Carried a Russian Defence Ministry communications satellite. First attempted flight of the Khrunichev Briz-M upper stage in place of the usual Block DM. After the second stage explosion the remainder of the vehicle survived for 45 seconds before breaking up. Debris landed near Karaganda. As a result of this accident the Kazakh government suspended launches from Baikonur pending Russian agreement to pay back part of rent owed.

The launch was from one of the three active R-7 class pads at Plesetsk (LC16/pad 2, LC43/pad 3, LC43/pad 4) and used the 8K78M launch vehicle, consisting of the 11S59 core packet, the 11S510 Block I third stage, and the Block-ML upper stage. The Block ML and the payload were placed in a 62.8 degree low parking orbit and then the ML fired to deliver the payload to a 12-hour operational orbit. This was the 52nd Molniya-3 to be launched.

Delivered supplies to the crew of the Mir complex. Docked with the Kvant port at 17:53 GMT on July 18. Remained docked to the station after the departure of the last operational crew in September 1999. Undocked on February 2. 2000, to clear the port for Progress M1, at 0311:52 GMT. Deorbited over the Pacific later the same day at 0610:40 UTC with an 8 minute burn.

First of a new generation of larger Okean oceanographic satellites, carried a side-looking radar (RSL-BO), and a set of visible and infrared scanners and radiometers. It is built by the Ukrainian Yuzhnoye company and is a joint project of the Russian Aviation/Space Agency (RAKA) and the Ukrainian National Space Agency (NKAU).

The Chandra Advanced X-ray Astrophysics Facility was one of NASA’s four Great Observatories (along with Hubble Space Telescope, Compton Gamma Ray Observatory, and the SIRTF). Chandra will study the composition and nature of galaxies, stellar objects and interstellar phenomena as well as basic issues in theoretical physics using the most sensitive X-ray telescope ever built. The IUS under-performed and placed Chandra in an orbit about 900 km lower than planned. Therefore Chandra's own IPS propulsion system had to be used to make up the difference. The first such manoeuvre was at 01:11 GMT on July 25 when the IPS engines fired for 5 minutes to raise perigee to 1192 km. Further perigee burns on July 31, August 4, and August 7 raised the orbit to its final 10,000 km x 140.000 km. Additional Details: Chandra.

Mir spacewalk started at 11:06 GMT. Afanasyev and Avdeyev installed a new experimental 6-meter antenna but failed to deploy it.

STS-93 was first rolled out to pad 39B on June 7 1999. The Chandra/IUS-27 vehicle was placed in the payload canister on June 19. The first launch attempt was on July 20, but controllers aborted the launch at T-6 seconds, just before main engine ignition, due to a data spike in hydrogen pressure data. This was determined to be due to a faulty sensor and a second attempt was on July 22. A lightning storm prevented launch during the 46 minute window, and the launch was again scrubbed. Finally the vehicle lifted off the pad on July 23, but five seconds after launch a short in an electrical bus brought down two of the three main engine controllers. Backup controllers took over, but a further failure on the backup controller bus would have resulted in engine shutdown and the first ever attempt at an RTLS (Return To Launch Site) abort. To further complicate matters engine 3 (SSME 2019) had a hydrogen leak throughout the ascent, causing the engine to run hot. Controllers sweated as temperatures neared redline. The hot engine’s controller compensated as programmed by using additional liquid oxygen propellant. The final result was that the shuttle ran out of gas - main engine cut-off (MECO) was at 04:39 GMT, putting Columbia into a 78 km x 276 km x 28.5 degree transfer orbit. Columbia was 1,700 kg short of oxygen propellant and 5 meters/sec slower than planned. The OMS-2 engine burn at 05:12 GMT circularised the orbit 10 km lower than planned.

The orbiter payload bay contained only the Chandra spacecraft, the IUS, and the IUS tilt tableTthe following payloads were carried in the shuttle’s cabin: STL-B (Space Tissue Loss), CCM (Cell culture module), SAREX-II (Shuttle Amateur Radio Experiment), EarthKam, PGIM (Plant Growth Investigations in Microgravity), CGBA (Commercial Generic Bioprocessing Apparatus), MEMS (Micro-electric Mechanical System), and BRIC (Biological Research in Canisters) and SWUIS (the Southwest Ultraviolet Imaging System, an 0.18-m UV telescope to be used for airglow and planetary observations); GOSAMR (the Gelation of Sols: Applied Microgravity Research experiment) and LFSAH, the Lightweight Flexible Solar Array Hinge. MSX and SIMPLEX experiments were also to be carried out.

Chandra/IUS-27 was deployed from Columbia at 11:47 GMT July 23. Flight duration was limited; this was the heaviest shuttle (122,534 kg) and heaviest payload (19,736 kg) to that date. Columbia landed at 03:20 GMT on July 28 on runway 33 at Kennedy Space Center. Post-flight inspection found the presence of holes in the cooling lines on the nozzle of SSME 2019 (engine 3) which caused a hydrogen leak. A loose repair pin in the engine broke free and caused the failure. The cause of the short was found to be chaffed wiring inside the shuttle. The entire fleet was grounded for inspection and replacement of wiring as necessary. References: 4 , 7 .

The spacewalk started at 09:37 GMT. Afanasyev and Avdeyev erected an experimental 6-meter antenna. At the end of the experiment the antenna was jettisoned.

The launch vehicle delivered its H-10-3 third stage and the Telkom 1 payload into a 221 km x 35687 km x 7.0 degree geosynchronous transfer orbit 21 minutes after launch. Telkom 1 was owned by PT Telkomunikasi of Indonesia and was a successor to the Palapa series of satellites. Mass of Telkom 1 was 1700 kg in geosynchronous orbit after its on-board engine made the apogee burn. Stationed at 108 deg E.

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 in Russia on December 15, 1999.

Geosynchronous communications satellite. Stationed at 112 deg E.

The first two Yamal communications satellites were placed into a 197 km x 36,311 km x 49.3 degree transfer orbit The DM-2M fourth stage made two successful burns, placing the satellites in circular 36,000 km geosynchronous orbits. Yamal 101 reportedly ran into problems after it was deployed. RKK Energia built the new Yamal satellites for AO Gazcom of Moscow, a joint venture of RKKE and RAO Gazprom, the Russian natural gas monopoly. The two satellites will support internal communications for RAO Gazprom.

Geosynchronous communications satellite. Stationed at 90 deg E.

Foton 12 carried European microgravity experiments. The spacecraft's descent module landed on Russian territory at 52.47 deg N 53.83 deg E on September 24, 1999.

The third stage put the complex into a 235 km x 906 km x 51.9 degree transfer orbit. The Ikar upper stage maneouvered, placed the four satellites into their final parking orbit, then made a deorbit burn and re-entered on September 24.

The Centaur second stage put Echostar 5 into a supersynchronous transfer orbit of 131 km x 45526 km x 26.6 degrees. The satellite's own engine put it into the final geosynchronous orbit. Echostar 5 was a Ku-band satellite, part of the Dish Network. Stationed at 110 deg W.

Commercial / civilian high resolution (1 metre resolution) photograhic satellite.

Telstar 7, owned by Loral Skynet, had 24 C-band and 24 Ku-band transponders. Dry mass was 1537 kg. After placement in final geosynchronous orbit it provided communications for North America from a position at 129 degrees East longitude. Stationed at 129 deg W.

Geosynchronous communications satellite. Stationed at 75 deg E.

Remote sensing film satellite. Recovered in Russia on October 22, 1999.