Expedition_Zero_Part

28 November - 4 December: Waiting for Endeavour

As preparations continued for the launch of Endeavour on the first Space Shuttle mission of the ISS programme, Zarya remained in excellent condition circling the Earth every 92 minutes. Flight controllers planned for Endeavour to carry replacement parts to resolve the problem with Battery No. 1, although the decision on the actual installation any of the extra equipment would be taken during the STS-88 mission itself. The orbiter was also loaded with two replacement electronics boxes, a current-converter unit and a storage battery regulator unit (using the Russian acronym PTAB), along with associated cabling.

It was also decided that TV inspection of the TORU antennas would be conducted during a standard survey of Zarya and Unity on Flight Day 4 (FD4). The question of whether EVA astronauts Jerry Ross and Jim Newman would manually deploy the antennas if required remained undecided as the launch of Endeavour approached.

During the first two days of December, flight controllers uplinked a minor software change to the computer, to rectify a time synchronisation problem with ground control.

The intended launch of STS-88 on 3 December was cancelled at T-4 minutes due to a problem with an unprecedented drop in pressure in one of the Shuttle's three hydraulic systems. Fixing the problem took the hold past the five-minute launch window for the day, so the launch was rescheduled for 24 hours later.

STS-88 Crew

Robert D. 'Bob' Cabana, NASA, Commander (CDR), 4th flight
Frederick W. 'Rick' Sturckow, NASA, Pilot (PLT), 1st flight
Jerry L. Ross, NASA, Mission Specialist 1 (MS-1), 6th flight
Nancy J. Currie, NASA, Mission Specialist 2 / Flight Engineer (MS-2/FE), 3rd flight
James H. 'Jim' Newman, NASA, Mission Specialist 3 (MS-3), 3rd flight
Sergei K. Krikalev, Roscosmos, Mission Specialist 4 (MS-4), 4th flight.

The First Shuttle Mission to ISS

Endeavour, carrying five American astronauts, one Russian cosmonaut and the Unity Node 1, finally left the launch pad at 02:36 Central Standard Time (CST) on 4 December 1998. At the time of the Shuttle's launch, Zarya was on its 222nd orbit, 386 km (240 miles) above the Kennedy Space Center (KSC), Florida, with all onboard systems functioning well. By the end of their first day in space, the Shuttle trailed Zarya by 2,092 km (1,300 miles).

Over the next two-and-a-half days, STS-88 closed in on Zarya and the crew prepared for the rendezvous and docking phase. The Canadian-built Remote Manipulator System (RMS) robot arm was activated and tested and the Extra-Vehicular Activity (EVA) equipment was made ready. The Unity module was released and mated to the Endeavour docking system early on 6 December, in preparation for the capture and docking of Zarya later that day.

Using the 15.25-m (50-foot) RMS, MS-2 Nancy Currie grabbed Zarya out of orbit at 17:47 CST on 6 December. She aligned the module with the docking mechanism on Unity, as CDR Bob Cabana fired Endeavour's downward jets to nudge the modules together gently for a soft docking at 20:07. After releasing the Zarya module, the hard docking was achieved at 20:48.

Mated to Endeavour's payload bay, the ISS now measured over 23 m (76 ft) long, with a mass of 35,562 kg (35 tons). Zarya was no longer the only module of the ISS in orbit. With the successful docking of Unity to Zarya, the first expansion of the station had ended, but the work of STS-88 had only just begun. EVA astronauts Jerry Ross and Jim Newman would conduct three spacewalks to complete various tasks on the newly expanded station, including installing cables, connectors and handrails.

The crew of Endeavour - and mission STS-88 - undocked from the Unity Node at 14:25 on 13 December, after being linked to the Unity/Zarya combination for the previous 6 days 20 hours and 38 minutes. Endeavour then completed a pre-planned fly-around manoeuvre before finally separating from the ISS and preparing for landing. The first Shuttle mission to the now-designated International Space Station (ISS) had been completed successfully.

While a team of NASA flight controllers at the Shuttle Mission Control Center in Houston concentrated on getting the orbiter home safely, a second team of controllers at the Korolyov Mission Control Centre near Moscow continued to monitor the status of Zarya. A third team, also at Houston, was now handling data from the Unity module attached to Zarya. Initial ground control of the combination would be handled by the Moscow MCC when a Shuttle was not docked to the station. The next Shuttle scheduled to fly to ISS would be the STS-96 mission of Discovery in May 1999.

A few hours after Endeavour undocked from Unity, flight controllers at Korolyov manoeuvred the station into a naturally stable X-nadir spin, which orientated the American Unity module towards Earth and the Russian Zarya module towards deep space. This was done to moderate temperatures across the station and to conserve fuel reserves, as the ISS completed a slow spin of no more than a few tenths of a degree per second.

It was planned for controllers to activate the onboard steering jets on Zarya to manoeuvre it - in order to update the onboard guidance system and to perform other tasks - once a week until Discovery arrived at the station in 1999. Russian controllers also checked the KURS rendezvous system aboard Zarya to ensure that it was functioning correctly, ready to accept the Zvezda Service Module which was planned at this point to launch in July 1999.

The first opportunity to complete such a manoeuvre occurred on 16 December. In a test of procedures and a dual firing of the manoeuvring engines, the steering jets were activated, the guidance platform updated and the two large thrusters fired simultaneously for nine seconds.

The burn moved the ISS from an orbit of 405.5 x 392.7 km (252 x 244 miles) to its new altitude of 412 x 397.5 km (256 x 247 miles). orbiting Earth every 92 minutes. On 21 December, two more five-second burns of the same engines were completed, separated by 45 minutes. These further raised the orbit slightly, to 412 x 400 km (256 x 248 miles). Checks were also completed on the software for the onboard systems required for the forthcoming Zvezda docking. Following this manoeuvre, the ISS was returned to its naturally stable spinning attitude, once again conserving fuel and restricting temperatures.

With no major activities planned over the festive holidays, controllers continued with several smaller activities, as well as maintaining a 24-hour round-the-clock watch on the station and its onboard systems. This would become a routine exercise throughout the operational life of the ISS and includes deep cycling (individually discharging and recharging) each of the six onboard batteries as part of a standard twice-monthly housekeeping operation to optimise battery performance.

Flight controllers also successfully tested the manually operated TORU back-up rendezvous system on Zarya. During the EVAs on STS-88, astronauts Ross and Newman had deployed the two stuck antennas on the station exterior that had previously prevented a full check-out of the system.

On 28 December, controllers commanded the station to re-orientate itself to maximise power generation, as part of a test to ensure the vehicle could be manoeuvred into a power-friendly attitude (solar arrays pointing towards the sun) in the event of low battery levels.

With all operations proceeding smoothly and no major anomalies reported, the ISS continued to orbit the Earth every 92 minutes, as 1998 became 1999.