• Question: How do space probes make it past the asteroid belt without crashing into asteroids?

    Asked by Mason The Amazing :) to Andrew, Hina, Ian, Kathryn, Leah-Nani, Xu on 14 Jun 2018.
    • Photo: Kathryn Burrows

      Kathryn Burrows answered on 14 Jun 2018:


      I don’t know. By luck I guess. Though there are many asteroids distances in space are vast so there may still be sufficient gaps between them for probes to slip through.

      Do one of the guys who have worked at NASA have an answer?

    • Photo: Leah-Nani Alconcel

      Leah-Nani Alconcel answered on 15 Jun 2018:


      The asteroid belt is actually mostly empty space. The average size of an asteroid is about a metre across. There is approximately 1 asteroid in an area the size of Cornwall. The chances of a space probe a couple of metres across encountering an asteroid while it travels across the belt are vanishingly small.

    • Photo: Andrew Margetts-Kelly

      Andrew Margetts-Kelly answered on 19 Jun 2018:


      There really isn’t that much stuff there. It’s nothing like the asteroid fields in films like Star Wars. It’s a long long way between the rocks in the asteroid belt; it’s not a case of being lucky to get through, it’s a case of being incredible unlucky if you hit something.

      To give it numbers the area in space that is known as the asteroid belt is only 0.0000000000000000003% full of rocks.

      We’ve never sent a probe through the asteroid belt and had to have any mission level plan to do a course correction (the risk is just too low to bother worrying about it).

      This is a picture of where the known asteroids are; it looks like there is no way through, but remember it’s a long way between the dots (about 7500000000 metres between then on average).

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