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*Hopefully I'm not repeating information previously posted! Sorry if so (not intentional). Saw this at space.com, in the "Astronotes" column (must copy and paste):
"Northrop Grumman, NASA Tout New Rocket Fuel Tank
WASHINGTON (AP) -- Northrop Grumman Corp. and NASA said Tuesday that testing has been successfully completed on a new rocket fuel tank that is lighter and cheaper to launch than previous technology.
The new tank puts Los Angeles-based Northrop Grumman in position to win more contracts during NASA's next big round of space exploration awards. The agency is currently accepting bids on 500 proposals that were narrowed down from thousands of initial ideas submitted by various companies.
Last week, NASA told Northrop Grumman that it has accepted 30 of the firm's proposal ideas for the next round of bidding. Some of these proposals, each worth between $10 million and $40 million, relate directly to the new fuel tank.
The tank represents a big advance for space planners and will play a role in future travel to the moon and Mars, said Drew Smith, fuel tank lead for NASA's advanced space technology program. It is made of a new, composite material designed to hold liquid hydrogen at extremely low temperatures.
The new tank is made of carbon fiber, similar to materials used in high-end bicycles and tennis rackets. It survived 40 simulated launches during nine months of ground testing, according to NASA and the firm.
Developing the new tank took about four years and cost NASA about $45 million (euro37.2 million). Two-thirds of that went to Northrop Grumman, which now has a leg up on the competition after the successful testing."
--Cindy
We all know [i]those[/i] Venusians: Doing their hair in shock waves, smoking electrical coronas, wearing Van Allen belts and resting their tiny elbows on a Geiger counter...
--John Sladek (The New Apocrypha)
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I had posed a why is this work continuing question with regards to this a few days ago. under this forum
http://www.newmars.com/cgi-bin....te+tank
Since the tanks where for the x series vehicles.
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I had posed a why is this work continuing question with regards to this a few days ago.
And I liked Martian Republic's answer: they're pursuing the technology because it's potentially useful in its own right, even if it never sees a spacecraft. Spin-off's, man, spin-off's.
"We go big, or we don't go." - GCNRevenger
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If it can shave a ton or two off a Lunar TLI stage fuel tank, or a few hundred kilos off a Lunar lander, then thats extra payload for an easy modification if the tank technology reaches a high level of maturity. About half the non-payload weight of your average launch vehicle is tankage, and a big portion of upper stage rockets too.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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If it can shave a ton or two off a Lunar TLI stage fuel tank, or a few hundred kilos off a Lunar lander, then thats extra payload for an easy modification if the tank technology reaches a high level of maturity. About half the non-payload weight of your average launch vehicle is tankage, and a big portion of upper stage rockets too.
Shaving weight off the Earth to LEO stage is all good, also.
Give someone a sufficient [b][i]why[/i][/b] and they can endure just about any [b][i]how[/i][/b]
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True, but the size of the tanks involved are pretty big, so there is a valid question if its cheaper to build a bigger rocket out of Aluminum or Lithium/Aluminum or a smaller one out of carbon composit.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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True, but the size of the tanks involved are pretty big, so there is a valid question if its cheaper to build a bigger rocket out of Aluminum or Lithium/Aluminum or a smaller one out of carbon composit.
If we are taking about a one time use and throw away the tank when we through, then it might be questionable whether it would be more cost effective to have a bigger aluminum tank with more fuel in it or a smaller carbon composite tank with less fuel in it. Which one would cost more for the same amount of payload, we don't know that question.
But, if we are reusing those same tanks as part of our rocket of shuttle configuration or if they are going to designed with a secondary purpose after being used as a fuel tank, that would open up other possibility.
But, currently I don't see a rocket or shuttle design that would use that tank several times or are hearing about secondary uses for those tanks.
Larry,
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If you are talking about using the tanks as a space station later on as a "Secondary Use Which Opens Possibilities," I would get the pretty pictures from the Space Island clowns out of your head... The requirements for a fuel tank are not the same as for a space station, so if you try to make it do both, it will do neither well.
Composit tanks are key to building a truely reuseable launch vehicle, and not a "refurbishable launch vehicle" like Shuttle, but since there is no good need for such a vehicle then expendable rockets are the obvious superior choice. As such, the cost of construction each is more important, so it is a valid cost/bennefit question to replace conventional metal tanks with composit ones.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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If you are talking about using the tanks as a space station later on as a "Secondary Use Which Opens Possibilities," I would get the pretty pictures from the Space Island clowns out of your head... The requirements for a fuel tank are not the same as for a space station, so if you try to make it do both, it will do neither well.
Composit tanks are key to building a truely reuseable launch vehicle, and not a "refurbishable launch vehicle" like Shuttle, but since there is no good need for such a vehicle then expendable rockets are the obvious superior choice. As such, the cost of construction each is more important, so it is a valid cost/bennefit question to replace conventional metal tanks with composit ones.
Even I admit that trying to use the External tank in a dual purpose mission might not be the best way to go. I just hate seeing a perfectly good tank go to waist. Under the present economic system with the many problems and cost with trade off all on the negative side to salvage those tanks, it will defenetly not see the light of day or even happen. Under current NASA funding, they have no way to redeem those tanks even it they wanted to. Just taking there tank into space they would probably lose about 15,000 thousand pounds that the space shuttle can carry in the cargo bay with 65,000 thousand pounds being the max they could take into space if they didn't take there aluminum tank into space with them. This is before any modification to the tank to make it simi-redeemable for some other use. That any serious reconfiguration of those tanks or of the shuttle stack that would be need could easily cost two or three billion dollar to re-engineer and the price of those tanks could go from 40 million dollars a tank to 80 million or more per tank. I understand that.
I pretty much agree with you on the re-useable part of the Composit tanks and buiding a whole new design of shuttle to make the attempt to get away from having to throw part of the space ship away to get into space.
Larry,
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At the risk of sounding like I'm back tracking, I'm going to throw out another idea. That a Composit tanks is possibly more redeemable that an Aluminum external tank for the shuttle.
The aluminum tank has several draw back as compared to using a carbon poxes composite tanks.
For example:
1. Aluminum tank is just going to be an aluminum tank and if you need insulation you will have to add it to the outside of the tank. With a carbon tank you can add that right into the design of the tank while your making it or possibly even add radiation resistant material to the mix also without significantly changing the design of or function of that fuel tank.
2. Second you can make it more puncture resistant than Aluminum and it naturally has three or more times the tinsel strength of aluminum has too.
3. Would also be easier to modify than an aluminum tank too. You can drill hole or cut out section in both an aluminum tanks and carbon tanks, but then you could add pre hung air lock and or re-in force the tank by adding another layer of carbon poxes or make beam out carbon poxes rope and/or netting and cloth, carbon rope, carbon netting or possibly have it a role like laying down carpet with wax paper on the back that you pull off when you get ready to use it to make a decks or cover some pre hung netting etc. Of course we would have to develop mixer and a way to dispense the carbon poxes. Then after that, how would you clean it up and do the finish work on it. Of course you will be locked into what ever shape that carbon tanks is in when you send it up, because you can't fold or bend that carbon tank or melt it down like you would aluminum.
I just thought I would bounce this idea out there and see what kind of legs this has on the discussion. I know how easy it is to get locked in to way of thinking when you can do it only one way and the limitation that are imposed on you because you only have one choice. However when new processes or new materials carbon fiber & poxes come along, you need to start afresh, because the old rule no longer apply, because the new process is not limited by the old concept by the old process.
So I would like to break this down into two discussion of either aluminum tanks or the carbon tanks, because we are dealing with two types of manufacturing process with different limitation or advantages to the other and so you might come up with different conclusions or possible choices.
Larry,
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So I would like to break this down into two discussion of either aluminum tanks or the carbon tanks, because we are dealing with two types of manufacturing process with different limitation or advantages to the other and so you might come up with different conclusions or possible choices.
Carbon composite construction is very different from aluminum frame & sheet construction on the scale of the shuttle external tank. The safety procedures are completely different, too. Converting the Michoud facility (where shuttle ET's are currently made) to make graphite tanks would, aside from giving the staff coniptions, end tours of the facility during work hours because it wouldn't be safe to have school children on the factory floor.
Carbon composite construction isn't as safe as building with aluminum.
The density difference between carbon fiber + epoxy and aluminum construction isn't all that great, but carbon fiber is stronger than aluminum, allowing carbon composite constructions to be lighter. However, carbon fiber is very brittle compared to aluminum, making a graphite part of the same design strength less reliable than an aluminum part under the same load.
Carbon composite construction is potentially lighter than aluminum, but also potentially less reliable.
The desirability of either is very dependent on the exact nature of the application. I'm not sure a blanket statement can be made about which is preferable.
However, I can say that I've always had a soft spot in my heart for amateur space travel projects, which carbon composite construction lends itself to because of its relative simplicity.
"We go big, or we don't go." - GCNRevenger
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