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NASA Probe Orbiting Asteroid Vesta
astroengine writes "Mission managers of NASA's Dawn asteroid probe had a long Saturday, waiting for news from the asteroid belt. Eventually they got the news they were hoping for: Dawn had entered Vesta orbit. This is the first time in history that an object in the asteroid belt has been orbited by an artificial satellite. It's taken four years for the ion thruster-propelled spacecraft to reach the asteroid and there was some uncertainty as to whether the probe had been captured by the asteroid's gravity at all. But after a long period of waiting, mission managers received the signal after Dawn was able to orientate its antenna toward Earth."
Wow, what loathsome editing by Discovery: they injected a video clip about a "Doomsday Asteroid" wiping out the earth into the middle of an article about Dawn visiting Vesta. The two are unrelated, but the juxtaposition somehow makes it sound like NASA is fulfilling some Hollywood fantasy about visiting the asteroid that will come smashing into Earth unless we send [current B-rate movie star] on the now-defunct Space Shuttle to nuke it.
I found this: "Orientate is more widely accepted in the U.K. than in the U.S.A., but it should be avoided in any formal or standard writing." Of course, correcting poor usage is WAY more important than orbiting an asteroid.
Sorry, but gray text on gray background is making my eyes bleed.
In only 14 years from now? I highly doubt it. Besides being a dumb idea, the US can't even put a man into earth orbit anymore. What makes anybody think they'll be sending anybody into deep space any time soon? Unless it's part of the war effort, it just ain't gonna happen
For justice, we must go to Don Corleone
To the science-abled fellas in here: How would conditions for astronauts/cosmonauts visiting this bodies be?
Can they walk up there or would they need some sort of exo-skeleton or something with more space for sponsors...?
There are so many cool things about this mission!
ION FREAKING ENGINES!
-- Counting backwards since 1984!
The possibility of successfully navigating an asteroid field is approximately 3,720 to 1.
Support Right To Repair Legislation.
FTFA:
Dawn will remain in orbit around Vesta for a year, before gently boosting away to begin the trip to Ceres, the second half of its asteroid belt adventure.
That was actually my first thought: "Why is this visiting Vesta and not Ceres?" Ceres (might) have surface water and an atmosphere, so it makes more sense as a base. Its also larger (about 4 times the mass/size, although, surprisingly, it has nearly the same gravity, .027g to Vesta's .022g) and looks one hell of a lot more interesting. I mean, both are just big rocks in space, but Ceres is actually dwarf planet class and looks like it could serve as a quite effective base for more missions past the asteroid belt.
Of course, visiting both makes sense. Vesta may have also been a nice test run for gravitational capture, since it doesn't have an atmosphere and its smaller, but has similar gravity. Establishing a (manned) base in the asteroid belt seems like it could be an enormous step forward in space. The asteroids could potentially be mined, providing a financial incentive to visit, plus their low gravity makes them easy to escape after loading up on fuel/ore or for constructing spacecraft (anyone else think the idea of a spaceship factory in the asteroid belts is pretty cool?). All in all, this is a pretty cool (if pretty small) step forward in getting off this rock. I can see why Obama wants to send an astronaut to the belt by 2025, even if I know it'll probably take till 2040 or so.
"None can love freedom heartily, but good men; the rest love not freedom, but license." --John Milton
That's because the only images they have are from the low-res navigational imager. They will fire up the high res camera and other instruments now that they're in Vesta orbit.
Now all we need to do is settle it.
When the ion drive isn't running, there is plenty of power. There's no reason to not gather as much data as possible. After all, if something went bung during insertion (when the probe was out of comms with Earth) it would be the only data they have. Given the detail in the last image (from ten days ago), what prevented them from at least getting a full surface sequence?
Other NASA probes take images from distant approach, trying to milk as much data as they can before the arrive, as well as PR for the mission. I can't find an explanation of why the Dawn team have been so reticent to image their target. It doesn't bode well for the rest of the mission.
Science is all about firing a drunk pig out of a cannon just to see what happens.
I would not begrudge our soldiers in Afghanistan small comforts. But still I was taken aback by the news that Pentagon spends more on airconditioning barracks in Afghanistan than the entire NASA budget. If Pentagon bought some more efficient air conditioners without compromising comfort, may be we could fund a few more of these missions. Quite sad to see the congresscritters make grand statements about government waste and then ram their pet pork projects through defense appropriations.
sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
When the ion drive isn't running, there is plenty of power. There's no reason to not gather as much data as possible. After all, if something went bung during insertion (when the probe was out of comms with Earth) it would be the only data they have. Given the detail in the last image (from ten days ago), what prevented them from at least getting a full surface sequence?
Other NASA probes take images from distant approach, trying to milk as much data as they can before the arrive, as well as PR for the mission. I can't find an explanation of why the Dawn team have been so reticent to image their target. It doesn't bode well for the rest of the mission.
I can think of a theoretical reason that may or may not have any application to reality.
We know the asteroid's orbit and our (the earths) orbit from a zillion years of position observation. We don't know the vehicle's relative velocity to the asteroid, and thats kind of important to put it in orbit. In ye olden days the stereotypical way to figure orbits was to put what amounts to a crossband linear repeater on the vehicle and spend inordinate amounts of effort on the earth measuring the doppler shift of signals transmitted thru the repeater. In ye olden days that was best done using an continuous information free carrier CW tone. Now a days the youngin's probably use some sort of spread spectrum solution to avoid ionospheric scintillation or just to plain ole be cool? At any rate the radios would probably be busy doing the navigation-thing as opposed to the science-thing.
Now a "news for nerds tech site" could make an interesting article about how this mission did navigation...
"Science flies us to the moon. Religion flies us into buildings." - Victor Stenger
I would not begrudge our soldiers in Afghanistan small comforts. But still I was taken aback by the news that Pentagon spends more on airconditioning barracks in Afghanistan than the entire NASA budget. If Pentagon bought some more efficient air conditioners without compromising comfort, may be we could fund a few more of these missions.
Sounds like it would be a heck of a lot more cost effective for NASA under DOD contract to launch a "solar umbrella" arrangement to cool Afghanistan. As a bonus we'd be able to use the required heavy lifter / orbital construction gear for other purposes. Finally we could sell advertising space on the solar umbrella.
As a side note, there are not many US barracks in the sandbox. They're air conditioning tents and trailers. I spent some time in the 90s baby sitting some computers in a US Army air conditioned trailer; We were very thankful the "computers required air conditioning", it was just a side effect that we got comfortable.
"Science flies us to the moon. Religion flies us into buildings." - Victor Stenger
If it makes you feel any better, (it did for me) that number ($20 billion) for air conditioning in Afghanistan is highly debatable and was put forward by a guy who was a brigadier general but now is in the private sector, selling technologies branded as energy-efficient to the Defense Department. More from the source article (http://www.npr.org/2011/06/25/137414737/among-the-costs-of-war-20b-in-air-conditioning): "Now it's important to note that wrapped up in Anderson's $20 billion figure are all kind of other expenditures – for instance, the cost of building and maintaining roads in Afghanistan, securing those roads, managing the security operations for those roads. That all costs a lot of money and is part of the overall war effort in Afghanistan." And, "The Pentagon disputes the calculation made by Anderson about air conditioning costs. Defense Department spokesman Dave Lapan says that in fiscal year 2010, the Pentagon spent approximately $15 billion on energy for all military operations around the world. The Pentagon says when it comes to Afghanistan, it spent $1.5 billion from October 2010 to May 2011 on fuel. That fuel was used for heating and air conditioning systems, but also for aircraft, unmanned aerial systems, combat vehicles, computers and electricity inside military structures."
It oriented its antenna, it didn't orientate it. Someone needs to documentate the English language a little bit better.
Maybe the quarter second signal lag vs the 30 minute signal lag has something to do with it? You cannot effectively remotely pilot things much beyond the Moon's orbit; and Vesta is definitely much beyond the Moon's orbit.
When our name is on the back of your car, we're behind you all the way!
Patience little monkey. There will be many glorious images soon.
Help stamp out iliturcy.
First orbit of an asteroid *in the belt*.
Eros was the first discovered near-Earth asteroid.
Itokawa is an Apollo and Mars-crosser asteroid.
sr
His ignorance covered the whole earth like a blanket, and there was hardly a hole in it anywhere. - Mark Twain
Science is a collaborative effort. Nearly every advance the parent cited can be traced back to development work done by people who were not born in the US. Von Braun, Tsiolkovsky, and Fermi come to mind immediately, along with Einstein, Turing, Goedel, Bohr, Pauling, Dirac, Mendeleev, and Roentgen. National pride is fine, but it rings kinda hollow when one is aware of just how connected all scientific advancement is. The idea that all of those achievements are somehow the sole purview of the US is absurd.
Thanks for the information. Oddly I feel better knowing that Pentagon is not wasting that much. Sorry to have fallen for some marketers' spiel.
sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
I've seen analysis that the number is about right, and that most of the cost is getting diesel out there for the generators.
I'm sure they could spray the tents with foam or something though to make it much more efficient. Tinfoil on the outside...?
No sig today...
Oh if i had mod points!
Would a T-shirt placate you?
Table-ized A.I.
*sigh* So much misinformation floating around here...
GP said
That's because the only images they have are from the low-res navigational imager. They will fire up the high res camera and other instruments now that they're in Vesta orbit.
Which is absolute bullshit, because there's only one science camera (well, two identical cameras, for redundancy), and it's currently getting crap resolution because it's ~2x10^7m away, while science orbits will range from 2x10^6 to 2x10^5m altitude. There's also the star trackers, which while technically cameras, are not used for imaging Vesta or Ceres at all.
When the ion drive isn't running, there is plenty of power. There's no reason to not gather as much data as possible. After all, if something went bung during insertion (when the probe was out of comms with Earth) it would be the only data they have. Given the detail in the last image (from ten days ago), what prevented them from at least getting a full surface sequence?
Other NASA probes take images from distant approach, trying to milk as much data as they can before the arrive, as well as PR for the mission. I can't find an explanation of why the Dawn team have been so reticent to image their target. It doesn't bode well for the rest of the mission.
(It's not a power issue, it's an attitude issue -- each of the three ion thrusters is gimbaled in a narrow range, and the high-gain antenna and cameras are fixed completely -- same result, though.)
The mission's design duty cycle for the IPS (ion propulsion system) is 95%; the remaining 5% of the time is divided between imaging Vesta and relaying data to DSN ground stations. There's certainly time for more pics than they've taken, but allocating more time for imaging and less for thrusting means postponing your arrival, which reduces your time for doing high-quality science in orbit.
Unlike many other missions, which use a chemical rocket to perform a Hohmann or similar transfer into a near-final orbit, with relatively small deltaV reserved for orbit adjustments, Dawn will be gradually spiraling in under power to reach any given orbit. It's completely free to stop thrusting at any point and coast in a nearly-circular orbit while doing science observations, then resume spiraling in later, though they will likely stick to the mission plan of 3 orbits (2700km, 950km, and 460km radius -- subtract ~280km to get altitude). So there's very little to gain from more low-res approach images that we won't already get from the two full-rotation sets already scheduled (and I presume completed) during approach, and especially the full surface mapping that will be done in the first (highest) orbit. For more info on the navigation imaging strategy, see the latest Dawn Journal.
The main issue is that they're not releasing the pictures they have -- particularly the full-rotation sets mentioned above, As I understand it this is mainly a manpower issue, but I certainly wish they could set up a low-overhead nerd-ready channel separate from their press-ready channel, so they could just dump all the images and let the bloggers sort 'em out.
I actually don't think any orbits were done of Itokawa. Hayabusa seemed to be using engines to maintain its distance from the asteroid. But I definitely agree that NEAR Shoemaker has the record here. I don't think it matters much that Eros is not in the main belt. And the landing on Eros was a genuine first. I can't see any way for Dawn to land on Ceres without a crash. There is too much gravity and it doesn't seem to have non-ion thrusters at all.
http://michaelsmith.id.au
the Chinese will be far more benevolent and altruistic than the running dog Yankees.
There is the good NASA (JPL) which run unmanned probes such as Dawn while there is the pointless NASA (Houston) that sends humans into space for stunts. Guess who gets the funding?
If we go to Ceres before meeting the Chozo, who's gonna use their power armor to defeat Ridley and the Mother Brain?
Use the laptop while sitting on the toilet, problem solved :-P
"When information is power, privacy is freedom" - Jah-Wren Ryel
the two full-rotation sets already scheduled (and I presume completed) during approach, [...] The main issue is that they're not releasing the pictures they have -- particularly the full-rotation sets mentioned above,
Thanks for the details. I didn't realise they had the images I wanted, and just weren't releasing them. At least if the probe dies, or the camera fails, or some other disaster, there will be some data available. What's left is just my nerd-rage-impatience.
Science is all about firing a drunk pig out of a cannon just to see what happens.
I'd like to orbit Princess Vespa.
Hmmm.
Mass of Dawn: ~1200kg
Weight of Dawn on Vesta: 0.022 * 1200 * 10 = 264 Newtons. Yeah its not going to work. Escape velocity 0.35 km/s. Its a pretty decent little planet. Enough to require something like the Apollo LM for a landing I would think.
http://michaelsmith.id.au