# How fast would a bullet reach Mars (if shot from the ISS)?

IANAPhysicist…

Could you use the forward velocity of the space station to add to the velocity of the bullet? In other words, fire forward, in the same direction the space station is traveling? (Of course, I have no idea how fast the space station is moving…)

Still not fast enough. ISS moves about 17,500 MPH. Put the bullet’s 2700 MPH on top of that, you get 20,200 MPH. Escape velocity from the earth is about 25,000 MPH, so you’ve still got about 5000 MPH to go.

If the bullet *was *lucky enough to reach Mars, would it melt in Mars’ thin atmosphere?

What about using the Earth or moon to set up a gravitational slingshot?

Selenic Law, of course.

Yes, the penalty for doing so is a lengthy incarceration in a lunatic asylum.

I can stand in my bedroom and shoot myself in the back of the head.

You need at least two bodies (other than your projectile itself) to do a gravitational slingshot, which means you’d need to have enough initial thrust to reach the vicinity of the Moon. Which is a little bit less than the amount needed to escape outright, but not by all that much.

Maybe Washoe should build a railgun - somehow W reminds me of Moe in the Simpsons.
http://en.wikipedia.org/wiki/Moe_Szyslak

It is the heat and pressure that the steel of the barrel can tolerate. Even though there is other fuel, the oxidizer in the powder is also working like a cutting torch on the steel of the barrel. The barrel life is fairly short at the top end of velocity spectrum. They erode at the throat, just ahead of the chamber where the heat and pressure is the highest. The steel is very thick there, so not a safety issue, but it kills accuracy.

If you don’t care about barrel life, then the combustion rate of the powder becomes the limit. This is where gas guns come in. They use pressurized gas, usually hydrogen to save mass, instead of powder. One of those puppie would probably get you to escape velocity.

The sabot helps, because the pressure gets to work on a light bullet with a large piston area.