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#2 Re: Single Stage To Orbit » SSTO to mars and back again. » 2007-09-19 13:26:41

How about using a fueling a base first, vtvl ssto in leo and sending it to mars.

The ship would use hydrogen and oxygen to get to mars; once on mars it would make methane and oxygen from hydrogen feedstock to fuel itself for the ride back to leo. To take off from Mars, the ship would need methane engines, carried in addition to the hydrogen ones.  Methane would be stored in the hydrogen tank, and the trip back would run fuel rich. I'd imagine that the heatshield for this ship would be cooled by excess hydrogen or water, via transpiration.


The ship would mass about 250 tonnes in leo, and around 50 tonnes on the surface of Mars. The  hydrogen feedstock would mass about 12 tonnes, leaving 38 tonnes for the ship, the nuclear reactor, isru equipment, crew of four and their consumeables, plus scientific payload. The stay on Mars would last around 18 months.

The actual size of the craft would be quite large: about 20 metres tall, plus the length of the landing legs. Its diameter would be roughly 10 metres, allowing a roomy crew cabin. Getting things down from the ship's cabin and hold to the surface would be inconvenient, and need some sort of winch or lift.

I know most people here on these forums aren't big fans of ssto, and I have a lot of sympathy with them. So what are my motivations for using a ssto to go to mars? They are chiefly because I fear the current plan to return to the moon and then go to mars is too slow, expensive and boring to succeed. The main problem is the need to develop a heavy lift launch vehicle, and then to maintain the production and launch facilities indefinitely

#3 Re: Interplanetary transportation » COTS - status » 2006-08-18 13:45:59

COTs to be decided today. I think that Spacehab are credible possiblity, but only if they use SpaceX's Falcon 9. I'd like to see Kistler chosen  - to get more data as to  how difficult it is to develop a reusable transport -  even though I think that the management is a little questionable.

If SpaceX and Spacehab are chosen, and the Falcon 9 is chosen as a lauch vehicle for both, then the Falcon 9 has a much greater chance of making it to launch. Otherwise I  think it will be too expensive to man-rate the delta/atlas vehicles.

So my choices are SpaceX and Spacehab with Falcon 9, or SpaceX and Kistler without.

#4 Re: Interplanetary transportation » COTS - status » 2006-07-24 15:01:18

Not sure if this is good news or not for KistlerRocketplane

http://www.orbital.com/NewsInfo/PR/NASA_COTS_072406.pdf

Orbital was a COTS contestant, but lost presumably because it hadn't been developing a launch vehicle before COTS. Kistler on the other hand has a lot of development behind it but lacks good management and capital.

I think that they are a credible alternative to SpaceX, and will take half the money along with SpaceX.

#6 Re: Interplanetary transportation » COTS - status » 2006-06-01 01:05:47

The Kislter rocket has two stages, both kerosene powerd, which are both supposed to be reuseable. They've been working on it for years and its still far from done, and despite a $400M bail-out from NASA years ago they went bankrupt and got bought by Rocketplane.

Sure, I know that. What I was asking was whether the second stage releases a crew capsule that returns to Earth like any other capsule, or whether the crew cabin stays with the second stage throughout the flight.

Spacehab has an interesting entry, and might actually work, because it doesn't need a new launch vehicle, using the tried-and-tested rockets from Lockheed/Boeing. However, they have no option for crew probably because of this.

Are those rockets man rated? I'm surprised that Spacehab didn't go for the Falcon 9 for its booster, instead.
I agree that Spacedev and Tspace are out of it.

#7 Re: Interplanetary transportation » COTS - status » 2006-05-31 13:25:53

More on COTS. http://space.com/businesstechnology/060 … _cots.html

Does anyone know if Kistler's K1 rocket is to use a crew capsule that returns separatly from the K1, or do the crew come back down with the main rocket?

Spacehab plan to use the Atlas and Delta boosters. Are they man rated? If not then won't it cost a lot to do so? I can't see nasa going for it, personally, they cost around $80 million already, add a capsule and it's CEV lite.

Still, Spacehab are part of SpaceX's bid, which must be the favourite. The only question is, how much of the $500 million will they get?

#9 Re: Interplanetary transportation » COTS - status » 2006-05-13 16:13:00

Apparently every one of the six offered crew transport, which might explain why the Aquarius scheme wasn't chosen.
It's good that Nasa is going for crew capability - it shows that they are taking COTS seriously.

#10 Re: Human missions » The Mystery of Jeff Bezos and Blue Origin » 2006-05-11 16:34:42

Looks like others are thinking the same thing

http://www.economist.com/science/displa … id=6911220

Like the other craft under development, New Shepard is, according to its backers, intended for suborbital flights. However, if this is really all that Mr Bezos is interested in, a VTOL vehicle is about the most difficult way of going about it.

One way of explaining this curious design choice would be if Mr Bezos ultimately intended to produce an orbital vehicle.

VTOL should be VTVL.

It's a good article, people should read it.

Possibly more coverage than NewSpace deserves, for such a fledgling industry.

How many people really believe that XCOR will actually build Xerus?

#11 Re: Interplanetary transportation » COTS - status » 2006-05-09 16:57:51

The 24 proposals have been cut down to 6. (SpaceDev is apparently the 6th)

http://spacetransportnews.com/

Obviously, Spacex and Kistler should be there, but I'm surprised that Orbital Sciences isn't there, also the Aquarius scheme by loral/spacesystems.

I wonder what was most important in the decision making: the proposal's technical merits; whether the company had actually built hardware; the company's size and financial resources; politics/cronyism?

Before today I would have said that Spacex, Kistler, Orbital Sciences, SpaceHab, Loral and Tspace, in that order, were the favorites. SpaceX would be number one by some margin, Kistler is nearest to completion but has serious management problems, the others are there because the companies actually have experience in building things.

Can a COTS system be built for $500 million or half or a third of that amount?
It seems a pittance compared to the $5 billion on CEV plus an other $5 billion on the CLV. Sure the Stick is bigger and more capable, but were talking about an order of magnitude difference in costs. Perhaps Nasa will pony up some more money later?

Does anybody know how many COTS flights a year are required for the ISS? It should be at least 4 cargo and two crew, as far as I can figure out. If the Europeans and Japanese decide to use it as well instead of their own craft, or Russian vehicles, then it could be quite a few launches.

Anyway, my money is on SpaceX and Kistler jointly sharing the pot - they seem to like Kistler, didn't they award a cargo resupply contract to them a few years ago?  I suspect, though, that SpaceX could put  the money to better use.

#13 Re: Human missions » The Mystery of Jeff Bezos and Blue Origin » 2006-04-18 16:30:06

Blue Origin is developing a suborbital vehicle (New Shepard) that is meant to be operational by 2009, according to a media report. As far as I know it is an X prize class vehicle only.

My question is, why?

Why repeat what Burt Rutan did 5 years earlier? Jeff has said that he wants to go into space and explore the solar system, as well as achieving an "enduring human presence in space", just as Elon Musk does.

If that is the case, why doesn't he invest a similar proportion of his money as Elon has into building an orbital vehicle? After all, Blue Origin is 6 years old, and it doesn't have much to show for itself.

One possiblity is that he is using suborbital as a smokescreen, and is in fact developing an orbital vehicle. This would be analogous to SpaceX working on the Dragon capsule in secret. However, it is much more difficult to work on a large rocket in secret, than on a tiny capsule.

Another possiblity is that the technologies that are being used to build this suborbital craft, which is VTVL, will be recycled in a future orbital vehicle.
Again, this possibility doesn't seem very likely, as there isn't much commonality between orbital and suborbital.

It must be that Jeff has learnt from Kistler and the other failed alt.space attempts, to be ultra cautious in spending money on risky projects, but if Jeff isn't willing to spend serious amounts of money, who else is?

Anyway, those are my thoughts on Blue Origin, I'd like to hear yours.

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