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#120
by
Chris Bergin
on 07 Feb, 2006 16:50
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#121
by
publiusr
on 10 Feb, 2006 21:44
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There is no science being sacrificed. Do you really think there will be no TPF eventually?
The rocket has to come first. The last LV we had outside STS since the ICBM days in the 60's was EELV--with no greater ability than Titan IV.
And how many new airplanes have come along since then? So much for the "We spend too little on aeronautics" myth.
Imagine the science assets launched by Magnum/Longfellow. Mars sample return missions with MARGIN
Europa LANDERS, Pluto LANDERS Heavy interplanetary probes, and Very Large Space telescopes.
And before you say "but that will cost so much.."
No--it won't. An HLLV called STS launched Magellan IIRC, and we flew that effective HLLV many times. It just had the orbiter holding it back.
How much good science came out of MIT before it was bricked up? We are in the construction phase, and the pointy heads and the white coats need to yield to the engineers for a change.
One good thing about the EELV program was that it at least gave us a better Atlas. Due to the boosters of bigger boosters, we have a very good probe in MRO and a Pluto shot to pass near Jupiter in a year or less.
See what you can do when you kick that Delta II to the curb? But the 'science-good, rockets bad crowd' got hoked on Delta II, and instead off perhaps waiting or supporting larger LVs, they just wanted to kick nickel and diming NASA to death with 2 yr. Mars missions just because they could.
Two scenarios for your consumption:
A Dad gives his kid a sucker to keep him quiet. He goes through a whole lot of suckers but his child is hushed. That is Goldin.
Another Dad says "Let's save that money for something more filling later--a full meal better for you." Yes the child screams bloody murder--but this Dad is wise enough to ignore his child's foolishness, and in the end the child is better off.
That's Griffin--and that makes him a better steward for NASA.
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#122
by
Jim
on 11 Feb, 2006 05:02
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Totally wrong. It doesn't matter if we had a HLLV today, you are not going to be able to fund "Mars sample return missions, Europa LANDERS, Pluto LANDERS Heavy interplanetary probes, and Very Large Space telescopes." It would take more than NASA's existing budget to fund all of those.
There always was launch vehicle available for big spacecraft
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#123
by
publiusr
on 17 Feb, 2006 22:15
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I don't agree with you at all. Voyager was going to be launched two at a time. And this concept that big spacecraft have to be more expensive than small spacecraft is also wrong. To start of with--if my shroud is big enough, I don't have to have as many articulating parts. I can also have margin built in. As Bob Truax also said, this idea that larger launch vehicles have to be more expensive is also for the birds. Some upper stages cost as much if not more than the boosters from his experience. We have the Venus probe launched atop R-7--which was the HLLV of its day--which proves my point very well.
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#124
by
Jim
on 18 Feb, 2006 15:14
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publiusr - 17/2/2006 5:15 PMI don't agree with you at all. Voyager was going to be launched two at a time. And this concept that big spacecraft have to be more expensive than small spacecraft is also wrong. To start of with--if my shroud is big enough, I don't have to have as many articulating parts. I can also have margin built in. As Bob Truax also said, this idea that larger launch vehicles have to be more expensive is also for the birds. Some upper stages cost as much if not more than the boosters from his experience. We have the Venus probe launched atop R-7--which was the HLLV of its day--which proves my point very well.
This is not a "concept". It is proven that bigger spacecraft are more expensive than small spacecraft. Mass is $. Articulating parts are not always because of fairing size, but that the parts can not be launched in their operation position because loads and vibration etc.
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#125
by
publiusr
on 24 Feb, 2006 21:04
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Jim - 18/2/2006 10:14 AM
This is not a "concept". It is proven that bigger spacecraft are more expensive than small spacecraft. Mass is $. Articulating parts are not always because of fairing size, but that the parts can not be launched in their operation position because loads and vibration etc.
Just because big spacecraft have been more expensive doesn't mean it HAS to be. Some of the larger spysats have a lot more equipment. That doesn't mean the quick and dirty aprach can't be helpful. The ZENIT spysat is basically a Vostok hull, as is the FOTON IIRC. A big pressurized hull shields circuits after all. Both Europeans and the Russians had (then) larger LVs which allow them to dominate the market, leaving underpowered Delta IIs in the dust. Titan IV was quite expensive and wound up not being cheaper than Saturn IB. That 20 ton to LEO craft should have been kept alive. But that was an Army rocket--and I imagine the AIr Force types weren't about to have that. I just wish General Medaris had kept the ABMA alive.
The biggest difference between the US space effort and the Soviet space firsts (where their pads involved artillerymen--missiles being artillary after all), is that the Soviets were smart enough to keep THEIR Air Force away from space.
Columbus did not go from the Pinta to a rowboat. Ships grew larger overtime and so did trade. If spaceflight is to progress, then rocketry will as well. No one ever build an elevator across the Atlantic, after all. But large ships were crucial in say, establishing the Mulberries at Normandy. We need a similar effort--along an incremental path to be sure--in space.
I for one don't won't space clogged with a bunch of small dead cubesat bits. I'd rather have something like this:
http://www.astronautix.com/craft/globis.htm
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#126
by
Jim
on 25 Feb, 2006 13:44
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publiusr - 24/2/2006 4:04 PM Just because big spacecraft have been more expensive doesn't mean it HAS to be. Some of the larger spysats have a lot more equipment. That doesn't mean the quick and dirty aprach can't be helpful. The ZENIT spysat is basically a Vostok hull, as is the FOTON IIRC. A big pressurized hull shields circuits after all. Both Europeans and the Russians had (then) larger LVs which allow them to dominate the market, leaving underpowered Delta IIs in the dust. Titan IV was quite expensive and wound up not being cheaper than Saturn IB. That 20 ton to LEO craft should have been kept alive. But that was an Army rocket--and I imagine the AIr Force types weren't about to have that. I just wish General Medaris had kept the ABMA alive. I'd rather have something like this:http://www.astronautix.com/craft/globis.htm
You can't choose and say I am going to build a big spacecraft and say it is going to be cheap, unless it is hollow. Your example, The Globis spacecraft, proves my point, it would cost nearly a billion
The Saturn 1B was a pig, 9 tanks, where 2 could do the job. It couldn't even do the Titan IV 's job unless you added a third stage (more costs)
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#127
by
MartianBase
on 08 Apr, 2006 05:45
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Jim - 11/2/2006 12:02 AM
Totally wrong. It doesn't matter if we had a HLLV today, you are not going to be able to fund "Mars sample return missions, Europa LANDERS, Pluto LANDERS Heavy interplanetary probes, and Very Large Space telescopes." It would take more than NASA's existing budget to fund all of those.
There always was launch vehicle available for big spacecraft
Looking further out, as we consider the science that the Vision will enable, our aspirations should not be limited to the moon and Mars. As an example, recall that budgetary constraints have forced us to call a halt in planning for a Europa mission. But sometimes when you close one door, others open. Our focus on Europa was due in part to the National Academy's decadal survey, which recommended a "follow the water" planetary exploration strategy. We've recently discovered liquid water geysers on Saturn's moon Enceladus and, who knows? Maybe Europa is still the right target. But because Enceladus exists in a much lower radiation environment, it may be an easier target to explore. We shall see.
http://www.spaceref.com/news/viewsr.html?pid=20189So, imagine what kinds of Europa or Titan or Enceladus missions we could plan in 2016, if we know that we will have the 100 metric ton Cargo Launch Vehicle available to put them out there. Maybe the 25 metric ton Crew Launch Vehicle would suffice for such missions. That's more capability than anyone was planning on having to low earth orbit until exploration came around. So, let's think creatively about what we could do with these launch vehicles, which would never be built to support robotic science missions alone.
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#128
by
Jim
on 08 Apr, 2006 13:47
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CLV is not for anything but CEV. It would need an upperstage and additional uses would interfere with CLV and CaLV ISS and Lunar missions. The DOD NASA agreement states that NASA can develop manned and heavy launchers but will use EELV's for non manned missions
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#129
by
publiusr
on 12 Apr, 2006 19:09
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That is a rational compromise. Let me ask you this. John Jumper is gone: Is his replacement more friendly to space--or do we have another member of the fighter-jock/pilots union running things who is hostile to all things space?
What I wouldn't give to have Pete Worden run the USAF.
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#130
by
mkirk
on 17 Apr, 2006 23:36
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#131
by
rcaron
on 17 Apr, 2006 23:58
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YES!!! We've known methane engines will come in handy sooner or later - ever since Zubrin's Case for Mars came out (which actually was surprisingly well received by most NASA centers). 100 second burn - that's something, even if its pressure fed. ESAS wants pump-fed, but still, this is a great first step! Nice throttleability too - not LEM descent stage throttlable, but methane would only be SM and ascent stage anyway. 90kN engine! (Apollo SM main engine was 98kN)
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#132
by
astrobrian
on 18 Apr, 2006 01:16
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60-100% throttlability, thats a nice range to play with.
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#133
by
Hotol
on 18 Apr, 2006 06:49
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#134
by
danw
on 20 Apr, 2006 16:07
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>>Maybe the 25 metric ton Crew Launch Vehicle would suffice for such missions. That's more capability than anyone was planning on having to low earth orbit until exploration came around.
Although the Delta IV Heavy has slightly less LEO capacity than the CLV, because of its lower liftoff thrust, the high-ISP LH2 engines mean the DIVH can put over 13MT on escape trajectory, more than the CLV can, and the DIV is ready NOW. Let's start fighting for heavy payloads. JIMO (Jupiter Icy Moons Orbiter) would be a good start. New imaging technology, new propulsion, a nuclear reactor. Now THAT'S new technology and new science.
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#135
by
Jim
on 20 Apr, 2006 17:12
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danw - 20/4/2006 12:07 PM>>Maybe the 25 metric ton Crew Launch Vehicle would suffice for such missions. That's more capability than anyone was planning on having to low earth orbit until exploration came around.Although a little sort of the CLV in LEO capacity, the Delta IV Heavy can put over 12MT on escape trajectory, more than the CLV, and its ready NOW. Let's start fighting for heavy payloads. JIMO (Jupiter Icy Moons Orbiter) would be a good start. New imaging technology, new prupulsion, a nuclear reactor. Now THAT'S new technology and new science.
CLV is only for LEO, never intended for escape.
JIMO required 3 launches of an advanced Heavy EELV.
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#136
by
kraisee
on 20 Apr, 2006 18:30
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I'm hoping that when Shuttle retires, there will be funds available again so we can fund JIMO again.
Maybe it could be lofted on the CaLV in a single flight, which would allow the designers to make it a little less complicated too.
Ross.
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#137
by
danw
on 20 Apr, 2006 18:45
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>>CLV is only for LEO, never intended for escape.
>>JIMO required 3 launches of an advanced Heavy EELV.
Sorry, I agree completely, I was just responding to an earlier post which suggested using CLV for planetary launch. And after reviewing the posts on JIMO I agree that there were some serious oversights in the plan that didn't come up in the viewgraphs I saw at Space Congress; on the other hand if the reactor were scoped for a planetary probe rather than a manned vehicle it might well be part of a feasible outer-planet mission.
However I was making the point that the EELVs are capable of carrying much heavier probes than we have launched in the past. Because it is thrust-limited the Delta IV Heavy is at a disadvantage for LEO launch vs-a-vis Atlas V, however the relatively high ISP means that it has a planetary launch capability (~ 13MT) well beyond any planetary mission launched so far; even MSL is only 3.3MT. Planetary missions are not being constrained by the lack of a big enough launcher, and I hate to see our most capable planetary mission booster abandoned, as seems likely if no missions that require it appear.
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#138
by
Jim
on 20 Apr, 2006 18:52
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MSL is heavier but not much. However, it constrained physically and fiscally. It can't get bigger than the fairing diameter and bigger costs more. So D-IV Heavy is overkill. 551 is not that bad thought
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#139
by
impulse
on 21 Apr, 2006 16:28
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Wow a totally new and unproven Methane engine that nearly duplicates what was done on the RL-10 years ago using hardware that has hundreds of flights under its belt. There's nothing like pushing the envelope- especially when someone else HAS ALREADY DONE IT. Yes there is a new machine but the end difference is what? Zippo as compared to what already existed.
But no matter- the choice of LO2 Methane is no magic solution and offers almost exactly nothing as compared to LH2/LO2. Especially if you insist on pressure fed systems as NASA originally did on CEV. Eventually this will soak in as the designers get more and more pressed to make any kind of mission to anywhere outside of LEO. The great challenge here is to make an optimal design- and that means being innovative. Based on my experience with NASA on the CEV LH2 and methane efforts, the masters at NASA do not have the direct technical experience to accomplish such an optimal design. In fact they are terrified of anything that looks even remotely different from what they saw once on Shuttle or Apollo hardware. This places them firmly in the 1960's of design. And with that design state you will accomplish precisely what Apollo did and likely less since they are more paranoid now. Even worse that this, it appears that many of these "engineers" have some fixation on a design they like. If you so much as suggest that it has some "design weaknesses" ( avoiding calling it piss-poor which is the real state of affairs) you will be excommunicated. The industry people who know what is what in the space design world are silenced by this fear of offending some knucklehead with a "vision". But perhaps these poor NASA minions are simply taking the lead from their leader?
Bottom line on methane: if you are willing to go pump fed it can be effective for some niche tasks. Without being VERY innovative pump fed is an incredible loser. In both of these cases you will propogate unique hardware that has no other space-borne application. It will be orphan hardware with no user base and will always have low demonstrated reliability and unbounded costs. In short it is a bad idea. I am comparing these two to already existing LH2/LO2 systems with moderately advanced cryostorage systems.
Want to to know the solution to CEV weight problems? Eliminate the whole propulsion element entirely. It is totally superfluous for LEO ops. Existing EELV's can loft the CEV capsule with oodles of margin to orbit and the Centaur element just stays attached. It will have TONS of unburned propellant and you will be placed in a real orbit- not a bogus suborbital trajectory like CLV. Nearly unlimited power and cooling capacity during pre-dock operations and no pesky solar panels or giant radiators. Minor mods to the Centaur can provide months of orbital time with cryos or you can just ditch the propellant and use batteries and a simple RCS to deorbit the capsule at the end of mission. The key is that with an EELV you can now afford to visit the ISS roughly four times more often. Who cares about a docked requirement for 180 days? It is irrelevant.
The whole CEV "TEI" propulsion concept in its present incarnation is a horrendous joke. It is a crutch to preserve an incompetent design for the CLV. The CLV just can't do what they need it to do so they create one of the most expensive kludges yet conceived.
When you get good and ready to really go to the moon and your CEV capsule "CM" has a few flights on it you can then transition to a real integrated in-space propulsion system that is good for every propulsion task & an extensible architecture that can get you to Mars. Hint: it aint' ESAS. There is a great solution: one common in-space propellant- LH2, Wide Body Centaur (75t propellant capacity), Phase 2 Atlas HLV (70-80t IMLEO), and most importantly settled propellant transfer. Based on CEV work we did it is a straightforward solution that is a key enabler for real lunar exploration- not the F&F stuff being proposed. People get to risk their lives for a purpose- not just public relations.
Organized properly such a system can do all of lunar exploration with two engine types, two stage types, the CEV-CM and a small lunar ascender. No new engines needed. No new complex or launcher (aside from crew access). Most hardware already flying. It costs <20% to develop, delivers far more mass and is directly extenisble to Mars. You can even contract with independent suppliers ( the Elon's of the world) to deliver your propellant if you want to further augment performance. Best of all it is not orphan hardware- all the commercial missions are done with the same machines. This suppresses costs and expands demonstrated reliability. Its a beautiful thing... But somehow never was considered by ESAS....Hmmmm....
