NASA Eyes Shuttle Replacements

jonerik writes "According to this article at Space.com, NASA yesterday released a status report on the first year of NASA's Space Launch Initiative; the search for a space shuttle replacement, currently planned to begin operating ten years from now. The competing contractors - Boeing, Lockheed Martin, and a team consisting of Northrop Grumman and Orbital Sciences Corp. - have their work cut out for them. NASA is looking for both a ten-fold improvement in per-pound launch costs (from $10,000 per pound to $1,000) and massive improvements in crew survivability." In related news, Rubyflame writes: "Aviation Now has a story about four new kerosene-fueled rocket engines being developed by Aerojet, Pratt & Whitney, Rocketdyne, and TRW. These are engines that will produce a million pounds of thrust, intended to outdo Russian designs in reliability and launch cost, and one of them may power a new reusable launch vehicle. Kerosene has the advantage that it's denser than hydrogen, so the fuel tanks can be smaller."

Comments

the usual suspects...defense contractors

[Sir Elton John]

The companies listed as possible contractors for the new project aren't incredibly surprising. When I met with Lockheed Martin executives a while back as part of a consulting gig that didn't pan out, I asked them a few questions about the industry.

Now, I am coming from a background where I am not incredibly familiar with either U.S. capitalism or with issues of defense. Basically, there are a handful of these companies that compete for every government contract. To maintain "competition," the government will try to spread the love around, going with different companies for succesive contracts.

But each individual contract is too big for a single company to fulfill on its own, so whomever ends up winning the contract will turn around and outsource some of the work to...the same "competitors" whose bids they beat out!

As a retired rocketman, I am the first to support expansion and improvement of any nation's space program. I just wanted to point out that the notion of "who will build the next generation shuttle" should be taken with a grain of salt.

Re:Crew survivability?

[Chairboy]

Aside from Challenger?

Please note that during the first 2.5 minutes of every shuttle launch, there are NO abort modes that are survivable. If there are any problems with the SRBs, they cannot be turned off. If there are any catastrophic problems with the ET, it doesn't matter, you must continue your launch profile until the SRBs have stopped.

Three engine shutdown during SRB burn? Shuttle disintegration.

ET rupture? Shuttle disintegration.

Pretty much anything, dead astronauts.

The russians use 40 year old technology, but at least they have survivable aborts throughout the entire flight profile.

Why does a moon base need to be 'metal'?

[kesuki]

Who says the 'moon base' has to be made out of metal? Why can't you ship up some excavation tools, and light weight polymers and build an airtight underground lunar base with the only imported metal being the airlock doors? True, this doesn't provide you with any method for creating food, but We Could have had a lunar base easily. One much larger than any of the space stations we've shipped up, because as you recall all of those ARE made out of tons and tons of metal. There is also a cumulative advantage, the longer you've been building stuff on the moon, the more resources are at your disposal to build more complex projects... Unlike the space stations which all fall back to earth after a few decades. Depending on how far we push nanotech we may not even need to build factories on the moon, we may just need to send up a few machines that recieve power wirelessly and process raw materials into usable resources.
The moon is a more practical environment to work in, the low G enables a person to remain there signifigantly longer than in the microgravity of space.
The Biosphere projects are partially aiming at researching the viability of building an enclosed, self sustaining habitat on the moon, but even if you build a moon base that requires resupplying like space stations do, it could easily be done for less money as long as you take advantage of the fact that you can always dig a hole use some plastic to make it airtight and cover it with a metal lid. Homsteaders used to build houses out of earth and mud where trees weren't available, so why should we build lunar bases out of 'industrial grade metal' when really the only part that has to be metal is the door.

Re:Multi-stage Launch

[WolfWithoutAClause]

> Unfortunately given our current level of rocket
> propulsion technology a single-stage-to-orbit
> (SSTO) isn't terribly practical. They made some
> prototypes and actually flew a scaled down
> prototype in the desert, but ultimately they had
>tremendous problems with the extremely high
>performance rocket engine they had to use, couple
>with the experimental composite cryogenic fuel
>tanks.

No. This isn't the case; I was talking to some engineers that worked on the Roton just last weekend. They indicated that they knew of no problem that would have precluded the design from working. The composite cryogenic fuel tank THEY used (as opposed to the X33 debacle) - it worked fine in all testing; including something like 50 pressure cycles IRC.

>I honestly don't think we'll ever get SSTO going
>with conventional chemical propellants. You simple
>have to carry too much weight in fuel, which means
>you need a bigger rocket, which means more fuel,
>then a bigger rocket...you get the idea.

No, the simulations converge- SSTO is definitely possible. I've seen atleast 2 hard and fast designs for SSTO vehicles- the Roton and Mockingbird. The Roton would have carried 3 tonnes to LEO; the Mockingbird design didn't have a payload of any note, but was really tiny (1.5 tonnes), and cheap. I've studied both concepts extensively; they both appear workable.

The biggest argument against SSTO is that it may be more expensive. TSTO may be cheaper. Still, the argument isn't totally watertight. There's a lot of ground processing for TSTO that SSTO doesn't require and that's going to cost something. Although SSTO designs use more fuel- fuel is cheapest bit of the whole rocket by far.

>What we need is a way to extract more energy from
>whatever fuel we use.

Another thing I saw on the weekend- I was at a presentation by a guy talking about a laser powered launch system. The idea is you take a large bank of lasers and point it at a hydrogen powered launch vehicle, which has a heat exchanger it uses to heat the hydrogen. The ISP is about 600 seconds, which is plenty for reaching orbit. The laser bank was priced at about $1 billion but its dropping at about 30% a year currently- only cheap semiconductor lasers are needed, and they're getting cheaper and cheaper.