic lack of cash on the part of the Russians had already caused several delays to the ISS construction schedule, which was revised for the fifth time in March of this year, but on top of that the unreliability of the Proton booster had recently been the cause of great worry to the international partners of the big construction site in space.

As the most powerful launch vehicle ever to have been built by the Russians, Proton had boasted a 98% success rate on earlier space missions, but a number of failed launches over the past year had shattered confidence in the missile. Specifically, problems with the upper stage block D had caused a spate of fatal payload losses.

As long as it was a matter of purely national projects such as geostationary communications or military satellites, the West was not that bothered, and in any case the launch of commercial satellites is a cut-throat business. Failure of Proton, which is marketed by International Launch Services (ILS) under the direction of Lockheed Martin, would have been only too convenient for Arianespace, for example.

But the ISS modules as well? Zarya had successfully reached its earth orbit and also docked with the Unity node. But the clocks were ticking. Zvezda was simply not ready, even though the hull of the module had been sitting at its manufacturer's, Khrunitchev, in Moscow for years. Originally it was planned that, as MIR 2, it would replace its predecessor, which is still orbiting the earth, but, as is known, that project died a quiet death with the collapse of the Soviet Union.

The cash-strapped Russian space agency Rosaviakosmos (RAKA) was forced to slow down drastically its work on equipping the service module. When it transpired that NASA itself was experiencing unexpected technical problems in building its own modules, the pressure on Moscow to progress the project eased off.

In February of this year the green light was finally signalled from Moscow with the announcement by RAKA that Zvezda would be launched in the period 8 to 14 July. However, the mission still required the approval of the International Steering Commission, which understandably imposed further hurdles to be surmounted before the launch could go ahead: Proton must demonstrate two faultless launches before confidence could be restored in the reliability of the launch vehicle.

In July and October 1999 two Proton boosters had exploded shortly after launch, resulting in a shower of debris and toxic fuel over Kazakh villages. The government of Kazakhstan had issued an immediate ban on further launches and demanded massive compensation from the Russians. The dispute over this money escalated, and immediately the issue of the annual rent Russia pays to the central Asian state reared its head. A number of times the Kazakhs threatened to shut down the Baikonur Cosmodrome. In fact this was only posturing, as they rely critically on the money.

And so it went on. No one was in position or prepared to give a guarantee that Zvezda would be launched safely into orbit. But without the module the entire ISS would have stood under a question mark, as Zvezda was the only module on the station to contain living quarters for astronauts together with life support, power supply, data management, flight control and propulsion systems. Without Zvezda it would only be possible for astronauts to work in the station hull when a space shuttle was docked.

Slowly NASA's patience began to run out. Undisguised threats from Washington that, if necessary, the ISS would be built without the Russians were becoming more frequent. Contracts once signed must be adhered to both in spirit and to the letter and not be subsequently reinterpreted into mere declarations of intent. NASA administrator Daniel Goldin was reluctant for the international space construction project to flounder due to the unreliability of a major partner, and ordered a separate, $200 million Interim Control Module (ICM) to be built which would be ready for use no later than December 2000. But if this had been launched, it would have signified the beginning of the end of Russian participation in the ISS.

At long last, two years late, the Russians woke up. The dispute about the future of the ISS developed into a high-profile political issue. The whole future of Russian manned spaceflight and the honour of the scientists and engineers involved on the project, and indeed of the entire country, were suddenly at stake. It was the last of these which proved the critical factor, as completion of the job was now declared a top priority of the President and his government. Funding was finally made available, not only to get Zvezda ready for launch but also to pay for design modifications to the Proton launch vehicle.

NASA's tough attitude was only too understandable. When it invited the Russians to participate in the International Space Station project back in 1993, it had hoped that the benefits of the Russians' many years of experience in operating permanent space stations and using their hardware would save around $2 billion. But this reasoning had turned out to be a fatal error, as the constant launch delays together added almost $3 billion of unplanned costs. The unscheduled maintenance and repair mission STS-101 in May 2000 constituted a major extra expense which the Americans had to bear on their own. The Russians were thus in a tight spot, if they wanted to regain the confidence of the international spaceflight community, and along with it their honour. Once again they demonstrated that they were capable of extraordinary technical achievements - as long as the work was going to be paid. In an astonishingly short time they redesigned the second and third stages of Proton and also solved some problems with their engines. At the same time they worked flat out on the integration of Zvezda and completed all the necessary tests on the module in record time.

The launch date in July now seemed a certainty - apart from the two remaining tests on Proton - when the US General Accounting Office (GAO) suddenly intervened quite unnecessarily. Quite unexpectedly, the concerns which Congress' watchdog agency now voiced were not over the financing of the ISS but the alleged safety shortcomings of the Russian module. In Moscow people might not work to NASA's standards, but future crews would have to endure high levels of noise which would be harmful to their health. On top of this there was the permanent risk of decompression of the station due to collisions with micro-meteorites or space debris, because the Russians had taken only inadequate precautions against such occurrences.

As expected, the Russian specialists reacted with mild irritation, suggesting to the ladies and gentlemen in the General Accounting Office in no uncertain terms that perhaps they might care to stick to matters they knew something about, such as financial matters. The Russian scientists had more expertise at designing space stations than an organisation full of US accounting officials, whose intervention on such technical issues was therefore inappropriate. However, the Russians would be happy to install quieter American fans in their modules - that is, if they existed. The matter was subsequently dropped, and NASA held back in gentlemanly fashion.

But the uncertainty persisted. Had the Zvezda been lost on launch due to another failure of the Proton booster, the result would have been a further three-year delay to the assembly of the ISS, to say nothing of the associated cost explosion. Just to re-boost the steadily slipping altitude of the ISS's orbit from time to time would have required additional shuttle flights or five to six unmanned Progress supply missions a year, which, given RAKA's financial plight, was not realistically on the cards.

On top of this there were problems with the construction of NASA's Interim Control Module, whose anticipated date of being ready for use was suddenly put back drastically from December 2000. Sadly the Americans were forced to admit that the earliest possible launch date would now be April 2001. Meanwhile, their planned Propulsion Module is already years behind schedule and will not be ready for launch before 2005.

Now the Russians showed just what they were capable of. On 6 June and 4 July 2000 they launched a modified Proton K with the new four-stage Breeze M, replacing the old Block-DM. During this period they also flew two of the older rocket launchers, again without mishap. 12 July was confirmed as the Zvezda launch date, even though concerns were being voiced in the West that the ground crew in Baikonur might be overworked due to all these launches, and that this in turn might jeopardise the success of Zvezda. There was no reaction from Moscow to these nervous prophecies of doom.

The launch date loomed nearer. The nervous tension mounted. But the Russians had confidence in their launch vehicle and in the Kurs rendezvous system. This confidence was not shared by all those involved since Zvezda, at 21 tonnes, was far bigger and heavier than either Zarya or Unity, which together weighed only 35 tonnes.

The station engines would have sufficient fuel for two docking attempts. If neither of these was successful, a Soyuz spaceship was on standby with the experienced cosmonauts Gennadi Padalka and Nikolai Budarin. In an emergency they would have formed the first ISS Expedition Crew and performed the docking manoeuvre manually.

But in the event everything went superbly. The launch on 12 July could not have gone better, and the docking operation on 25 July is viewed in specialist circles as a technical masterstroke. Confidence in Russian space technology, which proved so reliable on the day, has been largely restored, and Russia's international partners now have one less thing to worry about. It is only a matter of weeks now before human life moves into the station for the start of a new phase of scientific research on the station. One of the first European experiments planned, Global Transmission Services, will test the global synchronisation of clocks. Other experiments will follow soon afterwards.

Only the detailed schedule is now likely to undergo further revisions. The latest postponements have hit the Japanese spaceplane HOPE-X (H-2 Orbiting Plane-Experimental), which has been frozen for the time being due to technical problems with the new H-IIA space launch vehicle. The Japanese Experiment Module (JEM), known as "Kibo" (Japanese for "hope"), will not be ready until at least 2006, two years behind schedule. And finally Boeing has received a caution from NASA due to huge cost overruns on the Propulsion Module and now has to submit new plans. Meanwhile the Russians can at last sit back and relax - this time it is the other side who are in the hot seat.

From page 48 of FLUG REVUE 10/2000