You are not logged in.
Although Atlas has a more powerful engine, it also is heavier because of the lower efficency of Kerosene/LOX fuels. I think that Lockheed could make a compelling case for a clean-sheet light HLLV rocket if they can keep development low enough. They already have the engines in hand.
The mission arcitecture will probobly be different from Apollo. The Apollo CSM had to carry enough fuel for Lunar orbit braking for itself, the Lunar lander, and the TEI fuel. It also had to lug along fuel for its fuel cells on top of life support and such.
In the likly even the lander will likly be sent seperatly and everything will be sent up by EELV... a Lunar ship is launched in two or three flights, one for the TLI stage, one for the TEI/supply/solar pannels (and perhaps a seperate flight for the crew CEV) then a 20MT estimate should be enough for a six-man crew.
[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]
Offline
Part of the problem with the Aviation Week piece is that it doesn't reveal what the specific mission of the CEV is. If the CEV is supposed to simpy fly to ISS and back, a 20 MT spacecraft should be an easy goal. 20 MT for an Apollo replacement is much more challenging.
Even if the CEV was forced to use its engine for lunar orbit braking and trans-earth injection with a docked LSAM (Lunar Surface Access Module,) I think significant cost savings could be made with regards to Apollo. Solar panels will likely be lighter than fuel cells, and composite fuel tanks have been cited for application to the CEV.
Who needs Michael Griffin when you can have Peter Griffin? Catch "Family Guy" Sunday nights on FOX.
Offline
Only twenty tons for a capsule with four and option for six seats and TEI fuel and Lunar orbital insertion fuel... I don't know how they would pull that off without using cryogenic fuel.
[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]
Offline
I have actually heard cryogenic fuels mentioned in some of the CEV articles I've read. I also feel that hydrogen peroxide / kerosene may make a good propellant combination. It can't match any of the cryogenic propellants, but it's storable, not carcinogenic, and has better performance than hydrazine / nitrogen tetroxide.
Who needs Michael Griffin when you can have Peter Griffin? Catch "Family Guy" Sunday nights on FOX.
Offline
Cryogenics will certainly be used for the TLI burn, no doubt about that, but I don't see it as such a good idea for TEI or landing/acent. I don't see how else NASA could chop a CSM-style ship down so many tonnes though.
LOX/Methane is probobly the best combination, high performance, modest density, and easy enough to store for a while despite being mildly cryogenic... Oh, and you can use the same engine on your Mars lander/ERV.
[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]
Offline
Are there any methane/LOX engines currently flying?
If the plan really is to make propellant insitu then the earlier we start racking up expertise in Methane/LOX the better.
It would have been nice to build a 2million pound thrust reusable liquid engine to replace the SRBs. That would be some useful legacy shuttle hardware and thus a justifiable moneyhole.
This does really highlight the benefits of the 'Mars back' approach.
Come on to the Future
Offline
I think the Russians were playing with a LOX/Methane engine for small orbital payloads, kind of a competitor to Pegasus/Athena/Falcon-I.
Anyway, liquid methane acts not too unlike liquid hydrogen, so it should not be a huge problem to derive a LOX/CH4 engines from small cryogenic ones... perhaps run them a little oxidizer-rich to prevent coking like the Russian RD-170/180.
LOX/Methane offers a number of advantages...
-High performance, ~390sec Isp in theory
-Decent thrusts, plenty for Lunar/Martian landing or acent
-LOX can be produced on the Moon from the soil
-LOX and CH4 can be produced on Mars
It is not quite as dense as peroxide/kerosene, but the engines should be less suseptable to coking and easier to design due to similarities with LOX/LH2 engines. No stability problems like with peroxide, and no problems with it freezing in the Lunar "night."
LOX/CH4 are moderatly cryogenic, but not too bad. Boiloff would not be a big problem if the fuel were used within a year or so if there were a very small condenser.
High performance, no reactivity problems, can be produced by ISRU, acceptable density, no freezing problems. We should use them for the TEI stage and Lunar Lander of whatever VSE ship we build.
[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]
Offline
In The Case for Mars, Zubrin says that Pratt and Whitney had tested some of their engines with methane/oxygen and said that they would require little modification to switch to that fuel. Dual methane/hydrogen engines are also possible; they could use hydrogen for TMI and methane for TEI.
-- RobS
Offline
NASA DRM also calls for a common LOX/CH4 engine for all non-TMI engines, based on the RL-10.
[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]
Offline
The Russians converted the RD-0120 (the Energia core engines) to run on methane and LOX as well.
Who needs Michael Griffin when you can have Peter Griffin? Catch "Family Guy" Sunday nights on FOX.
Offline
The big SSME-sized RD-0120 is way too big for anything except launch from Earth.
The RL-10 I bet would need modifications to make it restartable after a multi-year length of time 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]
Offline
I was simply using the RD-0120 as an example of how a hydrogen-burning engine could be converted to burn methane.
It's also worth mentioning, on a tangent, that Pratt & Whitney is buying Rocketdyne from Boeing. The deal is not expected to impact the lines of engines being produced and developed by either firm.
Who needs Michael Griffin when you can have Peter Griffin? Catch "Family Guy" Sunday nights on FOX.
Offline
Yup news of this started coming out on the 22 nd about the 700 million deal to Pratt & Whitney which is an United Technologies company . Rocketdyne's programs include the Space Shuttle Main Engine (SSME); the RS-27A Delta booster; the RS-68 engine that powers the Delta IV, and a variety of advanced propulsion programs. It employs about 3,000 people at sites in Alabama, California, Florida and Mississippi. Of couse this is a stage setter for when the shuttle no longer is flying as well. Off loading its responsibility from the joint Lockheed venture in the United Space Alliance while the getting out is good IMO.
Pratt & Whitney Space Propulsion Products include the RL10, the space industry's most reliable, safe and high-performing upper stage rocket engine used on the Boeing Delta and Lockheed Martin Atlas rockets, high-pressure turbopumps for the Space Shuttle's Main Engines (SSME) and the RD-180 booster engine, offered by RD AMROSS, a partnership between Pratt & Whitney and NPO Energomash of Russia, for the Atlas III and V programs.
Under Rocketdyne space power and energy segment the UTC's Hamilton Sundstrand unit will work with Pratt & Whitney to ensure a smooth transition of these products. In energy systems, Rocketdyne is developing products that would enable terrestrial-bound "clean energy" as well as space-bound systems that would create new levels of power and maneuverability for vehicles in space.
Offline
Now they have a monopoly.
Atlas III I loved. The RD-180 (a two nozzle half-strength RD170 with two--not four nozzles) was good under a balloon tank.
That original Atlas design is dead, coming after the last sustainer Atlas.
When they lopped off two nozzles and put it under Atlas V--the lift-off was also painfully slow--just like Delta IV 'heavy.'
The wide body Atlas V with Two RD-180s is not much better than Zenit with one, four-nozzle RD-170.
Not buying it.
Two engines isn't enough for engine out.
Two recoverable five segment solids and three RS-68/SSMEs?
I'll clear the pad and have real hydrogen engine out.
And Keep the ET in orbit:
Offline
The Space Island Group (SIG) are a band of crazy lunatics, the chance that their plan would ever work is exactly zero. "Saving" the external tank is a foolish idea, no reuseable space vehicle should have a drop-tank to begin with, and modifying it for use without killing the payload would be impractical
The Atlas-V actually uses the regular RD-180 just as the Atlas-IIIB did. Same engine, one pump, two nozzles. The RD-180 is a derivitive of the bigger twin-pump/quad-nozzle RD-170/171 designed for Russia's Energia & Zenit.
The Atlas-V was intended to use solid rocket boosters for large payloads, but also able to launch smaller ones without wasting a huge RD-170 unlike Zenit.
My "ideal" rocket at the moment would be a larger 5-6m version of Atlas-V, and would be equipped with a pair of RD-170s and an upper stage with a pair of RL-60/ML-60 cryogenic engines. Something of a modernized Saturn-IV.
In its booster-free form, it would be capable of launching 40MT to orbit and be safe enough to fly people on. This is not unreasonable with a rocket with only two main engines, having an engine-out capability isn't nessesarry as long as you have a good escape system given the extremely low chance of engine failure. The RD-170 has an excelent reccord, and infact is so good that Russia intends to fly Klipper on the single-engine Zenit booster.
In the heavy-lift version, it would be equipped with a pair of Shuttle solid rocket boosters (and look like a giant Titan-IV), perhaps adding an additional upper stage engine and definatly including a bigger payload faring (Boeing proposes 6.5m). Target payload mass of 80MT to orbit.
Powerful enough for large Lunar payloads, Mars ships in 2-3 pieces, supply missions to either Moon or Mars, and yes... a space station. But it would also be suitable for launching an eight-seat "family model" capsule, or large space probes, or a CEV with TEI stage for Lunar missions with the very same rocket. I think that it would be efficent enough that getting Boeing to build a man-rated Delta-IV Medium might be redundant.
"Two recoverable five segment solids and three RS-68/SSMEs"
If you are referring to the SDV option, it wouldn't have engine out in the basic twin RS-68 configuration; it would never make orbit if it lost one of its engines. It couldn't make it into space at all without the big SRBs either, which can't be shut off and makes them less suitable for manned flight.
[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]
Offline
Yesterday I talked to an employee of Lockheed Martin who said they will develop a Shuttle Derived Vehicle. We need heavy lift to get to the Moon or Mars and the "only" way to do that is an SDV. KSC will not be shut down after Shuttle is decommissioned because it'll still be needed for SDV. I don't think it's that simple, but it does express one opinion. Lockheed Martin is partnered with Boeing to form United Space Alliance, the joint venture to service Shuttle. Lockheed Martin also has the contract to operate Michoud to build Shuttle external tanks. I imagine they are very motivated to retain Shuttle infrastructure.
Offline
We don't HAVE to have it for a Lunar program, but it wouldn't hurt if you could launch a mission in two SDV shots (and maybe one EELV for crew).
SDV is probobly the most politically acceptable option, and might have the lowest development cost.
[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]
Offline
Bet you though that any SDV will keep for the most part the standing army that the shuttle has. It may well be the cheapest to actually design and build but I wonder if over time it becomes the more expensive option.
Still with an SDV we will get a decent quaranteed throw weight designed straight into the vehicle rather than have to rely on simply putting more and more booster side by side and adding SRBs to get the same capacity. As the more you attach to a basic vehicle like Atlas or Delta just increases the possibility of a failure in one segment so destroying a whole mission.
Id much prefer a clean sheet HLV but I can quarantee it wont happen.
Chan eil mi aig a bheil ùidh ann an gleidheadh an status quo; Tha mi airson cur às e.
Offline
Yea, I am ambivalent about SDV. I have described my ideal configuration of Shuttle-C many times on this message board. Most importantly, the configuration I think is good could lift ~104 tonnes to LEO instead of the leading configuration listed in Encyclopedia Astroanutica which would only lift 77 tonnes but cost more. Magnum is another SDV, but it would require rebuilding the Mobile Launch Platforms and would only lift 80 tonnes.
But an efficient design isn't the only issue. As Grypd mentioned, any SDV would retain the Shuttle's standing army of engineers and technicians, so continue an extremely high annual overhead cost. Emotionally I'ld hate to see Launch Complex 39 shut down, but Cape Canaveral Air Force Station is also on Merrit Island, not the mainland. In fact, LC41 for Titan 3, 3E, and 4 was converted to Atlas V. Launch pad LC41 is the one closest to LC39A. NASA has been tinkering with Shuttle continuously. That's not how you operate an affordable transportation system. Cost control requires you design a system then make periodic upgrades, say once every 5 years or so. Look at NASA's budget and you'll see they've been making changes every year. At any point in time they're working on several Shuttle modifications, and several space center changes. I'm worried any SDV will continue this same practice. As long as they continuously tinker with the launch vehicle, they'll never have staff or resources available to develop new vehicles or equipment. The Moon and Mars require a lot of new stuff, and NASA already has sufficient staff and resources to go there. Adjusted for inflation, NASA's budget now equals what it had during Apollo. Is NASA capable of converting Shuttle to a heavy lift vehicle, then freezing the design? As recommendations for upgrades come in, are they capable of saying "Good idea, we'll include that in the next upgrade 5 years from now. But for now we change absolute nothing and continue to fly the model we currently have." Cost control requires that. Focusing on Moon/Mars equipment requires that. Are the current Shuttle guys capable of it?
Offline
"SDV would retain the Shuttle's standing army of engineers and technicians, so continue an extremely high annual overhead cost."
Question is not most of this cost the rehabab, refurbishment of the shuttle and not the remaining items of launch, refurb of the SRB's or the making of a new external tank per launch? ???
If I recall the the srb's and external tank would cost around 120million and even after throwing the development time and engines to the external tank that average figure probably would not be that much more than 240 or 300 million IMO.
Even if the transfer stage and engines for the payload where say the current cargo capability of the shuttle for weight fueled. That would still leave the weight of the shuttle for the payload for this launch system.
Offline
See my link on the HLLV thread.
And look at this fireball...
http://www.aviationnow.com/media/images … ...5_L.jpg
Offline
The big question is how the adoption of an SDV will affect the shuttle workforce. For politicians, protecting the workforce is a positive, but it's a big negative for NASA and its industry partners.
My guess is that over 60% of the shuttle workforce deals exclusively with the orbiter. The potential exists for streamlining operations once the orbiter is retired and an SDV is adopted. At the same time, an SDV creates new positions for employment, particularly if the engine pod can be recovered or if an uppe stage is added. Much of the orbiter-only workforce will probably be moved to new aspects of the SDV.
Who needs Michael Griffin when you can have Peter Griffin? Catch "Family Guy" Sunday nights on FOX.
Offline
And see my reply...
Again, the fireball is harmless, as the vehicle itself is not flammable. Nor does it need its insulation to be pristine for the breif minutes the tanks are filled with fuel.
[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]
Offline
Yea, I am ambivalent about SDV. I have described my ideal configuration of Shuttle-C many times on this message board. Most importantly, the configuration I think is good could lift ~104 tonnes to LEO instead of the leading configuration listed in Encyclopedia Astroanutica which would only lift 77 tonnes but cost more. Magnum is another SDV, but it would require rebuilding the Mobile Launch Platforms and would only lift 80 tonnes.
But an efficient design isn't the only issue. As Grypd mentioned, any SDV would retain the Shuttle's standing army of engineers and technicians, so continue an extremely high annual overhead cost. Emotionally I'ld hate to see Launch Complex 39 shut down, but Cape Canaveral Air Force Station is also on Merrit Island, not the mainland. In fact, LC41 for Titan 3, 3E, and 4 was converted to Atlas V. Launch pad LC41 is the one closest to LC39A. NASA has been tinkering with Shuttle continuously. That's not how you operate an affordable transportation system. Cost control requires you design a system then make periodic upgrades, say once every 5 years or so. Look at NASA's budget and you'll see they've been making changes every year. At any point in time they're working on several Shuttle modifications, and several space center changes. I'm worried any SDV will continue this same practice. As long as they continuously tinker with the launch vehicle, they'll never have staff or resources available to develop new vehicles or equipment. The Moon and Mars require a lot of new stuff, and NASA already has sufficient staff and resources to go there. Adjusted for inflation, NASA's budget now equals what it had during Apollo. Is NASA capable of converting Shuttle to a heavy lift vehicle, then freezing the design? As recommendations for upgrades come in, are they capable of saying "Good idea, we'll include that in the next upgrade 5 years from now. But for now we change absolute nothing and continue to fly the model we currently have." Cost control requires that. Focusing on Moon/Mars equipment requires that. Are the current Shuttle guys capable of it?
The flip side of this argument is, that the accountants doomed both the Challenger and Colombian, because of there penny pinching so that the "O" rings on the Challenger didn't get replaced in a timely fashion and upgrades to the Colombian did not come on line in time. So I could just as easily argue that the accountants were the ones that killed those fourteen astronauts. While your trying to get the cost down, the accident rate will be going up. The present day shuttle is pushing the wire edge when it comes to either making it into space or having either a Challenger or Colombian disaster. So we are trading one problem for the other problem.
Larry,
Offline
Uhhh nooo MR, you got your facts wrong. It was also called the Columbia.
The shuttle managers were under pressure to show that Shuttle was capable of living up to its unrealistic billing, so they pushed the launch schedule too hard, not costs too low. It would have taken time to roll Challenger back to the pad, disassemble the stack, disassemble the bottom half of the booster, and install a new O-Ring from Thiokol which is based in Utah.
It was about time, not so much money, and the Shuttle managers making a life-or-death assumption to prove Shuttle could be what it was promised to be.
Same deal with Columbia... NASA knew that foam striking the wings was a problem, but in an effort to "prove" that Shuttle was at least half way as good as it was promised, ignored it as a trivial risk.
[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]
Offline
