-
#20
by
Jim
on 25 Jun, 2006 03:29
-
mlorrey - 24/6/2006 10:35 PM
zinfab - 23/6/2006 5:46 PM
The "requirement" for uncontrolled abort is curious considering it doesn't exist today (within STS) and all systems have to be dual fault tolerant.
Challenger proved the error in this strategy. Had there been a capsule/abort, the crew would still be with us.
FIRST was proven to have uncontrolled abort capability (that was its purpose: as an inflatable winged space station escape and reentry pod). Wings or lifting bodies does not mean no uncontrolled abort capability.
And why is uncontrolled abort so important? With human pilots and autopilot controls, there is no event in which an uncontrolled abort is needed. Such capability would NOT have saved Challenger or Columbia.
FIRST maybe designed but not proven.
Uncontrolled is a requirement, for reentry (some ascent aborts have reentry). There have been uncontrolled entrys. One of the recent expeditions had one. The requirement is for power or control system failures, which have occurred
-
#21
by
simonbp
on 25 Jun, 2006 03:35
-
But even if the VentureStar had flown and worked perfectly, it wouldn't have been all that useful for going to the moon. The amount of cargo the carried to LEO was only about 22 mT, and would probably have dropped down closer to 15 mT by the time it flew, thus requiring at least 10 flights for a Moon mission...
The utility of SSTO is one of the greatest myths in the space community; the energy of chemical rockets is such that two-stage to orbit is the most economical (see Tsiolkovsky's rocket equation if you don't belive me). Until a high-thrust rocket technology with greater efficiency than LOX/LH2 becomes feasible, SSTO will remain economically useless...
I can't see how putting wings on a
spacecraft is going backwards; wings are for
aircraft. Putting wings on a spacecraft is like sticking a boat anchor on a car; it might be handy occastionally, but is mostly useless...
Simon
-
#22
by
mlorrey
on 25 Jun, 2006 04:54
-
Jim - 24/6/2006 10:16 PM
mlorrey - 24/6/2006 10:35 PM
zinfab - 23/6/2006 5:46 PM
The "requirement" for uncontrolled abort is curious considering it doesn't exist today (within STS) and all systems have to be dual fault tolerant.
Challenger proved the error in this strategy. Had there been a capsule/abort, the crew would still be with us.
FIRST was proven to have uncontrolled abort capability (that was its purpose: as an inflatable winged space station escape and reentry pod). Wings or lifting bodies does not mean no uncontrolled abort capability.
And why is uncontrolled abort so important? With human pilots and autopilot controls, there is no event in which an uncontrolled abort is needed. Such capability would NOT have saved Challenger or Columbia.
FIRST maybe designed but not proven.
Uncontrolled is a requirement, for reentry (some ascent aborts have reentry). There have been uncontrolled entrys. One of the recent expeditions had one. The requirement is for power or control system failures, which have occurred
FIRST unmanned prototype had a test flight, and, despite the nose fairing failing to eject completely, getting caught on the wing, it flew stably until the mass of the fairing dragged it too deeply below its proper trajectory. James Oberg documented this in an article of his.
-
#23
by
Jim
on 25 Jun, 2006 13:12
-
They never did find the impact, correct?
-
#24
by
mlorrey
on 26 Jun, 2006 04:11
-
Jim - 25/6/2006 7:59 AM
They never did find the impact, correct?
Incorrect:
http://www.jamesoberg.com/112003irv_his.html"The actual flight of the IMP, on an Aerobee-150 sounding rocket in 1964, had mixed results. The paraglider inflated properly but turned upside down. Then the nose-cone-jettison system failed to sever all the connecting wires, so the glider began its descent through the atmosphere dragging an anchor. Amazingly, it righted itself and flew briefly, until the aerodynamic pressure and heat got too much. At that point, one wing boom collapsed, probably from the stress of dragging the nose cone, and the IMP dropped to the desert like a wounded duck. It took weeks to find all the meteoroid collection panels that were torn off the wing as it fell."
You are likely thinking of ESA's launch on the Fregat that disappeared, but that design was a ballute, not a Rogallo Wing.
Aerodynamic pressure is the problem: too much wing loading results in too much heating.
-
#25
by
cozmicray
on 26 Jun, 2006 16:26
-
Jim
I have worked on NASA GSFC projects for 25 years, Landsat 4/5, UARS STS-48, TERRA, AURA, HRSDM.
Never have I seen in an RFP "Utilize lessons learned" show "How pass lessons learned will be applied"
and submit to the lessons learned document/database during the project development.
I have had access to the NASA LLIS and it is woefully inadequate.
Even within the VERY Large aerospace/ defense company I work for, can't get a Lessons learned database
that all programs use.
Programs at NASA are very isolated. Not Invented here program to program thing.
A group at GRC may have the greatest space component in the world
but a project at GSFC won't use it
GSFC to GSFC projects don't even share data, The EOS missions are in a world of thier own
and shall never co-mingle with the non-remote sensing projects
So there is Apollo lessons learned?
In a format that one does not have to spend a lifetime hashing thru?
I would not be at all surprised if a 100% oxygen atmosphere was used in CEV!
It will be neat to see the historians in 2080 trying to figure out "Why from STS to capsule"
No documentation at all, just a decision of the NASA admin at the time,
as the "Griffin Orbital Trash Collection System passes overhead.
cozmicray - 24/6/2006 7:51 PM
The "Not invented here" permeates ALL NASA projects.
NASA ran Apollo. So how can it be NIH?
Where is your proof for "ALL NASA projects"?
cozmicray - 24/6/2006 7:51 PM
All the lessons learned from Apollo have died with the old engineers.
Says who? They are still around. And there lessons to
Unfortunately you don't have access to the database NASA (windchill) is using for Constellation. Even the lessons from OSP are being used.
There is a whole lot of Apollo info being used. I have downloaded some of it for my own personal reading.
You are making a lot of accusations without showing any info to back them up
-
#26
by
Jim
on 26 Jun, 2006 17:37
-
cozmicray - 26/6/2006 12:13 PM
It will be neat to see the historians in 2080 trying to figure out "Why from STS to capsule"
No documentation at all, just a decision of the NASA admin at the time,
as the "Griffin Orbital Trash Collection System passes overhead.
Have you read the ESAS? It states the reasons for the capsule
NASA-STD-3000 or NPR 8705.2A
GSFC is in a different world than KSC, JSC and MSFC. The other centers interact better thanGSFC
-
#27
by
Jim
on 26 Jun, 2006 17:58
-
I just want to make a clarification. I was using a wrong term. The requirement is for passive entry, not "uncontrolled"
-
#28
by
Smatcha
on 26 Jun, 2006 18:45
-
Current propulsion, material, and economic limits forces a minimalist design.
Anything reusable will be heavier than something that is not reusable due to fatigue and multiple wear and tear cycles.
Second by definition something that is reusable will have components necessary for ascent to be returned via descent, Shuttle main engines for example.
At the current cost of 10K/kg to LEO it just doesn’t pay to add a lot of additional LEO weight in order to return the “reusable” better described as “remanufactured” spacecraft. We need to be somewhere in the 1K/kg to LEO before the economics will shifts us towards a more reusable designs.
I also have a big problem with considering Space Ship One as anything more than a impressive stunt given it attained less the 10% of the required energy to orbit the earth let alone leave it. While I believe that private enterprise is ultimately more efficient than government the laws of physics “as we understand” them represent our primary barrier to space travel at this time.
-
#29
by
quark
on 26 Jun, 2006 20:25
-
nacnud - 23/6/2006 6:10 PM
I liked the idea of a fly-off, where different ideas could be tested and compared.
Great idea, want to pay for it? It is very very hard to try and justify space planes over capsules on safety grounds. There might be operational advantages but a lifting capsule and a steerable parachute can land with pin point accuracy and RLVs have the flight rate problem.
The fly-off was exactly NASA's approach in the Steidle days. Probably would save money in the long run. It definitely would result in a better product. Today's approach is to select the CEV winner based on mountains of paper, and may the best liar win. Steidle's approach of a fly-off provided real data, both in term of design/technical performance and management/cost/schedule performance. More data = better decision. Next time you buy a car, don't bother to test drive, just look at the glossy brochures...
-
#30
by
Smatcha
on 26 Jun, 2006 21:54
-
quark - 26/6/2006 1:12 PM
nacnud - 23/6/2006 6:10 PM
I liked the idea of a fly-off, where different ideas could be tested and compared.
Great idea, want to pay for it? It is very very hard to try and justify space planes over capsules on safety grounds. There might be operational advantages but a lifting capsule and a steerable parachute can land with pin point accuracy and RLVs have the flight rate problem.
The fly-off was exactly NASA's approach in the Steidle days. Probably would save money in the long run. It definitely would result in a better product. Today's approach is to select the CEV winner based on mountains of paper, and may the best liar win. Steidle's approach of a fly-off provided real data, both in term of design/technical performance and management/cost/schedule performance. More data = better decision. Next time you buy a car, don't bother to test drive, just look at the glossy brochures...
Using the F-22 and JSF as examples the only difference in a fly-off is in the percentage the loser and his subs gets of the winners work. The politics surrounding big budget items force this resolution regardless of who wins. The other factor is which large organization was the last one to significantly overrun the budget as prime. Given Boeing was prime on the ISS I would give better than even odds to LockMart for the CEV for that reason alone with Delta being the CLV as a consolation prize and closer association with RS-68 upgrade path for CaHLV.
The only solution to this is for NASA to hire the same engineers right out of school that Boeing and LockMart do lead by the same ones that will manage them. At which point it will only cost what it needs to cost without profit and designed in overruns intended to increase you guessed it profit. The other big advantage Apollo had was the tremendous amount of unpaid time all the young engineers put in to the program out of shear passion to beat the USSR an important component of the actual cost of Apollo. Now NASA wants to do twice of much with half the money with one fourth the passion. Not going to happen. The only way it happens is by bringing private industry in and I’m not talking about stunts like SpaceShip One but proving that a serious profit can be made by a large industry and/or a compelling nation interest beyond finding out just how inhospitable and rocky our local system is at finer and finer resolutions.
The new world was developed for political and commercial reasons not for exploration.
NASA’s structural problems, born of understandable survival moves made by NASA after Apollo, are still with us today. NASA had to transform itself into a research organization, similar to the Universities they fund, and spread most of the hardware money towards contractors who in turn fund local, state, and congressional campaigns.
Now that they are in this mode that can’t reverse it because the politics keeps this arrangement ultimately in place because NASA cannot fund campaigns. In addition because NASA had to become one big University research system all the hardware guys had to and continue to work for a small number of for as much profit as possible contractors. It is now at the point that NASA could not function on a day to day basis nor does it have a base of hardware guys to proceed from into any actual design without the contractors.
Like it or not most if not all significant $$$ design down selections will have little to do with the public reasons cited in the down select.
Capitalism and democracy go together because the efficiency of the former is the only way to pay for the inefficiency of the later.
-
#31
by
Jim
on 26 Jun, 2006 23:52
-
quark - 26/6/2006 4:12 PM
The fly-off was exactly NASA's approach in the Steidle days. Probably would save money in the long run. It definitely would result in a better product. Today's approach is to select the CEV winner based on mountains of paper, and may the best liar win. Steidle's approach of a fly-off provided real data, both in term of design/technical performance and management/cost/schedule performance. More data = better decision. Next time you buy a car, don't bother to test drive, just look at the glossy brochures...
The flyoff was not going to use full up complete spacecraft. They were going to be boilplate model, with only the outmold line, weight and CG modeled. The flights would have been only abort or reentry tests. They were scheduled for 08, which left little time for complete development.
-
#32
by
HailColumbia
on 27 Jun, 2006 01:22
-
Jim - 26/6/2006 7:39 PM
The flyoff was not going to use full up complete spacecraft. They were going to be boilplate model, with only the outmold line, weight and CG modeled. The flights would have been only abort or reentry tests. They were scheduled for 08, which left little time for complete development.
And now that NASA has dictated the outermold line, seems like a flyoff would be useless under these condiditons
-
#33
by
quark
on 27 Jun, 2006 06:10
-
HailColumbia - 26/6/2006 7:09 PM
Jim - 26/6/2006 7:39 PM
The flyoff was not going to use full up complete spacecraft. They were going to be boilplate model, with only the outmold line, weight and CG modeled. The flights would have been only abort or reentry tests. They were scheduled for 08, which left little time for complete development.
And now that NASA has dictated the outermold line, seems like a flyoff would be useless under these condiditons
Exactly! Once NASA dictates the solution, all opportunity for innovation by the contractor teams goes out the window. At that point, all we're left with is politics and jobs programs. Depressing...
-
#34
by
vt_hokie
on 27 Jun, 2006 07:28
-
There is a glimmer of hope. Maybe SpaceDev will manage to pull off its HL-20 derived "Dreamchaser"!
-
#35
by
Jim
on 27 Jun, 2006 11:14
-
quark - 27/6/2006 1:57 AM
HailColumbia - 26/6/2006 7:09 PM
Jim - 26/6/2006 7:39 PM
The flyoff was not going to use full up complete spacecraft. They were going to be boilplate model, with only the outmold line, weight and CG modeled. The flights would have been only abort or reentry tests. They were scheduled for 08, which left little time for complete development.
And now that NASA has dictated the outermold line, seems like a flyoff would be useless under these condiditons
Exactly! Once NASA dictates the solution, all opportunity for innovation by the contractor teams goes out the window. At that point, all we're left with is politics and jobs programs. Depressing...
It was done to save money and time. Testing and qualification was reduced. It was a smart move. The same thing was done for Apollo and Mercury. Saturn V was done the same way.
There is nothing wrong with this type of contracting. They weren't looking for advancing the state of the art.
-
#36
by
spfrss
on 27 Jun, 2006 15:39
-
Jim - 27/6/2006 6:01 AM
It was done to save money and time. Testing and qualification was reduced. It was a smart move. The same thing was done for Apollo and Mercury. Saturn V was done the same way.
There is nothing wrong with this type of contracting. They weren't looking for advancing the state of the art.
And you forgot Gemini, which worked fairly well, I remember, for a system which wasn't flown off against a competitor.
Yes, airplanes flying back from space are an amazing sight, but as we know too well now,
they have too many flaws to keep them flying. and I desperately want to see again someone walking on the Moon!!!
So, welcome back capsules and focus on exploration instead of technology development
mauro
-
#37
by
vt_hokie
on 27 Jun, 2006 18:46
-
spfrss - 27/6/2006 11:26 AM
So, welcome back capsules and focus on exploration instead of technology development
Unless we focus on both, we'll be stuck with the same technology forever. What if we said that a couple centuries ago? We'd still be traveling around in wooden sailing ships!
-
#38
by
nacnud
on 27 Jun, 2006 19:29
-
Well wich is more useful, lots of small sailing ships or the Great Easton stuck on the bank of the Thames?
-
#39
by
mlorrey
on 27 Jun, 2006 21:42
-
nacnud - 27/6/2006 2:16 PM
Well wich is more useful, lots of small sailing ships or the Great Easton stuck on the bank of the Thames?
You mean the Great Eastern? At almost 700 feet long, she was Brunel's masterwork, beyond being the largest liner of the day, she eventually laid the 1865 transatlantic telegraph cable. She was a technological pioneer, carrying both sail, paddlewheels, and screw propellers, and featured a double skinned hull, not seen again for a century. She was certainly ahead of her time, not to be equalled until the turn of the century in size or capacity.
Sure, the launch was problematic: it was longer than the Thames was wide and would have gotten stuck on the opposite bank if launched straight. She was launched sidways, and got stuck. She was a money loser since she was never used on the Australia route she was intended for, and always operated by owners who were short on capital to properly outfit and operate her.
