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]]>Let me make a slight correction here. For a 3/2 period you could use the same vehicle both ways. However, on the outgoing flight it would take you 1.5/2 years and the return flight would take you 4.5/2 years. That is quite a while to be on a space craft. However, perhaps this could be reasonable if a smaller crew went on the return flight. The would need less rations and could perform some maintenance. So you would have two flight options the quick flight and the slow economy class. However is someone is going to be in orbit for 4.5/2 years the cycler will need artificial gravity and more shielding. On the plus side this will make the fast flights that much better. I think the people on the slow flight might be put to work processing asteroids for science and industry.
I have been fired up about the 1.5 year cyclers for some time (aka the Niehoff VISIT 2 cycler). You are reaching the same conclusions I have that it could visit both Earth and Mars repeatedly. As you note, the delta vee isn't much more than Hohmann transfer orbit.
If the cycler is an asteroid nudged into the cycler orbit, folks on this slow flight could indeed be put to work for science and industry. It's believed asteroids and comets are much less changed since the solar system's formation than planet surfaces. They are of great scientific interest. Also many have very pure metals and some have water and carbon compounds.
]]>Cycler orbits between Earth and Mars that enable fast, frequent transfers between these planets
Small, human transport space ships, or Astrotels, on cycling orbits between planets,
Orbital Spaceports at the planets
Very small, fast, hyperbolic transfer vehicles, or Taxis, between Spaceports and Astrotels.
Propellant and life support in situ resource manufacturing plants
Cargo vehicles that utilize low-energy, long-flighttime orbits to transport propellant and low value cargo to and from planets
Shuttles to and from Spaceports and planetary surfaces
I wonder if the space ports are necessary and if they are if ISS could be used as one. One bit of optimize I have is the space ports don't have to be as big as ISS. I would think one or two bigalo hotels (A.K.A trans hab modules) would do just fine.
]]>I would propose not a single unit but since it is on a 3/2 resonance, why not make it 3 vehicles launched so that they have a few months in orbit around mars and each brings a fresh crew from Earth on each pass out to mars. Basically creating a 2 year cycle of crews for round trip or a 2 year cycle on the surface. Either way it keeps a fresh crew and supplies always in route.
Let me make a slight correction here. For a 3/2 period you could use the same vehicle both ways. However, on the outgoing flight it would take you 1.5/2 years and the return flight would take you 4.5/2 years. That is quite a while to be on a space craft. However, perhaps this could be reasonable if a smaller crew went on the return flight. The would need less rations and could perform some maintenance. So you would have two flight options the quick flight and the slow economy class. However is someone is going to be in orbit for 4.5/2 years the cycler will need artificial gravity and more shielding. On the plus side this will make the fast flights that much better. I think the people on the slow flight might be put to work processing asteroids for science and industry.
]]>Maybe you will find this NIAC study useful :
Sounds interesting .
I started reading this and I think a lot of people are thinking on the same lines. The choose a 70 ton vehicle. Sounds reasonable. Solar electric for course correction using liquid oxygen as fuel. Obvious . Hyperbolic transfer on taxi? Maybe, I have to study it further. I guess it is need to get to the cycler in a week. I think they make a convincing case. Must read more. They choose a 6 month transfer instead of a slightly slower hofmann transfer. Maybe that is the way to go. I would like to explore both possibilities.
edit: I think the hyperbolic transfer orbit for that taxi may be with respect to the earth and not the sun. Maybe? ???
]]>and those given by http://en.wikipedia.org/wiki/Hohmann_tr … ]wikipedia.
The formula at wikipedia rings a bell from a classical mechanics course so I think they are right. Also there formula above it on the mars academy website looks right so it must be a transcription error.
I tried to send them an email to inform the mars academy of their mistake but the adress given no loner accepts emals . By the way in my above figure I used the wikipedia formula.
I’m curious as to why wikipedia puts the units of the standard gravitational parameter in km/s^2 as opposed to AU/year^2 or AU/month^2.
]]>I would propose not a single unit but since it is on a 3/2 resonance, why not make it 3 vehicles launched so that they have a few months in orbit around mars and each brings a fresh crew from Earth on each pass out to mars. Basically creating a 2 year cycle of crews for round trip or a 2 year cycle on the surface. Either way it keeps a fresh crew and supplies always in route.
I agree that it would be more desirable to have a more continuous flow. You would need 3 vehicles in a hofmann trajectory if you were only concerned about going to mars. You would need 6 vehicles if you want a return flight. My point is if you can build a cycler without to much extra cost then a normal interplanetary transfer vehicle or trans mars injection vehicle then you will save money on your next flight in six years time. If you build three all the better. What would be the maxium continuous rate for Hofmann trajectories (every nine moths?) .
]]>1. You have to leave Earth or Mars orbit at exactly the right second or miss the launch window entirely. This problem will go away after maybe a dozen or so launches when everyone has experience and the equipment is well known.
Maybe true. I’ll try to figure out the launch window later for a given delta V and trait time constraint.
2. The bigger problem: You're creating a very big, expensive machine (because you want it spacious and well shielded), using it only once every few years for a few months (a huge waste), and you're counting on it not to break down the 90% of the time no one is on board.
If it is alright to go to mars with a craft that is not overly spacious and well shielded then it is alright to go in a cycle that is not overly spacious and well shielded. The advantage of the cycler is you do not need a circulizating burn and you can reuse it. Thus it becomes possible to make it more massive. As for how long it will last without breaking down, there are deep space probes that run for decades. What is it about life support systems that makes them break down quicker and what can we do to increase there longevity. As for the size of the cycler I suggest one or two biggalo hotels. Each one should have there own life support system so if one fails there is a back up. Each one should have four docking modals that can be docked to another hotel or a engine to push it or a space ship. This way it should be possible to increase the space of the cycler over the years if desired. One difficult of increasing the space in the cycler is it will require more thrust to keep the cycler on the same orbit. I see a problem with just staking engines side be side because there radiators might get in each others way and heat dissipation might become a problem.
]]>1. You have to leave Earth or Mars orbit at exactly the right second or miss the launch window entirely. This problem will go away after maybe a dozen or so launches when everyone has experience and the equipment is well known.
2. The bigger problem: You're creating a very big, expensive machine (because you want it spacious and well shielded), using it only once every few years for a few months (a huge waste), and you're counting on it not to break down the 90% of the time no one is on board.
-- RobS
]]>http://s243a.trap17.com/cycler1.htm]htt … ycler1.htm
There are 3 plots that cover 30 years for a hofmann transfer. Here they are.
Looking at the plot if the cycler had a period of 3/2 years it would be pretty close to a hohmann transfer and it would arive at earth every three years.
]]>There are cycler orbits that regularly fly both Earth and Mars. Buzz Aldrin has designed one that passes by both Earth and Mars each synodic period (about 2 & 1/7 years). The "castle" would be be well stocked with radiation shielding, food, air (maybe even self sustaining closed ecology life support systems). Then when the castle is in the neighborhood of either Earth or Mars a much less massive "taxi" can be sent to the planet (or from the planet to the castle). However Aldrin cyclers demand a lot of delta vee from their taxis since it passes Mars with a relative velocity of about 12 km a second.
Then there are two types of cyclers that pass by the planets somewhat less frequently but still regularly. Niehoff VISIT 3 passes by the earth every 3 years and Mars every 7.5 years. Niehoff VISIT 1 earth every 5 years and Mars 3.75 years.
I talk about nudging asteroids into Niehoff cycler orbits on this page:
http://www.clowder.net/hop/railroad/sch … sched.html
This is very interesting but I wonder if it would be better to have a cycler that passes less frequently but requires less delta V. As I said for each mission launch one cycle on a hohmann to mars and on scheduled to return from mars on a hohmann. Eventually there will be enough cyclers hohmann trajectories that you won’t need a new cycler/ITV for each mission. You only need one to rendezvous with it on mars and another one to rendezvous with it on earth.
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