Chris Bergin - 28/5/2006 7:31 AMThis will be interesting if you're willing to take questions?
NASA uses hydrogen wherever they can for a few reasons: one is that their budget is determined by political committees of senators and congressmen, whose election is often dependent upon the environmentalist vote, which tends to support a shift to a hydrogen economy; another reason is that a vehicle that is more difficult to reach orbit means it is more expensive, with more money to go to more contractors, which can be located in more congressional districts, which also serves the political ends of congressmen seeking pork for their constituencies. Additionally, NASA's mandate is about developing advanced technologies, which is used to spin off into the private sector to maintain US technological and economic supremacy. This also serves the political ends of congressmen; lastly, I believe that NASA engineers just haven't deeply analysed the issue, and are willing to go with the politically expedient choice.
Jim - 29/5/2006 8:55 AMHere is another one"Boeing and LockMart, run a duopoly both in satellites and launchers, selling launch services to those they build satellites for"Yes, sometimes the spacecraft manufacturer buys the launch service as part of the contract for the spacecraft services. But both LM and Boeing have firewalls (per FTC direction) between the spacecraft and LV divisions. They can not share any info that it outside of the few missions that fly on the same LV.The attached chart clearly shows that Boeing and LM do not fly on their own LV's and there is no "duopoly". Boeing and LM only have approx 40% of the spacecraft market (mostly because Boeing bought Hughes), yet only 20% of the LV market (Sealaunch not included due to previous Hughes contract).Additionally, It is the spacecraft driving the LV's to carry more and not by the choose of the LV contractors. The Atlas II - III growth path; the addition of solids to the EELV's, the Ariane ECA development and Sealaunch Zenit uprating were all driven by spacecraft mass increases. Not the reverse, the LV's just reacted to market pressure.
kevin-rf - 28/5/2006 9:56 PMFrom the Website :http://www.lorrey.biz/x-106/vision.htmlOuch, now I am no friend of Hydrogen as a first stage fuel due to the low density issue but that looks to be picking a fight where none is needed. Still looks to be a fun project...Have you done any research into Methane vs. Kerosene? It would be a lowwer density fuel than kerosene, but would have a higher ISP.
mlorrey - 29/5/2006 4:03 PMQuoteJim - 29/5/2006 8:55 AMHere is another one"Boeing and LockMart, run a duopoly both in satellites and launchers, selling launch services to those they build satellites for"Yes, sometimes the spacecraft manufacturer buys the launch service as part of the contract for the spacecraft services. But both LM and Boeing have firewalls (per FTC direction) between the spacecraft and LV divisions. They can not share any info that it outside of the few missions that fly on the same LV.The attached chart clearly shows that Boeing and LM do not fly on their own LV's and there is no "duopoly". Boeing and LM only have approx 40% of the spacecraft market (mostly because Boeing bought Hughes), yet only 20% of the LV market (Sealaunch not included due to previous Hughes contract).Additionally, It is the spacecraft driving the LV's to carry more and not by the choose of the LV contractors. The Atlas II - III growth path; the addition of solids to the EELV's, the Ariane ECA development and Sealaunch Zenit uprating were all driven by spacecraft mass increases. Not the reverse, the LV's just reacted to market pressure.Since Sealaunch is owned by the two (plus Energia), its launches should be included, so you are fudging the numbers. 62% of Boeing/LM satellites launch on Boeing/LM launchers, and B/LM launches 44% of all launches. That is pretty duopolistic.Also: what time span is this chart supposed to represent? Cherry picking a time frame beneficial to one's argument isn't appropriate, so lets see what time frame this refers to.
Jim - 29/5/2006 6:54 PMSince there is only 4 launch service providers in the same class, Sealaunch, Atlas, Ariane, and Proton (Delta is not available commercially). 2 of them would be 50%. So it makes sense that Boeing and lM have 50% of the market, but Sealaunch is only 40% Boeing, so Boeing and LM only have 35% of the LV market.Boeing Satellite Systems is just Hughes Space and Comm, most of the comsat and LV contracts were done before the acquistion. HSC was already the largest comsat manufacturer in the world, with no help from Boeing, so putting them as "Boeing" is misleading.Proton and Atlas have marketing agreements, as well as Arianespace and Sealaunch, this pits LM against Boeing. Even as LM and Boeing form ULA, commercial launches are not part of the agreement and the moneys not shared
mlorrey - 29/5/2006 10:21 PMAh, commercial launches are not shared? How are they going to work that? What is the point of ULA if they don't get economies of scale? sounds to me like 12 of one, dozen of the other.
Jim - 30/5/2006 1:54 AMSince there is only 4 launch service providers in the same class, Sealaunch, Atlas, Ariane, and Proton (Delta is not available commercially)
mlorrey - 29/5/2006 4:25 PMMy primary arguments are that air augmentation is needlessly being given short shrift by NASA, that NASA, as seems sadly typical, picked two wrong horses (scramjets and hydrogen, rather than ramjets and hydrocarbons) when it did study air augmented launching. The pattern of seeming to pick the wrong horse in so many key decisions (Thiokol over Aerojet on SRB contract, LH2 vs Hydrocarbons, Scramjet vs Ramjet, aluminum airframe vs hotframe on Shuttle, Blunt body vs SHARP TPS, composite vs metal tank on X-33, etc) just seems too glaring to be an accident to me.
aero313 - 30/5/2006 4:10 PMQuotemlorrey - 29/5/2006 4:25 PMMy primary arguments are that air augmentation is needlessly being given short shrift by NASA, that NASA, as seems sadly typical, picked two wrong horses (scramjets and hydrogen, rather than ramjets and hydrocarbons) when it did study air augmented launching. The pattern of seeming to pick the wrong horse in so many key decisions (Thiokol over Aerojet on SRB contract, LH2 vs Hydrocarbons, Scramjet vs Ramjet, aluminum airframe vs hotframe on Shuttle, Blunt body vs SHARP TPS, composite vs metal tank on X-33, etc) just seems too glaring to be an accident to me. Our company was one of the DARPA/RASCAL Phase 1 teams. We studied airbreathing ascent vs. rocket (albeit with mythical MIPCC performance vs. mythical ramjet or scramjet performance). The bottom line was that to get enough velocity to make the airbreather useful, you needed to fly very fast while down low in the atmosphere. Aero heating was a perpetual problem. More to the point, once you attained that useful velocity, your velocity vector was in the wrong direction, necessitating either the use of a lot of delta v to turn the velocity vector or else massive wings to do it aerodynamically. Of course, the wings have strutural, aeroheating, and drag problems. This hurts performance, which necessitates more velocity in the wrong direction, which requires bigger wings, etc, etc...
Spirit - 30/5/2006 4:08 PMQuoteJim - 30/5/2006 1:54 AMSince there is only 4 launch service providers in the same class, Sealaunch, Atlas, Ariane, and Proton (Delta is not available commercially)What about the Japanese, Chinese and Indian launchers?
mlorrey - 30/5/2006 5:54 PMWith heating, I'm looking at implementing the SHARP materials that nobody has yet been looking at using in their proposals. Its performance used as leading edge and nosecone materials allows mach 7 at sea level and mach 11 at 100,000 ft.
Deltav requirements: it is a bigger dv drain to waste lots of fuel and oxidizer accelerating straight up, then changing direction by 90 degrees, than to air breath up to mach 8 and 100k ft, pop a zoom maneuver to 250kft, then keep on trucking downrange. A third of a pure rocket launchers fuel gets consumed below mach 2 and 100kft.
I've looked at DARPA's RASCAL program, and IMHO it was designed to fail with both obsolete turbine engine technology (F-100's with terrible T/W ratios), burdensome low Isp/high mass upper stage technology (hybrids), as well as demands for unrealistic mission requirements like 30 minutes of loiter time before zoom, 300 mile ferry before launch, etc. As far as I'm concerned, DARPA duped a lot of companies with RASCAL with a Sisyphusian chore.
Nor is ramjet performance "mythical", though it may as well be, given that most all of the real experts from Marquardt are retired or dead, and engineering schools ignore the technology. Ramjets have a rather well established history of performance that some engineers consider mythical only because they've never been exposed to them.
mlorrey - 30/5/2006 2:54 PMDeltav requirements: it is a bigger dv drain to waste lots of fuel and oxidizer accelerating straight up, then changing direction by 90 degrees, than to air breath up to mach 8 and 100k ft, pop a zoom maneuver to 250kft, then keep on trucking downrange. A third of a pure rocket launchers fuel gets consumed below mach 2 and 100kft.
