Shuttle Replacement

[vulture2]

>>There are not yet sufficient missions to justify the development of a launch a week vehicle. <br /><br />It is not clear that development of a reusable launch vehicle is more expensive than an ELV, as Kistler and SpaceX are trying to demonstrate. After one of the Mercury launches, the Redstone booster was found floating in the ocean and recovered intact! With no parachutes! One of the Gemini capsules was actually flown twice! (unmanned). Virtually EVERY private company developing manned launch vehicles is going the RLV route despite the cost. There's a simple reason for this. At US costs, ELVs are simply not cost-effective for human space flight at any flight rate. IMHO NASA should be supporting the RLV developers, as NACA did in the early days of aviation, not competing with them with a very expensive ELV that will consume the very funds that could be used for R&D, which, so I have read, was NASA's original mission.

 

[rocketman5000]

Welcome to my soapbox!!

 

[jimfromnsf]

"It is not clear that development of a reusable launch vehicle is more expensive than an ELV, as Kistler and SpaceX are trying to demonstrate. After one of the Mercury launches, the Redstone booster was found floating in the ocean and recovered intact! With no parachutes! One of the Gemini capsules was actually flown twice! (unmanned). Virtually EVERY private company developing manned launch vehicles is going the RLV route despite the cost. There's a simple reason for this. At US costs, ELVs are simply not cost-effective for human space flight at any flight rate."<br /><br />1. It is clear. Recovering is not the same as reusing<br /><br />2. Spacex is not developing a reusable only recoverable.. Just adding a parachute doesn't mean reusable. The second stage isn't recoverable<br /><br />3. Kistler hasn't demostrated anything yet. Their design isn't efficient with the extra tankage and systems to fly the LAP back to the launch site and the TPS on the OV to allow entry<br /><br />ELV ARE more cost-effective at lower flight rates

 

[docm]

PIT = Pulsed Inductive Thruster<br /><br />It's a form of pulsed electric drive with advantages: no electrode wear, a problem with ion & MPD drives, and a relatively simple design vs. VASIMR. <br /><br />From above link;<br /><blockquote><font class="small">In reply to:</font><hr /><p>ABSTRACT:<br /><br />The pulsed inductive thruster (PIT) is an electrodeless, magnetic rocket engine that can operate with any gaseous propellant. A puff of gas injected against the face of a flat (spiral) coil is ionized and ejected by the magnetic field of a fast-rising current pulse from a capacitor bank discharge. Single shot operation on an impulse balance has provided efficiency and Isp data that characterize operation at any power level (pulse rate). The 1-m diameter MkV thruster concept offers low estimated engine mass at low powers, together with power capability up to more than 1 MW for the 1-m diameter design. A 20 kW design estimate indicates specific mass comparable to Ion Engine specific mass for 10,000 hour operation, while a 100,000 hour design would have a specific mass 1/3 that of the Ion Engine. Performance data are reported for ammonia and hydrazine. With ammonia, at 32 KV coil voltage, efficiency is a little more than 50% from 4000 to more than 8000 seconds Isp. Comparison with data at 24 and 28 kV indicates that a wider Isp range could be achieved at higher coil voltages, if required for deep space missions.<p><hr /></p></p></blockquote><br />A few of these in an array powered by a small reactor and you might really have something, not to mention it actually looks like a spacecraft engine. <div class="Discussion_UserSignature"> </div>

 

[nyarlathotep]

<font color="yellow">The SSTO RLV was and is not practical with the level of our technology. If it could make it to orbit with a astronaut the max payload capability would be about a single roll of dimes in his/her pocket.......</font><br /><br />What about with an added pair of very low cost H2O2/kerosene 3.5MN pressure fed expendable liquid boosters? I know someone was auctioning a filament winding machine, test stands and a working engine around that time.

 

[j05h]

<i>> Cost is not the problem. The problem is that the technology for propulsion and materials is not advanced to a point where SSTO RLV ops is practical.</i><br /><br />What about an SSTO ELV? Alternatively an RLV of Sea Dragon scale? Admittedly the Sea Dragon would be TSTO RLV. If an ELV could be constructed cheaply enough, it could start the CATS revolution just as well as an RLV. <br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[radarredux]

> <i><font color="yellow">The problem is that the technology for propulsion and materials is not advanced to a point where SSTO RLV ops is practical.</font>/i><br /><br />Which is why it would be nice to have a robust, long-term R&D program to develop the technologies and X-programs to validate the research and mature the technologies. Unfortunately, at NASA (as well as most organizations, both government and commercial), the needs of the immediate (e.g., building out ISS) tend to cannibalize long-term R&D budgets.</i>

 

[gunsandrockets]

[2. Spacex is not developing a reusable only recoverable.. Just adding a parachute doesn't mean reusable.]<br /><br />What is your evidence the Falcon 1 first stage is not being developed for reusability?<br /><br />The SpaceX website claims both stages of the Falcon 9 are being developed for reusability. So it only makes sense for the first stage of the Falcon 1 to be reusable, as a developmental precursor of the Falcon 9. <br /><br />http://spacex.com/updates_archive.php?page=0606-1206<br /><br />"Apart from a few minor bits & pieces, both Falcon 9 and Dragon are intended to be fully reusable. The F9 first stage, F9 second stage and Dragon are all designed to land via parachute in water, although we could always add airbags later for a land landing, if that turned out to be lower cost. If the recovery and reuse is successful, the F9/Dragon vehicle will be the world's first fully reusable system (the Shuttle system loses the large orange tank every flight, so is considered partially reusable). Making the economics of reusability work well, which is not a given even if all pieces are recovered, is fundamental to achieving a revolutionary reduction in spaceflight costs. If a Boeing 747 could only be used for a single flight, your ticket cost would be enormous and this is no less true for a rocket."<br /><br />

 

[gunsandrockets]

As for how SpaceX plans to recover the Falcon 9 second stage intact from LEO, your guess is as good as mine! I vaguely recall some rumor about atmospheric re-entry of the second stage in nozzle-forward attitude and running propellent through the engine for cooling, though it's hard for me to believe that would work.

 

[jimfromnsf]

"What is your evidence the Falcon 1 first stage is not being developed for reusability? "<br /><br />Basic design engineering<br /><br />A stage designed for recovery in salt water and reusability wouldn't have parts that corrode in salt air.<br /> <br />Reusability was not a design requirement, just an afterthought. Basically, let's put a parachute on it and see what we get mentally. Watertight compartments and material suitability obviously were considered

 

[gunsandrockets]

I'll take the word of SpaceX over your personal beliefs.

 

[jimfromnsf]

Not "beliefs", but engineering reality<br /><br />1. Where is the "reusable" stage from the last launch? Like I said, there is more to reusability than just attaching a parachute. <br />2. 1st launch corroded on the pad<br />3. The fire affected an open engine section much like salt water would on a slower scale. <br />4. Believe what you want, but that doesn't change reality<br />5. Also I am leading you down a path where you, just as other people, can realize that there is more info out there than just PR releases, ***Ad-Hominem Deleted*** and read between the lines

 

[yevaud]

That was an uncalled for Ad-Hominem. Please cease attacks on the person, and debate the topic matter at hand.<br /><br />Thank you. <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[vulture2]

>>>Where is the "reusable" stage from the last launch? Like I said, there is more to reusability than just attaching a parachute.<br /><br />Successful programs have been built on a combination of analysis and flight experience. To reuse a rocket, one must develop experience at recovering it, identify the areas of potential damage, then evolve and modify the design to minimize cost of reuse. The Shuttle SRBs were reusable from the first flight, but, primarily because of the solid-fuel design, the cost of reuse is very high. Achieving full capability with the very first flight, or indeed the first design iteration, is not (and never was) a practical approach to development of aerospace systems.<br /><br /> />>>1st launch corroded on the pad; The fire affected an open engine section much like salt water would on a slower scale.<br /><br />Corrosion in salt water is a challenge, but seaplanes, jet-propelled target drones that are recovered at sea by parachute and reused many times, and of course marine systems have demonstrated clearly that, with proper design and maintenance, corrosion can be controlled. This was not a priority in the design of the prototype. <br /><br />This is not to say I favor ocean recovery; landing on land is preferable if a practical method can be developed. I would favor a small guided parasail (commercially available) which would have a high sink rate but could reach a prepared landing zone under precise GPS guidance, followed by powered deceleration just prior to landing using either solid rockets, as with the Soyuz, or preferably by restarting the primary engines and landing under active control, as demonstrated by the DC-X and others. This could be accomplished, even from a very high sink rate, with perhaps 10 seconds of thrust. <br /><br /> />>>Believe what you want, but that doesn't change reality<br /><br />Reality includes the extraordinary cost of human spaceflight with ELVs, and the fact that the plan to return to the moo

 

[marcel_leonard]

Why are you talking about recoveries at sea when we have the technology to go from the tarmac all the way to geosynchronous orbit? Don’t twist the subject we can have reusable spacecraft it is just a matter of researching, and developing the technology necessary to carry this out. <br /><br />Back in the early seventies X-window UNIX sessions and the GUI created at Xerox Parc sat on the shelf collecting dust for nearly a decade before Steve Jobs and Steve Wazniack founders of Apple Inc. found a way to put it good use. Who knows what new technology is sitting around collect dust over at NASA because their executives don’t see any value in it?<br /> <div class="Discussion_UserSignature"> "A mind is a terrible thing to waste..." </div>

 

[jimfromnsf]

"Don’t twist the subject we can have reusable spacecraft it is just a matter of researching, and developing the technology necessary to carry this out."<br /><br />We don't have the technology to do it cost effectively to LEO much less GSO. Nor are there the flight rates to support it

 

[docm]

Here we go, back to the chicken-egg scenario again <img src="/images/icons/tongue.gif" /> <div class="Discussion_UserSignature"> </div>

 

[rocketman5000]

Jim you have stated multiple times that there isn't a high enough flight rate. You are discrediting future technological breakthroughs that will allow for the cost to come down. <br /><br />Not all costs are related to the vehicle. The cost of the "standing army" could be reduced by having multiple carriers sharing the same work force. This way the workers are always busy preparing a vehicle. Salaries and fixed overhead can be therefore reduced.

 

[j05h]

<i>> Not all costs are related to the vehicle. The cost of the "standing army" could be reduced by having multiple carriers sharing the same work force. This way the workers are always busy preparing a vehicle. Salaries and fixed overhead can be therefore reduced.</i><br /><br />You might be confusing NASA's Socialist space program with commercial entities. Standing Armies of technicians are extremely bad for the bottom line, hence none of the commercial firms have so many workers building/refurbing rockets. Everyone except NASA uses as few workers as is practical, including the EELV lines. Also, there would be significant issues in having KSC workers (for example) servicing a private RLV.<br /><br />JimfromNSF, you still haven't explained why SpaceX is lying about their attempts at reusable Falcons. In their public statements they have said they will eventually reuse Falcon stages, you say it is impossible. Evidence, please?<br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[rocketman5000]

I wasn't thinking of NASA employees servicing a private launch vehicle although if the workforce was rearranged it should be possible. You could spin off a company that was contracted by NASA to referb the Shuttle and therefore could legally contract to rework other vehicle.<br /><br />Maybe the number of workers would also be reduced. With many new startup companies there should be plenty of room in the coming years in the aerospace industry for expirenced technicians.<br /><br />As for Jims arguments they are largely biased to big Aero and the culture of historical NASA. I daily run into people that fall into the category of the "that's the way we always did it" Maybe I am too young yet to be jaded into thinking we can never change.

 

[rocketman5000]

I wasn't thinking of NASA employees servicing a private launch vehicle although if the workforce was rearranged it should be possible. You could spin off a company that was contracted by NASA to referb the Shuttle and therefore could legally contract to rework other vehicle.<br /><br />Maybe the number of workers would also be reduced. With many new startup companies there should be plenty of room in the coming years in the aerospace industry for expirenced technicians.<br /><br />As for Jims arguments they are largely biased to big Aero and the culture of historical NASA. I daily run into people that fall into the category of the "that's the way we always did it" Maybe I am too young yet to be jaded into thinking we can never change.

 

[jimfromnsf]

"Not all costs are related to the vehicle. The cost of the "standing army" could be reduced by having multiple carriers sharing the same work force."<br /><br />Huh? When do Ford and GM share production line workers? Boeing and Airbus? United and Delta?<br /><br />Competitors don't share workforces

 

[jimfromnsf]

"JimfromNSF, you still haven't explained why SpaceX is lying about their attempts at reusable Falcons. In their public statements they have said they will eventually reuse Falcon stages, you say it is impossible. Evidence, please? "<br /><br />They say the current first stage is reusable, which it has demonstrated is not. Anyone could say that they planned to reuse stages in the future. A Falcon stage that could be reused would be to the current Falcon 1 stage as a Delta II first stage is to a Thor

 

[jimfromnsf]

The key isn't designing a rocket with a small workforce. That is the easiest part. The hard part is to keep flying it over and over successfully. I have been involved with small orgs doing things that only big ones had do before. All the workers are enthused and work long hours to attain the goal, which is a usually a "first" (first launch, first flight, first release, etc). The problems start arising when work rate can't be maintained (vacations and other things get in the way). More workers are hired, the developers get bosed and leave to find another program, etc. Processes need to be documented since tribal knowledge may get lost. Pretty soon the program looks like all the rest. Sustaining the program is the hard part<br />

 

[rocketman5000]

I am thinking similiar to airports, they share their ground personel, Also auto makers share personel, oftern in strategic partnerships. I am thinking Toyota and GM in particular