Kevin Forsyth Home

 

History of the Delta Launch Vehicle



Current Delta News

(What about Delta IV?)

27-Sep-07 | Delta flight 327 – Dawn

Two Dawns over Florida

Twenty-one minutes after local sunrise today, a three-stage Delta II-Heavy lifted off from Cape Canaveral’s SLC-17B into a gorgeous deep blue sky. Aboard was the Dawn spacecraft, which has successfully begun its eight-year asteroid tour.

No major technical issues arose during the three-hour terminal countdown, which began at 04:20 EDT. The weather forecast improved throughout the count, as isolated rain showers remained over Patrick Air Force Base to the south of the Cape and did not violate launch rules. Meanwhile, the countdown’s final hold at T-minus 4 minutes was extended for nearly fifteen minutes due to a civilian ship that had intruded into the offshore hazard area. The Coast Guard quickly shooed away the interloper and the countdown was able to resume for a T-zero near the middle of the twenty-nine-minute launch window. The official range liftoff time was 07:34:00.372 EDT.

The Delta 7925-Heavy, with its upsized GEM-46 booster motors, sprinted from the launch pad and performed typical first and second stage firings, placing itself just over nine minutes later in a nominal parking orbit of 99.99 by 100.6 nautical miles altitude with an inclination of 28.6 degrees. After a 42.5-minute coast phase, the second stage re-lit to achieve an elliptical orbit with a 95.29-mile perigee and 3681-mile apogee. The third stage and spacecraft spun up, separated, and fired to place the spacecraft in a heliocentric departure orbit. Dawn was released at T+plus 61 minutes, 58 seconds, and within a couple of hours was judged by mission controllers to be “stable, power positive, and safe.”

NASA Launch Director Omar Baez summed up the Delta II performance by saying, “we’re right on the money.” The launch extended Delta II’s record-setting benchmark for reliability, which now stands at 76 consecutive successes.

Dawn is the ninth mission* in NASA’s highly successful Discovery Program. Dawn’s mission plan includes a gravitational swing-by of Mars in February 2009 prior to intercepting asteroid Vesta in August 2011. It will remain there for about nine months before departing for asteroid Ceres, a six-month visit that is expected to occur in 2015. Dawn will navigate toward these rendezvous using a xenon ion engine similar to that used on the highly successful Deep Space 1 mission, which launched aboard Delta 261 in 1998.


Your comment:

     

Archives

Back to top