• Question: In the future do you think its possible that we could use gravity its self to say launch a telescope or satellite into space?

    Asked by MichaelM15 to Daniel, Hannah, Maggie, Ry, Scott on 7 Nov 2017.
    • Photo: Maggie Lieu

      Maggie Lieu answered on 7 Nov 2017:

      We do this already, this is called gravity assist. Most satellites don’t have enough fuel to get to the outer solar system planets so they usually orbit a few times the sun to gain momentum, kinda like a slingshot.

      Also when the Apollo 13 mission (a manned space mission that intended to land on the moon) had a big accident (they almost ran out of oxygen!) they had to do an emergency manoeuvre to get back to Earth. What they did was they used the moon to slingshot themselves back!

    • Photo: Hannah Middleton

      Hannah Middleton answered on 7 Nov 2017:

      We don’t really use gravity to launch satellites – then it’s more like we are fighting against gravity to launch something. But just like Maggie said we can use gravity to help us after launch, once in space! The Voyager space probe did this too, on it’s travels through the solar system.

    • Photo: Ry Cutter

      Ry Cutter answered on 7 Nov 2017:

      We don’t use gravity so much to help launch satellites off Earth as it’s the main thing we’re fighting against, but like the other two said we can use the gravity to slingshot things to save fuel.
      We also use gravity to keep the satellites up there. Most GPS satellites use Earths gravity to orbit around us. We can put certain satellites in what is called a geosynchronous orbit (which means it goes around the Earth at the same speed the Earth rotates). It means we’ll never lose the satellite as it will be in the same position in the sky all the time. This is great for monitoring the weather!
      We also plan on putting the space gravitational wave detector (LISA) in the L1 point. This is a point between the Earth and Sun where a satellite can have a stable orbit. It follows our orbit around the sun! So we do harness gravity in a lot of ways to help us with space based missions.
      Great Question,
      Ryan

    • Photo: Scott Melville

      Scott Melville answered on 9 Nov 2017:

      I’m a bit late to this party – looks like everyone covered all of the important things 🙂 On the surface of the Earth, gravity pulls directly downwards – which is precisely the wrong direction for launching things into space. But once you can get something a little ways off the ground, you can start to use to gravity to help you do things – like keep you in orbit or as a slingshot.
      Using gravity as a propellant is hard because it’s always attractive. Really what we’d want is something like ‘anti-gravity’, which would repel different masses. This might let you launch a rocket – but it would require some very new and exotic kind of matter (all of the matter we’ve ever found produces regular gravity, we don’t know of anything which produces anti-gravity). But there’s always science fiction 🙂

Comments