What would the bandwidth requirements be for streaming IMAX quality video? During the fly-bys, of course, especially if small cameras could be deployed in constellations, each camera linked to the mother ship.
Instead of a typical bigelow module the company could be contracted out to make a roughly wheel shaped hab .I think the Rigid Station 2 intended to be launched by a Saturn V would be a good starting point.http://www.astronautix.com/craft/selation.htmThis can be made to fit inside one J120 with an upper stage.Also it has six sections which means redundancy .
As for propulsion use two VASIMR engines for departure.http://www.adastrarocket.com/home1.html
A VASIMR engine would require a nuclear reactor or a giant solar array to power it. And even then it would not have enough thrust to do a trans mars or trans venus injection burn deep in the earth gravity well. You could use a low-thrust engine such as VASIMR to get the ship from LEO to a highly elliptical orbit, but the departure burn needs to be done with a high thrust engine.
So, how about using the Castor SRM suggested by rklaehn as the EDS and keep an SEP VASMIR as the sustainer/course correction motor?
Finally - Video blog, video blog, video blog. Even if nothing much is actually happening, millions will want to know about it. The actual flybys would need to be streamed live with pictures of the 'drop off' probes being released being particularly important high points, IMHO.
Tens of billions of dollars? Why so much? A billion dollars, maybe two or three billion but not ten.
A high-ISP/low thrust engine would certainly be useful for mid course corrections. But VASIMIR is too big for such an application. And besides, it is not even clear if it will work as advertized.A hall effect thruster such as one of these http://www.busek.com/halleffect.html would make much more sense.
Quote from: Bill White on 02/13/2009 04:20 pmTens of billions of dollars? Why so much? A billion dollars, maybe two or three billion but not ten.Yes, it could definitely be done on the cheap - but that's not how I would do it. If I had the money, I would spend some extra $$ for as comfortable and robust a spacecraft as I could muster within a reasonable timeframe.
Quote from: rklaehn on 02/14/2009 10:29 amA high-ISP/low thrust engine would certainly be useful for mid course corrections. But VASIMIR is too big for such an application. And besides, it is not even clear if it will work as advertized.A hall effect thruster such as one of these http://www.busek.com/halleffect.html would make much more sense.Agreed. This is a mission where you're trying to keep costs and tech developments to a minimum. Most of the effort will be in a life support system that can keep this guy alive for two years in a variety of solar insolation levels and radiation fluxes.
The whole point of the trajectory is that, once launched, no "deterministic delta-V" maneuvers are required. It's all course corrections til you get back to Earth. Venus and Mars's gravity does all the work for you, which is pretty remarkable to take a cruise like this and never have to "hit the gas".
What is the delta-v for a grand tour anyway? In the paper they mention 13 900 fps, which is 4 236.72 m / s. Is that from LEO?
The DV to start the tour varies from opportunity to opportunity.
The 1977 numbers were specific to that particular mission. At any rate, the initial DV to start the tour would be provided by the upper stage of the launch vehicle.
Unfortunately there is no launch vehicle that can send a 15t stack (sundancer and dragon) to escape velocity. A propellant depot would help.
QuoteInstead of a typical bigelow module the company could be contracted out to make a roughly wheel shaped hab .I think the Rigid Station 2 intended to be launched by a Saturn V would be a good starting point.http://www.astronautix.com/craft/selation.htmThis can be made to fit inside one J120 with an upper stage.Also it has six sections which means redundancy .I think this is way too big for an initial interplanetary mission. A single small bigelow habitat is completely sufficient for one person. For artificial gravity, use the upper stage as a counterweight with a rotating tether like proposed in mars direct. But even zero gravity would be acceptable. The explorer would have all day to exercise, and somebody who is crazy enough to embark on such a dangerous mission is probably not that concerned about bone loss anyway.QuoteAs for propulsion use two VASIMR engines for departure.http://www.adastrarocket.com/home1.htmlA VASIMR engine would require a nuclear reactor or a giant solar array to power it. And even then it would not have enough thrust to do a trans mars or trans venus injection burn deep in the earth gravity well. You could use a low-thrust engine such as VASIMR to get the ship from LEO to a highly elliptical orbit, but the departure burn needs to be done with a high thrust engine.
A Soyuz is way too big and heavy for this mission. All the pilot needs to do is survive reentry, slow to subsonic velocities, and bail out and parachute to the ground. He doesn't need a big fancy Soyuz reentry capsule for that. He needs a good parachute and minimally sized aeroshell.
As for using VASIMR for the injection burn you can but it'll take 30 days to spiral out of earth's gravity well.
It's performance is far above a hall thruster which I believe will be largely obsolete for this task in 10 to 20 years.
This why I'd have the ship spiral out to L1 or at least 80,000km and the crew rides some small fast vehicle to rendezvous with it.Using chemical for the injection burn you get stuck with using a monster stage like the EDS or a wide body centaur and this equals big $$$$.
We're talking at least 15,000kg that needs to be place on an escape trajectory.I'll be more realistic and go with 20,000 to 35,000Kg as these things always end up heavier then expected.
Though a refueled F-9 upper stage with stretched tanks could be used as a low cost injection stage and storing LOX and kerosene is going to be easier then hydrogen.
A block DM may not have enough impulse to even get the ship into GTO let alone escape.
This is assuming the lightest combo a Sundancer and a Soyuz and three crew which should come in around 15,800kg though add an extra 3,000 to 5000kg of consumables to that plus extra solar collectors to power the energy hungry air and water recycling equipment.Just carrying all the food you need will be lighter then any closed loop system.So the lightest possible mission would be around 20,000Kg it would fit on an EELV,F9 or in the back of a shuttle.
I guess a Centaur might be able pull off being the injection stage here.The hard part would be getting it into LEO without burning much of it's propellant.
One big fear I have about a small crew in a small vehicle on long missions is the possibility they will kill each other.The data from simulated Mars missions done by the Russian space agency is anything but encouraging.
Why not use two or three or even four Block Ds, if necessary?
Buy them off the shelf and design the attachment points so they can fire simultaneously.
A single Jupiter 120 would seem sufficient to loft the habitat and an RL-10 based Earth Departure Stage. ~$250 / ~$300 million for the launch, right? If we trust Ross's figures & if US Congress agrees to sell a launch.
Or, use a smaller habitat and "rough it" more at a much lower cost.
Free flying camera modules could also be deployed AFTER the Venus insertion burn with solar sail experiments being conducted by using those camera modules to maneuver around the Sundancer.
People have gotten in rather small sailboats and sailed around the world solo. This is more analogous to that, but with far less workload. Every 90 days or so, the pilot will do a course correction. The rest of the time he'll be reading and answering email. Three times on the mission he'll have a wondrous sight out the porthole. At the very end he'll go screaming through hell on the way in.
Quote from: Bill White on 02/14/2009 04:14 pmA single Jupiter 120 would seem sufficient to loft the habitat and an RL-10 based Earth Departure Stage. ~$250 / ~$300 million for the launch, right? If we trust Ross's figures & if US Congress agrees to sell a launch. That is a pretty big assumption. Given all the trouble dennis tito had just visiting the ISS, I don't think that NASA would be willing to sell a jupiter. A privately financed interplanetary mission would be a huge embarrasment for nasa, so I think they would try to fight it.
You can spiral out to a highly elliptic earth orbit with electric propulsion. But you can not do the trans mars/trans venus injection maneuver with electric propulsion. You need a high thrust propulsion system that is capable of delivering the entire delta-v close to the perigee of the highly elliptic orbit in order for the oberth effect http://en.wikipedia.org/wiki/Oberth_effect to work.