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Who thought asteroids were dull, dumb rocks?

Jonathan Amos | 08:27 UK time, Tuesday, 8 June 2010

There's no doubting the big space story of the coming days - it is the return to Earth of Japan's Hayabusa spacecraft.

Asteroid ItokawaThe mission visited the asteroid Itokawa in 2005 and acquired some stunning up-close imagery and remote-sensing data. It also made an attempt to grab samples off the potato-shaped object's surface.

The capsule containing those rocky fragments is now hurtling home. The 40cm-wide disc should slam into our atmosphere on Sunday, slowing sufficiently in its fiery descent for a parachute to give it a reasonably soft landing in the Australian Outback at about 1400 GMT.

Hayabusa's seven-year round trip has been quite an adventure. Communications with Earth have been patchy, it lost a small deployable probe, its sample-grab mechanism malfunctioned, and - to cap it all - it's had to limp home because of a severely compromised propulsion system.

No-one really knows if the capsule carries some Itokawa dust or is completely sterile, but most people I think will cheer this mission home. It strikes me Japanese scientists and engineers have already demonstrated remarkable skill in recovering what seemed on many occasions to be an utterly lost cause.

I'll speak more of Hayabusa's return later in the week but I really just wanted to mark your card for the future because we have an exciting year ahead as far as asteroid studies go.

These objects fascinate because they represent the leftovers - the rubble - that were never incorporated into the big planets that now dominate the Solar System. In other words, they're an eye into our past some 4.5 billion years ago.

RosettaBoth Europe and the US are also planning major encounters.

First up will be the European Space Agency's (Esa) Rosetta probe, which is due to pass just 3,160km from Asteroid Lutetia on 10 July. The 100km-plus-wide Lutetia is a bit of a strange beast.

Earth-based observations had at first classified it as a primitive object, little changed since its formation (a so-called C-type asteroid). Further measurements then spied an unexpectedly high metal composition on its surface, suggesting it might have undergone a greater degree of evolution than previously thought.

Rosetta will just race by. Its main quarry is an unpronounceable comet (67P/Churyumov-Gerasimenko) which it will meet out near Jupiter in 2014, but the opportunity to test its instruments on this fascinating lump of space rock is too good an opportunity to pass up.

Dr Rita Schulz, Esa's Rosetta project scientist told me:

"Asteroids are all different; you can't just visit one or two and say 'now we know all about the asteroids'. There's such a large variety. We cannot identify, or define, them all from ground-based observations and so we need to visit a whole bunch of asteroids. And they're rather easy to reach because they are in a belt between Mars and Jupiter. It is much more difficult reach objects that are further away or out of the ecliptic - out of the plane where all the planets lie in."

Rosetta will have all of its remote-sensing instruments switched on - cameras, plasma experiments, magnetometers, dust instruments, radio science experiment, etc. It will nail Lutetia's true state.

It will be fascinating to see if the probe catches any dust as it whizzes by, as the spacecraft carries an atomic force microscope. An AFM was used on Mars by the Phoenix lander, but Rosetta's high-resolution instrument must be the most distant such microscope yet deployed.

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Rosetta-Lutetia is just the appetiser, though.

Ceres and VestaNasa's Dawn spacecraft will be bearing down on the 530km-wide Vesta asteroid this time next year.

The probe will be spending about 12 months at this rock before moving on to Ceres which, at 950km in diameter, is by far the largest and most massive body in the asteroid belt.

It is what they call a "dwarf planet" these days - the same classification we're supposed to use now to describe Pluto.

Their sheer size means gravity has pulled these bodies into a spherical form, Ceres more so than Vesta.

The latter unfortunately has the look of a punctured football, the result of a colossal collision sometime its past that ripped a big chunk out of its south polar region.

The debris from that smash-up was sent far and wide. About one in 20 of the meteorites that falls to Earth is probably a bit of Vesta.

Ceres and Vesta will make for interesting subjects. These really are evolved bodies - objects that have heated up and started to separate into distinct layers.

In the case of Vesta this probably means it has an iron core. For Ceres, scientists don't think it got quite so hot, and it probably retains a lot of water, perhaps in a band of ice deep below the surface.

Like Rosetta, Dawn has a suite of instruments to investigate these rocks' present state and their history. Lead scientist Professor Christopher Russell summed up the mission for me thus:

"The name is a suggestion of what we're trying to do. We're trying to go to the dawn of the Solar System. We're looking at two bodies that were formed right at the beginning, in the first five million years, and that have remained intact. They weren't destroyed; they weren't knocked apart and reassembled. We think when we go there, we'll understand how the building blocks of the Solar System were put together. You could say we'll learn about the childhood of the Solar System."

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Asteroids rock!


  • Comment number 1.

    The important question if some of these asteroids contain water ice is are they carrying life or the building blocks of life from elsewhere in the galaxy? Something like an anthrax spore frozen deep within a block of water ice could potentially last for a long time in space. Even on earth they can survive temperatures up to 120'c and twice normal atmospheric pressure for 10-12 mins and can stay viable and dormant in the soil for centuries.

    Well worth checking out but to further our knowledge of the universe and for self-protection.

  • Comment number 2.

    Excellent introductory piece for the general reader, and congratulations (perhaps a bit premature) to the Itokawa team. One hopes the payload makes it down intact. Presence or absence of alien anthrax aside, there is a practical and compelling rational for this, the Rosetta mission and US mission to Vesta and Ceres as well.

    From its inception, US space policy has been largely driven by aggressive, short sighted and chauvinistic motives; beating the Russians, getting there first, dominating the high ground, etc. Sensible enough for Generals and Engineers, but not the best way forward in the long run.

    US space policy has been without a clear existential purpose since the first lunar landing. "We won, now what?" What is needed is a compelling, long term narrative, one capable of sustaining public support for decades, even, dare one say it, centuries. Space is big, going anywhere takes time and money, and lots of both.

    The best reason to go into space is to STAY in space, to inhabit it, to live there. When we are living there we will need water, fuel and other raw materials and the shallowest resource containing gravity wells available are asteroids.

    Now there is an inspiring project with no end date, a project that must be based on cooperation and one that is deeply tied to the ultimate survival and prosperity of humanity. (And dogs too, there will definitely be dogs;-)

  • Comment number 3.

    The asteroids are not only an eye into our past, as you said, but also an eye into our future.

    The resources they hold are the key to our economic expansion into space. The most immediate resource is water, which can be used in its raw state as radiation shielding and as feedstock for in-space propellant manufacture. John S. Lewis of Arizona University has done the most detailed studies on this to date, so far as I know.

    The asteroids of most immediate interest for resource use are the near-Earth asteroids, about a quarter of which are easier to reach, in terms of rocket propulsion, than the surface of the Moon, though with much longer journey times of course.

    In the longer term, the main belt has sufficient material resources to support a human population millions of times greater than our current terrestrial population, as several authors have noted (Drake; Lewis; Savage).

    If our space agencies had any strategic plan for our growth into space, we would be studying them much more energetically than we are at present!


  • Comment number 4.

    Am Sure That Space Junk That We Put Into orbit Will Some Day Be The Talk At A Distant Dinner table If They Have Dinner Tables On A Planet Out Side Our Own.I Wonder What That Would Be Like to have An Alien Sit Back And Say ((( them Humans On That Rock Over There Are Pigs Throwing There Trash Out where ever them pigs Feel Even In Space.Why Would Any One Want To Visit That Junk Yard filled with Care Less Creatures.

  • Comment number 5.

    "About one in 20 of the asteroids seen to fall to Earth are probably bits of Vesta."

    Only one asteroid has ever been seen to fall to Earth.
    Known as 2008TC3, known by me (unofficially) as Top-Cat,
    was tracked to its impact in October 2008.

  • Comment number 6.

    #2 The anthrax analogy was an obvious stereotype... I don't seriously think that fully formed pathogens exist in the asteroid belt, but anthrax is a well known example of a very advanced life form (compared to viruses and most other bacteria) capable of surviving in very harsh enviroments. If asteroids from outside our solar system contain large chunks of water ice then they could be vectors for small molecules of DNA that could have been the seeds of life on earth. If any small traces of DNA or RNA can be found on an asteroid it would imply that simple life is widespread and not unique to earth.

    While I agree that US space policy is what you say it is, its worth pointing out that without cold war pressure they'd never have spent the money needed for the apollo programme and we'd probably still be talking about a moon landing sometime. War or threat of war is a big driving force for getting science off the drawing board and into action. In 1939 the RAF had biplanes in front line service... in 1944 it had jets.

  • Comment number 7.

    Ibuz (post 2): I agree with you totally.

    The problem is that the long-term narrative you describe is not widely understood. I've just been reading Paul Rincon's interview with Spencer Wells, author of a new book about human history and prehistory:

    Wells surveys the history of our species over the longest timespans, and talks about "finding a mythos for the modern age that's perhaps more inclusive than the mythos we have today". Yet in the interview he does not even mention our expansion into space. It's people like him who have to be brought on board before asteroid exploration is widely seen for its true potential for the long-term future of our species.


  • Comment number 8.

    Venture aside, it would be a bit of a party killer if this probe came back empty handed. Aren't the Japanese the forerunners of robotics and computer technology? I'm surprised they couldn't make the asteroid cook their probe a hearty breakfast, a packed lunch and a wholesome dinner after a day at space school! Now I will be suprised if their recovery team makes it back in one piece after a day (or two) in the wonderfully hospitable Australian Outback...

    I agree with alot of what has already been mentioned, however I would have preferred a "face-hugger" rather than anthrax to be on the "what-if" list.

    Asteroids could very well be laiden with information, but the key question I saw noted above - "then what?" - plays a far bigger role in the future of space exploration that we all could think. Putting archane answers with their equal counterparts will not coo our inquisitive minds, infact it will do quite the contrary. Knowledge can be an obsession to some...dare I say it...a drug. So bare with me when I say, substantiated findings on asteroids would be tantamount to handing me a rolled up $20 with a freshly cut line of "then what".

    I am aware of asteroids (and some of Jupiters moons) being viewed as potential "refuelling stations" for hydrogen based propulsion in the current space race, the solar race. "One hundred years to conquor" - is what I was quoted, and since this is China's century (according to economists), we should be hearing alot more "Ooo's and Aah's" from East Asia in the near future.

  • Comment number 9.

    @Ibuz: Well, I spoke last night with Hitoshi Kuninaka from the Hayabusa team who is in Australia awaiting the capsule's return. I put it to him that the capsule might be empty and he made quite a compelling case for why it should contain something, albeit perhaps in tiny quantities. This basically comes down to the fact that the probe was in contact with Itokawa for an extended period. It had a ball mechanism for kicking up a sample which didn't work, but he was very confident some material would have been disturbed by the probe's close proximity to the surface and this would have found its way into the chamber. We'll see. Scientists only need an itsy-bitsy amount to keep them busy for years. And yes, there will be dogs in space (my two labradors are spaced out most of the time, usually in front of the TV).

    @Stephen. Keep the vision thing going. We need it.

  • Comment number 10.

    Boy, couldn't get past the second comment on here without the obligatory USA bashing.

  • Comment number 11.

    Adjutant (post 10):

    "From its inception, US space policy has been largely driven by aggressive, short sighted and chauvinistic motives; beating the Russians, getting there first, dominating the high ground, etc."

    This is not "USA bashing", but a statement of fact. Otherwise why would Apollo have been cancelled at the height of its success? Do you really think it was driven by science or a plan for economic growth in space? Was the Soviet Moon-landing programme of 1964-1974 driven by more ethically correct motives?

    "US space policy has been without a clear existential purpose since the first lunar landing."

    Another statement of fact. Otherwise why are there no plans to regularly maintain the ISS with replacement modules (Zarya and Zvezda will come due for replacement around 2018)? Why is the Shuttle being scrapped rather than developed into an improved mark II Shuttle? Why has the success of Spirit and Opportunity on Mars been greeted by scrapping their design and going back to the drawing-board?

    I would suggest that the problem is not USA bashing, but the politics of large organisations and vested interests, which is why all the original thinking is coming from recent start-ups like Virgin Galactic and SpaceX.







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