Author Topic: LIVE: Full Committee Hearing - A Review of NASA's Space Launch System  (Read 342145 times)

Offline sergeante

  • Full Member
  • *
  • Posts: 117
  • SW Utah
  • Liked: 0
  • Likes Given: 0
Eh, spoilsport.  ;D

Check this out -- if the pass at your longitude happened right around evening or morning nautical twilight, the Sun would still be on the vehicle. That might give you a pretty good show if it was also close to perigee, because it would be going really freakin' fast.

See, I'm not just a taker.
« Last Edit: 07/27/2011 09:31 PM by sergeante »

Offline Robotbeat

  • Senior Member
  • *****
  • Posts: 28369
  • Minnesota
  • Liked: 8226
  • Likes Given: 5439
Eh, spoilsport.  ;D

Check this out -- if the pass at your longitude happened right around evening or morning nautical twilight, the Sun would still be on the vehicle. That might give you a pretty good show if it was also close to perigee, because it would be going really freakin' fast.

See, I'm not just a taker.
Plus, there would be water vapor illuminated by the Sun. :)

(By the way, there are some ways to get to Mars via a Lagrange point for less energy than a direct route... http://www.esm.vt.edu/~sdross/papers/AmericanScientist2006.pdf
http://www.chemistrydaily.com/chemistry/Interplanetary_Superhighway ... and back. It's really slow, but sometimes uses next to no energy...  which is how we get Mars meteorites, etc. Part of the reason it's slow for asteroids and such is that for them, it's chaotic, so there's just a certain probability they move through the network, but with computers and thrusters we can cheat and pick which path to take with very, very little energy... multi-body dynamics are very complicated and don't always observe our naive notions learned from two-body dynamics. But yes, sometimes it's actually superior to the direct route.)
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline sergeante

  • Full Member
  • *
  • Posts: 117
  • SW Utah
  • Liked: 0
  • Likes Given: 0
But yes, sometimes it's actually superior to the direct route.)

In delta-v terms. In delta-t terms, it's juuust a bit pokey. <very big kiss>
« Last Edit: 07/27/2011 09:47 PM by sergeante »

Offline FinalFrontier

  • Senior Member
  • *****
  • Posts: 3945
  • Space Watcher
  • Liked: 377
  • Likes Given: 154
We are quite a bit off topic here.


I will make my final comment on this thread:

At this point, we:

1. Do not know what the details of the report are
2, Know that nothing can move forward until this report is made public and Congress approves of it.
3. Do not know for sure if there will or will not be a congressional investigation to determine what if any laws NASA leadership has broken
4. Know that the next hearing and associated processes are now stalled until after the debt crisis is either resolved, or until how the government will function in a default is known.
5. Know that NASA is not likely to continue function in the event of a default, which seems all the more likely to happen. The first effects would be felt on Tuesday of next week.

With that said, I don't really think there is anything more we can do or talk about in the short term. We will have to watch and wait, and we will have to see how much damage is done to the agency if the federal government defaults. Its time to lock this thread.
« Last Edit: 07/27/2011 09:49 PM by FinalFrontier »
3-30-2017: The start of a great future
"Live Long and Prosper"

Offline Robotbeat

  • Senior Member
  • *****
  • Posts: 28369
  • Minnesota
  • Liked: 8226
  • Likes Given: 5439
But yes, sometimes it's actually superior to the direct route.)

In delta-v terms. In delta-t terms, it's juuust a bit pokey.
Quite right... Now I'm all interested in this topic... Going to start a new thread.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline sergeante

  • Full Member
  • *
  • Posts: 117
  • SW Utah
  • Liked: 0
  • Likes Given: 0
Quite right... Now I'm all interested in this topic... Going to start a new thread.

Please drop a link here, if you could.
« Last Edit: 07/27/2011 09:59 PM by sergeante »

Offline Robotbeat

  • Senior Member
  • *****
  • Posts: 28369
  • Minnesota
  • Liked: 8226
  • Likes Given: 5439
Quite right... Now I'm all interested in this topic... Going to start a new thread.

Please drop a link here, if you could.
http://forum.nasaspaceflight.com/index.php?topic=26217.msg784299#msg784299
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline Prober

  • Senior Member
  • *****
  • Posts: 10313
  • Save the spin....I'm keeping you honest!
  • Nevada
  • Liked: 701
  • Likes Given: 728
We are quite a bit off topic here.


I will make my final comment on this thread:

At this point, we:

1. Do not know what the details of the report are
2, Know that nothing can move forward until this report is made public and Congress approves of it.
3. Do not know for sure if there will or will not be a congressional investigation to determine what if any laws NASA leadership has broken
4. Know that the next hearing and associated processes are now stalled until after the debt crisis is either resolved, or until how the government will function in a default is known.
5. Know that NASA is not likely to continue function in the event of a default, which seems all the more likely to happen. The first effects would be felt on Tuesday of next week.

With that said, I don't really think there is anything more we can do or talk about in the short term. We will have to watch and wait, and we will have to see how much damage is done to the agency if the federal government defaults. Its time to lock this thread.

The investigation continues and Chris has some news item to write.
 
2017 - Everything Old is New Again.
I have not failed. I've just found 10,000 ways that won't work. ~ by Thomas Alva Edison

Online Chris Bergin

Good work with the splinter, Robo. I'm going to leave this thread live, but we will be starting a new thread for the next SLS article, which I've now sourced enough to start writing.  ETA 2 hours.

Due to the nature of the article, it promises to be a good natured, happy, positive debate thread, with everyone singing "kum ba yah" round the NASA camp fire.......

....I'm being sarcastic, if you haven't realized yet ;)

Offline Proponent

  • Senior Member
  • *****
  • Posts: 5475
  • Liked: 990
  • Likes Given: 653
And I'm with Bill White in that I think kerolox, to power the cis-lunar tug, should get much more consideration.  I believe that ease of handling will outweigh the ISP advantages of H2, at least when coming from Earth.

I too can imagine that hydrogen might turn out not to be worth the deep-cryo hassle for some applications, but my first fall-back would be methane rather than kerosene, especially for a re-usable system.  The reason is that methane evaporates cleanly, whereas a heavy hydrocarbon like kerosene tends to leave residues behind, which could explode on contact with lox during a re-start.

Methane's specific impulse is also better.  It is less dense than kerosene, meaning tanks will be heavier, but gravity losses aren't going to be big deal anyway for chemical-propelled cis-lunar systems.

Maybe it would also be possible to mix in a bit of propane (or maybe propene [propylene]) to make a VAPAK self-pressurizing system, eliminating the needed for a separate pressurant.   
« Last Edit: 07/28/2011 02:40 AM by Proponent »

Offline Robotbeat

  • Senior Member
  • *****
  • Posts: 28369
  • Minnesota
  • Liked: 8226
  • Likes Given: 5439
And I'm with Bill White in that I think kerolox, to power the cis-lunar tug, should get much more consideration.  I believe that ease of handling will outweigh the ISP advantages of H2, at least when coming from Earth.

I too can imagine that hydrogen might turn out not to be worth the deep-cryo hassle for some applications, but my first fall-back would be methane rather than kerosene, especially for a re-usable system.  The reason is that methane evaporates cleanly, whereas a heavy hydrocarbon like kerosene tends to leave residues behind, which could explode on contact with lox during a re-start.

Methane's specific impulse is also better.  It is less dense than kerosene, meaning tanks will be heavier, but gravity losses aren't going to be big deal anyway for chemical-propelled cis-lunar systems.

Maybe it would also be possible to mix in a bit of propane (or maybe propene [propylene]) to make a VAPAK self-pressurizing system, eliminating the needed for a separate pressurant.   
Propane might be better than methane, and not because it can be self-pressurized. Propane has nearly the Isp of methane but if cooled to near liquid oxygen temperatures, it has just as high bulk density as using kerosene... Thus your mass fraction would be better.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline Proponent

  • Senior Member
  • *****
  • Posts: 5475
  • Liked: 990
  • Likes Given: 653
Propane might be better than methane, and not because it can be self-pressurized. Propane has nearly the Isp of methane but if cooled to near liquid oxygen temperatures, it has just as high bulk density as using kerosene... Thus your mass fraction would be better.

That's a good point.  I had rejected chilled propane for deep-space use, because it wouldn't self-cool through evaporation.  But if you have a tank full of oxygen that boils a bit below the fuel's freezing point, the oxygen vapor could be used to cool the fuel.

From what I've heard, you may not want to chill propane all the way to the freezing point, because of increasing viscosity.  And let's not forget propylene, which I suspect would turn out to be a bit better than propane.

Offline Robotbeat

  • Senior Member
  • *****
  • Posts: 28369
  • Minnesota
  • Liked: 8226
  • Likes Given: 5439
Propane might be better than methane, and not because it can be self-pressurized. Propane has nearly the Isp of methane but if cooled to near liquid oxygen temperatures, it has just as high bulk density as using kerosene... Thus your mass fraction would be better.

That's a good point.  I had rejected chilled propane for deep-space use, because it wouldn't self-cool through evaporation.  But if you have a tank full of oxygen that boils a bit below the fuel's freezing point, the oxygen vapor could be used to cool the fuel.

From what I've heard, you may not want to chill propane all the way to the freezing point, because of increasing viscosity.  And let's not forget propylene, which I suspect would turn out to be a bit better than propane.
In deep space, it's perfectly feasible that soft-cryogenics are completely storable with basically no boil-off... Hydrogen is a different story, but propellants like oxygen and methane are considered "space storable" by some.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline Proponent

  • Senior Member
  • *****
  • Posts: 5475
  • Liked: 990
  • Likes Given: 653
We're on the same page there.

Offline alexw

  • Full Member
  • ****
  • Posts: 1229
  • Liked: 0
  • Likes Given: 0
The capability is already being rebuilt, Aerojet already is setting up production for it's AJ-26, new build over the warehoused 1970's engines it is currently rebuilding.
    In the US? Has there been a public announcement?
              -Alex

Offline JohnFornaro

  • Not an expert
  • Senior Member
  • *****
  • Posts: 9167
  • Delta-t is the salient metric.
  • Planet Eaarth
    • Design / Program Associates
  • Liked: 620
  • Likes Given: 324
Quote from: me
Again, it's not clear where you're headed with your line of reasoning.

Quote from: Seargente
It's a very accessible destination, but only if one wants to go there -- realism about technology and economics, and accepting the implication thereof.

Well, thanks for clearing that up.  Definitely the impression I got from your earlier comments.

As has been discussed over and over again on this forum:  The technology is capable, within reason; the money is there in principle; the political choices favor elective war which makes the money scarce; the populace is less educated, thus less concerned about HSF in general; Congress represents the populace, far too accurately, in the lack of education, and is beholden to corporate insiders in any case.

So the general thoughts of many posters, even when they are passionate about delta-vee, SEP, or MTV are that, first, Congress would agree in principle to fund a multi-administration HSF exploration plan.  This is clearly a big assumption, when Congress has demonstrated mostly a willingness to borrow money for elective war, to overlook the lack of accomplishment in many government programs, to subsidize the wealthy without cause, and to cap it all off by not balancing the books.  That is the massive handwave.  Fortunately, in principle, it is still possible to fix Congress.

A couple of my observations on your comments, not that I'm the expert or anything:

Quote
And I simply don't believe anybody is going to invest the payload capacity to do it, not for a long time.

Well, Orbital, SpaceX and the several other players, are investing money to deliver payloads.  True, their major customer seems to be NASA, but there are other customers as well.  So somebody is investing something in payload capacity, most likely with the expectation of economic return.  How sufficient an investment is all that?  Clearly, more than is in my checking account, and less than would be necessary to do the whole thing.

Quote
It should be in the orbit that best uses the injection impulse for the specfic opportunity ...

That is the current paradigm for NASA's robotic exploration missions.  When I was in college in Albemarle County in the sevnties, a group of us virtually memorized the Albemarle County VDOT map, which showed all the itty bitty dirt roads that permeated the county.  Informally, we explored them all; we knew which route was the shortest between two points, as the wheel rolls.  However, the less "efficient" "orbits" between destinations sometimes involved taking I-64 to Route 29: a few more miles, a bit more gas, but less time and less wear and tear on the suspension.  As with all analogies, this one only goes but so far, and it should not be stretched to where it no longer applies.

IOW, the ISS could become Wheeling, West Virginia.  Etc.

Quote
That all of this speculation about the utility of an EML assembly point ignores technological and economic reality.

The theoretical utility of an EML assembly point has been substantiated to a certain extent for decades in older papers.   [Edit: Papers don't do much demonstration:  The utility of an EML assembly point has been demonstrated for decades in older papers.]  The technology for transferring hypergolics has been demonstrated.  We know that you can go to the Moon on hypergolics, so that is technically feasible, although there are other efficiency issues which pertain.  The technology for transferring RP-1, and H2 needs demonstrable improvement, but it's not an issue that has been ignored, except by Congress.  I'd say there's plenty of technological reality, altho crucial bits need to be instantiated.

Furthermore, the economic reality could be there, I believe under current budgeting, since I have basically accepted the President's budget numbers, every time.  Innocent me assumes everybody is rowing in the same direction.  It is the managerial and oversight processes which need improvement.  Probably worst of all, it is the selection of strategic missions, and their prioritization, which is so dysfunctional as to be virtually worthless.  These guys can barely recreate a Redstone launch, left unsupervised.  And they continue to posit worthless destinations, which, if left unsupervised, morph from pre-decisional to post-decisional, where they will doom whatever the title of the mission may be.

Quote
Remember, I don't believe in the utility of the Moon any time soon. So my concern is with how to optimize interplanetray exploration payload utilization.

That's fine, but I do.

Quote
We're crawling right now. Even a beginning EML/lunar infrastructure is well into walking.

That's more like a tomayto/tomahto sort of thing, since we're still in LEO.  Whatevs.

Quote from: Robo
In-space infrastructure is basically what we need in order to keep the boundaries pushed back.

That is a good summary.  Without the infrastructure of the Intercontinental Railroad, and these new fangled flying machines and horseless carriages, you'd still have to walk to California.  This new infrastructure of space will be capital intensive as no other infrastructure has yet been.  So it's interesting to see how the Republicans can't see the forest of capital for the pork of the trees.  And how the Democrats can't see the forest of actual, inspirational accomplishment from the trees of powerpoints.

Quote from: Bill White
I also believe we need to look plug-n-play cryogenic tanks rather than fuel transfer. ...And these issues suggest at least looking at kerolox ...

Clearly, this is the case, I'd say.  The propane tank analogy makes more sense in space than the gas nozzle analogy.  One point of robotic hookup.  And the tanks are built rugget, and stay in LEO, to be towed to the Moon, rather than thrown away, in a concerted effort to develop that prop factory in the craters.  And the cis-lunar tug uses the same tank. 

Ease of robotic, teleoperated handling is the salient metric here, I think.

TANSTAAFL ?  Not in my acronym list!

Quote
It's really slow, but sometimes uses next to no energy...  which is how we get Mars meteorites...

Which just brings up yet another one of those things I don't know.  Where do the meteorites keep their computers for figuring out their orbital mechanics?
« Last Edit: 07/29/2011 01:08 PM by JohnFornaro »
Sometimes I just flat out don't get it.

Offline A_M_Swallow

  • Elite Veteran
  • Senior Member
  • *****
  • Posts: 8459
  • South coast of England
  • Liked: 338
  • Likes Given: 146
{snip}

Which just brings up yet another one of those things I don't know.  Where do the meteorites keep their computers for figuring out their orbital mechanics?
I am sure that they use virtual computers. ::)  ;D

They need new software, something that can handle planetary gravity wells without crashing.  8)

Offline sergeante

  • Full Member
  • *
  • Posts: 117
  • SW Utah
  • Liked: 0
  • Likes Given: 0
Quote
And I simply don't believe anybody is going to invest the payload capacity to do it, not for a long time.

Well, Orbital, SpaceX and the several other players, are investing money to deliver payloads.  True, their major customer seems to be NASA, but there are other customers as well.  So somebody is investing something in payload capacity, most likely with the expectation of economic return.  How sufficient an investment is all that?  Clearly, more than is in my checking account, and less than would be necessary to do the whole thing.

What I mean by "investing payload capacity" is allocating payload capacity that can be bought to a certain task. It says nothing about who delivers the capacity or how. It's about being able to buy so many tons to LEO, and so many tons to BEO, and what to do with it. I simply don't believe that EML/lunar infrastructure is a good investment for the next several decades, nor that anybody will invest in it for at least that long.

Quote
Quote
It should be in the orbit that best uses the injection impulse for the specfic opportunity ...

That is the current paradigm for NASA's robotic exploration missions.  When I was in college in Albemarle County in the sevnties, a group of us virtually memorized the Albemarle County VDOT map, which showed all the itty bitty dirt roads that permeated the county.  Informally, we explored them all; we knew which route was the shortest between two points, as the wheel rolls.  However, the less "efficient" "orbits" between destinations sometimes involved taking I-64 to Route 29: a few more miles, a bit more gas, but less time and less wear and tear on the suspension.  As with all analogies, this one only goes but so far, and it should not be stretched to where it no longer applies.

IOW, the ISS could become Wheeling, West Virginia.  Etc.

It's not an apt analogy, sorry. There's no side trip around an energy requirement in orbital mechanics. You lift propellant up to EML1/2, you can't get more energy out of it than to spent to lift it. If you can find propellant somewhere else that's cheaper to deliver to EML1/2, that might change things a little bit, but only if your propellant extraction/refinement/delivery investment doesn't wipe out the nominal energy savings -- and it very well could.

Quote
Quote
That all of this speculation about the utility of an EML assembly point ignores technological and economic reality.

The utility of an EML assembly point has been demonstrated for decades in older papers.

Apologies in advance, but I've never heard somebody with a science or engineering education assert that papers demonstrate anything. In science, experiment demonstrate things. In engineering working hardware demonstrates things. Nobody has done any experiments in EML space or put hardware there to demonstrate EML utility to BEO exploration.

Offline Prober

  • Senior Member
  • *****
  • Posts: 10313
  • Save the spin....I'm keeping you honest!
  • Nevada
  • Liked: 701
  • Likes Given: 728
{snip}

Which just brings up yet another one of those things I don't know.  Where do the meteorites keep their computers for figuring out their orbital mechanics?
I am sure that they use virtual computers. ::)  ;D

They need new software, something that can handle planetary gravity wells without crashing.  8)

NASA computers should be able to do just about anything.  This still ticks me off.....

NASA has awarded HP a $2.5 billion contract over four years for desktop services and devices, HP said Thursday.

http://news.yahoo.com/s/zd/20110428/tc_zd/263749

read # 254 onward.....NASA waste of funds IMHO.   
http://forum.nasaspaceflight.com/index.php?topic=24821.240

Lets say these funds went into Commercial.  What could SpaceX etc have done 600 million a year?
or
Should these funds been assigned to the new launcher?


Edit missing forum link
« Last Edit: 07/29/2011 02:37 PM by Prober »
2017 - Everything Old is New Again.
I have not failed. I've just found 10,000 ways that won't work. ~ by Thomas Alva Edison

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 32377
  • Cape Canaveral Spaceport
  • Liked: 11063
  • Likes Given: 329
{snip}

Which just brings up yet another one of those things I don't know.  Where do the meteorites keep their computers for figuring out their orbital mechanics?
I am sure that they use virtual computers. ::)  ;D

They need new software, something that can handle planetary gravity wells without crashing.  8)

NASA computers should be able to do just about anything.  This still ticks me off.....

NASA has awarded HP a $2.5 billion contract over four years for desktop services and devices, HP said Thursday.

http://news.yahoo.com/s/zd/20110428/tc_zd/263749

read # 254 onward.....NASA waste of funds IMHO.   

Lets say these funds went into Commercial.  What could SpaceX etc have done 600 million a year?
or
Should these funds been assigned to the new launcher?


Huh?   So are you saying NASA should have no PC's and networks for its workers?

Tags: