Nice update for this topic!
SearchTerm:Phobos as Transit Station for Aldrin Cyclers
SearchTerm:Cycler Aldrin style or variations - Update by Calliban showing options available with Starship concept from SpaceX
Note need for specialized transport vehicles to catch cyclers as they pass Earth and Mars.
Impressive!
(th)
]]>The principle advantage of a cycler is that it allows human beings to transit to Mars and other destinations without having to accelerate and decelerate a heavy ship at each end of the journey. It is also unnecessary for each passenger to take with them victuals for the journey, as cyclers will be equipped with CELSS. Instead, relatively small taxi craft would take passengers from Low Orbit to the cycler and back. Total mass shipped per passenger travelling on an established cycler, may be as little as 100kg. The taxi would be a lot more like an airliner, than a cruise ship.
The idea works best if most of the mass used to build the cycler can be sourced from Mars, with only complex systems being provided by Earth. The flow of people to an from Mars would be staggered something like this:
1) Starship launches would operate more or less continuously between Earth surface and LEO. People would wait on LEO space stations until a cycler came in range.
2) People would then be ferried in large batches to the cycler, using low mass and somewhat cramped taxi vehicles, a journey that would take no longer than a few days.
3) The journey on the cycler would take 4-8 months. During this time, passengers would have shipboard duties maintaining the cycler internal systems.
4) At approach to Mars, taxi vehicles would dock at the cycler and carry passengers to a Phobos station.
5) Starship would operate continuously between Mars surface and Phobos, ferrying passengers to and fro.
]]>I was reminded by reading a bit of the comments that once the optimal window for launch is passed that no rescue or repairs can be had by those on the cycler in either directions that one might be launched from. Which is also true for the mars return wind as well.
]]>The message by Hop at 2005-04-04 02:17:34 is not displaying properly.
Any chance you can tweak it?
It contains discussion of tethers for momentum transfer.
Thanks (th)
]]>Before long--we will still be stuck in LEO--but with capsules: we will have reduced budgets--but still have a lot of make-work to keep politico's happy--for they will not support any space venture if jobs are killed.
It all depends on what the next war will be.
Thankfully, a lot of people do not want the 39-pads dead.
You must be related to Proxmire somewhere down the road :laugh:
]]>NASA never persued it seriously because it isn't a serious idea, its nonsense. Good call NASA.
"So having the 39 series pads with the ABANDON IN PLACE placards on them "may not be a bad thing?"
Only a kook like you wants to wreck our architecture."
Not at all, I would be quite happy if Pad-39 closed tomorrow and the Smithsonian took custody of the Orbiters this week. Our "arcitecture" has been so horribly expensive for the last thirty years and it has been the millstone around our necks, keeping us from going anywhere or doing anything. Getting rid of the Shuttle Army is nessesarry, and if NASA can't do that willingly, then NASA should not be permitted to fly Shuttle Derived either. If that means starting over from scratch when we need a heavy lifter, so be it, its a do-or-die situation.
]]>Buzz Aldrin is not a space engineer, and his opinion doesn't make the Space Island kooks any less totally insane.
Losing the KSC infrastructure may not be a bad thing since it is so expensive.
How about Mark Wades opinion?
http://www.astronautix.com/craft/stsati … sation.htm
NASA studied several concepts in the 1980's using the 'wet workshop' approach to the capacious External Tank carried into orbit with every shuttle flight. Despite the incredible logic of this, NASA management never pursued it seriously - seeing it as an irresistable low-cost alternative to their own large modular space station plans.
Or the opinion of Mark Holderman at Johnson?
So having the 39 series pads with the ABANDON IN PLACE placards on them "may not be a bad thing?"
Only a kook like you wants to wreck our architecture.
]]>Losing the KSC infrastructure may not be a bad thing since it is so expensive.
]]>http://www.spaceislandgroup.com]www.spaceislandgroup.com
This infrastructure will be lost if we go to EELV.
]]>Perhaps in a few centuries we will attach tethers to large numbers of inner solar system asteroids and by use of ultra high powered computational methods allow spacecraft to "swing" from asteroid to asteroid using momentum transfers. Vessels travelling in different directions can replenish momentum borrowed from these objects.
I love it! Let's call this the "Tarzan propulsion system"! Better than going from tree to tree. . . . I guess the questin them will be, can we equip enough "trees" with "vines" for it to work!
-- RobS
George of the Jungle was my image.
RobS, I know you enjoy writing fiction. Think about some of the lingo that inhabitants of a cycler city might develop. For example, imagine a cycling "castle" with a few thousand inhabitants:
"Hi guy, haven't seen you in a while. What's going on?"
"Not much, just 'taining mo'"
'taining mo' = maintaining momentum which would be one of the ongoing critical issues for the city.
At Aldrin CIty, Martin Lo's papers are taught in junior high.
= = =
I have long believed L5 cities are a fairly daft idea except as small outposts. Get those suckers moving in free return orbits and build them as big or bigger than any L5 fantasy city.
]]>Perhaps in a few centuries we will attach tethers to large numbers of inner solar system asteroids and by use of ultra high powered computational methods allow spacecraft to "swing" from asteroid to asteroid using momentum transfers. Vessels travelling in different directions can replenish momentum borrowed from these objects.
I love it! Let's call this the "Tarzan propulsion system"! Better than going from tree to tree. . . . I guess the question them will be, can we equip enough "trees" with "vines" for it to work!
This is a cool idea. If you want to send a spacecraft to Jupiter or a more distant destination, you'll need a tether on a highly elliptical object, such as a comet. The tethers will have to be pretty strong and reliable, though.
-- RobS
]]>BWhite mentions the use of tethers to impart momentum to taxis. I've played around with cycler mass-drivers to help send the taxis on their way. Either of these would change the cycler's momentum and make course correction necessary as White notes.
Ion engines may be a good way to do this. The continuous thrust trajectories are not the conics I've become accustomed to, so, sorry, I can't do the math on those.
Simple solar thermal might be a low tech solution to provide continuous thrust during the extended transits betweeen Mars and Earth.
The math detail is waay over my head however the idea that some fancy computers could "play billiards" and design trajectories to place cyclers at specific points in space (& time) seems conceptually easy enough.
= = =
Perhaps in a few centuries we will attach tethers to large numbers of inner solar system asteroids and by use of ultra high powered computational methods allow spacecraft to "swing" from asteroid to asteroid using momentum transfers. Vessels travelling in different directions can replenish momentum borrowed from these objects.
Fuel efficient travel.
Heh! - - Who "owns" the right to use the momentum possessed by this or that NEO?
]]>Since any "Cycler" would probably have to have a nuclear power source anyway I think an array of ion drives or a medium sized VASIMIR should be attached in order to maintain a reasonably high Delta-V during transit and also for any required trajectory shaping that might be required. When the cycle arrived in the vicinity of mars a landing module with an Aeroshell could be employed so that it could either aerobrake into orbit or into a direct decent trajectory. The same mathod could be used as the cycle approached earth and in that way the cycler never bleeds off all that much energy as it interacts between the gravity fields of either Earth or Mars.
Charles
Trajectory shaping will be required.
Aldrin (and Niehoff) cyclers exploit the fact that 15 earth years is very nearly 8 Mars years. But "very nearly" isn't the same as "exactly" so the cycler will drift from the rendesvous points as time goes on. This can be corrected by rotating the line of apsides. Which makes it necessary to change trajectory.
If a cycler can rotate its line of apsides with only planetary gravity assists, then it's known as a "ballistic cycler". But even ballistic cyclers need to shape their trajectory to pass within the correct distance of the planet to turn the line of apsides by the desired angle. So a cycler _will_ need some way to change velocity whether it's ballistic or not.
The Aldrin cyclers are not ballistic. They'll need heavy duty burns to rotate their line of apsides even with planetary gravity assists.
I believe the Niehoff cyclers (1.5 year and 1.25 year orbits) are ballistic. These orbits are much closer to the minimum energy Hohmann transfer orbit than is the 2+ year orbit of the Aldrin cycler. Consequently they pass by Mars and Earth much slower than Aldrin cyclers (this is much nicer for the cycler to planet taxis, also). With a lower Vinfinity, the hyperbola's turning angle can be greater (the turning angle can be controlled by how far the hyperbola's periapsis is from the planet).
BWhite mentions the use of tethers to impart momentum to taxis. I've played around with cycler mass-drivers to help send the taxis on their way. Either of these would change the cycler's momentum and make course correction necessary as White notes.
Ion engines may be a good way to do this. The continuous thrust trajectories are not the conics I've become accustomed to, so, sorry, I can't do the math on those.
]]>