Robots and humans target asteroids

OSIRIS-REx (Nasa) Nasa's asteroid sample-return mission will cost about a billion dollars to mount

There were two key announcements this past week relevant to the human exploration of space beyond low-Earth orbit and the space station.

The first was the confirmation by Nasa that it would press ahead with the development of a Multi-Purpose Crew Vehicle (MPCV) based on its "cancelled" Orion concept.

Orion, originally conceived under the US agency's now defunct Constellation programme, was to be equipped with the systems needed to sustain astronauts on long journeys away from our planet. The MPCV (Orion in all but name) will be similarly equipped.

The other important bit of news was the selection of Osiris-Rex [2.5MB PDF] to launch in 2016.

This robotic mission of Nasa's will travel out to an asteroid called 1999 RQ36; its arrival is expected in 2020. After some remote-sensing of its target, Osiris-Rex will then attempt to pick up some grit and dust from the space rock before returning those samples to Earth for study in labs across the world.

What links these two announcements? Well, President Obama has set Nasa the objective of getting humans to an asteroid by 2025. The crew will undertake that venture in the MPCV, and their encounter will benefit from the lessons learned on Osiris-Rex.

All this ought to be viewed with some relish. As I've written on many previous occasions, asteroids are anything but dull, dumb rocks.

  • In exploration terms, these objects are stepping stones to even more distant destinations. The 2025 asteroid expedition would be followed at a later date by a mission to circle Mars, perhaps even to land on one of its two moons, before trying to get down on to the Red Planet's surface itself.
  • Asteroids are also key science targets right now. It's oft said that they are left-overs from the formation of the Solar System - bits of rubble that never quite got incorporated into planets proper. The more pristine examples out there hold critical clues to those early formation processes and the materials involved.
  • Asteroids will be a resource one day, too. Some contain large amounts of platinum and other precious metals; some contain substantial quantities of water. These rocks could be used like filling stations - their water could be split into hydrogen and oxygen to make rocket fuel for the next leg of an interplanetary journey.
  • And asteroids are the potential foe we need to understand. There could be a big rock out there that we haven't yet identified which is on a collision course with Earth. We must learn how these mountains of rock are constructed in order to develop the best strategies for deflecting any that pose a serious risk of impacting our home planet. We don't want to go the same way as the dinosaurs.
Asteroid size comparison Itokawa is quite small compared with some of the asteroids the MPCV could visit

On the issue of Earth protection, one of the tasks for Osiris-Rex will be to measure accurately something called the "Yarkovsky effect" for the first time.

This describes what happens when an asteroid radiates energy absorbed from the Sun back into space. Releasing heat in one direction nudges the object in the opposite direction. The resulting acceleration is tiny, but over the centuries acts like a weak rocket and could make the difference between a hit or a miss in some circumstances.

But the main objective of Osiris-Rex will be to try to grab a sample from the surface of 1999 RQ36. This is really hard, as the Japanese discovered when their Hayabusa spacecraft visited Asteroid Itokawa.

Most asteroids have crazy, irregular shapes, and exert very little gravitational attraction. Disturbed material has a tendency to float up off the surface, making it more difficult to handle. The Japanese tried to fire a small ball at Itokawa, hoping the impact would kick up dust into their sample collector. It did, but in minuscule amounts.

Astrium tests for MarcoPolo (Astrium) A lot of effort has gone into working out how to pick up a sample from the surface of an asteroid

The Osiris-Rex team will try a different approach. The spacecraft will push its sample-grabbing mechanism into the asteroid's surface on the end of a long arm.

Michael Drake, of the University of Arizona in Tucson, is the mission's principal investigator. He explains: "On the end of the arm is the sample collection device, which is a rather simple device which looks a bit like a car filter, and we actually blow nitrogen gas into the surface on contact to agitate the surface and collect the sample inside this thing that looks like a car filter.

"It's a very elegantly simple design that Lockheed Martin came up with."

Let's hope it works. Here in Europe, a lot of work has been done on this topic because we have our own asteroid sample-return concept, currently called MarcoPolo-R. This is still in competition with other mission ideas at the European Space Agency but, if selected, could launch in about 2021.

Space company Astrium UK has tested a variety of sample-grabbing mechanisms for the MarcoPolo effort. The exercise proved the need to be prepared for every type of surface.

If you go to the asteroid expecting to pick up gravel and pebbles and find only fine sandy material or large boulders - you're in trouble.

Marie Claire Perkinson, a mission design specialist at Astrium, told me: "In the past, people have taken a rather optimistic view of what the regolith might be like. That view has been based on what we know of the Moon's surface. But you have to make sure you can handle every type of surface; you have to test your mechanism before you go at all levels.

"We investigated samples that were individual sizes but also mixes of sizes, to see what performance we could get. We found success with a corer mechanism - like a wide-bore drill - with a shutter at the bottom."

This actually highlights one of the advantages of humans over robots in space. For all the intelligence we're now able to program into computers, nothing compares to the astronaut's capability for on-the-hoof decision-making.

Astronaut works up close to a comet Astronauts moving across a small body can make instant decisions, reacting in real-time

Paul Abell, at Nasa's Johnson Space Centre, has been looking at how an astronaut mission to an asteroid might be carried out.

"Asteroids present some real challenges for robotic spacecraft, and having human beings there in direct contact with the asteroid - they're very adaptable and can react to situations," he says.

"Keep in mind that for Hayabusa, the light-delay time for communication was about 32 minutes; it was an object on the far side of the Sun. The robot was doing really well but we were limited by what we could do because of those communications delays.

"When you have humans directly interacting with the surface, they can do things in real time. Humans can look at a rock and perhaps decide to take the sample from underneath the rock."

I'm really looking forward to Osiris-Rex even if its samples won't make it back to Earth until 2023.

What difference the American decision to select Osiris-Rex makes to European thinking on MarcoPolo-R, and whether also to green-light a sample-return mission, is anyone's guess. Antonella Barucci from the Paris Observatory is leading the MarcoPolo-R proposal and will be a co-investigator on Osiris-Rex. She believes the American selection supports her cause.

"I think this is good news because this opens up a new era on asteroid research, because in this moment all the major space agencies in the world want to go to a near-Earth asteroid for sample return," she told me.

"It's very important we go to different targets. The Obama declaration to send humans to an asteroid means we must have precursor missions to characterise all these objects; and they are all so different - in shape, gravity, density, in surface structure, regolith and porosity.

"We need to visit several before we recognise their general characteristics."

Jonathan Amos Article written by Jonathan Amos Jonathan Amos Science correspondent

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  • rate this

    Comment number 80.

    .... A far more realistic and cheaper solution to achieving local gravity in space is to suspend two heavy bodies together by a rope and rotate them. There are many configurations and ways of doing this but the technology for doing so is still a way beyond what we are yet able to do. One common idea for a Mars mission is that one counterweight is a reactor and the other is the life support area..

  • rate this

    Comment number 79.

    #76 The old rotating 'donut' station hasn't been used for a very simple reason, that its design inevitably ends up weighing about 10,000 tons or more. It came from an era when it was assumed we would be using nuclear rockets and would have a big future in space literally. With very large rockets lifting very large payloads, examples are 500 or 1000 tons to LEO.
    .. There s another solution..

  • rate this

    Comment number 78.

    President Obama won't be around (as president) in 2025, so it doesn't matter if this is another empty promise, like those before him.
    Kennedy was the only president with guts to follow through with the Moon program.
    Sorry to be so negative, but presidents and governments are big on words but small on deeds......

  • rate this

    Comment number 77.

    ... And whilst I'm at it, why not re-use all those dumped Shuttle external tanks as add-on accommodation for the ISS? A bit late now of course but just dumping them and letting them burn up on re-entry always seemed a bit wasteful.

  • rate this

    Comment number 76.

    (I see the nutters have been let lose again - who gave them all computers anyway?) Slightly of topic, but I have oft wondered why the age-old 'rotating doughnut'- style space station/ship was never used - a la '2001: A Space Odyssey'? All those 0 gravity problems (health, eating, going to the loo) could be nearly eliminated making long trips much more practical.

  • rate this

    Comment number 75.

    This is a good choice for a mission. Asteroids are fascinating objects. We also have a choice. One day, either we learn to mine them and harvest them, or one of them is going to us hard.

  • Comment number 74.

    This comment was removed because the moderators found it broke the house rules. Explain.

  • rate this

    Comment number 73.

    Jacky C
    31st May 2011 - 15:52

    how on earth did an article about visiting asteroids end up like this with xenophobic/nationalist name calling?..


    I know but on the subject I think a BA330 and Dragonlab would be a better choice than the ATV, cheaper and quicker to put together. The ATV would need a lot of work to produce a manned version.

  • rate this

    Comment number 72.

    @62 Vyom

    Ok so you are another fanatically anti-American person. But when you look at the wars. Many of them weren't even started by the United States.

    Revolutionary War, War of 1812, World War I, World War II, and several of the other wars you listed were started by other countries and then the US got involved in them.

    Please stop with spouting idotic facts. no country is perfect.

  • rate this

    Comment number 71.

    Thank you Jonathan, fascinating article about something that actually matters.

    Hopefully the politicians don't ruin this project. It's seems like a while away though. I wonder what kinds of technology we will have by 2020.

  • rate this

    Comment number 70.

    But back to asteriods. I'm wondering that if we get the technology to mine them in the future, wouldn't the price of the resources that different asteriod provide drop. After all just look at the asteroid belt.

    Lots of resources to be had, if only we had the technology to get to it.

  • rate this

    Comment number 69.

    The worst invention in the history of mankind has be the currency. This is by far the only reason that there are wars, poverty, agrression, and all of the other problems.

    People will say that not all wars are due to money, but they are. In all wars, and revolutions, the underlying cause is about money.

  • rate this

    Comment number 68.

    having their anti-US parades, with their hateful slogans.

    It's time the US said "shove it" and let the other countries deal with their own problems.

    Maybe I will live long enough to be sent off into space. On a last journey before I "kick the bucket" A one way journey that is.

    Maybe they will have those hybernation things. So that we can live super long in stasis. One can only imagine.

  • rate this

    Comment number 67.

    Let the US spend money on space exploration. I'm all for it. I live in the US and would rather see my money spent on projects on exploring the universe than having my taxes go to help solve the worlds problems.

    Since when did the US have to provide for the world. Not only that but when the US gives aid, those countries don't even thank us. Most just go about complaining about the US .......

  • rate this

    Comment number 66.

    @53 cheryl

    Yup you are just another super religious person shoving their "belief" of God down everyone throat.

    You have to accept the fact that Earth is billions of years old. God or whatever didn't create it in seven days. It's funny how you point out all the intelligency that "HE" has given you when you can't even prove that "HE" exists.

  • rate this

    Comment number 65.

    People need to stop using the excuse of poverty, wars, and agression to halt space exploration. If those 3rd world countries could get their acts together and the leaders actually dealt with the corruption there would be money for the people.

    But no, it's the greed of the people who govern others that cause all of these problems.

    colinbell - I'd be happy to go with you.

  • rate this

    Comment number 64.

    @23 cheryl

    "There is no way this asteroid will ever hit earth or any other"

    That is the biggest load of nonsense I have ever read. No one said that this asteroid would hit the Earth. But there are so many others out there that haven't been discovered yet.

    Your selfish view that we humans shouldn't pay attention to anything else but ourselves is what is wrong with this world.

  • rate this

    Comment number 63.

    how on earth did an article about visiting asteroids end up like this with xenophobic/nationalist name calling?...returning to the subject it would be interesting to see how a Near Earth Asteroid mission like this could evolve with especially interesting to see whether Europe's ATV could be modified to support a longer missions by providing a larger habitat volume and things like an airlock maybe

  • rate this

    Comment number 62.

    Revolutionary War
    Indian Wars
    War of 1812
    Mexican-American War
    Utah War
    American Civil War
    Spanish-American War
    Philippine-American War
    Banana Wars
    Boxer Rebellion
    Border War
    World War I
    World War II
    Korean War
    Vietnam War
    Gulf War
    Somali Civil War
    Kosovo War
    War in Afghanistan
    Iraq War

    This is the list that shows how peaceful country US is....Liars

  • rate this

    Comment number 61.

    Peter Nunn wrote:

    "Our democracy is ours, you did not provide it - though I acknowledge our shared efforts to protect ourselves in the 20th century."

    I never said America provided your "democracy." Please read more carefully. What I wrote is simple and clear. Lets not get carried away.


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