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Archive for 1998

21-Oct-98 | Delta III failure investigation completed

The unexpected roll oscillation during the Delta III launch on 27-Aug-98 was the result of a single roll mode out of 56 in the control software. The mode caused the Thrust Vector Control motors to gimbal back and forth in unison, generating torque vectors which became significant at altitude as the rocket shed propellant mass. A bug fix in the software should have the Delta III ready for its scheduled return-to-flight in early 1999. Boeing press release

19-Oct-98 | NEAR TCM uses upgraded software

Near-Earth Asteroid Rendezvous (NEAR) will be the first spacecraft to orbit a near-Earth asteroid when it arrives at 433 Eros on approximately 10 January. Launched on Delta 232, NEAR recently received upgraded Flight Computer software which will provide “fancy burn” control for use in orbit. TCM 15 using the fancy burn software was successfully completed on 14 October at 1659 UTC.

19-Oct-98 | Delta IV news

Big news about the next-generation Delta IV!

17-Oct-98 | Mars probe processing update

Both Mars Surveyor 1998 spacecraft are now at KSC and will launch on Delta 7425s. Their science payloads are assembled, tested, and ready for flight. Both spacecraft have had problems with cracked glass-body diodes in their power distribution systems, but change-outs are proceeding with no apparent effect on the launch dates.

13-Oct-98 | Iridium vehicle preparation

At Vandenberg AFB, vehicle prep continues for Iridium MS-11, where simulated flight testing is proceeding. Delta II rockets have already launched 50 Iridium satellites, and this flight will carry 5 more. The Iridium system will have its customer debut on 1 November.

01-Oct-98 | Gamma ray flare

A tremendous gamma ray flare reached Earth on 27 August (29-Sep-98 NASA Press Release). The flare, emitted from a newly discovered type of star called a magnetar, was so bright that it saturated the gamma ray detectors aboard the Rossi X-Ray Timing Explorer (Delta 230) even though RXTE was pointed over 40 degrees away. At least 6 other spacecraft were similarly affected, including NEAR.

28-Sep-98 | Web site news

History of the Delta Launch Vehicle has a new location! Please update your bookmarks to The site at will continue to be updated as long as it exists.

28-Sep-98 | MGS resumes aerobraking

Mars Global Surveyor (Delta 239) had a successful apoapsis burn on 23 September and has resumed aerobraking. (Latest info)

15-Sep-98 | Delta flight 259 – Galaxy 10 (FAILURE)

At 71.5 seconds into flight, the first Delta III was destroyed. Around 55s into flight, a 4-Hertz roll oscillation began. All control systems — the main engine gimbal, two vernier engines, and three Thrust Vector Control (TVC) solid motors — attempted to compensate for the roll. Ten seconds later, the TVC system used up the last of its expendable hydraulic fluid, which left two motors providing an over-turning movement. The main engine and verniers were unable to compensate, and the vehicle yawed too far and broke apart, triggering the self-destruct system. Investigators now seem to believe the unanticipated oscillation was caused by a control failure in the TVC system.

11-Sep-98 | Globalstar moves to Delta

Following the loss of a Ukraine-built Zenit vehicle with 12 satellites aboard, and the embarrassment of a pre-written launch commentary which claimed a success, Globalstar has remanifested 12 satellites to 3 Delta II vehicles to be launched in 1999.

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