posted by Sara on .
y is a chemical rocket incapable of getting us to our nearest neighbor proxima centauri?
Is it incapable of not getting us to our nearest neighbor proxima centauri because there isn't enough fuel in the universe to provide for the rocket?
Have you read the WIki article? it sums it up nicely. Yes, there is not enough fuel chemically to do it.
No, that is not the reason. You could get there in several thousand years with a chemical rocket, by just coasting, but everyone on board would be dead.
When going long interstellar distances in rockets, you have to achieve a very high speed. The good news is that there is a lot of time to accelerate. You do not need to have a lot of thrust, but if you want to accelerate to a large fraction of the speed of light and get there in under 100 years, you have to achieve a high spacecraft speed without having to having to exhaust a lot of mass. Such performance requires a property called "specific impulse" that is too low for chemical rockets. Specific impulse is proportional to the speed of the gas in the exhaust. With chemical rockets, the maximum chemical exhaust speed is about 3 km/s. It's too low to achieve a high enough spacecraft speed for a 'short" (under 100 years) trip. "Freezing" astronauts to prolong life may help.
Electrical thrusters that can eject propellant at a higher speed are needed. This has been an active field of development, and there are several alternatives.
thank you drwls :-)