The Kvant-2 hatch had been fixed from within and was used for the EVA. Objective was to repair the damaged Spektr solar panel. Handrails were installed near the panel but the crew could not complete the work before the scheduled time ran out.

NASA's third Small Explorer, the Transition Region and Coronal Explorer (TRACE), was successfully launched by an Orbital Pegasus XL. The L-1011 carrier aircraft took off from Vandenberg and dropped the Pegasus over the Pacific Ocean. TRACE, a project led by Lockheed's solar physics group, carried a 30-cm extreme ultraviolet imaging telescope which will study the Sun. The telescope mirrors were made by the Smithsonian Astrophysical Observatory. TRACE had an 8.5 arcmin field of view and 1 arcsecond resolution.

The crew succeeded in completing repair of the damaged Spektr solar panel. However the EVA was cut short when Mission Control in error commanded the Mir to drift. This was then misdiagnosed as a depletion of fuel of the VDU orientation engine, and the crew was ordered back into the station.

Plane 1. Ascending node 167.9 degrees.

Plane 1. Ascending node 167.8 degrees.

Plane 1. Ascending node 167.6 degrees.

Plane 1. Ascending node 167.9 degrees.

Plane 1. Ascending node 167.8 degrees.

Plane 1. Ascending node 167.8 degrees.

The Proton launch vehicle placed the Iridium cluster and the Block DM2 stage into low parking orbit. The DM2 fired twice to enter the deployment orbit and dispensed the seven satellites, which used their own propulsion units to reach operational altitude. The DM2 stage then fired again to deorbit itself, to avoid creating space debris. SV068 placed in Plane 1. Ascending node 167.8 degrees.

The cosmonauts began a series of three EVA's to install the new VDU station orientation engine (delivered by Progress M-38) into the Sofora boom. On this first spacewalk they disconnected the old engine (in use for six years) and pushed it into space.

Installation of the new VDU station orientation engine assembly was completed at the end of the Sofora boom.

Columbia rolled out to pad 39B on March 23. Payloads:

• Spacelab transfer tunnel
• Spacelab Long Module, with Neurolab experiments for the following life science studies:
  • Chronic Recording of Otolith Nerves in Microgravity
  • Development of the Aortic Baroreflex under Conditions of Microgravity
  • Neural-Thyroid Interaction on Skeletal Isomyosin Expression in OG
  • Spatial Orientation of the Vestibulo-Ocular Reflex and Velocity Storage
  • Autonomic Neuroplasticity in Weightlessness

• Extended Duration Orbiter pallet
• Two Get Away Special beams with canisters G-197, G-467, G-772 (Colorado's COLLIDE experiment, which collided small particles into each other to simulate the formation of planets and rings).

The Neurolab mission was managed by NASA-Johnson at Houston, unlike earlier Spacelab flights which were NASA-Marshall/Huntsville's responsibility. Landed at Kennedy Space Center May 3 1998. References: 4 , 7 .

Two truss structures on the Kvant module and the new Sofora VDU station orientation engine assembly was unlatched from Progress M-38.

Plane 2. Ascending node 90.2 degrees.

Plane 2. Ascending node 88.0 degrees.

Plane 2. Ascending node 90.4 degrees.

Plane 2. Ascending node 88.9 degrees.

Geostationary at 109.9 degrees E.

Egypt's first satellite. Geostationary at 7.0 degrees W.

Geostationary at 73.0 degrees E.

Plane 2. Ascending node 199.4 degrees. Not in service.

Plane 2. Ascending node 199.3 degrees. Not in service.

Geostationary at 148.0 degrees W.

GT-27PA

NOAA K carried a new microwave sensor in addition to the standard optical/near-infrared radiometers and imagers and the SARSAT search and rescue package. It was the first NOAA launch to use the Titan 23G launch vehicle, a refurbished ICBM. Titan 23G-12 placed NOAA K into a suborbital trajectory 6 minutes after launch. A Star 37XFP solid motor on the satellite fired at apogee to put NOAA K in orbit.

Docked with Mir at the Kvant port at 23:51 GMT on May 16 1998, bringing supplies and scientific experiments to the station. Undocked 09:28 GMT on August 12 1998 in order to clear the port for Soyuz TM-28. Deorbited over Pacific Ocean on October 29, 1998.

Plane 1. Ascending node 167.8 degrees.

Plane 1. Ascending node 167.8 degrees.

Plane 1. Ascending node 167.8 degrees.

Plane 1. Ascending node 167.8 degrees.

Plane 1. Ascending node 167.7 degrees. Not in service.

Also known as Chinastar 1; comsat to serve China, India, Korea and Southeast Asia with 18 C-band and 20 Ku-band transponders. Operated by the China Orient Telecommunications Satellite Company, part of the Chinese telecommunications ministry. Zhongwei 1 and the CZ-3B's final liquid hydrogen upper stage were placed in an initial supersynchronous 216 x 85,035 km x 24.4 deg transfer orbit. Geostationary at 87.6 degrees E.

The final shuttle-Mir mission, STS-91 recovered NASA astronaut Andy Thomas from the Mir station and took Russian space chief and ex-cosmonaut Valeri Ryumin to Mir for an inspection tour of the ageing station. This was the first test of the super lightweight Aluminium-Lithium alloy external tank, designed to increase shuttle payload to the Mir / International Space Station orbit by 4,000 kg. At 22:15 GMT Discovery entered an initial 74 x 324 km x 51.6 deg orbit, with the OMS-2 burn three quarters of an hour later circulising the chase orbit. Discovery docked with the SO module on Mir at 17:00 GMT on June 4. NASA equipment was retrieved from the station, and Discovery undocked at 16:01 GMT on June 8, and landed on Runway 15 at Kennedy Space Center at 18:00 GMT on June 12. References: 4 , 7 .

GT-167GB

The spacecraft was delivered to its final orbit in a complex series of five engine burns by three rocket stages. The Delta's second stage demonstrated its restart capability in 4 burns: Burn 1 placed the rocket and payload into a low circular orbit; Burn 2 raised the apogee to 1400 km; Burn 3 circularised the orbit at 1400 km. The second stage then separated, and Burn 4 lowered the spent stage's perigee to a low altitude to ensure the stage would decay quickly and not add to the space junk already on orbit. Stage 3 burned once to place the payload and its kick motor into a high 1400 km perigee geosynchronous transfer orbit. The Stage 4 Star 30 apogee kick motor circularised the spacecraft's orbit at geostationary altitude. Geostationary at 0.8 degrees W.

Six Strela-3 military communications satellites launched as usual by a single launch vehicle. However the S5M third stage cut off early during its circulisation burn, leaving the satellites in elliptical 1300 x 1900 km orbits. References: 279 .

Satellite had 28 C-band and 3 Ku-band transponders, and initially served the Atlantic Ocean region for INTELSAT. Launch vehicle put payload into geosynchronous transfer orbit with GCS trajectory option. Geostationary at 55.5 degrees W. References: , 278 .

High resolution photo reconnaissance; returned film in two small SpK capsules during the mission and with the main capsule at completion of the mission. Landed October 22, 1998.

Two Minuteman 3 missiles launched from Vandenberg to Kwajalein Atoll, one from silo LF-09 and the second from LF-10. Each carried three re-entry vehicles.

GRP IDF-1

GT-168GB

Photo/digital surveillance. Entered an initial 170 x 290 km x 64.9 deg initial orbit. It manoeuvred to its operational orbit of 240 x 302 km x 64.9 deg on June 27.