Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: katieHaylor on 17/05/2018 09:34:04

Title: Can thrust from a rocket affect an orbit?
Post by: katieHaylor on 17/05/2018 09:34:04

Paul asks:

When a rocket lifts off from say, the moon, is there any backward thrust from said rocket changing the orbit of the moon?

What do you think?

Title: Re: Can thrust from a rocket affect an orbit?
Post by: Colin2B on 17/05/2018 09:42:02

Yes, but the effect is proportional to the mass of each body, so the rocket moves a lot and the moon such an infinitesimal amount that the motion is to all intents and purposes zero.

Title: Re: Can thrust from a rocket affect an orbit?
Post by: Bill S on 17/05/2018 12:50:15

Think of standing on the Earth's surface and dropping a small stone.  Each moves towards the other, but you would have fun trying to detect the movement of the Earth.

To actually address your question about the orbit would require more knowledge than I have about the forces involved.  Pete might be the man for that job.

Title: Re: Can thrust from a rocket affect an orbit?
Post by: PmbPhy on 17/05/2018 13:07:08

Quote from: katieHaylor on 17/05/2018 09:34:04

Paul asks:

When a rocket lifts off from say, the moon, is there any backward thrust from said rocket changing the orbit of the moon?

What do you think?

There's virtually no effect on the moon. Don't forget that meteors hit the moon every year and that the sub hits the moon and its ight exerts forces on it too. Same with Earth.

See: https://www.nasa.gov/press-release/goddard/2016/lro-lunar-cratering