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Impulse transfers for interplanetary travels

What is best to send humans to Mars? A lightweight station with few commodities that makes the travel in a few months, or a big and comfortable station that takes nearly a year to arrive? In the first case you spend the money on high technologies and propellant. In the second you spend the money to assemble a big cruise station. The second possibility is not that comfortable since it implies a longer travel.

A compromise could be to launch a big and comfortable station towards Mars, with lots of redundancies and spare room, and shoot loads at it with an electromagnetic linear accelerator, from Earth orbit or from Moon orbit. The station would carry an electromagnetic decelerator to capture the loads. By sending that way bits of impulse towards the station it would accelerate towards Mars. Arriving at Mars it can rely on aerobraking to be caught by the planet. On the way back, again it can be shot at to fall to Earth orbit.

Many scenarios exist for the loads being shot towards the station:
I like the idea of the astronauts constantly receiving fast deliveries and be able to send items back to Earth (for example medical samples). I also like the idea of the station having sealed habitable parts for emergencies and safety, altogether with many different sources of food, water and air. Part of these items can be left in Martian orbit, for the next to come.

What kind of orbit would be best for the station once around Mars? If it can still rely on loads shot from the Earth (or from Mars' moons) this is a secondary problem. Otherwise, I suppose best is to leave most of the station in very high orbit above Mars, get a part to low orbit and descend to the ground with landing and return devices. Another way round is to use one station to get to Mars and another station to travel back to Earth. Then none of these two stations would have to get into orbit around Mars. Maybe in a near future a set of stations will constantly travel from Mercury to Mars, along elliptical orbits. Their paths would constantly change, using several methods altogether. Astronauts would embark and leave as they pass near Mercury, Venus, the Earth and Mars. It seems around Venus only a space station would be habitable. On Mercury, the Moon and Mars, scientific stations can be established and later on permanent settlements. I suppose industrial activities can be held aboard the cruise stations to pay for at least a part of their costs, just like industrial activities are currently being held aboard the ISS. Once the technology involved in the stations is deemed reliable on the long term and their size grew sufficiently, those drifting villages can be sent further away, to Jupiter, Saturn and their inhabitable moons.

Stations can shoot at one another to transfer loads and to help each other change trajectories. Two stations traveling towards each other at high speed can exchange loads to slow down and be able to dock. Two stations continuously exchanging loads can make one fall down to close Sun orbit and the other to leave the solar system. A station with a giant electromagnetic accelerator can land on an asteroid and shoot its dust towards another station to allow it to leave the solar system at high speed.

Can a station shoot loads towards a planet or moon, have the loads accelerated or decelerated by the planet or planetoid and catch the loads back? I suppose yes. That way a station can change its trajectory or orbit autonomously. This may take years in some circumstances...


Eric Brasseur  -  September 10 2006  till  October 4 2006