Courtesy photo by Jim Grossmann|
Technicians link Dawn with a Delta II rocket in preparation for a Thursday launch.
to launch Dawn
Decatur-made rocket set to take off Thursday
By Eric Fleischauer
Long after United Launch Alliance is expected to discontinue production of the Decatur-made Delta II rocket, NASA officials hope to cheer its success.
The cheers, if they come, will be in August 2011, and again in February 2015. Those cheers are dependent on a successful launch of NASA’s Dawn spacecraft, scheduled for Thursday at 6:20 a.m. from Cape Canaveral, Fla.
Triggering the cheers will be little bursts of radio waves that, after traveling 220 million miles in the first instance and 990 million miles in the second, will provide humans with an up-close and personal view of two elusive celestial bodies.
The exploratory spacecraft that will accomplish this feat is Dawn. The vehicle that will provide it with the oomph it needs to escape Earth’s orbit and begin the journey is a Decatur-made Delta II.
The Delta II will point Dawn on an elliptical path that has it traveling 1.8 billion miles before it gets to Vesta.
The travel distance to Ceres, its second destination, is 3 billion miles.
NASA and the U.S. Air Force have announced plans to discontinue use of the reliable Delta II, which on Sept. 19 celebrated its 75th consecutive successful launch, by the end of the decade.
They instead will use the Delta IV and the Atlas V. Decatur’s United Launch Alliance facility is the sole producer of Delta IVs. ULA expects to add an Atlas V production line in Decatur next year.
ULA has said it will continue to offer the Delta II to commercial customers, but most expect the program — which depends on volume to keep the launches cost competitive — to wind down after it loses the government customers.
Mike Rein, a ULA spokesman based in Cape Canaveral, said every launch is an emotional rush.
“It never gets old. It’s like an Alabama or Auburn football game. You can watch 30 years in a row, but when Florida rolls into town and they get ready to tee it up, it doesn’t matter how long you’ve watched,” Rein said. “It’s the same thing with a launch. You can see 50 of them, but when you hear the ‘10-9-8,’ if that doesn’t get your blood going, I don’t think you’re alive.”
Vesta is a massive asteroid and Ceres is a dwarf planet. Scientists believe both bodies formed early in the history of the solar system.
Aside from their similar size and early origins, Vesta and Ceres are vastly different. Their differences were a major reason NASA chose them as targets for the Dawn mission.
Vesta is rocky, with a surface resembling that of Earth and other planets in the inner solar system. Ceres, though, has a primitive surface containing water-bearing minerals. Scientists believe it has a weak atmosphere. It has more in common with the large icy moons of the outer solar system than with the planets closer to Earth.
“By studying both these two distinct bodies with the same complement of instruments on the same spacecraft, the Dawn mission hopes to compare the different evolutionary path each took as well as create a picture of the early solar system overall,” a NASA statement explains.
“Data returned from the Dawn spacecraft could provide opportunities for significant breakthroughs in our knowledge of how the solar system formed.”
Vesta, discovered in 1807, is about 300 miles in diameter. The Earth is 7,900 miles in diameter.
Ceres, in 1801, became the first asteroid discovered. In 2006, along with its more famous colleague Pluto, it was reclassified as a dwarf planet. It is about 600 miles in diameter. Scientists believe Ceres may harbor water, some of it possibly in liquid form.
Providing the boost
The Delta II’s job will be to hoist the 2,684-pound spacecraft beyond Earth’s greedy gravitational pull.
The spacecraft is 5 feet long, 4 feet wide and 6 feet tall. It carries a high-gain antenna with a 5-foot diameter. After it leaves the Delta II, the caterpillar will sprout wings — 65 feet from tip to tip — covered with solar panels.
Among the scientific instruments on Dawn: cameras, a gamma ray and neutron detector, and a visible and infrared mapping spectrometer.
Not including the launch vehicle, the mission will cost $358 million.
On its way to Vesta and Ceres, Dawn will get close enough to Mars — within 300 miles — to permit NASA to perform quick research. The purpose of the approach is to get a gravity assist. The Mars boomerang effect will increase the spacecraft’s overall velocity by 2,500 mph.
The launch window Thursday extends to 6:49 a.m. If pushed back to Friday, the launch window begins at 6:09 a.m and ends at 6:38 a.m.
How to watch
If you want to start Thursday morning with a bang, supplement your morning coffee with a view of a Decatur-made Delta II rocket launching the spacecraft Dawn.
To view the launch at 6:20 a.m., check out one of the following:
NASA-TV, which will begin its broadcast at 4:15 a.m.
For a Webcast, go to www.ulalaunch.com and click on “webcast,” or go to www.nasa.gov.
If you have a high-definition television package, check out your local HDNet listings. The broadcast will begin at 6 a.m.
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