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Originally Posted by MentalAvenger
Only if the missions are always return-to-Earth missions. For missions where the passengers (colonists) stay on Mars, that is not an issue.
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Except it will still take more mass and propellant to do it via a cycler than directly.
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Originally Posted by MentalAvenger
Another good point. Perhaps having larger but fewer missions would be the solution, that is, sending 40-50 people instead of 7-8.
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I agree, I can see a possible role here.
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Originally Posted by MentalAvenger
Since the launch to the cycler would be made from orbit, I think that rendezvous would not be a big problem.
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Possibly, if the window if several orbital periods long. I haven't been able to find any calculation of the window in any of the stuff I have read.
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Originally Posted by MentalAvenger
That is correct. But given enough maneuvering fuel, that should not be a critical problem.
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Given enough propellant is the rub. If it takes more propellant to go via the cycler than directly, what is the point?
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Originally Posted by MentalAvenger
AFAIK, it would require almost exactly the same amount of fuel. That is because the shuttle would be accelerating to the exact same velocity as it would if it were going solo.
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From memory transfering to a cycler orbit requires several km/s more dV. it also varies significantly from encounter to encounter
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Originally Posted by MentalAvenger
I don’t understand why that would be the case. If the transit velocity is the same, and the orbital path is the same, the entry/reentry velocities should be the same.
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Again, here is the rub. The orbits are not the same. You have to match orbits with the cycler first. The orbit the cycler takes is close to but not exactly the same as the transfer orbit. In fact you don't want the cycler in an orbit too close to the one taken by a transfre spacecaft because it will pass to close to earth and Mars and be peturbed. This can be corrected, but requires propellants. Al of which have to be ferried to the cycler.
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Originally Posted by MentalAvenger
Initially, it would be difficult if not impossible to justify cyclers. However, eventually, using large cyclers, possibly asteroids, the advantage would be in providing luxury accommodations for passengers on the long voyages between planets. Although the initial energy requirements to get the cycler into the proper orbit would be very large, the payoff would be in being able to provide perhaps 10-20 times the amount of living space for passengers as well as freshly grown food, fancy entertainment, and larger passenger loads. It would be something like the difference between a 30 foot yacht and a 600 foot cruise ship.
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Again, I agree, there may be a role here. However but the time we need to ferry large numbers of people we may also have more powerful rockets that can make the trip in 4 months with larger payloads. I have no idea which is more probable.
cheers
Jon