Oh No! Bye -Bye Ares 1

kyle_baron · Nov 29, 2008

http://www.space.com/spacenews/spacenews_summary.html#BM_3The questionnaire, "NASA Presidential Transition Team Requests for Information," asks agency officials to provide the latest information on Ares 1, Orion and the planned Ares 5 heavy-lift cargo launcher, and to calculate the near-term close-out costs and longer-term savings associated with canceling those programs. The questionnaire also contemplates a scenario where Ares 1 would be canceled but development of the Ares 5 would continue. Obama's NASA transition team also asked agency officials to investigate how much it would cost and how long it would take to build a smaller version of Orion and human-rate an Atlas 5 or Delta 4 expendable rocket to serve as its launcher. Additionally, the questionnaire requests that NASA "[e]stimate the feasibility of designing a resized Orion capsule that could be launched by international launch vehicles such as the [European] Ariane 5 or the [Japanese] H2A." The transition team also wants information from NASA about accelerating plans for using the agency's Commercial Orbital Transportation Services (COTS) program to fund demonstrations of vehicles capable of carrying crews to the international space station, a proposal Obama supported during his campaign. NASA is not asked what it could save by canceling COTS. Nor is NASA asked to contemplate canceling the space shuttle or space station programs, although the transition team does request the budget implications of flying the shuttle until 2015 and committing to U.S. utilization of the space station through 2020. Meanwhile, a page of questions devoted to NASA's Science Mission Directorate requests status reports on various flight projects currently in development. The transition team asked NASA to estimate the cost of implementing the full slate of 15 Earth science missions recommended by the National Research Council last year as part of its first-ever Earth science decadal survey. Under NASA's current budget plans, the agency would make only a small dent in the list by 2020. Obama's NASA transition team also appears to be interested in a number of specific projects that have more or less languished in recent years. Among those projects are: the Deep Space Climate Observatory;, a mothballed Earth-observing satellite formerly known as Triana; agency efforts to catalog asteroids and comets that could threaten Earth; and the harnessing of space-based solar power for use on Earth.   <div class="Discussion_UserSignature"> </div>

edkyle99 · Nov 29, 2008

Ares/Orion isn't perfect, but it is the plan for returning U.S. astronauts to the Moon.  It has been strenuously opposed by certain armchair engineers who believed they had a better idea.  Their opposition, heavily publicized by certain news outlets, has, I believe, contributed to the possible cancellation of Ares I by the Obama administration, which will mean no U.S. astronauts on the Moon.  It will be a shame. - Ed Kyle

aphh · Nov 29, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Ares/Orion isn't perfect, but it is the plan for returning U.S. astronauts to the Moon.  It has been strenuously opposed by certain armchair engineers who believed they had a better idea.  Their opposition, heavily publicized by certain news outlets, has, I believe, contributed to the possible cancellation of Ares I by the Obama administration, which will mean no U.S. astronauts on the Moon.  It will be a shame. - Ed Kyle Posted by edkyle99</DIV>Are you sure Delta 4 or Ariane 5 could not launch the crew to orbit to rendezvous with the moon hardware? At first glance I thought the Obama team seemed pretty smart and informed, but that was just the first impression.I could be wrong, ofcourse. In any case, it seems like decisions will be made.

rubicondsrv · Nov 29, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Are you sure Delta 4 or Ariane 5 could not launch the crew to orbit to rendezvous with the moon hardware? At first glance I thought the Obama team seemed pretty smart and informed, but that was just the first impression.I could be wrong, ofcourse. In any case, it seems like decisions will be made. Posted by aphh</DIV> delta IV heavy could perform most if not all of the requirments of ares 1except for the developement of J2siirc the aresV and ares 1 srb's use different grain geometry so i dont know if the lack of ares 1 SRB would affect ares V  <div class="Discussion_UserSignature"> </div>

DrRocket · Nov 30, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>delta IV heavy could perform most if not all of the requirments of ares 1except for the developement of J2siirc the aresV and ares 1 srb's use different grain geometry so i dont know if the lack of ares 1 SRB would affect ares V  Posted by rubicondsrv</DIV> Without Ares I, the infrastructure to desig and produce the solids for Ares V and many other solids will be sorely stressed for lack of business support.  I don't think the geometries are all that different.  I was under the impression that the difference was the addition of 1/2 segment extending the length, but that the top segment, with the fins, was the same.  I would have to get more information on that to be sure though.  <div class="Discussion_UserSignature"> </div>

ThereIWas2 · Nov 30, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>...build a smaller version of Orion and human-rate an Atlas 5 or Delta 4 expendable rocket to serve as its launcher.</DIV>Finally, a reality check on NASA's plans.   Returning to the moon is hardly a top priority when facing a depression, climate change, and international instability.  <div class="Discussion_UserSignature"> </div>

frodo1008 · Nov 30, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Finally, a reality check on NASA's plans.   Returning to the moon is hardly a top priority when facing a depression, climate change, and international instability.  Posted by ThereIWas2</DIV>Returning to the moon still should be a priority.  Your other points are not valid, and have not been valid for the entire space program.  Perhaps we should then just cancel NASA entirely (which would do absolutely nothing for even the deficit, let alone the entire federal budget.What is at stake is the design of the Ares I, which may very well be flawed enough to have NASA seriously look for other means of placing human beings into LEO.  And that may very well be a good thing in the long run!  It seems that every time I come onto these forums there is another problem with the Ares I design.  Personally, I think that NASA re-inventing the wheel is both expensive and quite necessary.  We are the only country that even uses such large solid rocket motors at all.  Perhaps all the other rocket people in the world just might have something going for them after all?

vulture4 · Nov 30, 2008

Some of the Obama proposals are unlikely to work out, but their basic point is right on the mark. The only mission that requires the Ares I is sending people to the moon on a crash program basis. At this point in time, America is facing a financial crisis and needs programs that will provide practical benefits. We said we would produce these benefits with the ISS and got $100B to build it. The main reason given by some for dropping the ISS and rushing to the moon now is that "we are bored with LEO". I have never met anyone who was actually IN LEO and was bored with it. I have personally worked on a program that could save thousands of lives, but can't get funding because there's no money for anything that isn't on the "critical path" to the moon. Just how many lives is it worth? I suggest we pull the plug on this turkey and start doing some useful work, both on earth and in space.

edkyle99 · Nov 30, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Are you sure Delta 4 or Ariane 5 could not launch the crew to orbit to rendezvous with the moon hardware? At first glance I thought the Obama team seemed pretty smart and informed, but that was just the first impression.I could be wrong, ofcourse. In any case, it seems like decisions will be made. Posted by aphh</DIV>The Obama team asked about launching a scaled back (which means less capable) Orion on an EELV,   Regardless, the currently available EELV models can not launch a full weight, lunar-mission Orion.  Launch vehicle upgrades would be needed. It wouldn't save time and it would probably cost more money.  Use of EELV would also mean that J-2Xand five-segment booster, necessary for the lunar mission, would not be developed.This would be a disasterous U.S. retreat from human space exploration leadership. - Ed Kyle

rubicondsrv · Nov 30, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>The Obama team asked about launching a scaled back (which means less capable) Orion on an EELV,   Regardless, the currently available EELV models can not launch a full weight, lunar-mission Orion.  Launch vehicle upgrades would be needed. It wouldn't save time and it would probably cost more money.  Use of EELV would also mean that J-2Xand five-segment booster, necessary for the lunar mission, would not be developed.This would be a disasterous U.S. retreat from human space exploration leadership. - Ed Kyle    Posted by edkyle99</DIV> delta IV heavy with uprated rs68 is already in the works.there is no need to scale back orion for DIVh. <div class="Discussion_UserSignature"> </div>

oscar1 · Nov 30, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Returning to the moon still should be a priority....  Posted by frodo1008</DIV>I would think that going [back] to the Moon would have to have some tangible benefit before we do it. If we'd go there to go and mine and enrich uranium, we would be investing in something that can secure a long term energy source. But if we don't go there for the latter purpose, the only thing we would achieve is that we can proudly say to ourselves that we have managed some sort of colony on another body than Earth'. I am all for the [prolonged] ISS, because it can teach us a lot, and does it indeed enhance worldwide co-operation, but the Moon is like the middle of a desert or of [ant]Arctica; nothing there to excite any human being. As a way-station it is also not that practical, for we'd need extra docking (landing) and departing rigmarole due to the Moon's gravity.

edkyle99 · Nov 30, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>delta IV heavy with uprated rs68 is already in the works.there is no need to scale back orion for DIVh. Posted by rubicondsrv</DIV>Griffin has said that Atlas V was NASA's preferred crew launch EELV, if an EELV was to be used.  That would require development of Atlas V Heavy and of a domestic production source for RD-180. - Ed Kyle

trailrider · Nov 30, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>http://www.space.com/spacenews/spacenews_summary.html#BM_3The questionnaire, "NASA Presidential Transition Team Requests for Information," asks agency officials to provide the latest information on Ares 1, Orion and the planned Ares 5 heavy-lift cargo launcher, and to calculate the near-term close-out costs and longer-term savings associated with canceling those programs. The questionnaire also contemplates a scenario where Ares 1 would be canceled but development of the Ares 5 would continue. Obama's NASA transition team also asked agency officials to investigate how much it would cost and how long it would take to build a smaller version of Orion and human-rate an Atlas 5 or Delta 4 expendable rocket to serve as its launcher. Additionally, the questionnaire requests that NASA "[e]stimate the feasibility of designing a resized Orion capsule that could be launched by international launch vehicles such as the [European] Ariane 5 or the [Japanese] H2A." The transition team also wants information from NASA about accelerating plans for using the agency's Commercial Orbital Transportation Services (COTS) program to fund demonstrations of vehicles capable of carrying crews to the international space station, a proposal Obama supported during his campaign. NASA is not asked what it could save by canceling COTS. Nor is NASA asked to contemplate canceling the space shuttle or space station programs, although the transition team does request the budget implications of flying the shuttle until 2015 and committing to U.S. utilization of the space station through 2020. Meanwhile, a page of questions devoted to NASA's Science Mission Directorate requests status reports on various flight projects currently in development. The transition team asked NASA to estimate the cost of implementing the full slate of 15 Earth science missions recommended by the National Research Council last year as part of its first-ever Earth science decadal survey. Under NASA's current budget plans, the agency would make only a small dent in the list by 2020. Obama's NASA transition team also appears to be interested in a number of specific projects that have more or less languished in recent years. Among those projects are: the Deep Space Climate Observatory;, a mothballed Earth-observing satellite formerly known as Triana; agency efforts to catalog asteroids and comets that could threaten Earth; and the harnessing of space-based solar power for use on Earth.   Posted by kyle_baron</DIV>Why do you ass-u-me that the RFI is pointed at any program in particular?  "John Logsdon, a space policy expert at the Smithsonian National Air and Space Museum, cautioned against reading too much into the transition team's questions. 'After all, these are the questions that everyone is asking, and the transition team certainly must get NASA's best answers to them," Logsdon said, adding that the questionnaire "is unlikely to reflect the totality" of the transition team's investigation of current programs and alternatives."That is likely to take some weeks and involve lots of questions to lots of people. So I would not overinterpret and come to any conclusion regarding what direction the team may be headed — after all, there is still almost two months left in the transition.' " Sounds like "due dilligence" to me!  How can we expect any kind of intelligent...or not so intelligent...decision to be made without Obama's team learning just what the costs and results might be from any number of different actions?  If it turns out that "Bye-bye Ares I" is the better way to go, then so be it.  Personally, I want to see America go back to the Moon, and then Mars, and beyond.  But, I don't care if the means to get there is Wiley E. Coyote's Acme Slingshot!  What I don't want is for the United States to become the "Portugal" of the Space Age!  Let's see what happens before we panic.  Then, after the decisions are made...then we can panic!Ad LEO! Ad Luna! Ad Ares! Ad Astra!

frodo1008 · Nov 30, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>I would think that going [back] to the Moon would have to have some tangible benefit before we do it. If we'd go there to go and mine and enrich uranium, we would be investing in something that can secure a long term energy source. But if we don't go there for the latter purpose, the only thing we would achieve is that we can proudly say to ourselves that we have managed some sort of colony on another body than Earth'. I am all for the [prolonged] ISS, because it can teach us a lot, and does it indeed enhance worldwide co-operation, but the Moon is like the middle of a desert or of [ant]Arctica; nothing there to excite any human being. As a way-station it is also not that practical, for we'd need extra docking (landing) and departing rigmarole due to the Moon's gravity. Posted by oscar1</DIV>The upgrading of the RS68 engines would take those engines from their current 665k thrust up the 1.0 meg thrust level (a far less expensive undertaking than upgrading those huge solids is going to be).  I can back this up as I was a small part of the original RS68 people at Rocketdyne.  The ENTIRE EELV project of the Air Force cost about $3 billion, and that includes a totally new liquid engine in the RS68.  Originally I was for using the existing shuttle four segment SRB's for the Ares I, as I thought that would be cheaper than building a whole new rocket.  However, it turns out that the existing SRB's will not be enough, so NASA asked ATK for a price to upgrade the current shuttle srb's.  ATK comes up with a $5 billion dollar price tag!  That is almost twice as much as the entire Delta IV, and Atlas V EELV's cost, totally!  And NASA is going along with this due to some very powerful congress people from the state of Utah!  Using all three engines at that upgraded thrust for the RS68's gives a first stage thrust of some 3,0 megfor the Delta IV Heavy.  This is just as much, if not more than the extended solids would give.  This would also mean that the J2-X would still be quite usable for the second stage, giving that particular configuration just as much ability to place the Orion capsule into LEO as the trouble plagued current Ares I design!The only downside that I can see is that NASA has already sunk so much money into the current design.  But then I can think of a great many such projects that both NASA and the US military have done that very thing with.NASA's entire budget is nothing but noise when compared to such budgets as the military's anyway.  So I would actually not like to see NASA going down its present path here.  While I do support going back to the moon, I would like to see it done with far less politics involved, and if possible with far less cost due to those politics!

frodo1008 · Nov 30, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>I would think that going [back] to the Moon would have to have some tangible benefit before we do it. If we'd go there to go and mine and enrich uranium, we would be investing in something that can secure a long term energy source. But if we don't go there for the latter purpose, the only thing we would achieve is that we can proudly say to ourselves that we have managed some sort of colony on another body than Earth'. I am all for the [prolonged] ISS, because it can teach us a lot, and does it indeed enhance worldwide co-operation, but the Moon is like the middle of a desert or of [ant]Arctica; nothing there to excite any human being. As a way-station it is also not that practical, for we'd need extra docking (landing) and departing rigmarole due to the Moon's gravity. Posted by oscar1</DIV>I have on numerous other occasions given a detailed essay here on why going on to the moon. not only for further exploration, but even more importantly to exploit the easily obtainable space age materials there.  However, as I have been sick with bronchitis lately, a detailed answer will just have to wait for awhile here.  But rest assured, I can and eventually will, give you such an answer!!  Heck, I even started an entire thread over on Open Forum as a counter to all the political mess that usually occurs there! Please be patient, and thanks for your interest!

franontanaya · Nov 30, 2008

It makes lots of sense. If in the future the US has spare money to go back to the Moon, it may aswell design a (international?) multiple launches mission with existing rockets. If not, then it's as unlikely that sending Orion sized capsules to LEO on non-commercial rockets would pay off.Solar Farms could be a good prospect for processing easier-to-lauch materials into fuel and boosting solar/ion probes. <div class="Discussion_UserSignature"> </div>

kyle_baron · Nov 30, 2008

I'm glad to see, at least we have a balanced view of Ares 1, here at space.com.  Over at NasaSpaceflight.com the only voice for Ares 1 is Ed Kyle.  For what it's worth, I'm also a fan of Ares 1.  It's an unconventional rocket, and that's why I believe it receives all the hatred.  But, I believe the SRB is the safest way to orbit, by using a single engine for each stage, as opposed to multiple throw away engines.  In the long run, I also believe it will be more economical.  <div class="Discussion_UserSignature"> </div>

Slava33 · Dec 1, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>The Obama team asked about launching a scaled back (which means less capable) Orion on an EELV,   Regardless, the currently available EELV models can not launch a full weight, lunar-mission Orion.  Launch vehicle upgrades would be needed. It wouldn't save time and it would probably cost more money.  Use of EELV would also mean that J-2Xand five-segment booster, necessary for the lunar mission, would not be developed.This would be a disasterous U.S. retreat from human space exploration leadership. - Ed Kyle    Posted by edkyle99</DIV> Actually, EELVs family was designed with heavier missions capability in mind.  Phase 3B Atlas would surpass Saturn V capability.  Of course, there is a lot of extra development to be done, especially with the upper stage(s), but probably wouldn't be as bad as designing Ares I/V from scratch. <div class="Discussion_UserSignature"> </div>

frodo1008 · Dec 1, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>I'm glad to see, at least we have a balanced view of Ares 1, here at space.com.  Over at NasaSpaceflight.com the only voice for Ares 1 is Ed Kyle.  For what it's worth, I'm also a fan of Ares 1.  It's an unconventional rocket, and that's why I believe it receives all the hatred.  But, I believe the SRB is the safest way to orbit, by using a single engine for each stage, as opposed to multiple throw away engines.  In the long run, I also believe it will be more economical.  Posted by kyle_baron</DIV>There are certain safety advantages to both solids and liquids.  In the case of solids they are simpler that liquid engines, with no moving parts.  Occam's Razor principle tells us that makes solids inherently safer that liquids.So why is NASA the only agency in the world that uses such large solids?  After all, if they are inherently safer then everybody should be using them, right?There is another factor however in using solids, that while perhaps not as well known as the simplicity factor, is so important that if taken advantage of makes liquid engines far safer than solids.It is simply that if you test a solid (large or small, it does not make any difference) that particular solid is history, it no longer exits.  Now you must depend totally upon you manufacturing process (and quality statistical process control) to make sure that every other solid motor is exactly the same as the one(s) that you tested. Indeed, ATK is to be congratulated on its having done this so very well with the large solids of the shuttle.  But, the very real potential is always there for even the smallest slip up to result in disaster (by the way, the Challenger solid rocket motor disaster was NOT of this kind). The huge advantage of liquids is that after you have tested an engine, that very same engine is just as ready to run as the actual engine used on the flight vehicle as it was to be tested originally.  For instance, the RS-27A liquid engine that is used on what is quite probably one of the most reliable launch systems in history, the Delta II launch system that NASA uses for most of its deep space probes (after all, it would be very embarrassing for NASA's deep space probe to not even make it to LEO due to a launch failure).  Rocketdyne runs a full minute "Green Run" on every RS-27A engine it manufactures.  During that run all the engine parameters that tell the engineers that the engine is performing both safely, reliably, and with the performance the engine is supposed to tun at are checked thoroughly. Then that very same engine is now certified, put into storage, and awaits the actual launch of its vehicle. Now, that does not always mean that engine will automatically be perfect either, but launches are of such a short duration that the probability of that engine failing is a whole lot smaller that that of a failure of an intested large solid motor.Now, when it comes to the SSME's their testing is on an entirely different level.  In order to pass its certification many such test runs are made on the engine, including at least one full duration (8.5 minutes) run.  So the likelihood of an engine failure is very, very low. So, when you consider the incredible performance levels that the SSME operates at routinely, such tests have created not only the highest performing engine in history, but one the most reliable ones as well!This might just be why nobody else is using, or even contemplates using, such large solid rocket motors! As to the use of multiple engines, within reason such multiples are just another guarantee of safety.  Much of the time if there is an engine failure, is is not catastrophic, and that particular engine can then be shut down.  The safety factor lies in that the rest of the engines can be run a little longer, and the mission itself still be a completed.  I believe that happened once with the central engine of a Saturn V.  Heck, it may even have happened with one of the engines of the shuttle, I don't know, perhaps somebody can tell us.On the other hand, if the only engine that us pushing your vehicle should fail for any reason, you are in for a world of hurt!!!

CalliArcale · Dec 1, 2008

A question for those who know more about rockets.....Wayne Hale, on his blog,  alluded to the fact that EELV's follow a very different flight profile than manned rockets do, because they don't have to worry about survivable abort modes.  In a satellite launch, you are pretty much operating on the assumption that if anything goes wrong, the spacecraft is a complete loss.  So they can launch more vertically and thus get better payload capacity.  Manned rockets, he said, have to launch more gently not only to reduce stresses on the crew but so that any capsule, if it has to separate during an abort, is on a trajectory that won't result in too much heating during reentry.Is this why Delta IV Heavy is said to be inadequate for an Orion launch, despite its published payload capacity exceeding the mass of Orion?   Because it's published capacity applies only to an unmanned (aka "ya ain't comin' back") trajectory? <div class="Discussion_UserSignature"> "People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff." -- The Tenth Doctor, "Blink" </div>

DrRocket · Dec 1, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>A question for those who know more about rockets.....Wayne Hale, on his blog,  alluded to the fact that EELV's follow a very different flight profile than manned rockets do, because they don't have to worry about survivable abort modes.  In a satellite launch, you are pretty much operating on the assumption that if anything goes wrong, the spacecraft is a complete loss.  So they can launch more vertically and thus get better payload capacity.  Manned rockets, he said, have to launch more gently not only to reduce stresses on the crew but so that any capsule, if it has to separate during an abort, is on a trajectory that won't result in too much heating during reentry.Is this why Delta IV Heavy is said to be inadequate for an Orion launch, despite its published payload capacity exceeding the mass of Orion?   Because it's published capacity applies only to an unmanned (aka "ya ain't comin' back") trajectory? Posted by CalliArcale</DIV>You probably need Shuttleguy to tell you why the shuttle uses a more gentle trajectory.  But I can tell you why unmanned launches go as nearly vertical as they do.In designing a rocket there is an optimization process that is used, and it includes an optimization of the trajectory, to maximize payload on orbit.  There are two major competing factors.One factor is "gravity loss".  Gravity loss is the inefficiency that occurs because one is lifting not only the payload, but also the propellant present in the rocket at any particular point time agains the force of gravity.  Energy spent in lifting propellant that is eventually burned up is basically wasted, since it does not contribute to the kinetic energy imparted to the ultimate payload.  This affects the optimization of the rate at which the propellant is burned.  In principle, if there were no other factors involved the optimal burn would be a so-called "impulse burn" in which all of the propellant would be consumed instantaneously on the launch pad, providing the necessary velocity for orbit and to overcome gravity at time 0 and then simply coasting to orbit.  That is not practical even as an approximation or else you would destroy the payload jsut through the g loads, and if the mission were manned you would wind up with a bunch of short squat astronauts.The other consideration is aerodynamic drag.  Aerodynamic drag is a function of both speed and atmospheric density.  If Aerodynamic drag were the only constraint, the speed would be kept low until the rockete was high in the atmosphere, where density is low, and then it would increase rapidly to build orbital speed with little or no drag.Clearly the concerns of aerodynamic drag and gravity losses are in conflict.  The resolution involves some detailed optimization, but that optimization allways results in a trajectory that is quite steep, so that the rocket gets out of the dense part of the atmosphere as quickly as possible, minimizing the distance (note the switch from time considerations to distance here)  traveled in dense atmosphere.  In addition the burn rate and velocity-time profile are then optimized to minimize the combination of gravity losses and aerodynamic losses along the steep trajectory.I must admit to a great deal of personal skepticism with respect to survivable abort modes.  That notion is perhaps comforting, but I am not sure that they really exist as a practical matter.  I have seen quite a few rocket motor failures, and they usually happen very very quickly -- it is not unusual for films at 400 --1000 frames per sec to look perfectly normal for most of the footage, show perhaps the start of something in one frame, and everything be gone or disentegrating in the next frame.  A one millisecond response time is not much if you have to get out of Dodge. Sometimes you might have a lot of time -- say 2 or 3 frames where you can see things happening before all is gone -- but the message is that 10 milliseconds is a long time (and it takes about 30 milliseconds for you to blink).  My personal inclination is to spend a lot of time on quality and reliability and make sure that an abort system never has to do its job.   <div class="Discussion_UserSignature"> </div>

rubicondsrv · Dec 1, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>.Is this why Delta IV Heavy is said to be inadequate for an Orion launch, despite its published payload capacity exceeding the mass of Orion?   Because it's published capacity applies only to an unmanned (aka "ya ain't comin' back") trajectory? Posted by CalliArcale</DIV> that problem has been solved for some time.ares-1 exists to enable ares V and to keep politicians happy.there is not a problem with either of those reasons however to claim eelv cannot perform ares-1 mission is misleading.  <div class="Discussion_UserSignature"> </div>

j05h · Dec 1, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>A question for those who know more about rockets.....Wayne Hale, on his blog,  alluded to the fact that EELV's follow a very different flight profile than manned rockets do, because they don't have to worry about survivable abort modes.  In a satellite launch, you are pretty much operating on the assumption that if anything goes wrong, the spacecraft is a complete loss.  So they can launch more vertically and thus get better payload capacity.  Manned rockets, he said, have to launch more gently not only to reduce stresses on the crew but so that any capsule, if it has to separate during an abort, is on a trajectory that won't result in too much heating during reentry.Is this why Delta IV Heavy is said to be inadequate for an Orion launch, despite its published payload capacity exceeding the mass of Orion?   Because it's published capacity applies only to an unmanned (aka "ya ain't comin' back") trajectory? Posted by CalliArcale</DIV>Calli - the whole "lofting trajectory" and "EELV black zone" thing is a canard floated by the anti-EELV crowd. Both Lockheed and Boeing have shown they can fly Atlas & Delta with nominal crew capsules in safe trajectories.   -Josh <div class="Discussion_UserSignature"> <div align="center">We need a first generation of pioneers. </div> </div>

DrRocket · Dec 1, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>There are certain safety advantages to both solids and liquids.  In the case of solids they are simpler that liquid engines, with no moving parts.  Occam's Razor principle tells us that makes solids inherently safer that liquids.So why is NASA the only agency in the world that uses such large solids?  After all, if they are inherently safer then everybody should be using them, right?There is another factor however in using solids, that while perhaps not as well known as the simplicity factor, is so important that if taken advantage of makes liquid engines far safer than solids.It is simply that if you test a solid (large or small, it does not make any difference) that particular solid is history, it no longer exits.  Now you must depend totally upon you manufacturing process (and quality statistical process control) to make sure that every other solid motor is exactly the same as the one(s) that you tested. Indeed, ATK is to be congratulated on its having done this so very well with the large solids of the shuttle.  But, the very real potential is always there for even the smallest slip up to result in disaster (by the way, the Challenger solid rocket motor disaster was NOT of this kind). The huge advantage of liquids is that after you have tested an engine, that very same engine is just as ready to run as the actual engine used on the flight vehicle as it was to be tested originally.  For instance, the RS-27A liquid engine that is used on what is quite probably one of the most reliable launch systems in history, the Delta II launch system that NASA uses for most of its deep space probes (after all, it would be very embarrassing for NASA's deep space probe to not even make it to LEO due to a launch failure).  Rocketdyne runs a full minute "Green Run" on every RS-27A engine it manufactures.  During that run all the engine parameters that tell the engineers that the engine is performing both safely, reliably, and with the performance the engine is supposed to tun at are checked thoroughly. Then that very same engine is now certified, put into storage, and awaits the actual launch of its vehicle. Now, that does not always mean that engine will automatically be perfect either, but launches are of such a short duration that the probability of that engine failing is a whole lot smaller that that of a failure of an intested large solid motor.Now, when it comes to the SSME's their testing is on an entirely different level.  In order to pass its certification many such test runs are made on the engine, including at least one full duration (8.5 minutes) run.  So the likelihood of an engine failure is very, very low. So, when you consider the incredible performance levels that the SSME operates at routinely, such tests have created not only the highest performing engine in history, but one the most reliable ones as well!This might just be why nobody else is using, or even contemplates using, such large solid rocket motors! As to the use of multiple engines, within reason such multiples are just another guarantee of safety.  Much of the time if there is an engine failure, is is not catastrophic, and that particular engine can then be shut down.  The safety factor lies in that the rest of the engines can be run a little longer, and the mission itself still be a completed.  I believe that happened once with the central engine of a Saturn V.  Heck, it may even have happened with one of the engines of the shuttle, I don't know, perhaps somebody can tell us.On the other hand, if the only engine that us pushing your vehicle should fail for any reason, you are in for a world of hurt!!!     Posted by frodo1008</DIV>Your liquids background and bias is showing.The plain truth is that the reliability of liquids and solids are about equal.  There are advantages and disadvantages to each.With solids the key to reliability is the simplicity of design and the attention to detail in process control.  There is also need to be rigorous in review of each booster before it is accepted for use.  With solid technical rigor solids are very reliable.  When companies get sloppy (and I have seen that happen) and do stupid things unexpected failures can occur in flight.The same comment applies to liquids.  And while it is true that liquid engines can be tested prior to flight use, it is also true that the complexity of the engines and the attendant large number of failure modes drives the need for such tests.  Ariane V ignites the liquids on the launch pad, not because the thrust is needed, but because they are afraid the liquids may not ignite in flight and can abort on the pad if they fail to ignite there.  The next solid that fails to ignite will be the first one.  They also tend not to have fuel leaks.That same Delta II, with an outstanding record of reliability,  that you mentioned flies with 9 solid boosters.  The one recent failure in which a solid motor burst at launch was also shown to not be a result of any manufacturing defect in the motor, but rather to damage sustained after delivery.  That statement also applies to another test failure of the same basic motor in another application.  You are correct in that the Challenger disaster was not the result of manufacturing or design failure.  It was a direct result of failure to operate the system under the conditions for which it was designed.  That failure was due to some poor system management, some inappropriate pressure on and by management, and pure human stupidity.  Not all of the story has been widely told.  <div class="Discussion_UserSignature"> </div>

edkyle99 · Dec 1, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>A question for those who know more about rockets.....Wayne Hale, on his blog,  alluded to the fact that EELV's follow a very different flight profile than manned rockets do, because they don't have to worry about survivable abort modes.  In a satellite launch, you are pretty much operating on the assumption that if anything goes wrong, the spacecraft is a complete loss.  So they can launch more vertically and thus get better payload capacity.  Manned rockets, he said, have to launch more gently not only to reduce stresses on the crew but so that any capsule, if it has to separate during an abort, is on a trajectory that won't result in too much heating during reentry.Is this why Delta IV Heavy is said to be inadequate for an Orion launch, despite its published payload capacity exceeding the mass of Orion?   Because it's published capacity applies only to an unmanned (aka "ya ain't comin' back") trajectory? Posted by CalliArcale</DIV>The lofted trajectory is part of it.  The fact that a manned system would have to be mounted with a heavy launch escape system not used by unmanned satellites is another part of it.  The fact that NASA requires more residual propellant margins may be part of it.  Finally, I suspect, there is a chance that Delta IV Heavy can't really do to low earth orbit what was originally claimed - which may explain why the Air Force is rapidly pushing forward with an upgraded RS-68 engine.  Seriously, why would a more powerful engine be needed if the rocket met its specs?And yes, it is a fact that Delta IV Heavy, in its current configuration, cannot meet the lunar mission Orion lift requirements.  The upgraded RS-68 version probably would meet the specs, but, as I mentioned earlier, NASA prefers Atlas V over Delta IV regardless.   - Ed Kyle

Oh No! Bye -Bye Ares 1

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