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20-Nov-04 | Delta flight 309 – Swift

Swift arrived safely in orbit on Saturday, 20 November, thanks to the efforts of Delta 309.

The launch was delayed for a couple of days by an issue with the vehicle’s command receiver decoder, equipment that can receive self-destruct commands from Range Safety in the event of a malfunction. That resolved, a unique issue cropped up overnight prior to the launch. At liftoff, ground support umbilical connections disconnect from the launch vehicle and are quickly retracted to the fixed tower on the pad. A cable that measures tension in one of the pullaway bungee cords that retract the umbilicals snagged somehow and could not be trusted to ensure proper retraction. Prior to fuel loading, a crew was dispatched to Space Launch Complex 17A, where they were able to lasso the cable and free it. The resolution took very little time, but nevertheless the launch team played catch-up for the rest of the terminal countdown. During the T-minus 4 minute hold, it became clear that all tasks could not be completed in time, and so the hold was extended for six minutes. This presented no problem for a one-hour launch window.

The Delta 7320-10C leapt off the pad at 12:16:00.611 EST and roared into the bright Florida sky, dropping its three spent booster motors about 66 seconds into the flight. Following second stage ignition, a “videoroc” showed a static-free shot of a payload fairing separation Boeing’s Marc Lavigne called “crisp.” Unlike several recent NASA launches, which carried several cameras, inside and out and facing fore and aft, this was the sole on-board video camera. It was mounted on the second stage, facing forward inside the fairing, and was mainly intended to show spacecraft separation. (Cameras ride aboard flights at the cost of payload capacity, and are only begrudgingly added in the planning stages of a mission. But “come launch day,” NASA launch manager Chuck Dovale commented, “everybody loves the camera.”)

The flight included three second-stage burns to place the spacecraft in its proper orbit. The first burn lasted about 5.5 minutes and ended in a nearly-circular parking orbit, 99.88 by 100.161 nautical miles, with an inclination of 28.47 degrees. A 16-minute coast phase was followed by the second burn of only about 32 seconds. This burn raised the apogee to about 334 nautical miles, and lowered the inclination to about 26 degrees. A longer, 44-minute coast came next as Swift and its Aerojet-built impeller rose toward apogee. Finally, a 54-second burn circularized the orbit at 324 nautical miles and 20.5° inclination.

Tracking was somewhat different than other recent flights due to the flight profile. As usual, early tracking and telemetry was provided by the Cape Canaveral Range and the Air Force’s tracking station on Antigua. The second of the three Aerojet burns, off the west coast of Africa, was followed by a station at Libreville, Gamon, and a mobile site deployed by the USAF at the small island of Sao Tomé. However, for unknown reasons Kwajalein was not able to relay data of the third burn as expected, and for several minutes the fate of the spacecraft was unknown. But the Hawaii tracking station came through in time for separation, and clean data and video both showed the release as the spacecraft faded into darkness. The second stage slowly backed away using gentle venting from its helium pressurization system in anticipation of its propellant depletion burn, and the flight was complete.

Swift is a gamma-ray observer that will have the capability to turn itself rapidly and view the afterglow of bursts in that wavelength. It will spend two years in orbit, helping scientists study massive star explosions and the subsequent formation of black holes. By the end of the day, Swift had unfurled its solar panels and was reported to be in an excellent state of health.

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