#rocket equation

[toneburst]

The Tsiolkovsky rocket equation, also known as the ideal rocket equation, describes how the velocity of a rocket changes based on its mass and the velocity of the exhaust gases it expels. It is fundamental in understanding rocket propulsion and is expressed as Δv = ve ln(m0/mf), where Δv is the change in velocity, ve is the effective exhaust velocity, m0 is the initial mass, and mf is the final mass of the rocket.

[ecunderbase]

s/o to whoever put the actual fucking rocket equation in this kids’ cartoon

[physicsbelike]

staring at this and thinking how you struggled with the basic rocket equation... wow

[tediousfact]

Generation Ship Part 3, Trade-Off

Last time, I picked a propulsion system for my generation ship. I’ll be using a variant of the Orion nuclear pulse propulsion system known as Medusa. Using the best nuclear weapons we could reasonably manufacture using current technology in terms of yield to weight ratio, the tyranny of the rocket equation gives us this chart:

We’re talking about launching a modest-sized town from our solar system to it’s nearest neighbor, using what might be the most powerful propulsion system we could actually build using essentially current technology. And to reach the closest star in a single human lifetime would mean expending a pile of nuclear bombs massing twenty times as much as the town itself. Slowing the trip from one to three hundred years would reduce that pile of nukes to only twice the size of the town. Cutting that pile of nukes in half adds another 150 years to the trip, and another 300 years the next time you do it, and another 650 years beyond that the next time.

Of course, that chart doesn’t include stopping. Which is kind of important. And it makes things a little bit worse:

It would be nice to use something like a magnetic sail for braking instead, and hopefully see a reduction in travel times, but honestly the travel speeds we’re talking about here aren’t large enough to make good use of a magnetic sail for that purpose. And that’s without getting into any of the potential issues with using magnetic sails in the first place.

[cool-vish]

[astronauticalaspirations]

Do you realize the applications of gate-to-gate teleportation technology for rockets, though? THIS IS A WAY AROUND THE ROCKET EQUATION

[eliza-was-here]

This equation comes up a lot in What If calculations. I like it both because it says something fundamental about our ability to explore the universe, and because you can use it to get really good at Kerbal Space Program.

Randall Monroe on the Tsiolkovsky Rocket Equation

[spaceexp]

The Tyranny of the Rocket Equation