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Comment by ilrwbwrkhv | Hacker News Reader

It takes too long to go to these places. We need some sort of thrusters with which we can reach these places in months.

We can build a fuel station on Moon, which will make pellets of fuel, then shot them in direction of a spacecraft at Moon orbit. Spacecraft can collect them, then fuel an ionic drive for constant acceleration for weeks. Moon has low gravity, no atmosphere, thus it makes it ideal for a railgun[0].

With a fuel station on Moon, it will be much cheaper to reach Mars, so it will be possible to build second fuel station at Fobos. With two fuel stations, it will be even cheaper to refuel a spacecraft for long-range missions.

[0]: https://www.space.com/36442-could-moon-miners-use-railguns-t...

Apollo and Artemis dose the expensive, fast trajectories due to protecting human life. There is a mission currently enroute to the Moon that will take months due to a frugal propulsion system.

There's no getting around acceleration. Subjecting your crew to high g forces due to acceleration for months on end isn't going to be very good for them if not lethal.

It doesn’t take high acceleration. If you had a propulsion system that could do a sustained 1g acceleration a trip to Jupiter would take around 6 days, including deceleration. That is a quite reasonable transit time. There is just the small problem of finding such a propulsion system.

https://space.stackexchange.com/questions/840/how-fast-will-...

Absolutely. I think people don't really have a gut feeling for this, but you don't need high acceleration to get anywhere in the solar system; you just need sustained acceleration. Right now, our probes accelerate for minutes and then coast for years.

If you could sustain 1g acceleration for, say, weeks, it even makes interstellar travel reasonable. A day of 1g acceleration will get you up to about 850 kilometers per second... or, 73 million km per day. Thirty days of 1g acceleration gets you to 2 billion km/day. That's close to 1% of the speed of light.

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