Yes! It's 2009 and finally we are entering the era that most sci-fi writers of last century assumed we would have been in for 30 years by now. I haven't got the words to say how much I hope we have a manned expedition to Mars in my lifetime.

Lets see what ESA has to say first.

That's insane.

Yes, it's probably not a good idea to send up anything particularly valuable or difficult to replace, but why not send up a few tonnes of consumables?

If it goes horribly wrong, the consumables go up the way they were going to anyway, and if it works fine then there's more space on the next mission for valuable stuff.

Have a look at the Falcon 9 heavy.

Now imagine shortened boosters & fairings...

Your figures are obviously complete rubbish. Be emotional if you wish but please don't attempt to lie about the numbers, it's childish.

Oh dear, oh dear.

If things fail, you certainly want the pod to be empty.. or the innertial forces could destroy /severely damage de space station...

>Your figures are obviously complete rubbish. Be emotional if you wish but please don't attempt to lie about the numbers, it's childish.

Eh, OK, maybe they can keep a space station up for more than 10 minutes without maintenance (it should be obvious that 10 mins was a joke), but if you have a look at the paper "Maintenance, reliability and policies for orbital space station life support systems" by James F. Russella and David M. Klausb, their detailed analysis of skylab and the ISS concluded that over 3 hours a day should be reserved for Environmental Control and Life Support System (ECLSS) maintenance if you have a crew of 2 or 3 people, think about that, 3 hours a day just to keep people alive on a craft in orbit!

So completely unemotionally, the maintenance required to keep people alive in a space station is significant, and new parts take a while to send up, the risk of a failed part on a mars mission is 100% life threatening when you're minutes away, let alone hours, let alone days or months.

Secondly, it would take approximately 9 months to get to mars (at currently attainable speeds), given, when you start the journey don't forget the earth is moving, so you'll have to wait about 3-4 months for a return window (so the earth will be closest after another 9 months), therefore the mission time is approximately 21-22 months round trip (9 months there, 3-4 months wait and 9 months back).

Important numbers; earth is moving about 100,000Km/h, the fastest manned spacecraft (so far) goes about 40,000Km/h, so you have plan to be where the earth will be, coz you won't catch it.

So all my figures so far are "about right".

I admit a couple of fag packet estimates, there has been about 120 space shuttle missions, these have been a combination of low earth orbit (LEO) and geostationary, LEO is obviously no good for transfer to a space station, geostationary missions with a skeletion crew the space shuttles cargo capacity drops from 25,000kg to less than 4,000kg, given a space shuttle weighs about 2,000,000kg it would take 500 missions to get enough "stuff" in geostationary orbit to build something the size of the space shuttle, so as an estimate I'll imagine that you only need about 500,000kg craft (no large first stage, but a much larger biosphere and lots of redundant equipment, there will be no resupply).

Now, these are all (gu)estimates, but they sound about right, certainly not a factor of 10 out.

Finally (I think), I estmate a 36hour mars mission "point of no return", due to the speed of the earth the only way of getting back (while stll moving relatively and on the earth-moon eliptical) is to sling-shot back round the moon ~36 hours, I am not going to attempt the trig to validate this, but I suspect it's about right.

So, nope, my figures are not "obviously complete rubbish" they are in fact "broadly accurate", for a mars mission we need a much larger cargo capacity, much more reliable technology and a very long time to build it, if we do have a successful mars mission this century (mars and back, still alive), then it will be more costly than you could possibly imagine and do very little for "mans colonisation of space".

Moi childish? I think not baby puppy, the idea of manned mars missions are "childish", for decades to come anyway (unless you add the word "suicidal").

Your number are totally incorrect.

First, how many maintenance and safety hours does a plane need to take off? learn that and you

will be astonished.

Second: the word is plasma/ionic, and not only for the speed & power: you can have acceleration all/most of the way to mars (think about art. grav), you get very strong magnetic fields (defense from radiation) and you get there faster, all with a fraction of the weight. The ionic reactors are in actual use, and the plasma ones will be in a couple of years o a bit more.

But you can get there with chemical ones, and while complicated, that's why we have ph's and computers...

Third: you don't want yo build something like the shuttle? why? something of that weight woul be good to go to pluto and beyond, and not mars.

You don't need a strong structure: no reentry.

That huge wait called thermal tiles is useless.

Wings?? what for? Tail? redundated aerodinamic control surfaces and related hidraulics?

Landing gear?

So you see, you actually don't need MOST of the weight..

Let's assume you need 10% of that weight. (200.000 Kg? are you crazy? that's roughly the wait of the whole ISS!!).

And let's use the cost to geosync.. for example the cost for Sealaunch:

6000Kg max.. at about 15000$ per Kg.(if you contract sutch a volume, costs are way lower)

You would need 34 launches, and a launch cost of 3.000.000.000.

But if you put that weight up, I assume you would like to put colonists on mars, right?

http://www.spaceref.com/news/viewnews.html?id=301

6000Kg for a craft to get to mars and back, using experimental (or nonexistent) engines, working for months without a single new replacement part, if only they had you to design the ISS!

ISS ~ 230,000Kg = living spaces/recyclers/only manouvering engines

Mars mission ~ 6,000Kg = living spaces/totally self sufficient for months/accelerators and retarding/manouvering engines/every single part resilient or redundant, really do ya think? I wonder why the ISS is so big then? ballast? for a laugh?

Probably need nuclear power as that naughty old inverse square law will dramatically reduce the available solar power, plasma/ionic drives offer very low acceleration, therefore read deceleration, you'd need to start deceleraing half way there (unless you have chemical/retro, oh wait they would need to be as powerful as an engine accelerating to that speed)

And "something the size of the space shuttle" doesn't have to look like a space shuttle, fool.

So yet again.... My number are not totally incorrect, please *think* what is needed, not what you would like to need.

I'm not going to agree or disagree totally with either of you. But the moon shots were done in 10 years starting from nothing. Don't discount Ion or VASIMR. Yes it would have radioactive decay generator onboard, no big deal. 30,332 kg + 14,696 kg for moon modules as a reference. So about 50,000Kg for 3 dudes to the moon. @ 4000kg per load it would take 13 shuttle missions to = 1 apollo mission.

Good thing they were not stupid enough to try to use a shuttle to try to leave LEO. Now Mike, put that brain of yours to good work and figure it out using appropriate heavy lifter craft for the job. Right tool for the right job people.

-Bounty

>the moon shots were done in 10 years starting from nothing.

Really? no rocket tech? no life support systems? in fact there was a huge amount of technology back to the 30s directly used on the moon missions, the "from nothing to the moon in 10 years" thing is just american propaganda (in fact a lot of german military tech was used when their scientists defected for an easy life after WW2).

Definitely not discounting VASIMR, it's the only viable option at the moment, but let's not forget the low acceleration, even at the best possible estimates a low mass (1000Kg) craft could take less than 40 days (with a big 200Mw engine), but that's one way and not decelerating, as soon as you up the mass (for living quarters and supplies) it slows down significantly, with a smaller power source and assuming you want to pause at Mars and come back again (rather than go whizzing past) you're still talking several months.

>Yes it would have radioactive decay generator onboard, no big deal.

Nope, it's a big deal, how do you get rid of waste heat in space without convection or conduction? radiation is the only option, so large radiation panels are required, that's if nuke power is "allowed" in space.

Don't forget VASIMR is actually an old technology (25 years) that is only now becoming possible, it will be years before a probe uses it (probably to Mars), even it, at maximum theoretical speeds couldn't reach alpha centauri (our closest other star system) within 4000 years, even breaking the known laws of physics and traveling at light speed would take over 4 years and that's to a system that we don't think is habitable.

So let's pretend that a Mars mission is possible within 30 years, with huge resources and multi-governmental input, let's also pretend that the craft could keep people alive for a few months, possible? OK, possible, but not probable, but even if this very unlikely set of events did happen what is the point? spending billions (trillions?) of dollars to send people to dead planets, spend the money on unmanned craft and AI systems you'll get so much more for your money, go further, get there sooner and find out more.