vt_hokie - 23/5/2006 2:54 PMI actually find the SDLV vs EELV argument to be somewhat amusing, as I think both approaches are wrong. I'd rather see us revive programs like X-33 and X-34 and start building some new hardware based on new designs.
vt_hokie - 23/5/2006 7:54 AM I'd rather see us revive programs like X-33 and X-34 and start building some new hardware based on new designs.
Tap-Sa - 23/5/2006 3:01 AMQuotevt_hokie - 23/5/2006 7:54 AM I'd rather see us revive programs like X-33 and X-34 and start building some new hardware based on new designs.scramjet Venture Superstar with 125 tonnes payload? Mmm-kay ... *ringing White House* Mr President, the VSE budget just tripled, will you cover it? Mr President? Hello?back to topic, about question #4. I have a vague memory of chart showing the black zones are quite early in the flight, the CEV probably still has the LAS attached at that point so it pops just the CM and SM is of no use. Those who know better, please confirm or deny.I have a subquestion regarding the black zone issue. Are those zones with current EELV trajectories really unsurvivable, or has NASA set some arbitrary g-limit for abort conditions (and if so what is it) ? The CM has to survive at least 10g if LAS is activated. Suborbital Mercuries pulled 11g during nominal mission.
vt_hokie - 22/5/2006 11:54 PMI actually find the SDLV vs EELV argument to be somewhat amusing, as I think both approaches are wrong. I'd rather see us revive programs like X-33 and X-34 and start building some new hardware based on new designs.
Jim - 23/5/2006 4:23 AMQuoteTap-Sa - 23/5/2006 3:01 AMQuotevt_hokie - 23/5/2006 7:54 AM I'd rather see us revive programs like X-33 and X-34 and start building some new hardware based on new designs.scramjet Venture Superstar with 125 tonnes payload? Mmm-kay ... *ringing White House* Mr President, the VSE budget just tripled, will you cover it? Mr President? Hello?back to topic, about question #4. I have a vague memory of chart showing the black zones are quite early in the flight, the CEV probably still has the LAS attached at that point so it pops just the CM and SM is of no use. Those who know better, please confirm or deny.I have a subquestion regarding the black zone issue. Are those zones with current EELV trajectories really unsurvivable, or has NASA set some arbitrary g-limit for abort conditions (and if so what is it) ? The CM has to survive at least 10g if LAS is activated. Suborbital Mercuries pulled 11g during nominal mission.Don't remember the specific numbers but it was high g's sustained over a matter of minutes.
SMetch - 23/5/2006 9:55 AM[Do you know if the orbit of 30x160 is in nmi? No units are shown kind of important.Theoretically if we match this we should be close to NASA blessed ascent ellipse.Also notice that there is a delay of 80 seconds between the ignition of the 2nd stage and LAS jettison. My guess is they might have an abort re-entry problem after SRB separation as well due to the ballistic disposal requirement of the SRB.I would also assume that after the LAS is ejected the back-up for the crew abort is the SM thrust. I have often wondered why we through away the LAS thrust. It would seem that if we fire one solid at a time (as opposed to all at once for abort scenarios) we could then leverage some of that energy, leaving only the last one to clear the LAS from the vehicle, now even lighter from depleting most of its fuel.Also if it is nmi than the apogee is 296 km. I would also assume that circularization of the orbit is done by the SM. This would be poor use of resources since that would mean utilizing a lower ISP fuel and require us to carry around to the Moon and back a larger tank than absolutely necessary.
Jim - 23/5/2006 10:19 AMQuoteSMetch - 23/5/2006 9:55 AM[Do you know if the orbit of 30x160 is in nmi? No units are shown kind of important.Theoretically if we match this we should be close to NASA blessed ascent ellipse.Also notice that there is a delay of 80 seconds between the ignition of the 2nd stage and LAS jettison. My guess is they might have an abort re-entry problem after SRB separation as well due to the ballistic disposal requirement of the SRB.I would also assume that after the LAS is ejected the back-up for the crew abort is the SM thrust. I have often wondered why we through away the LAS thrust. It would seem that if we fire one solid at a time (as opposed to all at once for abort scenarios) we could then leverage some of that energy, leaving only the last one to clear the LAS from the vehicle, now even lighter from depleting most of its fuel.Also if it is nmi than the apogee is 296 km. I would also assume that circularization of the orbit is done by the SM. This would be poor use of resources since that would mean utilizing a lower ISP fuel and require us to carry around to the Moon and back a larger tank than absolutely necessary.nmiIt is not the orbit that determines whether there are black zones, it is how the LV flies to the injection point (this was illustrated in another thread).The LAS is not just used for the first stage, there can be failures in the upperstage that require aborts. The LASA is used until the SM can provide sufficent separation in an abort. One of the factors in determining this is how much propellant is left in the upperstage. Abort entry problems are not a function of the LAS use. The use of the LAS for propulsion is not a good idea (also see previous thread). Here are the reasons:1. There are not multiple abort motors in the system, just one motor with multiple nozzles.2. The CM/SM attach system is not made to take this type of load3. Loads on the crew. Ok for abort but not for an everyday occurancecircularization does not take that much energy (see the shuttle) and this greatly aids in upperstage disposal. Something similar is done for Mars trajectories. Spacecraft are not targeted directly at Mars but offset. This is to prevent a dead spacecraft and/or upperstage from hitting Mars. The spacecraft must carry the fuel to cancel the offset. Programs wanted to target the spacecraft directly to Mars and have the upperstage deflect after separation, but since this was another restart and blah, blah, blah, it wasn't allowed.
Jim - 23/5/2006 7:38 AMX-34 wasn't going to orbit. X-33 was never going to orbit either.
SMetch - 23/5/2006 9:55 AMAs far as the RLV stuff goes could you please start your own thread.
vt_hokie - 23/5/2006 6:24 PMQuoteJim - 23/5/2006 7:38 AMX-34 wasn't going to orbit. X-33 was never going to orbit either.I know that, but if the programs hadn't been killed, we'd be beyond the flight test phase by now and could be applying the technology toward an orbital vehicle.
Jim - 23/5/2006 5:10 PMQuotevt_hokie - 23/5/2006 6:24 PMQuoteJim - 23/5/2006 7:38 AMX-34 wasn't going to orbit. X-33 was never going to orbit either.I know that, but if the programs hadn't been killed, we'd be beyond the flight test phase by now and could be applying the technology toward an orbital vehicle.Or they could have ended up like the X-wing aircraft (the combo helicopter/airplane), a dead end.
Jim - 23/5/2006 6:38 AMQuotevt_hokie - 22/5/2006 11:54 PMI actually find the SDLV vs EELV argument to be somewhat amusing, as I think both approaches are wrong. I'd rather see us revive programs like X-33 and X-34 and start building some new hardware based on new designs.X-34 wasn't going to orbit. X-33 was never going to orbit either.
Jim - 24/5/2006 12:43 PMThere is no NIH wrt to the EELV's. NASA has 10 on their manifest and maybe more to come
SMetch - 22/5/2006 8:36 PMFirst Question:What are the off the shelf payload numbers to ISS for various models of EELV?(see attached table for my first shot at this)
Second Question:What is the performance reduction required to increase the structural and operational margins of the vehicle?
Third Question:What is the performance reduction (assuming only an escape tower and no CEV/SM abort thrust capability) to eliminate the danger zones from the baseline EELV ascent ellipse?
Fifth Question:What would be a good compromise between depressing the EELV ascent ellipse and relying on some emergency correction from the CEV/SM engine? i.e. either to shallow out the re-entry curve or abort to a temporary orbit.
In the end after interacting questions 1-5 what would be a reasonable (97% confidence) payload performance number for all launch vehicles to ISS.
vt_hokie - 22/5/2006 10:54 PMI actually find the SDLV vs EELV argument to be somewhat amusing, as I think both approaches are wrong. I'd rather see us revive programs like X-33 and X-34 and start building some new hardware based on new designs.
wannamoonbase - 25/5/2006 9:57 PMQuotevt_hokie - 22/5/2006 10:54 PMI actually find the SDLV vs EELV argument to be somewhat amusing, as I think both approaches are wrong. I'd rather see us revive programs like X-33 and X-34 and start building some new hardware based on new designs.I would like the Starship Enterprise too but we don't have 46 Trillion to spend and any of current technologies obviously were not even close to be enough to making it possible.If there were a silver bullet out there that would cut costs to 10% of the current value or revolutionize performance any one of the players world wide would have brought it to the table sometime ago.We are stuck with ELV tail of fire technology for at least a few more decades.
Kayla - 25/5/2006 6:17 PMThe Atlas V HLV/DEC provides sufficient upper stage thrust such that the nominal ascent profile only has to be slightly further depressed to close the black zones, causing almost no performance drop off.My memory is that accounting for the LVHM and minor other human rating modifications, the Atlas V HLV/DEC ISS performance is ~28.9 mT.
Kayla - 26/5/2006 4:15 AMQuotewannamoonbase - 25/5/2006 9:57 PMQuotevt_hokie - 22/5/2006 10:54 PMI actually find the SDLV vs EELV argument to be somewhat amusing, as I think both approaches are wrong. I'd rather see us revive programs like X-33 and X-34 and start building some new hardware based on new designs.I would like the Starship Enterprise too but we don't have 46 Trillion to spend and any of current technologies obviously were not even close to be enough to making it possible.If there were a silver bullet out there that would cut costs to 10% of the current value or revolutionize performance any one of the players world wide would have brought it to the table sometime ago.We are stuck with ELV tail of fire technology for at least a few more decades.These comments get to the heart of why I have suggested the use of smaller launchers with cryo transfer instead of the CaLV. The CaLV is so large that it will only fly occasionally, strictly for these NASA exploration missions. It will be a monopoly that no one will dare compete against. The monetary cost of entry is too huge, and the market opportunity is minimal.On the other hand, if NASA were to open up the 300 mT/year launch requirement for two lunar missions to competitive launch, this has just created a huge market. Added together the entire current US launch market consists of under 200 mT/year: 4 Shuttles (20 mT), 8 EELV’s (10 mT), few commercials (10 mT). In one swoop of a pen, NASA could over double this launch market, and I’m not including the crewed launches. If the exploration architecture is independent of rocket size, this new market opens the door wide for launch competition!!! It also means that to compete one doesn’t have to develop a Saturn V class rocket to get maybe 2 launches a year. Small Delta II, or EELV class rockets work just fine. Who can provide the low cost, reliable on orbit delivery? With this impetus, I’d love to see the incredible launch technology advancement 20 years from now. Going down the current path, one doesn’t need a crystal ball, the launch technology will not have changed. The high prices will still haunt us. Real space access will still be a dream.
SMetch - 26/5/2006 12:50 PMQuoteKayla - 25/5/2006 6:17 PMThe Atlas V HLV/DEC provides sufficient upper stage thrust such that the nominal ascent profile only has to be slightly further depressed to close the black zones, causing almost no performance drop off.My memory is that accounting for the LVHM and minor other human rating modifications, the Atlas V HLV/DEC ISS performance is ~28.9 mT.Thanks for the infoOne of the ways we could save a lot of money in servicing the ISS would be to ship up a lighter CEV/SM (ISS Config) vehicle in the first place. I’m pretty sure the Russians are not sending people up to ISS with anything heavy as the current SRB/CLV does.One of the big problems with the SRB/CLV is the first stage only has one general power setting. You have to add mass to hold it down. One size never fits all. As such they must send up a lunar configured CEV/SM to the ISS every time.What are the ISS performance (man launch) numbers for all the entire Atlas Line? I’m trying to match an ISS CEV/SM with another lunar architecture we are working on.If we can get the ISS mission done with a smaller EELV utilizing the same CEV with an ISS and Lunar SM variant we could save a lot of money and time.For the Boeing Delta Line, one core booster might be sufficient. With less engines to go wrong this should help in the reliablilty department.
Jim - 26/5/2006 10:06 AMQuoteSMetch - 26/5/2006 12:50 PMQuoteKayla - 25/5/2006 6:17 PMThe Atlas V HLV/DEC provides sufficient upper stage thrust such that the nominal ascent profile only has to be slightly further depressed to close the black zones, causing almost no performance drop off.My memory is that accounting for the LVHM and minor other human rating modifications, the Atlas V HLV/DEC ISS performance is ~28.9 mT.Thanks for the infoOne of the ways we could save a lot of money in servicing the ISS would be to ship up a lighter CEV/SM (ISS Config) vehicle in the first place. I’m pretty sure the Russians are not sending people up to ISS with anything heavy as the current SRB/CLV does.One of the big problems with the SRB/CLV is the first stage only has one general power setting. You have to add mass to hold it down. One size never fits all. As such they must send up a lunar configured CEV/SM to the ISS every time.What are the ISS performance (man launch) numbers for all the entire Atlas Line? I’m trying to match an ISS CEV/SM with another lunar architecture we are working on.If we can get the ISS mission done with a smaller EELV utilizing the same CEV with an ISS and Lunar SM variant we could save a lot of money and time.For the Boeing Delta Line, one core booster might be sufficient. With less engines to go wrong this should help in the reliablilty department.Why ISS orbit? Injection would be at the same inclination, but not at the same altitude. if you add SRM's with TVC for the Delta IV reliabity goes down, you are better off with a heavyAs for the SM, just offload fuel. Having two different SM's would be more expensive
Norm Hartnett - 29/5/2006 12:55 AMSo in amongst the massive amount of OT stuff in this thread we got some possibly good data on the Atlas packages. Anyone want to present the Delta packages?
Jim - 5/6/2006 6:03 PMThe wet design was rejected for Skylab but of qualifing materials for the cyrogenic environment. I am assuming that the fuel is H2 otherwise purging that tank would be hard. Is the outside of the vehicle also mmod proof? What would they be salvage for?
Jim - 5/6/2006 11:28 PMIn the old ET orbital use studies, it was found that the current foam was not good MMOD protection and also deteroirated quickly.
mlorrey - 5/6/2006 10:55 PMIf the ET were redesigned to handle LOX and RP-1, it would be structurally a bit heavier, but could carry twice as much payload into orbit for the same tankage volume. RP-1 remnants should evaporate to space upon venting.
kevin-rf - 6/6/2006 11:18 AMQuotemlorrey - 5/6/2006 10:55 PMIf the ET were redesigned to handle LOX and RP-1, it would be structurally a bit heavier, but could carry twice as much payload into orbit for the same tankage volume. RP-1 remnants should evaporate to space upon venting.The bulk of the hydrocarbons may "evaporate" out, but there will always be a thin film left on the tank walls. Ever try to pump down a vacuum chamber after it was contaminated with oil? You can pump against it until you turn blue (Cryo Pump,Diffusion Pump,Turbo Molecular Pump,chose your weapon) and never get much beyond the milli torr range because of the hydrocarbons left behind. The RP-1 will have to be scrubbed out by hand. I can lay may hands on a small vacuum chamber that had an oil handling accident (#@$! oil roughing pump) , It has been scrubbed, and I can still smell the oil in it. The RP-1 tank will be 1/16th the size of the O2 tank. Why mess with the RP-1 tank at all.
simonbp - 6/6/2006 11:35 AMQuotekevin-rf - 6/6/2006 11:18 AMQuotemlorrey - 5/6/2006 10:55 PMIf the ET were redesigned to handle LOX and RP-1, it would be structurally a bit heavier, but could carry twice as much payload into orbit for the same tankage volume. RP-1 remnants should evaporate to space upon venting.The bulk of the hydrocarbons may "evaporate" out, but there will always be a thin film left on the tank walls. Ever try to pump down a vacuum chamber after it was contaminated with oil? You can pump against it until you turn blue (Cryo Pump,Diffusion Pump,Turbo Molecular Pump,chose your weapon) and never get much beyond the milli torr range because of the hydrocarbons left behind. The RP-1 will have to be scrubbed out by hand. I can lay may hands on a small vacuum chamber that had an oil handling accident (#@$! oil roughing pump) , It has been scrubbed, and I can still smell the oil in it. The RP-1 tank will be 1/16th the size of the O2 tank. Why mess with the RP-1 tank at all.Also, any foam dust that "popcorns" off will possibly redeposit itself on other parts of the station, like the solar wings, for example. Over time, this could be a major problem...Simon
mlorrey - 6/6/2006 12:22 PMQuotekevin-rf - 6/6/2006 11:18 AMQuotemlorrey - 5/6/2006 10:55 PMIf the ET were redesigned to handle LOX and RP-1, it would be structurally a bit heavier, but could carry twice as much payload into orbit for the same tankage volume. RP-1 remnants should evaporate to space upon venting.The bulk of the hydrocarbons may "evaporate" out, but there will always be a thin film left on the tank walls. Ever try to pump down a vacuum chamber after it was contaminated with oil? You can pump against it until you turn blue (Cryo Pump,Diffusion Pump,Turbo Molecular Pump,chose your weapon) and never get much beyond the milli torr range because of the hydrocarbons left behind. The RP-1 will have to be scrubbed out by hand. I can lay may hands on a small vacuum chamber that had an oil handling accident (#@$! oil roughing pump) , It has been scrubbed, and I can still smell the oil in it. The RP-1 tank will be 1/16th the size of the O2 tank. Why mess with the RP-1 tank at all.Well, I know one way to get rid of the RP-1: after venting, seal and fill with 100 millibars of pure O2. Light a match. The resulting combustion will not overpressure the tank.
mlorrey - 6/6/2006 1:27 PMQUOTE]Any ET that uses RP-1 is going to need a lot less foam, ergo less popcorning, if any. However, the popcorn affect that is alleged is why I've proposed wrapping or sleeving the tank in orbit by orbital personnel.
mlorrey - 5/6/2006 5:35 PMHere's my proposed LV constellation, which would put into LEO a regular supply of ETs for salvage or use in space station modules. The ETs would launch with framing, grille decking, hatches, and conduits installed in the tanks, with a fuel scavenge system in the intertank and deployable solar panels on the sides. These ET launchers would drop all but one main engine at 65-70% of fuel burned, to boost payload in orbit. The engines may or may not be recoverable and/or reusable.
J Britt RSA - 6/6/2006 7:31 PMQuotemlorrey - 5/6/2006 5:35 PMHere's my proposed LV constellation, which would put into LEO a regular supply of ETs for salvage or use in space station modules. The ETs would launch with framing, grille decking, hatches, and conduits installed in the tanks, with a fuel scavenge system in the intertank and deployable solar panels on the sides. These ET launchers would drop all but one main engine at 65-70% of fuel burned, to boost payload in orbit. The engines may or may not be recoverable and/or reusable.mlorrey - do you have a bigger version of the ext_tank_ssto_small.jpg ? As a hobby rocketeer, i'm interested in your design.
Kayla - 26/5/2006 6:15 AMThese comments get to the heart of why I have suggested the use of smaller launchers with cryo transfer instead of the CaLV. The CaLV is so large that it will only fly occasionally,
bad_astra - 10/6/2006 12:32 AMRaytheon and others had perfectly acceptable plans that wouldn't have required too many launches to build a lunar base. For whatever reasons ESAS chose to ignore all of them.
publiusr - 9/6/2006 5:47 PMQuoteKayla - 26/5/2006 6:15 AMThese comments get to the heart of why I have suggested the use of smaller launchers with cryo transfer instead of the CaLV. The CaLV is so large that it will only fly occasionally, Same with Delta IV--which has no engine out. CaLV is a must for it reduces assembly and is a step into the future of real space. EELV assembly is daft--and ISS's delays are proof of that. This 20 ton at a time stuff is thre wrong way to go.
gladiator1332 - 10/6/2006 8:08 PMQuotepubliusr - 9/6/2006 5:47 PMQuoteKayla - 26/5/2006 6:15 AMThese comments get to the heart of why I have suggested the use of smaller launchers with cryo transfer instead of the CaLV. The CaLV is so large that it will only fly occasionally, Same with Delta IV--which has no engine out. CaLV is a must for it reduces assembly and is a step into the future of real space. EELV assembly is daft--and ISS's delays are proof of that. This 20 ton at a time stuff is thre wrong way to go.Totally agree with you. We have barely flown the Delta IV so we do not know if there are problems hidden somewhere. We'll have a delay and a half finished spacecraft floating around up there wasting away.
Norm Hartnett - 28/5/2006 11:55 PMSo in amongst the massive amount of OT stuff in this thread we got some possibly good data on the Atlas packages. Anyone want to present the Delta packages?Everything I read indicates that Griffin is not in love with the Stick and this thread http://forum.nasaspaceflight.com/forums/thread-view.asp?tid=2710&posts=5&start=1 indicates he isn't wed to ESAS's version of manrated either.
Kayla - 11/6/2006 9:25 AMGriffin:"Many, if not most, unmanned payloads are of very high value, both for the importance of their mission, as well as in simple economic terms. The relevant question may be posed quite simplistically: What, precisely, are the precautions that we would take to safeguard a human crew that we would deliberately omit when launching, say, a billion-dollar Mars Exploration Rover (MER) mission? The answer is, of course, “none”. While we appropriately value human life very highly, the investment we make in most unmanned missions is quite sufficient to capture our full attention."
mlorrey - 11/6/2006 4:59 PMQuoteKayla - 11/6/2006 9:25 AMGriffin:"Many, if not most, unmanned payloads are of very high value, both for the importance of their mission, as well as in simple economic terms. The relevant question may be posed quite simplistically: What, precisely, are the precautions that we would take to safeguard a human crew that we would deliberately omit when launching, say, a billion-dollar Mars Exploration Rover (MER) mission? The answer is, of course, “none”. While we appropriately value human life very highly, the investment we make in most unmanned missions is quite sufficient to capture our full attention."This is a good point. I'm not sure what current life insurance actuaries say a human life is worth, monetarily (and of course, the investment in training someone to be an astronaut increases that singificantly, but I recall at one time it was an average of $6.5 million per person), but with payloads themselves worth hundreds of millions, if not billions, of dollars, the idea that a rocket needs to be sufficiently more reliable to be "man rated" is ludicrous from a utilitarian standpoint: you lose as much economically by losing an expensive payload. Financially, losing 7 astronauts at once is a loss of less than a hundred million dollars worth of payload.Granted, this is very callously utilitarian, and many may feel that a human life is "priceless", the fact is that courts of law find the worth of a human life in jury awards for wrongful death every day.
SMetch - 26/5/2006 11:50 AMQuoteKayla - 25/5/2006 6:17 PMThe Atlas V HLV/DEC provides sufficient upper stage thrust such that the nominal ascent profile only has to be slightly further depressed to close the black zones, causing almost no performance drop off.My memory is that accounting for the LVHM and minor other human rating modifications, the Atlas V HLV/DEC ISS performance is ~28.9 mT.Thanks for the infoOne of the ways we could save a lot of money in servicing the ISS would be to ship up a lighter CEV/SM (ISS Config) vehicle in the first place. I’m pretty sure the Russians are not sending people up to ISS with anything heavy as the current SRB/CLV does.One of the big problems with the SRB/CLV is the first stage only has one general power setting. You have to add mass to hold it down. One size never fits all. As such they must send up a lunar configured CEV/SM to the ISS every time.What are the ISS performance (man launch) numbers for all the entire Atlas Line? I’m trying to match an ISS CEV/SM with another lunar architecture we are working on.If we can get the ISS mission done with a smaller EELV utilizing the same CEV with an ISS and Lunar SM variant we could save a lot of money and time.For the Boeing Delta Line, one core booster might be sufficient. With less engines to go wrong this should help in the reliablilty department.
Kayla - 11/6/2006 4:47 PMLEO performance for the Atlas V dual engine Centaur is 11.3 mT with an estimated reliability of over 0.996.Or for a little more performance, the Atlas Phase 1 (4 RL10’s) performance is 12.4 mT (or 13.3 mT with 6 RL10’s) with greater reliability than today’s Atlas V.Designing this minimal ISS only propulsion module now, would free up time for NASA to develop a high performance cryo (preferably LH2 over LCH4) propulsion module for the lunar missions.
Kayla - 11/6/2006 6:55 AMQuotegladiator1332 - 10/6/2006 8:08 PMQuotepubliusr - 9/6/2006 5:47 PMQuoteKayla - 26/5/2006 6:15 AMThese comments get to the heart of why I have suggested the use of smaller launchers with cryo transfer instead of the CaLV. The CaLV is so large that it will only fly occasionally, Same with Delta IV--which has no engine out. CaLV is a must for it reduces assembly and is a step into the future of real space. EELV assembly is daft--and ISS's delays are proof of that. This 20 ton at a time stuff is thre wrong way to go.Totally agree with you. We have barely flown the Delta IV so we do not know if there are problems hidden somewhere. We'll have a delay and a half finished spacecraft floating around up there wasting away. You are worried about the fact that the Delta IV has barely flown? With 5 successful flights under Delta's belt, and 8 for Atlas V the EELV program is well on its way of demonstrating its reliability and capability with 2 independent rockets. Yes, Delta has had some major delays, but that is typical of new rocket programs. The DoD is paying to get through this rough period and Delta will be fully operational in the next couple of years, long before the CLV even demo flight in 2009. Atlas V, having the advantage of being more derived than Delta IV, has been very successful in meeting its launch day promises, averaging about 1 day of delay for the past 6 launches.With the SDLV CLV on the other hand, NASA will have to pay for the full development cost and then all of the early flight glitches as well and then NASA gets the benefit of paying for the full infrastructure cost of this NASA only rocket system. CLV is currently the long pole for replacing the Shuttle, with an ILC of 2012 and first crew flight in 2014. Any additional delays will further delay America's human space program. A couple of years delay is likely based on past programs. Are we willing to have a likely 6 year period with no American crew access to space? Do we continue to launch shuttles during this period, draining $4 to $5B from exploration. These issues are likely to jeopardize sending astronauts to the moon prior to 2020!!!
A launch architecture as complex as Space Exploration surely would take more than a 6-month ESAS team study, then to have many of its key decision reverted in a few short months.
Kayla - 15/6/2006 6:18 PMWhat most people ignore here is that none of us are proposing reducing NASA’s budget. NASA’s money in the end pays for jobs. If we spend a lot on SDLV those jobs will be the current jobs tied up in shuttle with very little spent on the exploration end. If we choose a cheaper alternative launch architecture, NASA will be able to afford more in-space and lunar/Mars work. Once again this means jobs, not the shuttle jobs but new jobs. This change scares people. What needs to be remembered is that NASA’s money will wind up enabling jobs regardless of the architecture. With this in mind, we really should be seeking an architecture that creates results, actual astronauts on the lunar surface. Crewed missions to Mars. All while not sacrificing the unmanned science. A NASA that is showing America’s exploration preeminence is much more likely to get Congresses support than a NASA that can barely support ISS.
Kayla - 15/6/2006 6:18 PMWhat most people ignore here is that none of us are proposing reducing NASA’s budget. NASA’s money in the end pays for jobs. If we spend a lot on SDLV those jobs will be the current jobs tied up in shuttle with very little spent on the exploration end. If we choose a cheaper alternative launch architecture, NASA will be able to afford more in-space and lunar/Mars
Kayla - 15/6/2006 7:18 PMWhat most people ignore here is that none of us are proposing reducing NASA’s budget. NASA’s money in the end pays for jobs. If we spend a lot on SDLV those jobs will be the current jobs tied up in shuttle with very little spent on the exploration end. If we choose a cheaper alternative launch architecture, NASA will be able to afford more in-space and lunar/Mars work. Once again this means jobs, not the shuttle jobs but new jobs. This change scares people.What needs to be remembered is that NASA’s money will wind up enabling jobs regardless of the architecture. With this in mind, we really should be seeking an architecture that creates results, actual astronauts on the lunar surface. Crewed missions to Mars. All while not sacrificing the unmanned science. A NASA that is showing America’s exploration preeminence is much more likely to get Congresses support than a NASA that can barely support ISS.
Kayla - 11/6/2006 4:47 PMQuoteSMetch - 26/5/2006 11:50 AMQuoteKayla - 25/5/2006 6:17 PMThe Atlas V HLV/DEC provides sufficient upper stage thrust such that the nominal ascent profile only has to be slightly further depressed to close the black zones, causing almost no performance drop off.My memory is that accounting for the LVHM and minor other human rating modifications, the Atlas V HLV/DEC ISS performance is ~28.9 mT.Thanks for the infoOne of the ways we could save a lot of money in servicing the ISS would be to ship up a lighter CEV/SM (ISS Config) vehicle in the first place. I’m pretty sure the Russians are not sending people up to ISS with anything heavy as the current SRB/CLV does.One of the big problems with the SRB/CLV is the first stage only has one general power setting. You have to add mass to hold it down. One size never fits all. As such they must send up a lunar configured CEV/SM to the ISS every time.What are the ISS performance (man launch) numbers for all the entire Atlas Line? I’m trying to match an ISS CEV/SM with another lunar architecture we are working on.If we can get the ISS mission done with a smaller EELV utilizing the same CEV with an ISS and Lunar SM variant we could save a lot of money and time.For the Boeing Delta Line, one core booster might be sufficient. With less engines to go wrong this should help in the reliablilty department.NASA dropped the high performance cryo LO2/LCH4 propulsion module for the CEV because of the need to get the CEV flying quickly. I completely agree that if we want to use the CEV for ISS access as soon as possible following 2010 a storable propulsion module is what is needed. However, assuming that this storable propulsion module will also work for lunar missions is significantly degrading or increasing the launch requirements for the lunar missions.If CEV were to have a minimal storable propulsion module to support ISS missions the CEV weight would be a fraction of the 25 mT full up CEV. This is especially true if the CEV were delivered to an ISS proximity orbit. With the CEV (no propulsion module) weight under 10 mT: http://www.nasa.gov/pdf/140636main_ESAS_05.pdf page 223, how light could a very simple propulsion module be. Challenge the CEV team a little and it might be able to fly on the existing Atlas V single stick vehicle:LEO performance for the Atlas V dual engine Centaur is 11.3 mT with an estimated reliability of over 0.996.Or for a little more performance, the Atlas Phase 1 (4 RL10’s) performance is 12.4 mT (or 13.3 mT with 6 RL10’s) with greater reliability than today’s Atlas V.Designing this minimal ISS only propulsion module now, would free up time for NASA to develop a high performance cryo (preferably LH2 over LCH4) propulsion module for the lunar missions.
SMetch - 30/6/2006 1:28 PMKayla, how do you handle aborts after the Launch Abort System has been jettisoned? Under the current plan the SM Primary Engine performs that role. The only other way would be to carry the LAS higher up into the orbit. It seems to me if we had separate LAS motors we could fire at intervals on the way up we could add some deltaV, lighten the load and still have enough for lower deltaV abort requirements at the higher altitudes.
Jim - 30/6/2006 10:57 AMQuoteSMetch - 30/6/2006 1:28 PMKayla, how do you handle aborts after the Launch Abort System has been jettisoned? Under the current plan the SM Primary Engine performs that role. The only other way would be to carry the LAS higher up into the orbit. It seems to me if we had separate LAS motors we could fire at intervals on the way up we could add some deltaV, lighten the load and still have enough for lower deltaV abort requirements at the higher altitudes.The SM does it, just like the current CLV. LAS is only for abort and simple as possible. Adding all the extra circuitry, extra ignitors and modes defeats it's purpose. Just one motor for escape. The thrust for abort has to be enough for approx 15 g's.Lighting the LAS motors, subjects the CM to exhaust products, and imposes loads on the CM/SM interface, which don't exist in a standard abort. Breaking up the motor into smaller ones won't be too many Jettisioning early probably gives more performance than can be supplied by the motorThere is a thread on this elsewhere
Jim - 1/7/2006 7:26 AMThe late aborts not driven by "out of control" upperstages, but by reduced capabilitie like power failures in the upperstage, early depletion, engine shutdowns etc. That's why the LES/LES is/was jettison, the abort modes are less severe.The SM will need more than just RCS anyways. Some Rendezvous adjustments will need higher thrust i.e. main engine. 14 SRMs for an abort system? Control of them and timing? You just have complicated things greatly and for an emergency system The LES for Apollo had ONE abort motor with 4 nozzles and a very small pitch motor.
Jim - 3/7/2006 12:12 PM3 g's is not a requirement for the CLV (it is between 4-5 g's) and the J-2 does not throttle. Part of the abort sequence IS shutting down all stages, which the range safety system does also. Therefore, a stage can not be shutdown is not a credible failure. There never had been a requirement to out run a stage (except for the current CLV SRM), never. The requirement is to outrun a fireball/shockwave, which only happens in the lower atmosphere on lower stages. At altitudes, the thinner atmosphere doesn't transmit the shock wave. That is why the LAS can be jettisoned after a certain point. There was never an issue with outrunning the shockwave after LAS jsettison.There is only ONE motor for the LAS. Simplicity is the rule. No multiple motors and circuitry. Building demolitions use ordnance lines not electric circuits. and people's lives don't depend on them. Crew does not die with a J-2 failure.OMS was .05 T/W and really didn't do the abort to orbit (the SSME still had to provide the bulk of the impulse) The RCS for the CEV is .005 to .02 much less. Apollo's SME was 20K, close to 1your plan will increase the per flight costs with an extra segment, extra SRB components and extra J-2. Might as well do an heavy EELV.
Jim - 3/7/2006 7:57 PMOMS burns are just little burps, not the same abort to orbit. It is the same thing they want to do with the CLV. There is no need to protect against an exploding J-2. Those events happen at ignition, where the LAS is still there. You do a controlled shutdown if you lose TVC, or other associate systems. Or if chamber pressure, temp, turbine speed or other parameters are trending to the bad.The LAS is jettison at the appropriate time when analysis shows there is not threat from the shock wave and the CEV can survive. Why else did they do it this way for Apollo. It was to save weight, it was because it was no longer needed.the LAS is mostly for first stage. Once safe recovery altitude is reached
SMetch - 6/7/2006 12:21 PMSo given that an out of control upper stage could out run any in space designed spacecraft thrust unit the minimum design of an attached spacecraft thrust unit would for final orbit insertion and de-orbit maneuvers correct?Stated another way after second stage ignition and LAS jettison, if the upper stage fails catastrophically or cannot be shut down the crew would be in trouble.While our approach would save the crew in that contingency it has a price in terms of weight to orbit regardless of whether we partially fire the LAS motors on ascent or not. If everyone is fine with the above failure scenario no need to penalize our approach.
Jim - 6/7/2006 9:57 AMQuoteSMetch - 6/7/2006 12:21 PMSo given that an out of control upper stage could out run any in space designed spacecraft thrust unit the minimum design of an attached spacecraft thrust unit would for final orbit insertion and de-orbit maneuvers correct?Stated another way after second stage ignition and LAS jettison, if the upper stage fails catastrophically or cannot be shut down the crew would be in trouble.While our approach would save the crew in that contingency it has a price in terms of weight to orbit regardless of whether we partially fire the LAS motors on ascent or not. If everyone is fine with the above failure scenario no need to penalize our approach.Not a credible failure. Do you actually think Apollo ignored this? Same with Gemini. Shutting down engines is easy. Ask Elon Musk. All engines use valves that need power to stay open. Remove power (multiple ways of doing this) and the engine shuts down.
Kayla - 16/6/2006 1:18 AMWhat most people ignore here is that none of us are proposing reducing NASA’s budget. NASA’s money in the end pays for jobs. If we spend a lot on SDLV those jobs will be the current jobs tied up in shuttle with very little spent on the exploration end. If we choose a cheaper alternative launch architecture, NASA will be able to afford more in-space and lunar/Mars work. Once again this means jobs, not the shuttle jobs but new jobs. This change scares people. What needs to be remembered is that NASA’s money will wind up enabling jobs regardless of the architecture. With this in mind, we really should be seeking an architecture that creates results, actual astronauts on the lunar surface. Crewed missions to Mars. All while not sacrificing the unmanned science. A NASA that is showing America’s exploration preeminence is much more likely to get Congresses support than a NASA that can barely support ISS.
SMetch - 3/7/2006 9:34 AMExplain to me how an upperstage, which needs to be throttled back so as not over accelerating a combinded vehicle beyond 3g’s, does not over take a vehicle at its nose with a thrust to weight less than ½ g.This has always been a problem. Even during Apollo the crew would have been killed after the LAS jettison if the 2nd stage could not be shut down. Given an explosive event in the 2nd stage they would be dead again with the SM engine not capable of getting outside the range of explosion in time. Either way this has always been a dangerous condition which our solution will solve and at the same time not require carrying the complete weight of the LAS to orbit. It’s amazing how this danger zone is somehow ignored when discussing steps that must be taken to “man-rate” a vehicle. In fact this means that for half of the manrated ascent the crew will die, go figure.
josh_simonson - 13/7/2006 5:41 PMHere's an interesting question: Does the SM of the CEV have enough delta-V to save it if it were stranded on a lofted trajectory by an EELV failure? If the SM fails, the crew will be lost anyway, might as well count on it to save the crew in an emergency - 1500m/s delta-V is quite a bit for use in a pinch.
yinzer - 13/7/2006 7:03 PMThe lofting can be solved - requires either reduced payload or additional upper-stage thrust. Lockheed explicitly considered both, I'm not sure what Boeing did. In any event, the current CLV/CEV combo relies on the SM motor during aborts to keep the capsule out of the North Atlantic during winter.What could, and probably should (IMHO) be done, is to provide triple-redundant IMU/RCS so that they can control the entry and fly a lifting trajectory. This would pay off especially well with the biconic/ellipsled entry vehicles and their higher L/D.
Jim - 13/7/2006 5:15 PMQuoteyinzer - 13/7/2006 7:03 PMThe lofting can be solved - requires either reduced payload or additional upper-stage thrust. Lockheed explicitly considered both, I'm not sure what Boeing did. In any event, the current CLV/CEV combo relies on the SM motor during aborts to keep the capsule out of the North Atlantic during winter.What could, and probably should (IMHO) be done, is to provide triple-redundant IMU/RCS so that they can control the entry and fly a lifting trajectory. This would pay off especially well with the biconic/ellipsled entry vehicles and their higher L/D.there will be a backup RCS/control system on the CEV
yinzer - 13/7/2006 5:28 PMQuoteJim - 13/7/2006 5:15 PMQuoteyinzer - 13/7/2006 7:03 PMThe lofting can be solved - requires either reduced payload or additional upper-stage thrust. Lockheed explicitly considered both, I'm not sure what Boeing did. In any event, the current CLV/CEV combo relies on the SM motor during aborts to keep the capsule out of the North Atlantic during winter.What could, and probably should (IMHO) be done, is to provide triple-redundant IMU/RCS so that they can control the entry and fly a lifting trajectory. This would pay off especially well with the biconic/ellipsled entry vehicles and their higher L/D.there will be a backup RCS/control system on the CEVBut not a full-flegded backup RCS/control system. In the ESAS report, they used the requirement for passive entry to eliminate slender body re-entry vehicles, but then when it turned out that they couldn't guarantee safe re-entry of the capsule, they added the back-up RCS.