4 ms·

That's actually a fun thought... once you've got your probe up to a third of the speed of light or whatever... how are you going to slow down again in order to

by mfoy_ 8y ago

That's actually a fun thought... once you've got your probe up to a third of the speed of light or whatever... how are you going to slow down again in order to actually do anything useful? Or maybe this is a solar sail that was part of an ACCELERATION stage for a probe that already passed through our solar system millions of years ago.

api 8y ago
I'm not a rocket scientist (heh) but I'm imagining a many-stage nuclear rocket. You'd have a whole bunch of acceleration stages followed by a much smaller number of deceleration stages followed by the payload. You wouldn't need as many deceleration stages since you've already spent all the mass in your acceleration stages. Building such a thing in space would involve sending up the stages themselves with some kind of heavy lift vehicle, assembling them in orbit, and firing it. The number of stages you could assemble would be quite large since there's no air resistance or (relative) gravitational stress in space. You'd just have to not exceed the tensile strength of the material during acceleration. You could put together 100 stages or more I'm sure. It's one rather brute force but workable way of reaching some nontrivial fraction of the speed of light. Someone should do the math on this for fission (NERVA-like), thermonuclear pulse (Orion), and pure fusion.
AtlasBarfed 8y ago
If we were to do an interstellar ship with current physics it would probably rely on: - Preacceleration strategies that speed up the craft without using its onboard/deceleration reaction mass/fuel (gravity whips, launching lasers for a solar sail, cannon-fired fuel pods) - Pulse nuclear acceleration using "preseeded" fuel pods launched ahead of the craft and captured as the craft caught the pod - ion drive once the preseeded fuel pods weren't practical anymore - ion drive, solar sail, and pulse nuclear and more gravity whips to slow down Pulse nuclear/orion ships are the only thing that gets close to specific impulse and performance to get to Alpha Centauri in anything reasonable. It becomes a LOT more feasible if fuel pods are prelaunched, or seeded by a leading disposable fuel seeding ship (it doesn't have to slow down, it can just, uh ... .... fly through the target system once it's done. Uhoh.
- mfoy_ 8y ago
  This kind of makes me want to play KSP again...

by mfoy_ 8y ago

api 8y ago

I'm not a rocket scientist (heh) but I'm imagining a many-stage nuclear rocket. You'd have a whole bunch of acceleration stages followed by a much smaller number of deceleration stages followed by the payload. You wouldn't need as many deceleration stages since you've already spent all the mass in your acceleration stages. Building such a thing in space would involve sending up the stages themselves with some kind of heavy lift vehicle, assembling them in orbit, and firing it. The number of stages you could assemble would be quite large since there's no air resistance or (relative) gravitational stress in space. You'd just have to not exceed the tensile strength of the material during acceleration. You could put together 100 stages or more I'm sure. It's one rather brute force but workable way of reaching some nontrivial fraction of the speed of light. Someone should do the math on this for fission (NERVA-like), thermonuclear pulse (Orion), and pure fusion.

AtlasBarfed 8y ago

If we were to do an interstellar ship with current physics it would probably rely on: - Preacceleration strategies that speed up the craft without using its onboard/deceleration reaction mass/fuel (gravity whips, launching lasers for a solar sail, cannon-fired fuel pods) - Pulse nuclear acceleration using "preseeded" fuel pods launched ahead of the craft and captured as the craft caught the pod - ion drive once the preseeded fuel pods weren't practical anymore - ion drive, solar sail, and pulse nuclear and more gravity whips to slow down Pulse nuclear/orion ships are the only thing that gets close to specific impulse and performance to get to Alpha Centauri in anything reasonable. It becomes a LOT more feasible if fuel pods are prelaunched, or seeded by a leading disposable fuel seeding ship (it doesn't have to slow down, it can just, uh ... .... fly through the target system once it's done. Uhoh.

mfoy_ 8y ago
This kind of makes me want to play KSP again...