Maybe get to Mars in 39 days ?

a reply to: samkent

Actually, a rocket's top speed will be the exit velocity of rocket engine: IE if the rocket's exhaust exits at 500,000 Mph, and the rocket has enough fuel to maintain this, then it will continue to accelerate until it's velocity matches that of the exhaust. Newton's law of reaction

This only works, however, if there are no other forces acting upon the rocket, such as gravity. Here in our solar system, once you get far enough away from a planet or other body, the sun's gravity will be pulling on your rocket, trying to slow it down, until you get far enough away from the sun (which is pretty far out there beyond the Oort cloud).

The main problem is having enough fuel to maintain that acceleration. For conventional chemical rockets: the bigger the engine, the more and faster the fuel it will consume. Ion engines are able to work with very small amounts of fuel, but their acceleration times are much slower.

Sort of like a car engine: Two cars going up a hill (the hill being the Sun's gravity), the car with a huge V8 engine will accelerate up that hill quite well, but will be sucking the gas out of the fuel tank like water through a hose. The other car with a small 4 cylinder engine will not use as much fuel, but the hill will slow it down quite a bit, and it won't be able to accelerate up the hill as fast as the car with the huge V8 engine.

originally posted by: Chrisfishenstein
a reply to: nelloh62

Really, how does nobody but me question this? Not necessarily the timeframe to get to Mars, but the distance aspect of what we have been told forever? If it is true and their distance stats are true, how in the hell minus some kind of faster than light speed travel could we possibly make it to Mars in a little over a month? Once that satellite was launched and made it out of the solar system, this made me question this over and over in my head! Our supposed distances of our own solar system have to be waaaay off for us to be able to achieve this in the time they are saying!

Does this not add up to being completely lied to? Unless they thought this to be true and if so, how isn't everything they have said a lie? Like the size of planets, weights (not to mention how a weight of a planet would be calculated) and much more...This just stinks of being completely lied to about how far away from us things in outer space actually are....

IF there is enough fuel, travelling at a constant 1 g, the time to get to Mars at its nearest, is three weeks, only trouble is, at the other end of the journey, braking would be rather fierce to say the least.

a reply to: samkent

Dawn isn't the fastest. New Horizons was the fastest. It was launched with a velocity of about 100,000 mph relative to the sun. And its the solar-centric velocity that matters when traveling between planets. Every spacecraft leaving Earth orbit can get up to 67,000 mph of velocity just from the Earth's orbital velocity.