Skip to comments.NASA's Dawn Spacecraft Begins Trek to Asteroid Belt
Posted on 09/27/2007 1:10:44 PM PDT by saganite
A NASA probe blasted into space early Thursday, kicking off an unprecedented mission to explore the two largest asteroids in the solar system.
Riding atop a Delta 2 rocket, NASA's Dawn spacecraft launched toward the asteroids Vesta and Ceres at 7:34 a.m. EDT (1134 GMT) from Cape Canaveral Air Force Station in Cape Canaveral, Fla.
"In my view, we're going to be visiting some of the last unexplored worlds in the solar system," said Marc Rayman, Dawn director of system engineering at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif.
Dawn's eight-year mission will carry the 2,685-pound (1,212-kilogram) probe across three billion miles (4.9 billion kilometers) on NASA's first sortie deep into the asteroid belt, a ring of space rocks that circles the Sun between the orbits of Mars and Jupiter.
By visiting the bright, rocky asteroid Vesta and the large, icy Ceres, researchers hope Dawn will shed new light on the formation of planets and solar system's early evolution.
Aside from a wayward ship, which delayed today's launch by 14 minutes when it encroached into the Atlantis Ocean splashdown zone for segments of Dawn's rocket, the liftoff went as planned, NASA launch director Omar Baez said.
Long journey ahead
Dawn is expected to rendezvous and orbit the 330-mile (530-kilometer) wide Vesta between August 2011 and May 2012, then move on to Texas-sized Ceres by February 2015. With its spherical shape and 585-mile (942-kilometer) diameter, Ceres is so large it is also considered a dwarf planet.
"It will be the first mission to journey to, and orbit around, two celestial bodies, and the first to visit a dwarf planet," said Dawn program manager Jim Adams, at NASA's Washington, D.C. headquarters, of the asteroid-bound flight.
Dawn carries an optical camera, gamma ray and neutron detector and a mapping spectrometer to study Vesta and Ceres. Some of those tools will get a trial run during a planned Mars flyby in 2009, researchers said.
To power those instruments, the spacecraft is also equipped with the most powerful solar arrays ever launched into deep space.
With a wingspan of nearly 65 feet (almost 20 meters), or about the distance from the pitcher's mound to home plate on a baseball field, the arrays will generate more than 10 kilowatts near Earth, though that output will decrease as the spacecraft moves further from the Sun.
NASA officials set Dawn's mission cost at $357.5 million excluding the cost of its Delta 2 rocket, according to a September update. In a July briefing, Dawn researchers said the asteroid-bound flight could cost a total of $449 million and incur an extra $25 million in overhead due to launch delays.
Attempts to launch the mission in July were thwarted first by poor weather and rocket glitches, then by difficulties arranging ship and aircraft tracking equipment in time for liftoff. NASA also canceled the mission outright in March 2006, only to reinstate the expedition a few weeks later.
"It has been quite an emotional rollercoaster," Chris Russell, Dawn's principal investigator at the University of California, Los Angeles, said of the mission. "And part of the emotional rollercoaster is the gratitude that we have for all of the people that defended Dawn in those times."
An asteroid trek on ion power
Built by Virginia-based Orbital Sciences, the Dawn spacecraft has been touted as the Prius of space probes because of the uncanny fuel efficiency of its three-engine ion drive.
Dawn carries 937 pounds (425 kilograms) of Xenon gas, to which it gives an electric charge to create ions that are then catapulted out of its engines at nearly 90,000 miles per hour (144,840 kph). Over time, the ion push builds up, and allows Dawn to change its flight path to first rendezvous, then orbit, multiple targets like Vesta and Ceres without requiring massive amounts of conventional rocket fuel.
"The first time I ever heard of ion propulsion was in a 'Star Trek' episode," said Rayman, adding that such engines are also touted to propel the TIE fighters or Twin Ion Engine - of "Star Wars" fame. "Dawn does the TIE fighter one better because it has three ion engines."
While it will take Dawn four days to go from zero to 60 miles per hour (96 kph), the probe will gradually pick up speed as it fires its ion drive nonstop for the next six years, NASA has said, adding that the mission is the agency's first operational science expedition powered by ion propulsion.
"That would make it the longest powered flight in space history," said Keyur Patel, NASA's Dawn project manager at JPL, just before liftoff.
Each of the three ion engines weighs about 20 pounds (nine kilograms) and is about the size of a basketball.
"From such a little engine you can get this blue beam of rocket exhaust that shoots out at 89,000 miles per hour," Patel said before launch day. "It is a remarkable system."
The unmanned side of NASA works really well. I agree the manned program needs to be scrapped including the ISS. Bigelow will have something better and cheaper up and running in ten years anyway. As for Dawn not accomplishing anything worthwhile, scientists believe there’s water on Ceres (I think). That’s the kind of knowledge I would consider worthwhile, especially if we’re going to be sending those Conestogas out there.
Some of those bodies are water. All water. Frozen of course. We could hook up some ion motors and bring one or more to the moon.
Look, to a certain extent I’m playing the devils advocate here. I’m not here to pester you guys, but dang folks. You want to know if there’s water on Ceres. We haven’t been back to the moon in decades, but water on Ceres is a top priority. That is just senseless to me.
Pick a planet, any planet and let’s find out what we need to go there and do it. As we branch out, THEN we need to know about Ceres, not now.
What is NASAs budget each year. What does that amount to over 35 years? Where’s the beef?
Wheres the beef?
Cheaper to find out if there’s really anything worth going out there for with these (relatively) inexpensive probes. No sense funding a 100 billion dollar manned mission to Mars if there’s nothing there worth studying. Now, if one of those probes detects life? Then 100 billion would be cheap to go check it out.
Watched this Delta rocket take off this morning, jut after sun up and it was a beautiful launch.
Lots of rain lately so the sky was very clean and you could see this go for a very long time.
Was that you a couple months ago that commented he watched a launch from his boat?
Cousin Dale: Naw, but my dad does. Can't even sit on the toilet some days.
So let me see if I have this about right. We know the moon has no atmosphere, it’s gravity is much less than ours and we want to know about our solar system. So instead of building a base on the moon with a great telescope and other useful things, we spend a considerable sum of money on sending probes to asteroids and other planets we won’t be ready to explore for the next what, 250 years? Check that, at this rate lets make that 500.
Once again, what is the NASA budget and what have we gotten for the hundreds of billions spent over the last 35 years?
We went to the moon in about eight years. It will be at least 40, perhaps even 50 before we get back there. Is this really the proof that the unmanned space program is accomplishing all we want in space? If we’re just spending $10 billion a year, and I don’t think that is true, that’s $480 billion dollars. I’m not actually sure if that includes JPL’s budget, which does the majority of the heavy duty assessment of NASAs data recovery.
Sorry about that. Check the $480 billion figure and replace it with $350 billion plus. Thanks.
“Westerners continue to explore the expanse of space...meanwhile, Muslims continue to sit in the dirt and perfect the science of the suicide belt.”
That is my new tagline. Good work...
I watched the launch this morning. It was fantastic!
Clearly NASA’s goal is not primarily space exploration. Must be something else. What, then?
35 years, $350 billion dollars and about all we have to show for it is a shuttle that we cross our finges for every time it lefits off, and a space station for which we likely paid 75% of the cost, yet call it an international space station.
If you think I’m being too picky, so be it. I think that’s a fair judgement. It’s as fair as mine is.
Look, I’ve voiced my opinion and it’s okay by me if you folks want to come down on me for doing it.
I realize not all the decisions were made by NASA, but the end result is, we’re not getting the job done.
Where’s the technology spin-off today, like the R&D from the sixties gave us. A concerted effort to develop an effort to the moon and beyond would provide great boost to our economy today if we’d get with it.
NASA’s budget runs about 25 billion a year IIRC. Of that 80-90 percent goes to the useless manned program. That’s why you don’t see th benefits you’d expect from the unmanned side. It gets the scraps doing real work while the manned program sucks up most of the money accomplishing nothing.
Vesta is a very dense, igneous object from which we get plentiful meteorites. About 5 percent of the meteorites that fall on Earth come from the asteroid Vesta.
If the unmanned program could be run on the $2.5 to $5.0 billion you suggest, I’d support it. I’m not against scientific research per se, I’m just tired of us failing to move humans into space in a serious manner.
Currently our cost to put a pound of payload into space is too high. I would stop the manned program in eighteen months. I would provide funding for an x-prise for each of about three projects.
The first firm to develop a manned cargo/personel vessel that could take off from a runway and dock with the space station would get $10 billion dollars.
The first firm to develop a manned space trasnport and light cargo vessel that could leave the space station and fly to the moon, land spend one month and return, would get $7 billion dollars.
The first firm to develop a manned space vessel that would remain in space at the space station, and be utilized as part of a space maintenance and construction program would get $2 billion dollars.
I would like to expand on this, but I can’t now.
Thanks for the comments.
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