Posted on 09/25/2007 6:51:42 PM PDT by NormsRevenge
CAPE CANAVERAL, Fla. - NASA is about to embark on an unprecedented asteroid-belt mission with a spacecraft aptly named Dawn.
The 3 billion-mile, eight-year journey to probe the earliest stages of the solar system will begin with liftoff, planned for just after sunrise Thursday. Rain is forecast, however, and could force a delay.
Scientists have been waiting for Dawn to rise since July, when the mission was put off because of the more pressing need to launch NASA's latest Mars lander, the Phoenix. Once Phoenix rocketed away in August, that cleared the way for Dawn.
"For the people in the Bahamas, on the 27th will be one day where they can say that Dawn will rise in the west," said a smiling Keyur Patel, project manager from the Jet Propulsion Laboratory in Pasadena, Calif.
Dawn will travel to the two biggest bodies in the asteroid belt between Mars and Jupiter — rocky Vesta and icy Ceres from the planet-forming period of the solar system.
Ceres is so big — as wide as Texas — that it's been reclassified a dwarf planet. The spacecraft will spend a year orbiting Vesta, about the length of Arizona, from 2011 to 2012, then fly to Ceres and circle there in 2015.
Dawn's three science instruments — a camera, infrared spectrometer, and gamma ray and neutron detector — will explore Vesta and Ceres from varying altitudes.
"In my view, we're going to be visiting some of the last unexplored worlds in the inner solar system," chief engineer Marc Rayman said Tuesday.
Because Vesta and Ceres are so different, researchers want to compare their evolutionary paths.
No one has ever attempted before to send a spacecraft to two celestial bodies and orbit both of them. It's possible now because of the revolutionary ion engines that will propel Dawn through the cosmos.
Dawn is equipped with three ion-propulsion thrusters. Xenon gas will be bombarded with electrons, and the resulting ions will be accelerated out into space, gently shoving the spacecraft forward at increasingly higher speeds.
"It really does emit this cool blue glow like in the science fiction movies," Rayman said.
NASA tested an ion engine aboard its Deep Space 1 craft, which was launched in 1998. Ion engines have been used on only about five dozen spacecraft, mostly commercial satellites.
Dawn also has two massive solar wings, nearly 65 feet from tip to tip, to generate power as it ventures farther from the sun. Ceres is about three times farther from the sun than Earth.
NASA put the cost of the mission at $357 million, but said that does not include the Delta II rocket. Officials refused Tuesday to provide the cost of the rocket, saying that was proprietary information.
Switched to Raygun Test Site
Payload separation! DAWN is on her way. Good luck!
Spacecraft state of health report at 1300 EDT presser as ascertained by Goldstone Deep Space Network.
Mission Control says the desired orbit has been nailed.
Messenger is headed to Mercury, but it is not easy getting there. Sometimes someone suggests shooting something/someone into the sun, but it is easier to blast out of the solar system altogether. Plus, when you get to Mercury your solder joints will melt.
Messenger is headed to Mercury, but it is not easy getting there. Sometimes someone suggests shooting something/someone into the sun, but it is easier to blast out of the solar system altogether. Plus, when you get to Mercury your solder joints will melt.
I slept thru the whole thing. :-)
ap
It depends on where the Earth and Ceres are in their orbits at launch and at arrival. Everything is still moving the whole time, which is why orbital dynamics is tough work. :)
This photo provided by United Launch Alliance shows the Dawn spacecraft sitting atop of a Delta ll rocket as it blasts off from Cape Canaveral Air Force Station in Cape Canaveral, Fla., Thursday, Sept. 27, 2007. NASA's Dawn spacecraft rocketed away Thursday toward an unprecedented double encounter in the asteroid belt. (AP Photo/United Launch Alliance, HO)
Thursday September 27, 10:07 am ET
ATK Solid Motors Used To Launch Heavy Payload On Delta II Vehicle
MINNEAPOLIS, Sept. 27 /PRNewswire-FirstCall/ — Alliant Techsystems (NYSE: ATK - News) propulsion and composite technologies supported the successful launch of the United Launch Alliance’s Delta II rocket carrying NASA’s Dawn spacecraft that will use an ion propulsion system to visit and orbit the asteroids Vesta and Ceres.
Nine GEM-46 solid propulsion strap-on boosters manufactured in ATK’s Salt Lake City, Utah facility provided augmented thrust for the launch while the STAR 48B rocket motor, manufactured in Elkton, Maryland, acted as the third-stage rocket motors. ATK’s Clearfield, Utah facility produced the composite cases for the GEM-46 boosters using an automated filament winding process developed and refined through its 40-year-heritage in composite manufacturing.
Six of the boosters ignited at lift-off with the first-stage main engine and provided over 824,000 pound maximum thrust for the launch vehicle. Just over one minute later, the remaining three boosters ignited to provide an additional 427,000 pound maximum thrust. The spent motors were jettisoned from the rocket as it continued its ascent.
Following burnout and separation of the GEM-46 boosters and the rocket’s liquid second stage, an ATK-produced STAR(TM) 48B third-stage rocket motor fired approximately 55 minutes into flight to provide the final velocity increment needed by the spacecraft to begin its journey.
ATK is a $4 billion advanced weapon and space systems company employing approximately 16,500 people in 21 states. News and information can be found on the Internet at http://www.atk.com.
http://biz.yahoo.com/prnews/070927/aqth093.html?.v=20
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