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    Default SSTO's would have made possible Arthur C. Clarke's vision of 2001.



    Space Travel: The Path to Human Immortality?
    Space exploration might just be the key to human beings surviving mass
    genocide, ecocide or omnicide.
    July 24, 2009
    On December 31st, 1999, National Public Radio interviewed the
    futurist and science fiction genius Arthur C. Clarke. Since the author
    had forecast so many of the 20th Century's most fundamental
    developments, the NPR correspondent asked Clarke if anything had
    happened in the preceding 100 years that he never could have
    anticipated. "Yes, absolutely," Clarke replied, without a moment's
    hesitation. "The one thing I never would have expected is that, after
    centuries of wonder and imagination and aspiration, we would have gone
    to the moon ... and then stopped."
    http://www.alternet.org/news/141518/...n_immortality/

    I remember thinking when I first saw 2001 as a teenager and could
    appreciate it more, I thought it was way too optimistic. We could
    never have huge rotating space stations and passenger flights to orbit
    and Moon bases and nuclear-powered interplanetary ships by then.
    That's what I thought and probably most people familiar with the space
    program thought that. And I think I recall Clarke saying once that the
    year 2001 was selected as more a rhetorical, artistic flourish rather
    than being a prediction, 2001 being the year of the turn of the
    millennium (no, it was NOT in the year 2000.)
    However, I've now come to the conclusion those could indeed have been
    possible by 2001. I don't mean the alien monolith or the intelligent
    computer, but the spaceflights shown in the film.
    It all comes down to SSTO's. As I argued previously [1] these could
    have led and WILL lead to the price to orbit coming down to the $100
    per kilo range. The required lightweight stages existed since the 60's
    and 70's for kerosene with the Atlas and Delta stages, and for
    hydrogen with the Saturn V upper stages. And the high efficiency
    engines from sea level to vacuum have existed since the 70's with the
    NK-33 for kerosene, and with the SSME for hydrogen.
    The kerosene SSTO's could be smaller and cheaper and would make
    possible small orbital craft in the price range of business jets, at a
    few tens of millions of dollars. These would be able to carry a few
    number of passengers/crew, say of the size of the Dragon capsule. But
    in analogy with history of aircraft these would soon be followed by
    large passenger craft.
    However, the NK-33 was of Russian design, while the required
    lightweight stages were of American design. But the 70's was the time
    of detente, with the Apollo-Soyuz mission. With both sides realizing
    that collaboration would lead to routine passenger spaceflight, it is
    conceivable that they could have come together to make possible
    commercial spaceflight.
    There is also the fact that for the hydrogen fueled SSTO's, the
    Americans had both the required lightweight stages and high efficiency
    engines, though these SSTO's would have been larger and more
    expensive. So it would have been advantageous for the Russians to
    share their engine if the American's shared their lightweight stages.
    For the space station, many have soured on the idea because of the ISS
    with the huge cost overruns. But Bigelow is planning on "space hotels"
    derived from NASA's Transhab[2] concept. These provide large living
    space at lightweight. At $100 per kilo launch costs we could form
    large space stations from the Transhabs linked together in modular
    fashion, financed purely from the tourism interests. Remember the low
    price to orbit allows many average citizens to pay for the cost to
    LEO.
    The Transhab was developed in the late 90's so it might be
    questionable that the space station could be built from them by 2001.
    But remember in the film the space station was in the process of being
    built. Also, with large numbers of passengers traveling to space it
    seems likely that inflatable modules would have been thought of
    earlier to house the large number of tourists who might want a longer
    stay.
    For the extensive Moon base, judging from the Apollo missions it might
    be thought any flight to the Moon would be hugely expensive. However,
    Robert Heinlein once said: once you get to LEO you're half way to
    anywhere in the Solar System. This is due to the delta-V requirements
    for getting out of the Earth's gravitational compared to reaching
    escape velocity.
    It is important to note then SSTO's have the capability once refueled
    in orbit to travel to the Moon, land, and return to Earth on that one
    fuel load. Because of this there would be a large market for passenger
    service to the Moon as well. So there would be a commercial
    justification for Bigelow's Transhab motels to also be transported to
    the Moon [3].
    Initially the propellant for the fuel depots would have to be lofted
    from Earth. But we recently found there was water in the permanently
    shadowed craters on the Moon [4]. Use of this for propellant would
    reduce the cost to make the flights from LEO to the Moon since the
    delta-V needed to bring the propellant to LEO from the lunar surface
    is so much less than that needed to bring it from the Earth's surface
    to LEO.
    This lunar derived propellant could also be placed in depots in lunar
    orbit and at the Lagrange points. This would make easier flights to
    the asteroids and the planets. The flights to the asteroids would be
    especially important for commercial purposes because it is estimated
    even a small sized asteroid could have trillions of dollars worth of
    valuable minerals [5]. The availability of such resources would make
    it financially profitable to develop large bases on the Moon for the
    sake of the propellant.
    Another possible resource was recently discovered on the Moon: uranium
    [6]. Though further analysis showed the surface abundance to be much
    less than in Earth mines, it may be that there are localized
    concentrations just as there are on Earth. Indeed this appears to be
    the case with some heavy metals such as silver and possibly gold that
    appear to be concentrated in some polar craters on the Moon [7].
    So even if the uranium is not as abundant as in Earth mines, it may be
    sufficient to be used for nuclear-powered spacecraft. Then we wouldn't
    have the problem of large amounts of nuclear material being lofted on
    rockets on Earth. The physics and engineering of nuclear powered
    rockets have been understood since the 60's [8]. The main impediment
    has been the opposition to launching large amounts of radioactive
    material from Earth into orbit above Earth. Then we very well could
    have had nuclear-powered spacecraft launching from the Moon for
    interplanetary missions, especially when you consider the financial
    incentive provided by minerals in the asteroids of the asteroid belt.


    Bob Clark

    REFERENCES
    1.)The Coming SSTO's.
    http://www.secretprojects.co.uk/foru...c,13211.0.html

    2.)TransHab.
    http://en.wikipedia.org/wiki/TransHab

    3.)Private Moon Bases a Hot Idea for Space Pioneer.
    by Leonard David, SPACE.com's Space Insider Columnist
    Date: 14 April 2010 Time: 02:23 PM ET
    http://www.space.com/8217-private-mo...e-pioneer.html

    4.)Mining the Moon's Water: Q & A with Shackleton Energy's Bill Stone.
    by Mike Wall, SPACE.com Senior Writer
    Date: 13 January 2011 Time: 03:57 PM ET
    http://www.space.com/10619-mining-mo...ne-110114.html

    5.)Riches in the Sky: The Promise of Asteroid Mining.
    Mark Whittington, Nov 15, 2005
    http://www.associatedcontent.com/art...eroid_pg2.html

    6.)Uranium could be mined on the Moon.
    Uranium could one day be mined on the Moon after a Japanese spacecraft
    discovered the element on its surface.
    By Julian Ryall in Tokyo 4:58PM BST 01 Jul 2009
    http://www.telegraph.co.uk/science/s...-the-Moon.html

    7.)Silver, Gold, Mercury and Water Found in Moon Crater Soil by LCROSS Project.
    Catherine Dagger, Oct 22, 2010
    http://www.associatedcontent.com/art...found_pg2.html

    8.)NERVA.
    http://en.wikipedia.org/wiki/NERVA
    Last edited by RGClark; 07-18-2011 at 06:57 PM.

  2. #2
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    What vision that man had and what a great answer he gave to the question!!!!
    To the Moon and no further!!!!
    Seems like a waste to me as well...
    Declan.
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  3. #3
    RGClark's Avatar
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    This discussion thread on the SecretProjects forum, showed such
    SSTO's were already being proposed in the 60's, as well as ambitious
    lunar exploration proposals as exemplified by the lunar bases in the
    film, 2001:

    ROMBUS, Pegasus, Ithacus .
    http://www.secretprojects.co.uk/foru...p?topic=4577.0

    We didn't have the required high efficiency kerosene or hydrogen
    engines in the 60's. But we did in the 70's with the NK-33 for
    kerosene and the SSME's for hydrogen.


    Bob Clark

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    Do you think the ROMBUS design is practical? 450 tons to LEO is four times what the Saturn V was capable of, using a multi-staged rocket. It might have been proposed, but is that realistic? The link to the paper that you posted is broken, btw.
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    RGClark's Avatar
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    It would be a truly watershed moment just creating a SSTO even if it doesn't carry much payload. It wouldn't have to be anything extensive like perhaps what Boeing is planning with their X-37B derived SSTO.
    A small one could be demonstrated by amateur science or technical organizations, for instance by the British Interplanetary Society, or the Planetary Society.
    The Planetary Society is spending about $5.8 million total on their two attempts at solar sail demonstators:

    Cosmos 1 - Wikipedia, the free encyclopedia

    LightSail-1 - Wikipedia, the free encyclopedia


    A small SSTO demonstrator that could carry a few hundred pound payload could be developed for less than this amount and would be far more important for it would show that low cost SSTO's are possible.
    In fact the organization developing it could even make money on it because they could use it to launch small scientific payloads.



    Bob Clark

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    I didnt see this anywhere in the article but when we use abbreviations we should allways post what they mean. A SSTO is Single Stage to Orbit. case anyone was wondering.

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    Quote Originally Posted by RGClark View Post
    A small one could be demonstrated by amateur science or technical organizations, for instance by the British Interplanetary Society, or the Planetary Society.
    The Planetary Society is spending about $5.8 million total on their two attempts at solar sail demonstators:

    Cosmos 1 - Wikipedia, the free encyclopedia

    LightSail-1 - Wikipedia, the free encyclopedia


    A small SSTO demonstrator that could carry a few hundred pound payload could be developed for less than this amount and would be far more important for it would show that low cost SSTO's are possible.
    In fact the organization developing it could even make money on it because they could use it to launch small scientific payloads.

    Bob Clark
    I think you're being a little optimistic there. I don't think developing a SSTO capable of transporting a couple hundred pounds to LEO could be designed, built and launched for less than $10M. The SpaceShipOne that won the X Prize cost $25M to develop, only had to reach 100km, with a payload of a single person.

    I definitely think the SSTO concept is interesting and appealing, but anyone wanting to pursue it had better have deep pockets.
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    Isnt Blue Origins Space Shepard a SSTO? and the Amazon.com founder does have some deep pockets to be doing something like this. Nasa also had a design on the books that they canceled. The Delta Clipper.

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    Quote Originally Posted by DaveW View Post
    Do you think the ROMBUS design is practical? 450 tons to LEO is four times what the Saturn V was capable of, using a multi-staged rocket. It might have been proposed, but is that realistic? The link to the paper that you posted is broken, btw.
    Thanks for responding. The Astronautix site is down now. You can see an older version of the ROMBUS link here:

    Rombus.
    http://www.friends-partners.org/part...lvs/rombus.htm

    Notice ROMBUS is not actually an SSTO as it had jettisonable but recoverable tanks. So that helped for the high payload. There are some actual SSTO's discussed on that thread on the SecretProjects page though.
    The structural elements were doable then even in the 60's as judged by the mass ratios. We didn't have the high performance hydrogen engines then, but we have since the 70's with the SSME's.
    I was puzzled at first by the high mass ratio of the core stage, about 20 to 1. This would be very high for a hydrogen fueled stage as they are commonly in the range of 10 to 1. But then I realized this was because of the unusual and actually innovative idea Bono used for the jettisonable tanks. Instead of the jettisonable tanks containing both hydrogen and oxygen, they only contained hydrogen. The core stage contained all the oxygen. This is important because LOX is a dense propellant. (The word "propellant" is allowed to be used to cover both fuel and oxidizer.)
    Dense propellants have much reduced weights for tankage than hydrogen. So then this stage could indeed have a mass ratio more in line with those of dense propellant stages, which are commonly in the range of 20 to 1. The hydrogen mass to tank mass ratio of the jettisonable tanks is also in line with that commonly seen for hydrogen tanks.

    Further images of the ROMBUS are available here:

    Douglas R.O.M.B.U.S
    http://www.pmview.com/spaceodysseytw...lvs/sld008.htm


    Bob Clark

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    Quote Originally Posted by Anotheryahoo View Post
    Isnt Blue Origins Space Shepard a SSTO? and the Amazon.com founder does have some deep pockets to be doing something like this. Nasa also had a design on the books that they canceled. The Delta Clipper.
    Yes and no. It's single stage, but there's a huge difference in the energy required to get a ship up to 100km (like the New Shepard and the SSO) and that required to put something into LEO. Not that it's not cool, but in order to be an SSTO it has to reach orbit. The DC-X also wasn't designed to actually reach orbit, it was more of a test for VTVL systems.
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