Saturday, September 28, 2013

Free your mind, and the rest will follow.

Copyright 2013 Robert Clark 

The story has been told that when the Native Americans first saw the ships of the Europeans they could not grasp what they were seeing because it was so outside their experience. I've always been dubious of that story. But a recent study suggests something of this nature can happen:

Science confirms: Politics wrecks your ability to do math.

By Chris Mooney
Everybody knows that our political views can sometimes get in the way of thinking clearly. But perhaps we don’t realize how bad the problem actually is. According to a new psychology paper, our political passions can even undermine our very basic reasoning skills. More specifically, the study finds that people who are otherwise very good at math may totally flunk a problem that they would otherwise probably be able to solve, simply because giving the right answer goes against their political beliefs.

 So preconceived notions can affect your ability to reason effectively, even among the smartest among us. I'm reminded also of a brain puzzler stated on the "All in the Family" TV show during the '70s. Gloria presented to the family the following:

 A father driving his young son were in an accident and the father was killed, while the son was injured but survived. When the child was brought to the hospital, the surgeon said, "I can't operate on this boy. He's my son."

 That was a puzzler the rest of the family on the show couldn't solve then and neither could I when I first saw the episode back in the '70s. The answer of course is that the surgeon was the boy's mother. 

 With the advance of women in medicine now with most med school graduates being women that probably would not be such a great puzzle to solve now as then. But it indicates how your preconceived ideas can limit your ability to solve really simple problems.
 Something like this is currently occurring at NASA. The Constellation program that would have returned us to the Moon has been cancelled due to high cost. However, many space advocates in the public and in Congress would prefer us to return to the Moon rather than the asteroid mission NASA is embarking on. No doubt because of these calls to return to the Moon, NASA released a study on a return to the Moon without Constellation:

Dual SLS launch campaign required for NASA’s Lunar return.

August 21, 2013 by Chris Bergin

 I was surprised to read that the study assumed an Altair-sized lander at the ca. 45 mT range. But the Altair's size was a big reason driving Constellation's large size and therefore great expense. And in fact by using two SLS launches the mission size in this study turns out to be even larger than Constellation. 

 It was as if the study authors had never heard of the Apollo lander that was only one-third the size of Altair. The misperception that a lunar lander has to be as large as the Altair as well as being built from scratch rather than using existing propulsive stages and crew capsules drives the false conclusion that an additional $10 billion expense would be needed for such a lander, and therefore a lunar return is unaffordable

  A further misperception is what is the mass that could be transported to LEO by the SLS. The Block 0 version of the SLS was supposed to use three SSME's on the core and use the standard 4-segment SRB's used on the shuttle. This would have a 70 mT payload capacity to LEO.

 However, NASA decided to bypass the Block 0 and go directly to the Block 1. This would stretch the core tank by a third and use a fourth SSME. It would also use a fifth-segment on the SRB's. So the size and thrust of the core would be increased by 33% and the size and thrust of the SRB by 25%.

 Despite these increases in both size and thrust, NASA was still quoting 70 mT capacity for the Block 1 SLS. Logically the payload should have been increased but NASA continued to quote 70 mT. Finally, NASA did release a report that acknowledged the payload to LEO would be 90+ mT:

SLS Dual Use Upper Stage (DUUS).

  This is important because at 90+ mT it is much easier to do a manned lunar landing mission using a single launch of the SLS, assuming you use a lander at the Apollo scale not the Altair scale. Indeed it would be possible at the first launch of the SLS in 2017.

 Then it was these preconceived notions that prevented NASA from seeing that we can in fact return to the Moon as early as 2017, and not even at significantly greater expense than that already being spent on the SLS and Orion capsule.

  Another mental block is operating in regards to how much such BEO missions should cost. NASA's commercial space program has been a great success in producing both launchers and spacecraft at as much as a 90%(!) savings over what NASA would normally have to pay for them. If any other federal agency had managed to reduce costs for normally multi-billion dollar programs to only a few hundred million dollars this would be hailed to the skies as a remarkable success in reducing costs to the American tax payer. Yet NASA was regarding it as if it were something they were only allowed to talk about in hushed tones.

 Finally, NASA has released a report detailing the savings possible under the commercial space approach:

The Commercial Leverage Model and Public/Private Partnerships.
Daniel J. Rasky
Director, Emerging Commercial Space Office
NASA Ames Research Center
Founder & Director, Space Portal
NASA Research Park
Moffett Field, CA 9403
September 11, 2013 

 Imagine then these cost savings applied also to BEO missions to the Moon or asteroids. This would make these missions much more fiscally feasible. It was NASA not officially acknowledging such cost savings that made it so that they could not study possibilities for returning to the Moon in a low cost fashion.

 For return to the Moon missions conducted by NASA, NASA may initially choose to use the, still expensive, SLS launcher. However, just as NASA has realized commercial space can make flights to the ISS much more cheaply than the shuttle, so also can commercial space make flights to the Moon much more cheaply.

 Indeed, by going small, going commercial, and using preexisting propulsive stages and crew modules, crewed and cargo flights to the Moon can be made for comparable costs to what we are paying the Russians to send a crew of three to the ISS.  

 The conclusion you draw is that a Moon base can be sustained on the Moon for what we are currently paying to sustain the ISS.

 Just free your mind, and the rest will follow.

   Bob Clark

Budget Moon Flights: Ariane 5 as SLS upper stage, page 2.

Copyright 2013 Robert Clark

 In the blog post Budget Moon Flights: Ariane 5 as SLS upper stage, I noted that using an Ariane 5 core stage would be a quick and low cost means of getting a higher payload capacity than the 70 mT NASA was giving for the 2017 SLS first launch. This would make it much easier to conduct a manned lunar lander mission using the SLS. However, finally, NASA has acknowledged that the Block 1, first version of the SLS to launch in 2017 will have a 90+ mT payload capacity not the 70 mT always stated by NASA:

SLS Dual Use Upper Stage (DUUS).

 This is important since it means we will have the capability to do manned lunar landing missions by the 2017 first launch of the SLS:

SLS for Return to the Moon by the 50th Anniversary of Apollo 11, page 5: A 90+ metric ton first launch of the SLS.

  Still, because of the even higher payload possible using an upper stage, NASA might still want to consider getting a quick and low cost upper stage by using the Ariane 5 core. In that "SLS Dual Use Upper Stage (DUUS)" report are given some specifications for the DUUS. They state they want a highly weight optimized stage, which the Ariane 5 core would certainly fulfill. The Vulcain engine though has thrust size about twice that of the specified 100 - 120K lb range, and the 170 mT of propellant is also larger than the specified 130 mT propellant load. However, these are so much superior to the specified requirements it should result in significantly greater payload delivery than the stated 130 mT to LEO, perhaps to the 150 mT range.
 However, a problem is the 18.3 m specified max height. The Ariane 5 core is at 30.5 m height. Likely the height limitation is coming from limitations on the size and height of the facilities during stage integration. I'll find out if that is a firm limit.
 We could cut down the size of the Ariane 5 core to make it 130 mT in propellant load. Proportionally this would bring the height down to about 20 m, closer to the max. height. It turns out that shortening a stage is rather easy technically so this should still be doable by the 2017 first launch of the SLS.
 Another possibility would be to use the same propellant tank tooling for this DUUS stage as that used by NASA to make the 8 meter wide SLS tank, while using the other components such as the engine of the Ariane 5. However, the idea is to get a low cost upper stage in a short time frame. This might be a costly modification that might also be difficult to manage by the 2017 SLS first launch.
 This possibly though could open up an additional means of lightweighting the stage. We could use aluminum-lithium alloy instead of the standard aluminum used for the Ariane 5. NASA is also planning to use standard aluminum for the SLS core. But as I discuss in SLS for Return to the Moon by the 50th Anniversary of Apollo 11, page 4: further on lightweighting the SLS core, new versions of Al-Li have been developed that could be used for this purpose.
 However, due to the natural inertia of large agencies it might be difficult to change the decision and go with Al-Li for the SLS core. But this decision might be easier to make in regards to the smaller upper stage which wouldn't need as much of the more expensive Al-Li and for which getting a lightweight stage is a much greater priority.

  Bob Clark

Sunday, September 22, 2013

SLS for Return to the Moon by the 50th Anniversary of Apollo 11, page 5: A 90+ metric ton first launch of the SLS.

Copyright 2013 Robert Clark

 Finally someone at NASA acknowledges that the Block 1, first version of the SLS to launch in 2017 will have a 90+ mT payload capacity not the 70 mT always cited by NASA:

SLS Dual Use Upper Stage (DUUS).

 This is important since it means we will have the capability to do manned lunar landing missions by the 2017 first launch of the SLS.
 As discussed in the blog post SLS for Return to the Moon by the 50th Anniversary of Apollo 11, page 2: Orion + SEV design, a 90+ metric ton launcher means we can even use the Orion as the crew capsule. This is important for political reasons since the great expense spent on it means there would be a great desire among its supporters to see it be used. 
 There also is a preference at NASA for the departure stages from the lunar surface and from lunar orbit to use hypergolics, which have the surety of igniting on contact. Then another advantage of a 90+ mT SLS is that the heavier hypergolics can be used for these stages rather than the lightweight hydrogen-fueled stages I suggested in that blog post. In an upcoming post I'll show using existing hypergolic stages how we can get a lunar landing mission at less than 90 mT to LEO.
  For any of these methods it is important to use currently existing stages rather than developing them from scratch. A big reason that NASA ruled out a return to the Moon was because of the assumption that it required the development of new Altair-sized lander at a $10 billion development cost. But the need for a 45 mT Altair-sized lander is provably false as shown by the Apollo lander at one-third the size. And simply adapting already existing stages reduces the cost to a fraction of that needed for an Altair.
 So NASA is making expensive policy decisions such that we can't return to the Moon based on provably wrong assumptions. One is that the Block 1 would only have a 70 mT payload capability and so would require an expensive upper stage to increase the payload to do lunar missions, and another is that a lunar lander would require an additional $10 billion development.
 In fact, once you recognize the, obvious, fact that a lunar mission does not require an Altair-sized lander then so many possibilities become apparent. We did not have the great variety of existing launchers back in the Apollo days that we have now. If you allow your lander to be at or smaller than the Apollo lander then there are a variety of launchers that could be used for lunar missions, not just the SLS. And since they are already existing, or will be soon such as the Falcon Heavy, there would be no huge, multi-billion dollar development cost to use them. 
 So likewise also is the case for the in-space stages needed. They are already currently existing and would require relatively minor adaptations to be used for a lunar lander, for example.
 Indeed we could do manned lunar missions for what NASA is currently paying the Russians to send a crew of 3 to the ISS. The implications of that are jarring: we could have regular manned flights to the Moon for the same amount as what we are currently paying to send regular manned flights to the ISS.  And since the cargo flights to the Moon would be similarly low cost and using Bigelow style lightweight habs would allow a habitation module to be sent to the Moon on a single flight, we could have a manned lunar base for the same amount as what we are paying to sustain the ISS.
 All this comes from simply the mental reset that a lunar mission does not require the $10 billion Altair.
 Free your mind, the rest will follow.

    Bob Clark

Note: thanks to M. Moleman for discussing the NASA report "SLS Dual Use Upper Stage (DUUS)" on his blog.

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

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:


  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

Low cost approach to winged, air-breathing and rocket SSTO's, Page 1.

  Copyright 2024 Robert Clark  I'll take a few approaches to estimate the  technical  feasibility of a combined jet/rocket SSTO. But fir...