Shuttle Replacement

[jimfromnsf]

I cleaned it up

 

[qso1]

RobNissen:<br />If only. NASA could do a heluva lot of research at 50% GDP. I'm thinkin its probably closer to .05% GDP.<br /><br />Me:<br />Thanks for catching that glaring error. Guess I only checked that three times instead of the usual four times I check before posting. The 50% was in reference to the percentage NASA gets compared to what it got budget wise prior to the early 1970s but I screwed up the wording.<br /><br />NASAs current budget is somewhere between .75 to 1% GDP and thats what its been since the 70s. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[rocketwatcher2001]

<font color="yellow">they wouldn't be made on the moon, that is even less feasible. It would take more energy and expense to do it there.</font><br /><br />Actually it takes a lot more energy to launch a satellite around Earth from the Earth than it does from the moon. The assent stage of the LEM wasn't much bigger than my Dodge Durango, and it made it into lunar orbit, just a little more juice, and she would have made it into almost any kind of Earth orbit you want. I doubt the LEM could even lift itself off the ground on Earth.<br /><br /><br /><font color="yellow">I can see you have no concept of orbital mechanics, system engineering, logistics in space nor cost estimating (shipyard laborhours don't count) <br /><br />And it really bothers me that you propose these outlandish things based on fantasy and ungrounded technical beliefs and are allowed to fly an airplane.</font><br /><br />Actually, I do have a pretty good understanding of how it works.<br /><br /><font color="yellow">"<i>how much better is the world since we've deveolped those technologies?</i>" <br /><br />Some people might say it isn't better </font><br /><br />Usually the same kind of people who don't think that man doesn't have a requirement to exploit all of the resources in our solar system. <div class="Discussion_UserSignature"> </div>

 

[craigmac]

It seem to me that as long as I can remember you’ll have been saying that the X-33/Venture Star couldn't get of the ground and that the Aero Spike engines didn’t work. That my friend is a load of hoarse hockey. They tested at 75% submittal at Huntsville AL. just before the project was pulled by NASA officials.<br /><br />The only thing keeping X-33/Venture Star grounded is not that it is too ambitious; it’s the same idiots who decided to fly a shuttle designed in the early 1970s flying for thirty years without any significant upgrades…<br />

 

[docm]

http://www.nasa.gov/centers/marshall/news/background/facts/aerospike.html<br /><br /><blockquote><font class="small">In reply to:</font><hr /><p>Engine flight qualification testing began in 1998 at NASA's Stennis Space Center in Mississippi. By the spring of 2000, the first aerospike engine had been successfully operated at full power and exceeded the expected operating time that it will experience in test flights from California to Utah.<br /><br /><b><font color="yellow">The first aerospike engine for the X-33 program successfully completed 14 planned hot fire tests in the spring of 2000, accumulating more than 1,460 seconds of total operating time. In addition, engineers have successfully demonstrated the aerospike engines ability to vary its thrust from side to side and top to bottom. This capability to vary its thrust -- called differential throttling -- will be used to control the X-33s direction of flight.</font></b><br /><br />The test stand at Stennis was upgraded in the fall of 2000 to accommodate testing of two engines side-by-side, as they will be installed in the X-33. The dual-engine configuration is scheduled to begin testing in 2001.<p><hr /></p></p></blockquote><br />The Wikipedia article has this to say about the cancellation;<br /><blockquote><font class="small">In reply to:</font><hr /><p><b>Cancellation</b><br /><br />Construction of the prototype was some 85% complete when the program was canceled by NASA in 2001, after a long series of technical difficulties including flight instability and excess weight. In particular, the composite liquid hydrogen fuel tank failed during testing in November 1999. The tank was constructed of honeycomb composite walls and internal structures to be light enough in order for the craft to demonstrate necessary technologies for single-stage-to-orbit operations. A hy</p></blockquote> <div class="Discussion_UserSignature"> </div>

 

[jimfromnsf]

"The only thing keeping X-33/Venture Star grounded is not that it is too ambitious"<br /><br />Not true. What kept it grounded is that an SSTO RLV is not practical

 

[docm]

Care to expand on that or are you going to follow pattern by dropping a declarative and then clamming up?<br /><br />Just asking <img src="/images/icons/smile.gif" /> <br /><br />Given composite tanks look possible and the aerospike has been fired longer than a test mission would last IMO it's time to get our feet wet; "the journey of a thousand miles...." and all that. <br /><br />Hell, our govt. spends more money on Medicaid fraud in Florida a month than it did on the whole X-33 program. <div class="Discussion_UserSignature"> </div>

 

[jimfromnsf]

An SSTO RLV is too sensitive to minor weight changes. Since the payload is a small fraction of the total weight. A small change in ISP could eliminated the payload capability or the same for a slight increase in, instance, TPS mass. Or you discover that the trajectory shaping that reduces capability

 

[baktothemoon]

Would Venture Star be feasible if it would be dropped from an aircraft like SS2 is going to be? I know doing this would nulify it's status as an SSTO vehicle, but would air launching it allow it to reach orbit and become a feasible RLV system?

 

[radarredux]

> <i><font color="yellow">Not true. What kept it grounded is that an SSTO RLV is not practical</font>/i><br /><br />I think there are a more interesting points that are not being addressed: Could advances in technologies over the last 30 years help create a more cost-effective reusable vehicle? (Ignore SSTO, what about TSTO?)<br /><br />The STS program pushed the envelope of technology (perhaps too far) 30+ years ago. Could newer technologies (linear aerospike engines, composite fuel tanks, etc.), combined with different mission requirements (smaller payloads, less cross-range capability) lead to a significant cost savings over existing STS and EELV operations?</i>

 

[jimfromnsf]

Due to the high cost of development and the not so insignificant amount of work involved in reburbishment, the break even point for an RLV is 40-60 flights a year

 

[baktothemoon]

>the break even point for an RLV is 40-60 flights a year <br /><br />Where did you get that figure from? Just wondering.

 

[radarredux]

> <i><font color="yellow">Due to the high cost of development and the not so insignificant amount of work involved in reburbishment, the break even point for an RLV is 40-60 flights a year</font>/i><br /><br />I am familiar with the large number of people (and thus costs) that essentially tear-down and rebuild the shuttle between flights.<br /><br />But (for the moment... ignore development costs), have there been any advancements (or is there a strong reason to believe the advancements could be made) that would dramatically reduce the refurbishment costs? For example, would the Linear Aerospike Engine be easier to maintain than the SSME?</i>

 

[radarredux]

> <i><font color="yellow">Where did you get that figure from? Just wondering.</font>/i><br /><br />I know NASA used similar numbers back in the 1970s to justify the cost of the Shuttle.</i>

 

[radarredux]

> <i><font color="yellow">Due to the high cost of development and the not so insignificant amount of work involved in reburbishment, the break even point for an RLV is 40-60 flights a year</font>/i><br /><br />If there was a launch rate of 40-60 flights per year for ELVs, I would expect the ELV prices to drop significantly as they scale up production. I believe that was Boeing's model for their current Delta family -- using a single core that could be combined for larger rockets. Likewise, I believe SpaceX has a similar approach with their Falcon 9 -- using clusters of Falcon 1 engines. Even a recent video by Armadillo Aerospace showed large numbers of simple engines as they scale up their rockets.<br /><br />So maybe we are seeing a paradigm shift (at least for US-based launches) -- exploiting economies of scale by using simple (but disposable) components in ever larger clusters.</i>

 

[space_dreamer]

Some people on these boards love to go on and on about the X33, let it go! <br /><br />I think the program that should not have been cancelled was the Space launch Initiative (SLI). I liked the strategy of R&D into new technologies first before an overall design had been selected. (The RS-84 reusable engines would have been awesome!) <br /><br />If Space launch Initiative had not been scrapped we now would be in a position to build a two stage to orbit, fully reusable space shuttle system <br />

 

[jimfromnsf]

"Some people on these boards love to go on and on about the X33, let it go"<br /><br />The same goes for RLV's and Shuttle II's (TSTO's) in the near term<br /><br />"If Space launch Initiative had not been scrapped we now would be in a position to build a two stage to orbit, fully reusable space shuttle system"<br /><br />Not, so. current flight rates don't support it. Also it wouldn't separate crew and cargo. Another launcher would be required.

 

[soyuztma]

<blockquote><font class="small">In reply to:</font><hr /><p>If Space launch Initiative had not been scrapped we now would be in a position to build a two stage to orbit, fully reusable space shuttle system<p><hr /></p></p></blockquote><br />I hope you are aware there's a fully reusable two stage to orbit rocket under construction now: the Rocketplane Kistler K-1. <br />I'm a little amazed when people are currently discussing RLV's, they always seem to talk about some distant future. But they always seem to forget there's a RLV under construction now, which is partially funded with NASA money. Why is this? Is it because of lack of faith they will get the necessary money? Or because it doesn't have wings? Or is there another reason? <div class="Discussion_UserSignature"> </div>

 

[radarredux]

> <i><font color="yellow">That is not even close to the Orbiter turnaround ops.</font>/i><br /><br />That was how I hear/read it described, and I think it makes a good metaphor in the sense that it conveys that a lot of work needs to happen.</i>

 

[radarredux]

> <i><font color="yellow">Not, so. current flight rates don't support it.</font>/i><br /><br />There is a bit of a conundrum here -- a chicken and the egg thing. On one hand, people claim (is it true?) that flight rates would increase if prices came down dramatically. On the other hand, people claim that prices would come down dramatically if flight rates went up.<br /><br />In the mid-late 1990s there was an expectation of a large flight rate to support the expected phone and Internet satellite constellations (e.g., Iridium). Part of the argument for Freedom/ISS is that commercial companies would show up to do research and manufacture unique products in zero gravity. The current wave of suborbital efforts are predicated on huge number of "self-loading carbon-based payloads" (a.k.a. "people").<br /><br />I hope it works out better this time.</i>

 

[MeteorWayne]

The fact of the matter for the moment is that jimfromnsf is right about this. There are not yet sufficient missions to justify the development of a launch a week vehicle.<br /><br />However you are also correct that it's a chicken and egg thing.<br /><br />Hence our current conundrum. <img src="/images/icons/wink.gif" /> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[rocketman5000]

I got a couple of different ideas so bare with me.<br /><br />________________________________________________________________________________________________<br /><br />Chicken and Eggs: I think the same thing was being said about SpaceX a few years back. Yes they said they could do it cheaper, but there was also the thing at the time the EELV's took up most of the lauch capacity in the market. To some extent it is a build it and they will come situation. <br /><br />The conundrum is that the first person with deep enough pockets to finace the VERY high development costs and run at a deficit until his launch manifest is at capacity will be a big winner. I don't think we are at that point yet.<br /><br /><br />________________________________________________________________________________________________<br /><br />Big Stick: Could a composite fuel tank on the Aries I help to make up the proported shortfalls?<br /><br /><br /><br />________________________________________________________________________________________________<br /><br />NACA, I won't get on my soap box again, because I am sure that you have heard me saying we need an agency like the NACA that does pure research win, lose or draw if it turns out. <br /><br /><br />_________________________________________________________________________________________________<br /><br />SG: I am still a young engineer and I still believe that given a problem it can be solved. Yes if using only a rocket motor there is a very small margin of error in the design of the vehicle for it to remain pratical. There are higher isp alternatives out there NTR's and RBCC's NTR is probably not feasible from an enviromental standpoint. RBCC should be, capable of making an SSTO possible. Has the GTX been canceled? I can't find anything current about it.

 

[bdewoody]

After seeing new posts about the "Buran" soviet designed orbiter the following thought comes to mind. If, as is claimed by it's designers, the Buran was a completely independent design and not a copy of the U.S. space shuttle then it seems that the space shuttle must logically be the ideal vehicle for LEO payload insertion and therefore we should be pursuing a more evolved version of it instead of a return to the capsule mode of transport. <div class="Discussion_UserSignature"> <em><font size="2">Bob DeWoody</font></em> </div>

 

[jimfromnsf]

"Replacement<br /><br />After seeing new posts about the "Buran" soviet designed orbiter the following thought comes to mind. If, as is claimed by it's designers, the Buran was a completely independent design and not a copy of the U.S. space shuttle then it seems that the space shuttle must logically be the ideal vehicle for LEO payload insertion and therefore we should be pursuing a more evolved version of it instead of a return to the capsule mode of transport."<br /><br />The "design" could bave been independent but the requirement for the vehicle was one thing:<br /><br />Shuttle envy. <br /><br />Actually, the Soviets didn't believe the financial reasons for building the shuttle. They couldn't make the numbers justify reasonings. This and a reference mission where the shuttle deploys a spacecraft and completes a mission in one orbit out of VAFB made the soviets think is was for military purposes

 

[marcel_leonard]

The number one reason that people on SDC keep trying to down grade the venture star/x-33 project at skunk works is that it was never completed so people automatically think that the project didn’t work. Nothing could be further from the truth; they wouldn't have tested full scale rockets at Huntsville AL. if they had not already tested a fully functional prototype. <div class="Discussion_UserSignature"> "A mind is a terrible thing to waste..." </div>