‘
An Associated Press article is reporting that NASA has postponed the launch of Dawn indefinitely.
Dawn is an ambitious mission to visit two of the largest asteroids in the solar systems, Ceres and Vesta. It has an ion engine, which doesn’t use combustible chemicals for propulsion, but instead uses a powerful magnetic electrostatic field to fling individual atoms out the back at high speed. Although the thrust is low, it can be sustained for months, even years. It’s a tremendously more efficient way of propelling unmanned probes around the solar system.
Dawn has had a checkered history, with several mechanical and funding problems. I don’t know why NASA has postponed launch (the AP article vaguely states "cost overruns and technical issues"), as I just heard about this from Larry Kellogg’s lunar-update mailing list. When I get more information I’ll post again.
Note (Jan 24, 2006): I originally said the ion propulsion used magnetic fields to accelerate ions, but this is incorrect. A reader informed me that it’s a strong electrostatic field that does the trick.‘
January 22nd, 2006 at 7:12 am
Reminds me of a Xeroxed sign I saw on an office cubicle wall, years ago: “Due to circumstances beyond our control, the light at the end of the tunnel has been deactivated until further notice.”
Gosh, that was a long time ago. . . back when the “blinkenlights” joke was new, or so it seems. I wonder if they ever turned that light back on again?
January 22nd, 2006 at 8:29 am
Darn it all!
NASA is spending all this money on going to the moon when private industry might even beat them there. Meanwhile, pure science missions are being cut–missions that private industry would probably never do. Pure science missions should be all that NASA does! The private sector can and will do everything else soon.
January 22nd, 2006 at 11:29 am
I know someone who left my program to go work on Dawn, and just heard recently that he was looking for work. Possibly another piece in the puzzle.
January 22nd, 2006 at 1:16 pm
To be fair, people have predicted this kind of postponement / concellation. As soon as George W announced that he wanted NASA to focus on sending men to the moon and to Mars, commentators were saying things to the effect of “well, they’ll either need a whole heap more funding, or they’ll be cutting existing mission plans left, right and centre,”.
It came true.
January 22nd, 2006 at 7:35 pm
I heard of this ion engine years ago. Thought it could be the next big thing, but well, I guess we’re still stuck with soild fuel.
January 23rd, 2006 at 12:31 am
I’m very unhappy with this cancellation. I follow the space program pretty closely even hitting the DAWN site possibly once a month and the first I heard about it was from space.com. It is a bit of a sneak attack on the mission, if they just stop working on it how do we let our representatives know we want the mission?
The larger asteroids have never been visited by spacecraft. Asteroids are small but good things come in small packages. Consider the focus of the voyager missions was often the moons rather than the surfaceless gas giants themselves. When one considers the potential of asteroids for great harm as well as great wealth it seems to me the modest sum spent on a thrifty mission of this sort would be money well spent.
The ion engine is another aspect of the mission that would have been worthwhile.
January 23rd, 2006 at 9:57 am
Considering that we are already mining one asteroid (Sudbury, Canada), this had the potential to be the most lucrative (long term) mission of all time!
Oh well.
January 23rd, 2006 at 10:42 am
On the column about the delayed Dawn mission to asteroids Ceres & Vesta, I have some useless info. In keeping with the astronomicaly study of planets using Greek-based words (selenolgy, hermeology, & areology for the studies of the Moon, Mercury, & Mars), the study of the asteroid Ceres should be “demeterology,” & the study of Vesta would be “hestiology,” from Demeter & Hestia, their Greek equivalents.
Ceres is the Roman goddess of grain & agriculture. The word “cereal” comes from her name. If Will Keith Kellog of Battle Creek, Michigan, had preferred Greek to Latin, we would be eating Rice Krispies demeteral for breakfast.
Just being technical.
January 23rd, 2006 at 12:37 pm
I haven’t heard of this mission until now, and yet I feel for its probable loss.
It should be noted that missions to asteriods are not just to look at the thing, but also to learn enough about them that we would know how to deal with them if they threaten the Earth. That’s a realization I had when I heard of this possible cancellation.
Those who disagree with this should go to Meteor Crater in Arizona or reply footage of Shoemaker/Levy-9. The latter could just as well been Earth.
Aside from these issues, it would still be great to get close ups of these two infamous asteriods.
January 23rd, 2006 at 2:56 pm
Any guesses as to how much shorter New Horizon’s trip to Pluto would be if it had ion thrusters instead of coasting the whole way? Half?
I know that its hardware development was too far along when DS1 proved that ion thrusters can work for main propulsion, and that it would need a couple more RTG’s to power it, but looking at a five year mission (where have I heard that before?) instead of nine would be worth it.
- Jack
January 23rd, 2006 at 4:33 pm
If New Horizons had ion thruster it would take considerably longer. My impression of the technology is that it saves money not time. Ion thrusted probes allow less mass in the payload so you send it up with a cheaper rocket. DAWN won’t use the Hohmann transfer, instead it just orbits in progressively large circles. The European probe Smart-1 used ion propulsion to get to the moon it took about 18 months (give or take) compared to the 9 hours New Horizons took there is obviously no comparison. (I recognize smart-1 vs New Horizons is a bit of an apples and orange comparison.)
January 23rd, 2006 at 10:32 pm
There was a recent couple of articles on a new improved ion drive, though I can’t find any good descriptions currently on google. Here’s a short quote from a blurb:
The European Space Agency and the Australian National University have successfully tested a new design of spacecraft ion engine that dramatically improves performance over present thrusters and marks a major step forward in space propulsion capability.
Ion engines are a form of electric propulsion and work by accelerating a beam of positively charged particles (or ions) away from the spacecraft using an electric field. ESA is currently using electric propulsion on its Moon mission, SMART-1. The new engine is over ten times more fuel efficient than the one used on SMART-1. “Using a similar amount of propellant as SMART-1, with the right power supply, a future spacecraft using our new engine design wouldn’t just reach the Moon, it would be able to leave the Solar System entirely,†says Dr Roger Walker of ESA’s Advanced Concepts Team, Research Fellow in Advanced Propulsion and Technical Manager of the project.
January 24th, 2006 at 1:01 pm
Tom,
The new ion engine type simply means you can take higher power in the same size engine. It does not specify where that power comes from. Missions would need to find power sources of many kilowatts to make use of this- maybe giant solar arrays (not yet tested, or built) or nuclear Rankine generators (looking less and less likely). New Horizons, specifically, could not take a second RTG, because the Department of Energy could not have built one. Even the RTG that was built, a spare from Cassini, was loaded with less Plutonium than planned. DoE plutonium production fell behind schedule, and the spacecraft has less wattage than planned.
January 25th, 2006 at 8:30 am
They can’t cancel Dawn – its on my “A Decade of Discovery : The next Ten Years of space exploration” poster from “Astronomy Now’ which makes it official or the mag can get them for false pretences or .. well something!
What a short-sighted stupid decision.Sad news & I hope it turns out to be wrong or perhaps temporary – after all they tried to cancel ‘New Horizons’ a few times and that was launched last week.
Dare I suggest someone forms a lobby group for it :
Don’t
Undermine
Science
Kongress
perhaps?
Testing new technology and examing the largest asteroids seems a far, far better use of money than a lot of the things Amercian taxpayers are paying for. (Please, don’t spend it your money going and invading other countries America – ‘invade’ an asteroid or two instead – its much better for everyone!)
As for terminology : Thanks Tom Reesor but I would guess that Hesta and Demeter would likely have been used already to name other asteroids.
Thinking of that, what’s studying asteroids called again? Asteroidology? Bolide-ology? Not meteor-ology surely? Too close to the weather field and not really accurate as they’re not quite meteors are they – yet?
Finally, if I’m remembering right; wasn’t Demeter an earth mother goddess equivalent to Gaia and thus a bit more significent than Ceres who was only the goddess of Corn or am I getting my Grecian goddesses mixed up somewhere?
Another quirkefact : Spica (as in the star) apparently means ‘ear-of-corn’ or is mythologically associated with it somehow too.
January 25th, 2006 at 8:41 am
On reflection, maybe they’re worried Dawn will find too much evidence that Ceres and perhaps even Vesta deserve to be classed as planets?
Ceres at least is apparently spherical (from HST image?) or close to being so and I recall reading somewhere has a differentiated geology -ie. has seperated into core-mantle-crust layers. May well be wrong but heard it apparently has more water (ice?) than all the oceans on Earth going on some models / calculations?
Vesta too -again may be wrong on this -fuzzy memory of reading something along these lines – has apparently (from spectral analysis?) got some volcanic-type geology or at least shows signs of having once been molten …
Don’t know if they’ve got quite the same claim for planetary status but more than average asteroids and studying them and comparing them with Gaspra, Ida, Itokawa, Eros, et al would be a marvellous and possibly very useful achievement indeed.
(Apologies if I’ve breached netiquette by two long-ish posts.)
January 25th, 2006 at 11:25 am
This cancellation has little to nothing to do with the VSE. The DAWN team has consistently overpromised, underperformed, and overspent. The mission has already been significantly descoped both in instrumentation and in mission length.
At this point, the issue is not the sunk costs. It is whether the remaining funds meant to go to DAWN could be better used on another Discovery mission.
January 25th, 2006 at 11:28 am
Oh, another thing. DAWN is a Discovery mission. These are specifically designed to be cost-capped proposals. In essence, DAWN’s overpromising and underperforming means that a mission that could have been successful wasn’t funded. If that is overlooked, the entire Discovery program will be threatened.
January 31st, 2006 at 11:55 pm
Regarding the mythology in an earlier post. According to Edith Hamilton’s mythology Ceres and Demeter are the same entity the former is Latin the latter Greek. Gaea (Mother Earth) was not a goddess but along with Ouranos (Father Heaven) were considered ‘vauge personalities’ the rest of the monsters, titans, and lastly the gods sprung from them.
I like the D.U.S.K. idea, with even a small number of interested people and congress will resume the project otherwise it can go by another acronym D.O.O.M.
Dead
On Arrival, it’s all
Over
Man
That was quite interesting about Spica. Most star names are arabic and many have interesting traslations, one I read about recently was Algol which has the same origin as our word for ghoul, named such because it tends to wink as it changes in brightness.
March 4th, 2006 at 1:22 am
Phil, I don’t think it is fair to say the Dawn mission had (note the past tense since NASA announced its cancellation) a checkered history. When NASA cancels a mission in the beginning of the building phase for two months and then, 1.5 years later in the spacecraft integration phase, orders a standdown for 3 months, the end result is alot more money spent and time lost.
When NASA first cancelled Dawn in December 2003, people were moved onto different projects, and instrument parts were ‘unordered’. When the mission was reinstated (minus two instruments: the laser altimeter and the magnetometer and minus extra support from the spacecraft company in order to save money) two months later, the remaining instruments needed to scramble to make up for lost time. Why? Specialized parts such as gratings and mirrors are manufactored by third party vendors who have their own manufactoring schedules, so if you take a specialized part out of their queue, you cannot insert yourself back into their queue in the same place where you were and so you lose time. The VIR mirror was in this situation for example.
Everyone was working under the tightest of time and money constraints given the fact that we lost time in the beginning and their partner space agencies lost trust of NASA, and I think they performed miracles, delivering all instruments exactly to specifications. For example, DLR Berlin couldn’t build the camera after Dawn’s first cancellation, and so a new camera was solicited, which was built on time (after being several months behind) by the MPI Lindau group. Another example, is that the Rome Dawn science team had no money from ASI for the three years of the construction phase, going to science meetings and traveling to interact with the mapping spectrometer builders on their personal credit cards.
Another facet I read in the press is problems with the xenon tanks, but what is not reported is that the tests performed on the tanks went far beyond the tanks’ specificied operating conditions.
The Dawn Independent Assesment Team who gave their report to NASA in February recommended to finish the project and launch. Dawn was >90% constructed at the time of its cancellation. Yes there were things that were critical to address, but they also stated that the Dawn mission was not different in their problem solving from any other space mission in their late stage of development. The Dawn Team was an exceptionally fine team, they worked well together, the science team was top-notch, and payload team who managed the construction had decades of experience. If you read in the literature about cost overruns, I think it is wise to investigate more to see the larger picture.
March 4th, 2006 at 10:40 am
Anonymous, I didn’t mean that Dawn had “a checkered past” as in nefarious dealings, incompetency, or anything like that. I guess I chose the wrong phrase to use. I simply meant that a series of things had gone wrong during the construction and testing. Mark Sykes has said (see March 3 2006 blog entries) the Xenon tanks were tested at twice the pressure they were likely to face, and were fine at the correct pressures.
It seems to me we have a mission almost entirely ready to fly, with tested hardware, an amazing flight plan, and a high chance at some incredibly exciting results. I just hope NASA will reverse this short-sighted decision.
March 5th, 2006 at 11:40 am
I think DAWN’s cancellation is quite a blow to the whole program. As has been said, almost complete hardware and a nearly flight ready vehicle should be funded to completion and launched. To do less after coming so far is a total waste…Going back to the Moon is fine, and certainly going to Mars is nice. But what about after that…? Shouldn’t we be thinking in terms of what humanity needs (material resources-wise) in the next thousand years? Should we not support a longer vision of resource and energy sustainability for the species?
Or are we so conditioned to the ‘here-now’ that we are completely incapable of thinking in such terms…?