|
|
Thread Tools | Display Modes |
#21
|
|||
|
|||
NASA Encounters Problems With Ares 1 Launch Vehicle Design
Rusty wrote: There may be better ways to put together a launch vehicle using "shuttle derived". Take a look at Nasaspaceflight.com, it's called the "Direct Shuttle Derivative": http://forum.nasaspaceflight.com/for...ts=399&start=1 This is a direct link to the DIRECT website: http://www.directlauncher.com/ If one were only going to do lunar missions, that's a very straight-forward concept (it resembles some of the Apollo concepts using Saturn 1Bs or C-2s and orbital assembly), but it seems an awful lot of rocket to just get a CEV into orbit, as well as doubling the chance of SRB failure during a launch. It's capabilities seem to be around halfway between a Saturn 1B and Saturn V, and the question is do you want something in that size range or two separate sized boosters? You could build or add onto a medium-sized space station using these, or carry good sized unmanned payloads, but this looks too small to build a Mars ship with, and too large for simple crew/light cargo delivery to the ISS. If one were going to do lunar base resupply missions, this makes it look like it takes two launches to get each cargo lander there. Also, what's with the "Hurricane Safe Haven" in the VAB? http://65.33.118.71/Direct/Pics/VAB_Config.jpg About the last place I'd like to be during a hurricane is inside a big building with six SRBs. One can picture the wind coming way up, then there's a really funny sound, and you can hear things falling over...then it gets really, really, hot. :-) Pat |
#22
|
|||
|
|||
NASA Encounters Problems With Ares 1 Launch Vehicle Design
In article et,
Greg D. Moore \(Strider\) wrote: At one time they could design and build the Saturn V and land on the moon in 8-years... And look where it got us anyway. 12 men on the moon. (and would have been no more than 18 if all missions planned had flown and succeeded.) Don't remember that before summer 1967, "all missions planned" went far beyond Apollo 20 -- Saturn V production was never meant to stop at #15. -- spsystems.net is temporarily off the air; | Henry Spencer mail to henry at zoo.utoronto.ca instead. | |
#23
|
|||
|
|||
NASA Encounters Problems With Ares 1 Launch Vehicle Design
Henry Spencer wrote: Short of resorting to seriously unconventional configurations, I suspect the only way to save this turkey would be to ditch the idea of getting to orbit with two stages -- a perfectly reasonable idea, but not if the first is a shuttle SRB -- and concede that the Porklauncher IB has to have three stages, and the second has to be LOX/kerosene rather than LOX/LH2. But my guess would be that the hydrogen religion is too deeply entrenched by now for MSFC to swallow that. I'd like to see that one- if this thing's the stick; that one would be the pencil. I don't think they're going to make this one work without rethinking at least one major past decision -- something they've never been good at. So they've got a choice between using an EELV variant for crew launches, or biting the bullet and going straight to the Porklauncher V. I'd guess they will do the latter, just because the former smacks much too much of admitting defeat. Ares V is way-too-capable of a vehicle for earth orbital missions, unless you are going to build a very large space station. I think in fairly short order the new Congress is going to go looking around for things to cut out of the budget, and this particular space program will be one of them. Pat |
#24
|
|||
|
|||
NASA Encounters Problems With Ares 1 Launch Vehicle Design
In article et,
Greg D. Moore \(Strider\) wrote: As Scott points out, some of this appears to stem from the descision to not pursue the SSME air-startable version (money doncha know). Tied into that, also, is the unwillingness to reconsider earlier decisions when the results don't turn out well. E.g., we rejected the air-started SSME, so that option is forever off the table, no matter how much trouble the alternatives cause us later. (Granted that it had problems, would solving them really be harder than fixing the current mess? If you buckled down and insisted on minimum changes, rather than throwing in requirements for lower cost and maybe Rocketdyne's wishlist?) But going back even further it goes back because they want to "save money" and decided to go with "shuttle derived". And speaking of unwillingness to reconsider earlier decisions... :-) -- spsystems.net is temporarily off the air; | Henry Spencer mail to henry at zoo.utoronto.ca instead. | |
#25
|
|||
|
|||
NASA Encounters Problems With Ares 1 Launch Vehicle Design
|
#26
|
|||
|
|||
NASA Encounters Problems With Ares 1 Launch Vehicle Design
In article .com,
wrote: People often think that if a Completely Free launch Vehicle appeared, launched, say, from a runway, that NASA could simply shut down their other launch ops and have cheap space flight. Not so. Closing down the VAB, the Shuttle pads, the processing facilities and all the rest will cost *vast* sums of money. You can't simply turn off the lights and padlock the doors. You could come close... if you were sure you'd never want to use them again, and you didn't care about preserving them as historical relics or about dealing with things like the asbestos in the ceilings. :-) Witness other launch facilities on the Cape where the decision was "abandon in place". And further down the road, if "shuttle derived" is completely scrapped, America's ICBM/SLBM fleet is screwed. No RSRM = no ATK-Thiokol = No Minuteman/Trident missiles. However, one can reasonably argue that that's the USAF and USN's problem, not NASA's. If it's a choice between losing the big-solids capability and spending money propping up their suppliers, they either cough up the cash or learn to do without. -- spsystems.net is temporarily off the air; | Henry Spencer mail to henry at zoo.utoronto.ca instead. | |
#27
|
|||
|
|||
NASA Encounters Problems With Ares 1 Launch Vehicle Design
In article .com,
wrote: Heavy but skinny, so the second stage has to be skinny too -- a problem for a stage that needs lots of bulky LH2, and also it limits your engine options because there's no *room* for a multi-engine cluster in such a narrow stage. Ahem: aerospike or plug cluster. Would fit great. As would other hypothetical large LOX/LH2 engines, but the point was to try to do something with nearly-off-the-shelf designs. Of course, the J-2X may have gotten pretty hypothetical by now... they've got a choice between using an EELV variant for crew launches... Which? The Putinsky or the Fireball? Preferably both, at least long enough to insist that P&W really go through with setting up US production capability for the RD-180. (The only way to make that happen is to have a US alternative, and give LM/P&W a deadline after which they get no orders if they haven't gotten their act together.) -- spsystems.net is temporarily off the air; | Henry Spencer mail to henry at zoo.utoronto.ca instead. | |
#28
|
|||
|
|||
NASA Encounters Problems With Ares 1 Launch Vehicle Design
Henry Spencer wrote: In article .com, wrote: People often think that if a Completely Free launch Vehicle appeared, launched, say, from a runway, that NASA could simply shut down their other launch ops and have cheap space flight. Not so. Closing down the VAB, the Shuttle pads, the processing facilities and all the rest will cost *vast* sums of money. You can't simply turn off the lights and padlock the doors. You could come close... if you were sure you'd never want to use them again, and you didn't care about preserving them as historical relics or about dealing with things like the asbestos in the ceilings. :-) Witness other launch facilities on the Cape where the decision was "abandon in place". Look at the former United Tech/CSD facility in California for pointers on what the current practice is on shutting down big aerospace facilities. Ain't pretty, and it ain't cheap. In any event: it'd be far easier and cheaper to close down all the Putinsky and Fireball facilities. So if closing down infrastructure is a driver, start with those. And further down the road, if "shuttle derived" is completely scrapped, America's ICBM/SLBM fleet is screwed. No RSRM = no ATK-Thiokol = No Minuteman/Trident missiles. However, one can reasonably argue that that's the USAF and USN's problem, not NASA's. NASA is a tiny little branch of the Fedguv, and has to play nice with the others. If it's a choice between losing the big-solids capability and spending money propping up their suppliers, they either cough up the cash or learn to do without. Or they talk NASA into not abandoning a useful technology and the infrastructure already in place. |
#29
|
|||
|
|||
NASA Encounters Problems With Ares 1 Launch Vehicle Design
In article ,
Pat Flannery wrote: limits your engine options because there's no *room* for a multi-engine cluster in such a narrow stage. Ahem: aerospike or plug cluster. Would fit great. Ignition altitude is pretty high for that; at the low ambient air pressure where the second stage will light, you might just as well use a conventional bell nozzle. No, an aerospike still has advantages for this one: it's a high-expansion nozzle that's physically short, so you don't have a big long interstage ring adding to the length and fragility of this already-overlong rocket. Of course, it's a bigger leap into the unknown than a new engine with a conventional nozzle. -- spsystems.net is temporarily off the air; | Henry Spencer mail to henry at zoo.utoronto.ca instead. | |
#30
|
|||
|
|||
NASA Encounters Problems With Ares 1 Launch Vehicle Design
In article ,
Pat Flannery wrote: ...and concede that the Porklauncher IB has to have three stages, and the second has to be LOX/kerosene rather than LOX/LH2... I'd like to see that one- if this thing's the stick; that one would be the pencil. It actually might end up shorter, given how much denser LOX/kerosene is. That's the point: a relatively compact LOX/kerosene stage plus a *small* LOX/LH2 stage. (That said, I haven't actually run numbers on this one.) they've got a choice between using an EELV variant for crew launches, or biting the bullet and going straight to the Porklauncher V. I'd guess they will do the latter, just because the former smacks much too much of admitting defeat. Ares V is way-too-capable of a vehicle for earth orbital missions, unless you are going to build a very large space station. So what? If you're going to need it anyway, it's cheaper and easier to launch it with a CEV and a tub of ballast than to develop and operate a second rocket just for LEO missions. (You leave the ballast on the station. Space stations *want* to be heavy, not light -- extra mass reduces the effect of air drag and lengthens the interval between reboosts, without changing the average annual reboost fuel consumption.) I think in fairly short order the new Congress is going to go looking around for things to cut out of the budget, and this particular space program will be one of them. The support for shuttle replacement is pretty bipartisan. If the Porklauncher V was *the* rocket for shuttle replacement, it would be fairly safe. It would be in a stronger position if it had been the chosen rocket all along, but I think they could still get away with making the switch now. (They can't wait too much longer, though.) What might get cut, or at least postponed, is an expensive new rocket that's needed *only* for beyond-LEO operations. -- spsystems.net is temporarily off the air; | Henry Spencer mail to henry at zoo.utoronto.ca instead. | |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Thumbs Down On Ares Vehicle Name | Joe Delphi | History | 40 | July 6th 06 03:10 AM |
NASA Encounters Possible Problems With Crew Launch Vehicle Design | Space Cadet | Space Shuttle | 45 | February 7th 06 04:51 PM |
NASA Encounters Possible Problems With Crew Launch Vehicle Design | Space Cadet | Space Station | 45 | February 7th 06 04:51 PM |
NASA Encounters Possible Problems With Crew Launch Vehicle Design | Space Cadet | Policy | 45 | February 7th 06 04:51 PM |
NASA REFINES DESIGN FOR CREW EXPLORATION VEHICLE | Jacques van Oene | Space Shuttle | 0 | January 11th 06 10:32 PM |