Estimate, how much hydrogen fuel would a 800 tonn spaceship need traveling to Mars from Earth n how much time?

Question

Answer is not intended to be absolute accurate. It can use estimation through your info. Does the hydrogen fuel take something like 3 quaters of a spaceship's weight. And would this hydrongen fuel spaceship take couple of months to get to Mars.

As far as I know that using hyrogen fuel has not been done yet, they've only used solar and chemical power till now. And 6 moths is the time taken for current spaceship method to get to Mars. I understand the answer is for current method but isn't this new hydrogen method meant to take much less than 6 months to get to Mars.

Answer 1

Assuming a deltaV of 14.4 km/s and an exhaust velocity of 4.5 km/s, I used the rocket equation to calculate that a 800 ton (no fuel weight) one stage rocket taking off from the surface of the Earth and landing on Mars by parachute, without any fuel needed, would need 2,690 tons of hydrogen and 16,140 tons of oxygen for a total of 18,830 tons of propellant. Remember that hydrogen cannot be burned without oxygen, and oxygen weighs much more than hydrogen. The trip would take about 6 to 9 months. That is using the lowest energy transfer orbit, which is pretty much what they always use because of the massive amounts of fuel needed. The faster you want to go, the more fuel you need, but there is a minimum speed you need to just get there at all, and then the time needed is determined by orbital mechanics.