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SMART Probe to Crash Into the Moon

Posted by ScuttleMonkey on Wed Aug 30, 2006 07:29 PM
from the player-nasa-cratered dept.
cyberbian writes "Amateur astronomers will be excited to note that they can witness the impact of the SMART-1 probe crashing into the moon. The impact is scheduled for the morning of September 2nd (PDT). From the article: 'There's nothing wrong with the spacecraft, which is wrapping up a successful 3-year mission to the Moon. SMART-1's main job was to test a European-built ion engine. It worked beautifully, propelling the craft in 2003 on a unique spiral path from Earth to the Moon. From lunar orbit, SMART-1 took thousands of high-resolution pictures and made mineral maps of the Moon's terrain. One of its most important discoveries was a "Peak of Eternal Light," a mountaintop near the Moon's north pole in constant, year-round sunlight. Peaks of Eternal Light are prime real estate for solar-powered Moon bases."
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  • by adnonsense (826530) on Wednesday August 30 2006, @07:35PM (#16011864) Homepage Journal

    The next step is to build a probe which doesn't crash at all ;).

    On an entirely more geeky note, I wonder if any of the Apollo ASLEP packages are still up and running and whether they would detect the impact?

    • by AJWM (19027) on Wednesday August 30 2006, @09:31PM (#16012455) Homepage
      I wonder if any of the Apollo ASLEP packages are still up and running and whether they would detect the impact?

      The ALSEP packages were turned off remotely when the budget for collecting data ran out. That was Sep 30, 1977. Although the Apollo 14 ALSEP had failed a year and a half earlier, the others (A12, A15-17) were still going strong -- and still would be, the RTG power source having about a 90-year half life. (Well, barring hardware failure.)

      Their seismometers did detect the impact of the S-IVB upper stages and LM ascent stages that were targeted at the Moon's surface. The SMART probe is much smaller so it would depend on how close it hit.
      • Re: (Score:3, Informative)

        The ALSEP packages were turned off remotely when the budget for collecting data ran out. That was Sep 30, 1977. Although the Apollo 14 ALSEP had failed a year and a half earlier, the others (A12, A15-17) were still going strong -- and still would be, the RTG power source having about a 90-year half life. (Well, barring hardware failure.)

        It's not the half life that matters - it's when the output voltage drops below a useable value. The half life of the RTG's on the Voyager probes is comparable - but they h

  • by Jeng (926980) on Wednesday August 30 2006, @07:47PM (#16011936)
    For if it is a truly smart probe, it will refuse its programming and assume a stable orbit rather than crashing.
    • Re: (Score:3, Informative)

      FYI there are no stable orbits around the moon: the perilune becomes smaller and smaller with time, so unless you periodically re-raise it using on-board fuel anything that orbits the moon will eventually crash on it.

      See question 5 from the ESA's SMART-1 FAQs [esa.int] for more details.

  • For Sale (Score:4, Funny)

    by ross.w (87751) <<moc.liamg> <ta> <yelrednowr>> on Wednesday August 30 2006, @07:50PM (#16011948) Journal
    The ideal property for sunlovers, the Peak of Eternal Light!(1)

    Guaranteed 24hr sunlight, all year round!

    Get the tan that will be the envy of your friends!(2)

    (1) Address available on application. Access to the property is the responsibility of the Purchaser.

    (2) Protective clothing required for outdoor activities.

  • krunk smash! (Score:4, Interesting)

    by gsn (989808) on Wednesday August 30 2006, @07:51PM (#16011951)
    nonsense - ESA is crashing it deliberately. From the TFA

    But now SMART-1 is running low on fuel. It has to come down sometime--and soon--so ESA mission scientists decided to crash it in a place where the crash can be seen from Earth and studied.


    You can learn a lot from crashes - how craters form and the composition of the ejecta. Astronomy Krunk style is still useful! Krunk smash! NASA did something similar with the deep impact probe and comet tempel.

    Sad thing here is they have no idea how bright its going to be - TFA says anything between 7 and 15 mag (5 mag difference is a factor of 100 in flux) so we may not see anything really.
  • by midori_yamari (998995) on Wednesday August 30 2006, @08:18PM (#16012099)
    Even if you can't see the explosion, you can either wait for the plume of ejecta to rise up into the sunlight (soon afterwards) or reflect earthshine, which may then be visible here on earth. Or, if you have the equipment, tune your radio gear to 2235.1 MHz and watch as the signal from SMART-1 goes from on (alive) to off (dead) - several radio telescopes in Australia and Chile will be watching as the probe hits.
  • by DavidD_CA (750156) on Wednesday August 30 2006, @08:40PM (#16012209) Homepage
    What does the MEPA have to say about this?

    You know, the Moon Environmental Protection Agency. Surely they're upset about this planned littering of our beloved Moon. Sure it's only a probe now, but that's setting the stage for all sorts of lunar trash. What's next? A satellite? Space shuttle? An entire station?

    Won't somebody PLEASE think of our children's children's children's children's children's children's children's future home?
  • by amyhughes (569088) on Wednesday August 30 2006, @09:11PM (#16012361) Homepage
    Overheard in mission control...

    "That was cool! What else can we crash?"
  • Uh, yeah... (Score:4, Funny)

    by macemoneta (154740) on Wednesday August 30 2006, @10:30PM (#16012711)
    ...propelling the craft in 2003 on a unique spiral path...after which it will crash into the Moon.

    Uh, yeah. We meant to do that.

    • Re:Real Estate (Score:5, Interesting)

      by phulegart (997083) on Wednesday August 30 2006, @07:52PM (#16011953)
      the sooner we stop thinking about the moon as some mystical magical pixie home where ancient one-eyed green cheese eating creatures hide from our attempts to photograph them, and start thinking about in terms of real estate with a long-ass trip to the beach.... ... the sooner we will advance off the planet and into our own solar system with any kind of manned progress.

      The moon is not a rainforest we have to save so that we can continue to breathe. We should avoid blowing it up, but other than that, it's a big hunk of rock we just haven't put to good use yet.
    • Re:Real Estate (Score:5, Interesting)

      by kfg (145172) * on Wednesday August 30 2006, @07:56PM (#16011969)
      I hate hearing such business-evolved terms such as "real estate"

      Real estate is not a business evolved term, in fact it's rather the opposite. It's a fuedalism evolved term.

      "Real" means "royal" and "estate" means "status"; real estate is that property, status; held by royal grant, one's condition under the power of the king.

      If you don't like the term applied to the moon; go complain to the King of the Moon.

      KFG
    • So, any ideas as to if any particular location on Earth will have a better show?

      From the article (which also has links to tips for backyard astronomers wanting to witness it):

      The time to watch: Saturday, September 2nd at 10:41 p.m. PDT (Sept. 3rd, 0541 UT)...The nominal impact time favors observers in western parts of North America and across the Pacific Ocean.

      10:41 PM on the west coast or 1:41 AM on the east coast. It will probably have set or be setting at that time on the east coast, and the twilig

    • Re:Silly question (Score:5, Informative)

      by RsG (809189) on Wednesday August 30 2006, @07:59PM (#16011991)
      Couldn't the orbit decay and finally crash on the far side of the moon?
      Not totally sure about the rest of your post, but I the answer here is "no".

      Orbital decay only occurs when a satelite is within the atmosphere of the body it orbits. It's caused by air resistance sapping the satelite's orbital velocity.

      Since the moon is essentially airless, this won't happen. You could (at least in theory) orbit as close to the moon as you like as long as your path doesn't smack into the side of a mountain. In practice, I'm not sure I'd want to risk it, but it's certainly not against the laws governing orbital mechanics.

      Over extremely long time periods, you'd run into problems, since "essentially airless" is not quite the same as "totally airless" (even in deep space there is no true vacuum), but I suspect we'd be talking about decades at a minimum here.
    • Re: (Score:3, Insightful)

      Even in a total lunar eclipse, there's always a reddish glow on the moon's face--the light of every sunrise and sunset in the world hitting it after passing through Earth's atmosphere. So it's eternal sunlight...it's just not 100% constant.
    • by Roduku (950552) on Wednesday August 30 2006, @09:53PM (#16012567)
      How did such an ignorant statement get modded insightful?
      What did you do, make the post then log in with a different name and mod yourself?

      Even during a total eclipse, tha moon is not totally dark. Sunlight gets refracted towards the moon through the Earth's atmosphere. A mountain peak at the Moon's pole could indeed be in eternal light.

      One thing that really irks me is people that base the validity of a statement on their personal assumptions. In the words of Adam Savage of Mythbusters: "I reject your reality and substitute my own."
    • by wirefarm (18470) <jim@ m m d c.net> on Wednesday August 30 2006, @11:01PM (#16012877) Homepage
      That's when the low-paid lunar coders will sleep...

      What you really want to worry about are the Solar Eclipses of the Moon, when the Sun passes between the Earth and the Moon...
      • Then I will start calling my fridge a 'wellspring of eternal beers' since, most of the time, there's beer in there. Except on RARE occasions when there's not because some 'guest' drank it all.

        TLF
    • Re: (Score:3, Insightful)

      Unlike our early space travel, there's a treaty that says that you have to de-orbit material around the moon. There's not as much room to be sending missions up there and muck about with lunar-orbit space junk. Although it's still mondo rare to have an impact in Earth orbit, there's enough crap flying around us that some time ago they decided we didn't need to make the same mistakes up there.

      Old news actually.

      In fact in earth orbit you're supposed to bring spacecraft out of orbit at the end of their life. T
    • Re: (Score:3, Informative)

      the article says it could be possible to see the crash with a "backyard telescope", but also says that it might be too dim to be seen by a professional observatory:

      "How bright will it be? No one knows. Estimates range from 7th to 15th magnitude. In other words, it might be bright enough for backyard telescopes--or so dim that even big professional observatories won't see a thing. The only way to find out is to look."

      secondly..

      "The nominal impact time [esa.int] favors observers in western parts of North Ameri
    • by YA_Python_dev (885173) on Wednesday August 30 2006, @09:57PM (#16012584) Journal

      I know that yours was a joke, but FYI crashing into the moon is the end of every mission in lunar orbit (yes, this includes the ascent stages of the Apollo Lunar Modules); those orbits are not stable due to the gravity of the sun, the Earth and irregularities in the moon itself.

      And, considering that this is an ESA mission, why the summary has only a link to the NASA site? ESA has a lot of good information about the mission and the impact:

      IMHO the most important results from this mission (beside a lot of nice detailed images) are the successful use of a ion engine with a very complicated low-power path (that thing passed through the L1 Lagrangian Point, switching seamlessly from earth orbit to lunar orbit) and the extensive mapping of the moon surface chemical composition using X-ray and infrared instruments.

    • Re: (Score:3, Funny)

      You're the reason we have those 100 line disclaimers at the bottom of everything.