new launch vehicle

[spaceinator]

watching the launch about an hour ago i was reminded once again how much we need a new launch vehical. the shuttle should have been replaced decades ago. The The DC-X (Delta Clipper X) looked hopeful a few years ago but was cut because of funding problems. Or maybe something that was launched out of a long underground tube, and used magnetic propulsion and little fuel to get into space? (I heard of a design something like this somewhere but can't remember where..) But whatever the design, it needs to rely on something more than just huge amounts of expensive fuel to get into orbit.<br />I was wondering what people thought would make a good shuttle replacement...

 

[wvbraun]

The planned CEV will be a good replacement.

 

[tap_sa]

<font color="yellow">"But whatever the design, it needs to rely on something more than just huge amounts of expensive fuel to get into orbit. "</font><br /><br />Compared to actual hardware the fuel cost is insignificant. There's not much point in building multibillion dollar terrestial structures to save a few drops of practically free fuel. All sorts of sledges, vacuum tubes and whatnot share similar problems, such as limiting your possible launch azimuths and requiring heavier TPS and airframe to cope with much more severe conditions during first second of flight. Air-launch from motherplane a la White Knight/SS1 is worth considering for smaller spacecrafts (it doesn't scale to shuttle size crafts).

 

[thermionic]

<br />Watching the launch this morning, I was reminded once again what a fantastic and amazing vehicle the shuttle is. It should have been replaced decades ago? 1985? How long had it been operating at that point?

 

[john_316]

darn u beat me too it... <br /><br />"decade" isnt that like 10 years?<br /><br />"decades" twice the value of 10 thus meaning twenty or more right?<br /><br />ok just making sure i am correct here....<br /><br /><br />where is the 2 billion dollar HSL-20 and HSL-42 at???<br /><br /><br />CEV will come................ Eventually...........<br />

 

[no_way]

<blockquote><font class="small">In reply to:</font><hr /><p>Hopeful for what?<p><hr /></p></p></blockquote><br />Hopeful of becoming a space vehicle ( even if only suborbital ) whose operations costs wont eat billions of dollars a year regardless of flight rate.<br /><br />DC-X has some following, and its pretty certain that one of the followers will build an affordable operational space launch vehicle with the general concept of VTVL sooner or later.<br />

 

[nacnud]

The helicopter version was called Roton and was a seporate initative to the DC-X.

 

[spacefire]

<font color="yellow">The planned CEV will be a good replacement.</font><br />what exactly makes the CEV a launch vehicle?<br /> <div class="Discussion_UserSignature"> <p>http://asteroid-invasion.blogspot.com</p><p>http://www.solvengineer.com/asteroid-invasion.html </p><p> </p> </div>

 

[nacnud]

Fair enough <img src="/images/icons/smile.gif" />

 

[frodo1008]

You are correct once again! The DC-X was to lead to a totally SSTO type of vehicle. No, that is incorrect, the DC-X was going to lead to a vehicle much worse than an SSTO! Not only would it have been single stage on the way up (which would give the usual very small payload for a very large rocket of the typical SSTO), but not being either winged or even a lifting body concept it would have needed extra propellants just to have retro rockets that would stop it from crashing!<br /><br />If NASA cancelled the X33 and eventualy the Venturestar, and it WAS a lifting body concept, then what possible chance could the DC-X or any follow on have had? I think there are just people on these boards who would grasp at ANY kind of straw. But the simple laws of physics are against some concepts, and DC-X was one of those concepts. Glad to see that I am not the only one here who realizes this!

 

[gunsandrockets]

"but not being either winged or even a lifting body concept it [DC-X] would have needed extra propellants just to have retro rockets that would stop it from crashing!"<br /><br />Actually the Delta Clipper, for which the DC-X was only a limited small scale test vehicle, was a lifting body. It would have reentered the atmosphere 'sideways' and controlled it's descent with four body flaps. Crossrange was expected to be pretty good.<br /><br />The Delta Clipper use of rockets and footpads for soft landing was a sensible engineering choice and competitive in mass requirements with different choices such as parachutes or wings. The biggest question about the Delta Clipper concept was the ability of the vehicle to land safely under rocket power, hence the (successful) DC-X test vehicle project.<br /><br />The small payload of the Delta Clipper was a feature not a bug. Trying to force a RLV to have a massive payload makes a practical RLV almost impossible, just as the growth of the Space Shuttle in order to launch a much larger cargo doomed it to failure.

 

[radarredux]

> <i><font color="yellow">DC-X has some following, and its pretty certain that one of the followers will build an affordable operational space launch vehicle with the general concept of VTVL sooner or later.</font>/i><br /><br />Armadillo Aerospace has planned for a powered vertical landing for their suborbital rocket. They have done some DC-X type tests (impressive, including at least one impressive failure).<br /><br />TGV Rockets also are going with vertical landing with thier suborbital rocket, but I don't know if they are just business plan and paper designs or if they are bending metal yet. The Space Review has a great 3-part interview with the TGV.<br /><br />I am not sure how coming in engine-first from orbital velocities will work however.<br /><br />Armadillo:<br />http://www.armadilloaerospace.com/n.x/Armadillo/Home<br />Successful VTVL flight:<br />http://media.armadilloaerospace.com/2004_06_15/perfectBoostedHop.mpg<br />The crash:<br />http://media.armadilloaerospace.com/2004_08_08/48InchCrash.mpg<br /><br />TGV Rockets:<br />http://www.tgv-rockets.com/<br /><br />The Space Review interview:<br />http://www.thespacereview.com/article/409/1<br />http://www.thespacereview.com/article/412/1<br />http://www.thespacereview.com/article/417/1</i>

 

[nacnud]

A couple of things that I want to mention about the DC-X before it is totally slated. First off it showed that a very small team of people could operate a small rocket. From an operations point of view I think it lead to the spaceX approach were a small number of people in a trailer are able to look after the vehicle. <br /><br />Secondly the use of rockets to land the vehicle might not be as daft as it seams. Remember the Genesis probe that crashed a while back, how fast did that hit the ground? IIRC it was less than 200mph. So a vehicle trying to brake from orbit might only need that much delta v plus a safety margin. This could be less mass than for a parachute/air bag system. I'd not like to use it for a manned system as a parachute system seems safer but from a certain view point the rocket system makes sense.<br /><br />A TSTO with a DC-X second stage may have certain merits even if other systems are considered better overall.<br />

 

[thecolonel]

I firmly believe that the DC-X design should be brought back to life. Not as a means of reaching LEO SSTO, but as a baseline for a refuelable, reusable lunar lander architecture that performs taxi missions between Low Lunar Orbit (LLO) and the Lunar surface.<br /><br />The Apollo architecture delivered 0.5% of the initial vehicle weight to the lunar surface (3,000,000kg Saturn V vs. 15,000kg LEM), but 1.5% to LLO (LEM + 30,000kg Apollo CSM). Rather than following this classical throw-away LEM or fancied direct ascent approaches, if we could deliver a DC-Xesque SSTO lunar lander that refueled on in-situ propellant generation, we could greatly improve efficiency. All subsequent missions would only need to be delievered to LLO from where the taxi would rendezvous and then ferry the payload to/from the Lunar surface. Assuming we can generate similar performance margins to the Apollo architecture, this would lead to increase in the amount of payload delievered to the lunar surface by a factor of 3. If such a Lunar Taxi could be built that could make quick turnaround flights (making multiple rendezvous per LLO mission, say every 30 days or so) the factor easily increases into the 5 to 10 range. And in the world of tight budgets, efficiency is everything.<br /><br />And heck, if the craft were built to be capable of taxing between the L1 Earth-Moon point instead of LLO, then it could reach virtually any point on the lunar surface.<br /><br />And obviously, the drawbacks to the design that you mention (and you are absolutely right) are only a hinderence in atmospheric flight. Lunar landings require just such a vertical takeoff and landing spacecraft.

 

[frodo1008]

For THIS purpose a DC-X type of vehicle is not only fine it is imperitive! After all, with a gravity well of only 0.16 g's, and no atmosphere a winged or lifting body type of vehicle would look ridiculous on the moon! <br /><br />Even the original Aollo Lunar Lander was non aerodynamic, and was certainly NOT meant for Earth to Leo. <br /><br />I did not say (and I don't think that shuttle_guy would either) that the research work done with the DC-X itself was not valuable, it certainly was. And eventually a fully integrated conventional jet to hypersonic ramjet to internal propellant pure rocket type of NASP vehicle which would be a true SSTO is possible. But far more research is needed!<br /><br />Until then the Earth to LEO field is going to continue to be dominated by the TSTO type of vehicle. Whither a pure capsule type, or possibly a lifting body concept. I think with the shuttle we may have seen the last (and first for that matter) of a fully winged type of vehicle.

 

[no_way]

<blockquote><font class="small">In reply to:</font><hr /><p><br /><i>will build an affordable operational space launch vehicle with the general concept of VTVL sooner or later</i><br />I think not. Not for use in a large gravity well. <p><hr /></p></p></blockquote><br /><br />I think yes. Because nothing prevents one from building a two-stage VTVL system. The general concepts still apply. Big lower stage that gets you above the atmosphere and returns to pad, and a high-isp upper stage that gets you to orbit.<br /><br />Where is the fundamental problem with such approach, in large gravity well as you say ? <br /><br />EDIT: btw, such approach was also outlined in "The Rocket Company" novel published on HobbySpace. Well worth reading.

 

[propforce]

<i>"The The DC-X (Delta Clipper X) looked hopeful a few years ago " <br /><br />Hopeful for what? a new kind of very inefficient helicopter? </i><br /><br />Oh great, now I need to wipe coffee off my computer screen !!! <div class="Discussion_UserSignature"> </div>

 

[tomnackid]

What ever happened to ROMBUS? Phil Bono was designing SSTO (ok, it had drops tanks so not completely SSTO) VTOL launch vehicles back in the early 60s. If a respected McDonald Douglas engineer thought that it was doable with 60s technology why haven't we done it yet?

 

[spaceinator]

OK. I'll admit I was exaggerating when I said the shuttle should have been replaced decade<font color="orange">s</font>ago--but not by much. It was supposed to be this awesome, reusable launch vehicle, and a transition to a better, more efficient one. Instead, NASA has stopped here, and spent more resources and money into over-extending the shuttle's lifetime than seriously looking into a better option. (Also, the shuttle is far from reusable, it needs to be worked on so much and have so many parts replaced between missions that it is practically a new vehicle each time) What we really need, and should have had by now, is a completely reusable, preferably SSTO launch vehicle.<br /><br />Oh, and by the way, the DC-X was an extremely successful test of the technology to build a larger, SSTO ship capable of VTOL to service the Satellites for the Star Wars Missile Defense program. If it weren’t for funding problems the entire program probably would have been a success.<br /><br />http://www.hq.nasa.gov/office/pao/History/x-33/dcx-facts.htm<br />

 

[propforce]

<i>"...It never even got supersonic. How was it "extremely successful?" ..."</i><br /><br />It showed what you can do with begged, borrowed and steal old graveyard hardware without using a standing army to get anything done. It showed that, as a 'concept demonstrator', a rocket could do VTVL operation. It was never intended to go supersonic. The McDonnell Douglas version of X-33 would then demonstrate supersonic suborbital flight operation. But then again we are talking 4 SSME class engines instead of 4 small RL10s. It demonstrated GO2/GH2 RCS system, developed by Aerojet, which maybe used for the new space exploration. It used bolsa wood as insulation for the LO2 tank. It developed graphite composite vehicle base heat shield. It deomonstrated a launch crew of less than 15 and with 3 at the control console for launch operation. It spearheaded the idea that you can do better which smaller companies such as SpaceX are trying to emulate.<br /><br />Then again it can NEVER be a NASA program this way, what was I thinking ???? I just realized that DC-X was a very successful program under BMDO, while the failure occurred with the DC-XA under NASA's watch <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> </div>

 

[propforce]

<i><br />"DC-X has some following, and its pretty certain that one of the followers will build an affordable operational space launch vehicle with the general concept of VTVL sooner or later. " <br /><br />I think not. Not for use in a large gravity well. </i><br /><br />Well.... actually it not a bad statement as long as you do not stipulate the SSTO requirement. <br /><br />Think about it, a capsule configuration CEV will be VTVL, just that it will use a launch vehicle for the VT part and it may need a parachute as well as landing engines for the VL part. <div class="Discussion_UserSignature"> </div>

 

[no_way]

It also demonstrated an incredibly fast turnaround for a reuseable rocket. IIRC, they could have done 8 hours, but did 24 once because of some weather scrub or something. <br />It also sort of demonstrated very low operating costs which is obviously the most important parameter of cheap transportation system.<br /><br />And shuttle_guy still hasnt explained whats fundamentally wrong with reuseable VTVL rockets in deep gravity well. Mind you, SSTO is not necessary at all, two stages are good enough.

 

[no_way]

<blockquote><font class="small">In reply to:</font><hr /><p>Well.... actually it not a bad statement as long as you do not stipulate the SSTO requirement<p><hr /></p></p></blockquote><br />Hey, why do people keep extrapolating from DC-X to SSTO ?? <br />DC-X has little to do a SSTO, it was a demonstrator of vertical takeoff and landing, it was a demonstrator of low operations overhead, high maintainability and fast turnaround and of course reusability.<br />The fact that it had only single stage and didnt go very high is just because it was a tech demonstrator for aforementioned concepts.

 

[hurricane4911]

I cannot think of anything less efficient and more costly to operate than the DC-X.<br /><br />In my mind, that entire project was someones dream to re-create a 1950's space adventure, without the strings to lower the "spaceship".<br /><br />

 

[hurricane4911]

"I think not. Not for use in a large gravity well."<br /><br />As demonstrated by the Pathfinder and MERs, even in a small well, bouncing that baby in works, and works darn well.