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Archive for February, 2002


14-Feb-02 | Delta flight 290 – Iridium-12

After three scrubbed attempts, Delta flight 290 successfully launched five replacement satellites for the Iridium constellation on Monday, 11 February. The official liftoff time was 1743:44.382 GMT.

On Friday, 8 February, the count was stopped at T minus 55 seconds due to a strong gust of wind at the launch pad that violated launch constraints. The next day, the launch was scrubbed due to mechanical problems with a P-3 ARIA aircraft used as a downrange telemetry relay during the portion of the flight leading up to SECO 1. Then on Sunday, a faulty first stage fuel sensor was reading “wet” when tanking operations had not yet begun, resulting in replacement of all three sensors in that tank.

Finally, on Monday the weather was clear but breezy, and the count proceeded without a hitch, though a range issue did arise that this author had not previously seen. Range safety officers were concerned about covers over the nozzles of the three air-lit solid booster motors that are used to protect the interior of the motors from buffeting and exhaust impingement during the first minute of flight. Computer models of the wind conditions at launch time predicted that the covers, which pop off the air-lit motors when they are ignited, had a chance of falling near Vandenberg’s Titan launch pads. Fortunately, prior to relase of the last built-in hold at T minus 4 minutes, the range resolved that issue and gave the “Go” to proceed.

With that, the launch went smoothly and all five satellites were accurately deployed from their dispenser. This was the twelfth Delta/Iridium launch, bringing the number of satellites launched to 60 (93 total, including Russian Proton and Chinese Long March vehicles), and the first since Iridium’s bankruptcy and reorganisation in March 2000.


     

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