A Mars approach will be very difficult due to the speed. Even if you slow down first, youre most likey going much faster than some dinky shutttle in LEO. I assume the craft will remain high, perhaps geo sync., and send a craft down from there. Good job! (5)

Lotus253, Thank you for your comments and ratings. I don’t think I would characterize a Mars approach as difficult – it’s a rather straight forward application of physics and navigation. (So long as we keep useful idiots who cannot convert from English to metric clear of the equations – of course I speak of the Mars Climate Orbiter crash – but that was human error rather than a matter of the difficulty or the complexity of the problem.) DeltaV requirements are a function of the energy needs of the selected crossing (opposition or conjunction) and the mass of the vehicle – these can be known through straight-forward calculations. The required fuel load to slow to a particular orbit is calculated long in advance of the mission – so there is no constraint per se on what orbit one may select, nor any difficult choice facing the astronauts on the mission, rather it is a matter of what orbit one wants to select. Which gets to the point in selecting nuclear thermal or nuclear pulse propulsion – power-density. Propulsion systems which deliver the energy yield necessary to get the job done. I mean, if you are going to start sacrificing capability and goals – then we may as well give up and climb back up into the trees – which I’m sure some greenies would love, and I think we should leave them to that, civilization is not for quitters, it requires effort and a willingness to face adversity. I believe yesterday you mentioned ion drives – which presents opportunity for me to offer one of my favorite quotes: “Nature, in order to be commanded, must be obeyed.”—Ayn Rand. Though ion has admirably high exhaust velocity, there are theoretical limits that ensure all Ion drives are low thrust. Ion drive also shares the same problem as the other electrically powered low-thrust drives. In the words of a NASA engineer the problem is "we can't make an extension cord long enough." That is, electrical power plants are weighty enough to make the low thrust an even larger liability. In the words of Dr. John Schilling: “since you are accelerating ions, the acceleration region is chock full of ions. Which means that it has a net space charge which repels any additional ions trying to get in until the ones already under acceleration manage to get out, thus choking the propellant flow through the thruster. The upper limit on thrust is proportional to the cross-sectional area of the acceleration region and the square of the voltage gradient across the acceleration region, and even the most optimistic plausible values (i.e. voltage gradients just shy of causing vacuum arcs across the grids) do not allow for anything remotely resembling high thrust.” and Erik Max Francis: “You can only increase particle energy so much; you then start to get vacuum arcing across the acceleration chamber due to the enormous potential difference involved. So you can't keep pumping up the voltage indefinitely. To get higher thrust, you need to throw more particles into the mix. The more you do this, the more it will reduce the energy delivered to each particle. It is a physical limit. Ion drives cannot have high thrusts. “ This limits payload – making it particularly unfit for manned missions. If you are going to trade excessive time to build deltaV then you increase the exposure time to cosmic radiation, if you increase the shielding you pay penalty in weight, and spending hundreds of days slowly spiraling outward from earth demands a higher consumables load, and again you have a weight penalty—the up-shot of which limits scientific payload, and hence mission capability. Among propulsion experts, any serious discussion of manned missions beyond LEO always involve nuclear thermal or nuclear-pulse propulsion – these are the technologies we know will work, which have been extensively tested, and which we know will get the job done – and setting goals short, for any reason, merely sacrifices accomplishment and limits success.

how refreshing to see physics discussed here by folks who know what the heck they're talking about!!

superlative scene and model!!

Fntastic model and image! Corrie

Excellent work!

Excellent image! Really fabulous details on the ship and tanks. Agree with you on ion thrust. However, it could still be useful on long voyages once you've achieved escape velocity by other means. On a journey, say to the outer solar system, a low thrust ion propulsion system could shave off a considerable portion of an admittedly long voyage.

Excellent point, geirla, I think a case could be made for long-voyage duration missions -- outer planet targets like Jupiter and beyond. There is material I've been looking at for a (I believe it is a GE proposal) Mars mission using nuclear thermal for Earth escape and Mars trajectory insertion, supplemental nuclear electric propulsion en-rout, and nuclear thermal to brake for Mars capture. Perhaps the utility verses system weight might be partly relieved by using a Triton tri-modal LANTR in power-generation mode to power your ion system ... and on extremely long duration voyages the numbers probably come closer to a balance. I'm a boomer from way back you know, its almost like its in my blood -- and that GE design for a side-mounted 71 foot wide thruster array looks mighty cool, but I'm not completely convinced its a good choice for a Mars mission package.

Excellent modeling! Bravo!

I really like this POV, it shows off your supremely good model in all its glory. Very cool! You're work certainly hits the big problem for us if we try to send people out there: Higher thrust requires more propellent and/or massive power. Nuclear currently seems the only method for getting the most for the least, but there are always dangers with any kind of space system. Then there's the effects of long-term exposure and zero gravity. It's great to see how much research you're doing, and how accurate and plausible these models are. As always, it's a real joy to see what you've done and I always look forward to seeing what you'll do next!

what a tremendous series of images you have going here!