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11 January 2015

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William R. Cumming

The strategic vision of NASA failed at the beginning by its focus on manned spaceflight.

Rocketrepreneur

Babelfish,

Great writeup, though I don't think orbital launch is quite on the bleeding edge of materials technology anymore. I think there's still a ton we can do to improve reusability even with existing technology. The challenge isn't just technical but also one of markets. Most existing launch customers can afford the ridiculously high costs of launch, and so are relatively inelastic (demand-wise) to lower prices. So it hasn't made much sense for incumbents to invest too much in cost reductions. Hopefully SpaceX will help shake that up. I have a lot of friends at SpaceX and most of their competitors, and the good news is that most of my friends at ULA for instance (the main incumbent launch company) actually want SpaceX to succeed--so they can convince their management that reuse is something they need to invest in as well. They have different ideas, and I think there are lots of ways to crack this nut. Hopefully SpaceX will help shift the industry in better directions.

As for space elevators on Earth, I think we've still got a long way to go in making and using long carbon nanotubes. Progress has been a lot slower there than people had hoped. There are other variants (rotovators or hypersonic skyhooks) that might be feasible sooner. And lunar or Martian space elevators could be done with existing materials.

Great article though!

~Jon

mike

Babelfish - what ever happened to the RS-68? How come that program died, was it unworkable, or too expensive, or.....?

BabelFish

WRC, the changeover was made in 1958, during the hysteria of the Sputnik launch. And, regarding manned space flight, give a government agency and associated contractors a blank check and a very macho task to accomplish 'before this decade is over', and for sure everything else falls by the wayside.

NACA had it going! Not only the X-series of rocket planes but things like Richard Whitcomb coming up with the area rule and the super-critical wing were part of its portfolio!

BabelFish

Jon, thank you for the kind words. I am curious (means do research) on the 'birthday' of some of the materials that are in current use (Inconel?)

I remember when we were trying to qualify carbon filament wound SRB sections. Promising but way too much work, I think, was the decision. But, as was drilled into our heads, save a pound and put almost that much in orbit. And, bingo, we had lithium aluminum for the barrel sections of the ET.

Mike

BabelFish

Mike,

I think it died when Constellation stalled out and Wiki agrees. A big brute of a cryogenic motor but it was not man-rated. However, old rocket engines seem to never truly die. We could see it back in another application.

http://en.wikipedia.org/wiki/RS-68

VietnamVet

BabelFish

This is an excellent article. I rode on steam powered trains as a boy and saw Sputnik move across the stars. There were astonishing changes in my youth. The future in the movie “2001 A Space Odyssey” seemed possible at the time. Then progress came to a screeching halt. All we have of that future today is Skype. I blame financiers’ greed and perpetual war. Material roadblocks can be overcome if mankind has the will and direction

BabelFish

Thank you for the kind words.

One more thing that Arthur C. Clarke got right in 2001 was the use of 'Pads'. We've got IPads,etc.

I have to tell you that the first time I got to go to KSC for work, I just stared at all these places I had seen on TV. I felt I was at Disney for adults.

MK Logan

Babble,

Great read, thanks.

Material specs are where a lot of great ideas go pear shaped. Here we are living on a thin-skinned ball of fire..worried about energy.

I've seen some very daunting numbers on the tensile strength needed for a space elevator. Last I looked the most exotic stuff we have ever actually made is very, very far from the strength to weight ratio required.

BabelFish

MK, yea verily on the material specs! A few unicorns out there. Fusion power, anyone?

I agree with the specs being daunting. Even the old engineering mantra "when in doubt, make it stout" doesn't work when you have to haul something up to past 15,000 miles straight up. So, we need a space elevator to build a space elevator.

sglover

"Then progress came to a screeching halt. All we have of that future today is Skype."

Well... People living now have had the privilege of seeing the surfaces of:

Mars, Venus, Mercury, Europa, Ganymede, Titan, Enceladus, Callisto, Io, Triton, Iapetus, Vesta, Ceres -- and several dozen lesser bodies.

If it isn't already, Mars will soon be observed with more regularity and accuracy than the surface of the earth was 50-60 years ago.

In just a few months we'll be getting good images of the surface of Pluto. Those will include images of that planet's small moons, which were never even guessed at, when I was a wee lad.

Worlds around other stars are being catalogued all the time, now. In many cases the cataloguing includes plausible guesses about the temperatures and even atmospheres of these planets.

So progress in space exploration hasn't ended by a long shot. But it's sadly true that boatloads more money and effort have been squandered on follies like Iraq and the F-35 and bailing out the finance "industry".

BTW, anybody reading this comment thread might enjoy the "Centauri Dreams" site. It's a good source for both space science news, and imaginative speculation about methods for Getting Out There. Lousy and archaic as our political and social systems might be, we're really living in a Golden Age of Talent.

different clue

With all the thinking about living in space, nobody seems to think about living on the deep sea floor. Its so unthinkable it never gets thought of. And that's unthinkable.

Men will be living on Mars before men are living at the bottom of the Challenger Deep. Or the Marianas Trench.

MK Logan

Babelfish,

If a method of splicing unobtainium in space can be developed found it may be possible to lower cables from orbit. I can't picture a vehicle that could lift it in one shot.

João Carlos

Well, don't worry. The chinese will build the orbital elevator sooner or later. They are the number one economy now and for the next 5 decades...

Rocketrepreneur

Babelfish,
New materials can take a long time to implement in any demanding industry--some of the next-gen semiconductor materials are estimated to be >10yrs out.

But yeah, very few of the alloys or composites they're using are that new. Widespread use of friction stir-welded Li-Al has really only hit the launch vehicle world in the past 10-15 years. Composites have only really taken off over the same timeframe.

But if you compare the thrust to weight and Isp of Merlin-1D with the F-1 engines on the Saturn V, you'll see a huge improvement (double the thrust-to-weight, and over 20s higher sea level Isp, and 30s higher vacuum Isp), and that's for a gas-generator cycle engine using the same propellants.

For getting rockets off the "bleeding edge" materials-wise, the 30 or so % improvement you get from friction stir-welded Li-Al and composites use, and the doubling of T/W goes a long, long way.

And there are other cool technologies (my favorite is Thrust Augmented Nozzles) which just need flight demonstration.

I think we've got a lot of room for improvement in launch costs that are feasible within the realm of existing or near-term rocket technologies.

~Jon

Rocketrepreneur

Mike, Babelfish,

RS-68 flies on every Delta-IV launch vehicle. It was doing that before constellation, and will keep doing it until ULA gets their next-gen LOX/Methane rocket working (the one they're teaming with Blue Origin on). At that point, I wouldn't be surprised if they retired both Atlas V and Delta IV to fly everything on just that one LV.

~Jon

ISL

Dear Babelfish,

Thanks for the writeup. I recall some scifi stories about first building space elevators on Mars to retrieve mining and get people to and from the surface; however, they presumed a far more active space launch program.

Your point reminded me that the space shuttle and F-35 share a similar maladaption - trying to do too many things with non-mature technology and succeeding at almost nothing - while the Saturn V in terms of cost and payload size kicked b-tt. I am very proud of the ISS - but its so small compared to what I would have predicted in the 60s for half a century in the future, and a Saturn V could have launched it in two segments. The simplest way to reduce costs is by magnitude of scale (which requires creating a demand) - look at super-tankers, but as has been noted at SST often, govt agencies are cost centers.

Its not clear that the private enterprise will provide the needed kick start as opposed to adopting their client's mentality for me to book a reasonable priced ticket to the space wheel in my lifetime.

LeaNder

About the unicorns. ;)

I stumbled across materials science or engineering more than a decade ago. A very special material would have been the ideal solution in a sponsorship concept.

I haven't thought about it meanwhile, but that link is interesting:
http://www.extremetech.com/extreme/164594-the-wonderful-world-of-wonder-materials

Will we one day revisit the wave-particle-duality of light? Reminds me of Einstein's struggle with uncertainty

http://en.wikipedia.org/wiki/Bohr%E2%80%93Einstein_debates#Post-revolution:_Fourth_stage

BabelFish

Thanks, Jon. I stepped in that one! Been out of the business for too long.

BabelFish

Completely agree, MK. Clarke has it being lowered from orbit. Talk about playing pitch and catch!

BabelFish

Joao, I hope they do but they will need cooperation from everyone.

One of the unspoken issues here is 'what if the cable breaks'? It is hard to imagine that much kinetic force coming back down to earth but the destruction would be beyond imagining if it came back down rather than going out into deeper space. Everyone is going to have to buy into that risk.

BabelFish

I believe that is true and it is also true that, if anything, the deep ocean is as harsh an environment as humans will confront in the foreseeable future.

You can step out into space with a well constructed space suit. No human is ever going to go for a stroll through the Marianas trench. The quid pro quo is that there are untold riches on the seabed, if we can master technologies to access them for an economic cost.

pbj

The contraption in the diagram could probably be made simpler and safer by making it just a tiny bit shorter, so it doesn't have to go into the atmosphere.

Rocket to LEO, elevator thingy to GEO / anywhere. And heck, once its above the atmosphere, why not just build a smaller one and spin it up.

Places with no atmosphere let it get that much closer to the ground.

João Carlos

They will have cooperation from Russia, Brazil, South Africa and India, you know, the BRICS. They don`t need USA and Europe help if Russia help them. Take note, the only thing maintaining the IS operating is the russian good will, and that thing is ending fast...

BabelFish

PBJ, think of a rock on a string. You hold it over your head and spin it. The centripetal force keeps the string taught and the rock out at the end. This works because the string (cable) is anchored to your hand. If you let go, the rock flies off away from you. The space elevator needs to be anchored to the earth and so must come into the atmoshpere.

As Rocketentrepeneur has pointed out, there are actually other options. One is the 'Skyhook'. There are various configurations, including one where a large object has two counterbalancing cables spinning around it. One comes down into the atmosphere and scoops up stuff, bringing it up to orbit.

http://en.wikipedia.org/wiki/Skyhook_(structure)


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