[CoastalCoder]

Hopefully I'm not embarrassing myself with this question, but:

If you know an satellite's orbital path and velocity, and the Earth's gravitational strength, is that enough to compute the satellite's mass?

[martincmartin]

In a uniform gravitational field, it isn't. On the earth's surface, acceleration due to gravity is 9.8 m/s^2, independent of the mass of the falling object. See Galileo's Leaning Tower of Pisa experiment.

https://en.wikipedia.org/wiki/Galileo%27s_Leaning_Tower_of_P...

[staunton]

The field is not uniform though. So in theory, if you know the orbit and firld exactly, you can calculate it.

In the present case, I guess the precision with which one knows the orbit and other stuff (like the exact gravitational fiel of the earth) doesn't work out.

[martincmartin]

True. It turns out, it also applies for the two body problem, as long as one body is much more massive than the other.

https://en.wikipedia.org/wiki/Orbital_period#Small_body_orbi...

[CoastalCoder]

> Hopefully I'm not embarrassing myself with this question, but:

Yup, I'm kind of embarrassed :) I forgot that maintaining orbit is just a matter of falling at the same pace that the earth is falling away from you.

[mmh0000]

If you've never tried it, I highly recommend playing Kerbel Space Program[1] (it works on Linux, Mac, and Windows!).

That game taught me so much about orbital mechanics, which led to rabbit holes of textbooks and videos[2].

The first big lesson KSP taught me was: why, when launching a rocket, you don't just go straight up but, instead, have to lean over pretty aggressively.

[1] https://store.steampowered.com/app/220200/Kerbal_Space_Progr...

[2] https://www.youtube.com/watch?v=dhYqflvJMXc

[flainne]

> maintaining orbit is just a matter of falling at the same pace that the earth is falling away from you

Perhaps a better visualization: moving sideways fast enough that you miss the earth? :)