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Saturday, September 14, 2013

Budget Moon flights: will Canada and Europe take us back to the Moon?


Copyright 2013 Robert Clark




Canada and Europe want to send manned missions to the Moon, despite NASA's disinterest:

Canadian on Moon possible under latest space plan.
Roadmap for future missions includes lunar space station and trips to Mars.
The Canadian Press
Posted: Aug 25, 2013 8:39 AM ET
http://www.cbc.ca/news/canada/story/2013/08/25/tech-space-station-canadian-on-moon.html

In the blog post Medium Lift Circumlunar Flights, I noted that current medium lift rockets such as the Atlas V 401, Delta IV Medium, Falcon 9 could launch a Cygnus-sized capsule on a circumlunar flight. Then if the Cygnus were provided with a heat shield and life support this would provide a low cost means of performing a manned circumlunar flight.
 Orbital Sciences is investigating giving the Cygnus a heat shield based on the inflatable ones NASA is developing:


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  Another possibility for the heat shield would be to give the Cygnus capsule the same degree of small taper as the Dragon capsule. Then you could use the same type of PICA material, which was invented by NASA Ames, as used on the Dragon.
 Still another possibility is suggested by what SpaceX is proposing for the reentry of the upper stage of a reusable Falcon 9. The stage is a cylindrical structure, but according to the images released by SpaceX, heat shield material, presumably their PICA-X material, is applied to the entry end of the upper stage and partially along one side.



 Another possibility would be to use the capsule originally designed by Andy Elson for SpaceX, called "Magic Dragon". This was to be carried by the smaller Falcon 5 and only carry 3 crew. Since the Falcon 5 had half the payload capability to the Falcon 9 and the crew size was half of the current Dragon, this smaller version likely was also half-size, at ca. 2 mT.



 In the blog post Budget Moon Flights I discussed that two cryogenic in-space stages about half-size to the Centaur could take a Cygnus-sized capsule to an actual lunar landing and back. It will actually even be possible to do it with just one of these stages: the Falcon Heavy, according to Elon Musk, will be able to send 35,000 lb, about 16,000 kg to TLI.
 Use the same Ariane 4 H10-3 upper stage used in the "Budget Moon Flights" post. This had a propellant mass of 11.86 mT and dry mass of 1.24 mT. As discussed there, take the round-trip delta-v of 8,650 m/s. The delta-v to TLI is about 3,150 m/s. Then 5,500 m/s would have to be supplied by this single stage. The stage could carry 2.9 mT payload to greater than that delta-v:

445*9.81ln(1 + 11.86/(1.24 +2.9)) = 5,900 m/s.

 Actually, it could take 3.4 mT to a delta-v of 5,500 m/s but we are limited to how much total mass the Falcon Heavy can take to TLI.
 According to the Astronautix page on the Ariane H10-3 the cost of the stage was only $12 million. Then this could serve for a low cost demonstration mission for the Canadian Space Agency (CSA) and ESA to launch as early as the 2014 expected first test flight of the Falcon Heavy.
 It is important that such low cost missions be done to break the mindset that any manned flights to the Moon have to involve super heavy lift rockets such as the Saturn V, Ares V, or SLS.


   Bob Clark





1 comment:

  1. I rather think it will be a race among the Canadians, Europeans, and Chinese, to see who next lands men on the moon. I rather doubt NASA does this at all. Musk might, but only if someone hires him to do it (like maybe the Canadians or Europeans).

    I'm not holding my breath concerning inflatable heat shields, but I know the first test looked OK. They need lots more tests. Surely is promising, though.

    Meanwhile, NASA's original PICA went un-producible, but Spacex's version PICA-X is currently in production. As I found on the internet after looking hard, its sp.gr. is 0.27. That's way lighter than the old silica-phenolics and similar used on the historic capsules (between 1.5 and 2, as I recall).

    I see no reason why a smaller capsule on a currently-available rocket could not reach lunar orbit with enough oomph to come home.

    Might take two such shots with rendezvous either in LEO or in lunar orbit, to send a proper lander.

    The lander is the pacing item, and it need not look like the Apollo LEM. I don't even think it needs to be two-stage non-reusable.

    The lander really ought to be a reusable ferry, and it really needs the capacity to carry the equivalent of a front-end loader, or a small dozer.

    GW

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