# Delta-V formula?

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Xyphos    535
Posted (edited)

What's the math formula to compute the Delta-V required to reach full orbit around a specific celestial body from it's surface, including atmospheric pressure, if applicable?

sure, I could look at the cheat-sheat chart, but I wanna know the formula.

Edited by Xyphos

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KerbMav    917

Maybe you will find here what you are looking for:

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Xyphos    535
1 minute ago, KerbMav said:

Maybe you will find here what you are looking for:

that works, thanks!

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Xyphos    535

new question: what if the body is tidally locked? does that still count as rotation?

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Just now, Xyphos said:

new question: what if the body is tidally locked? does that still count as rotation?

Yes, a tidally locked body is still rotation, Lets look at the Mun for example. It's semi-major axis is 12,000km and has an orbital period of 138,984s. Now since the Mun is tidally locked, its rotational period is the same as its orbital period.

So, since the Mun's radius is 200km, we can find the circumference at the equator of about 1,256,640m.

Taking distance over time to find rotational velocity we get (1,256,640(m) / 138,984(s)) this equals a surface velocity of 9.04 m/s

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Xyphos    535
1 minute ago, Kyle Worden said:

to find rotational velocity we get (1,256,640(m) / 138,984(s)) this equals a surface velocity of 9.04 m/s

perfect. awesome. thanks

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You can also find that value by landing, and then clicking the navball over to show orbital speed instead of surface speed.

The exact value will vary by how close you are to the equator and the altitude of the terrain you're on.