Why does NASA hate the Atlas V and Delta IV?

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tomnackid

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I think safety was the main consideration for the "stick". It is the only launch vehicle design in the performance class that has a single first stage engine. Fewer engines = fewer accidents generally speaking. Interestingly NASA considered replacing the first stage of the Saturn Ib with a large, single, solid rocket motor (260 inch!) back in the mid 60s. Sort of a "proto-stick". Conversely a Boeing engineer once stated that launching a Delta IV Heavy (one common core and 2 liquid fueled strap on boosters) is the equivalent of launching 3 Delta IV Mediums. Meaning 3 times the chance for something to go wrong. NASA has always preferred fewer, larger engines for reliability and performance reasons.<br /><br />Of course clustering can work just fine. Just look at Soyuz or the Saturn Ib. But I guess NASA didn't want to spend the time working the bugs out. Also I imagine they consider the SRB to be a "mature" technology and want to keep production going. Also--and this is pure speculation--I think NASA feels that they are more likely to get the Ares V (the HLLV they have been pining for since the Saturn V was cancelled) if they already have the 5 segment SRB for the Ares I.
 
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JonClarke

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What makes you think they do? NASA has used the Atlas V twice already and has another two launches scheduled, and has used the Delata IV once.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>
 
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steve82

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There is going to be plenty of technical risk in the Constellation program when we get to developing the systems to return to the moon. Why take a risk on your LEO transport vehicle when you have the stick now, it works, and you have the infrastructure in place to fly it?<br />As much reservations as I have about the stick, I'd be a lot more confident in it from a safety and program success perspective, with it's hundreds of successful flights, than with the Delta IV or Atlas at this time.
 
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j05h

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<i>> There is going to be plenty of technical risk in the Constellation program when we get to developing the systems to return to the moon. Why take a risk on your LEO transport vehicle when you have the stick now, it works, and you have the infrastructure in place to fly it?<br />As much reservations as I have about the stick, I'd be a lot more confident in it from a safety and program success perspective, with it's hundreds of successful flights, than with the Delta IV or Atlas at this time.</i><br /><br />We don't"have" the Stick now: it will require almost a decade of development and billions of dollars to work. Compare this to Lockheed and Bigelow discussing man-rating Atlas with internal funds. If you swap 'stick' and "delta" in your statement you get the same results. Boeing's factory can make around 40 Delta IV cores every year, and they have more pads available than Stick ever will. Right Now, not in 2012. The Stick requires extensive mods of both the vehicle and facilities - it is unfair to claim the Stick (5 segment, different mounting etc) is the same as a Shuttle SRB. And remember, Atlas was the original US manned launcher.<br /><br />The Stick has ZERO successful flights. The Shuttle SRB is not the Stick - it is heritage hardware for said. Otherwise, you'd be more confident in Delta and Atlas with their hundreds of flights. Or Soyuz. <br /><br />Why do you and NASA insist on copying existing capabilities?<br /><br />Not to go to far offtopic, but NASA should be building deep-space hardware (which they are very good at) and buying launches of crew & cargo. The commercial sector is already there (Atlas, Delta, SeaLaunch, Arianne, Soyuz) for ground-to-LEO. Many smaller flights will drive costs down and demand up much faster than a few, monolithic launches. Lockheed is openly talking about various fuel depots and modular Lunar hardware. <br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>
 
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j05h

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> The new Delta and Atlas vehicles only share the names from the earlier models. They are entirely new families of boosters.<br /><br />Which is part of the punchline. I'm totally serious about the delivery to LEO being purchased. There is a huge glut in the medium-lift market right now and NASA could get enormous deals contracting out dozens of launches per year. Cheaper Access To Space can be made in incremental steps, so far the ESAS/VSE is working on a system that just barely makes it happen while almost breaking the bank. Reusable, modular deep space vehicles and propellant depots, all serviced with existing medium-lift rockets would instead be setting a standard.<br /><br />I've argued for international, corporate space development. Atlas' Russian engines, SeaLaunch etc are proving it out. <br /><br />Why does NASA hate the EELVs? Not Invented Here: they are USAF projects. Same goes for Soyuz and Ariane.<br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>
 
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steve82

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"Otherwise, you'd be more confident in Delta and Atlas with their hundreds of flights."<br /><br />There have only been a handful of Delta IV and Atlas V flights and not totally successful in the case of Delta IV. And their streamlined processing and turnaround, while very impressive, are for a satellite carrier hauling containerized freight and not for manned vehicles.<br /><br />I'm not saying the stick is a "better rocket" whatever that means. I'm saying there are fewer risks to the program (schedule, probability of success, safety) going for the stick in the near term than in reinventing Delta IV and Atlas V to carry manned spacecraft. Just because LM and Bigelow say they can man-rate an Atlas doesn't make it so. Let them go ahead and put their own money into it and we'll see.
 
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gunsandrockets

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"Forty cores a year, (maximum capacity,) sounds like a lot, but a single Delta 4-Heavy uses three per shot."<br /><br />"Military launches, deepspace missions and a possible upswing in the civil market could eat them up in a hurry."<br /><br />I don't think undercapacity is a realistic fear. You are talking 650,000 lbs of payload to orbit every year, and that's without expanding existing capacity. That's the equivalent of putting up mass equal to the International Space Station every year!
 
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space_dreamer

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The point of the stick is to develop some of the parts of the Ares 5 now, so it is less likely to be cancelled in 2009.<br /><br />The stick is just a stepping stone to the heavy lift moon/mars rocket and a back up if SpaceX and Rocket Plane Kisler don’t deliver.<br />
 
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propforce

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NASA doesn't "hate" anybody, they just want to design their own rocket just to be different. That plus they need to feed their engineers to keep them employeed, instead of sending money to Boeing or Lockheed. Nothing's wrong with all the above arguments, if only they come up with a "better" rocket than either the Atlas V or the Delta IV. But it's looking like it will cost MORE and it may not work as well. So now NASA is being "defensive" about its design.<br /><br />Initially, the "plan" was to use heritage Shuttle parts, mainly the 4-segment SRB (called "RSRM") and the SSME. But apparently these geniuses Mike Griffin hired to study the launch architecture, called the ESAS team (exploration system architecture study) FAILED to do their homework to see if the proposed system work or not, but they rushed to "rubber-stamp" Mike Griffin's concept - the concept he held before he became the NASA adminstrator - to use the RSRM and the SSME to reduce cost of new rocket development.<br /><br />So the ESAS's story falls apart almost as soon as its study was published. Folks in this industry who actually knew how RSRM and the SSME works soon pointed out the problems -- and they were major problems, not something they can put a band-aid on to fix.<br /><br />So like truly NASA geniuses fashion, they quickly devised an "alternate" approach before the concept was carefully studied and evaluated -- by the people who know how to design rockets!! -- so they came out with the current configuration of Ares 1. Again, they were criticized by the folks who know how to design and operate rockets. So instead of embracing the suggestions from people who's been doing this all their careers, NASA's senior management dug in their high heels and became very "defensive". Mike Griffin even called the VPs in Atlas V and Delta IV to tell their people to "shut-up" and stop criticize the Ares 1 (NASA's latest baby) if either company expects a contract from NASA.<br /><br />I guess I would be defensi <div class="Discussion_UserSignature"> </div>
 
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propforce

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<blockquote><font class="small">In reply to:</font><hr /><p> I think safety was the main consideration for the "stick". It is the only launch vehicle design in the performance class that has a single first stage engine. Fewer engines = fewer accidents generally speaking. Interestingly NASA considered replacing the first stage of the Saturn Ib with a large, single, solid rocket motor (260 inch!) back in the mid 60s. Sort of a "proto-stick". Conversely a Boeing engineer once stated that launching a Delta IV Heavy (one common core and 2 liquid fueled strap on boosters) is the equivalent of launching 3 Delta IV Mediums. Meaning 3 times the chance for something to go wrong. NASA has always preferred fewer, larger engines for reliability and performance reasons. <p><hr /></p></p></blockquote><br /><br />Are you nuts? <br /><br />Saturn V the MOST SUCCESSFUL launch vehicle & launch program in the U.S. history has <b>5 engines</b> on its first stage, with a 100% SUCCESSFUL launches. <br /><br />Space Shuttle has <b>5 engines</b> all going at once during lift-off. Are you saying the Shuttle is 5 times LESS SAFE than *the stick*?<br /><br />Delta II has <b>7 engines</b> going all at once. It has 100% mission success rate.<br /><br />You can't learn about rocket reliability from a textbook. Learn something about how real rocket works instead. <br /> <div class="Discussion_UserSignature"> </div>
 
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propforce

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<blockquote><font class="small">In reply to:</font><hr /><p>The new Delta and Atlas vehicles only share the names from the earlier models. They are entirely new families of boosters. <p><hr /></p></p></blockquote><br /><br />Not true.<br /><br />Atlas kept its Centaur upper stage with the RL-10. Delta's upper stage also uses the RL-10 engine.<br /><br />More importantly, these two rockets are designed by the two companies each with over 40 years of rocket experience. These guys know what they're doing.<br /><br />What rocket has NASA designed and <i>work</i> in the last 40 years?<br /> <div class="Discussion_UserSignature"> </div>
 
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propforce

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<blockquote><font class="small">In reply to:</font><hr /><p> I'm saying there are fewer risks to the program (schedule, probability of success, safety) going for the stick in the near term than in reinventing Delta IV and Atlas V to carry manned spacecraft. Just because LM and Bigelow say they can man-rate an Atlas doesn't make it so. Let them go ahead and put their own money into it and we'll see.<p><hr /></p></p></blockquote><br /><br />So what basis can you claim that *The Stick* has a fewer risks to the program? Just because NASA said so? <div class="Discussion_UserSignature"> </div>
 
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gunsandrockets

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"Mike Griffin even called the VPs in Atlas V and Delta IV to tell their people to "shut-up" and stop criticize the Ares 1 (NASA's latest baby) if either company expects a contract from NASA."<br /><br />Are you serious? Is this something you know about from personal experience? Was there a news story? details please... <br />
 
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bpcooper

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"Delta II has 7 engines going all at once. It has 100% mission success rate. "<br /><br />No, Delta 2 has had 1.5 failures in 125 flights. <div class="Discussion_UserSignature"> <p>-Ben</p> </div>
 
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propforce

Guest
<blockquote><font class="small">In reply to:</font><hr /><p>No, Delta 2 has had 1.5 failures in 125 flights. <p><hr /></p></p></blockquote><br /><br />Not the Delta II 6900 series. <div class="Discussion_UserSignature"> </div>
 
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bpcooper

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I'm replying to the Delta 2 remark. He didn't say 6000 series.<br /><br />Yes, both failures occured with the 7xxx series. <div class="Discussion_UserSignature"> <p>-Ben</p> </div>
 
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propforce

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Still... 1.5 failures out of 125 flights is darn near IMPRESSIVE !! <div class="Discussion_UserSignature"> </div>
 
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propforce

Guest
<blockquote><font class="small">In reply to:</font><hr /><p>"Mike Griffin even called the VPs in Atlas V and Delta IV to tell their people to "shut-up" and stop criticize the Ares 1 (NASA's latest baby) if either company expects a contract from NASA." <br /><br />Are you serious? Is this something you know about from personal experience? Was there a news story? details please... <p><hr /></p></p></blockquote><br /><br />G&R - sent you a PM<br /><br /><br /> <div class="Discussion_UserSignature"> </div>
 
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edkyle98

Guest
1.5 failures. Hmmmmm. I wonder what one-half of a failure is. <br /><br />On two occasions, Delta II failed to do what it was supposed to do. That sounds like two failures to me.<br /><br />That makes 123 successes out of 125 launch attempts, which still places Delta II at the top of the heap in terms of proven space launch reliability.<br /><br /> - Ed Kyle
 
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bpcooper

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An air-lit solid didn't separate on the Koreasat-1 launch in 1995, placing the satellite into a lower than desired orbit. The satellite was fully operational but had a lower lifetime as a result. It's more of a partial failure than D4H was! ;-) <div class="Discussion_UserSignature"> <p>-Ben</p> </div>
 
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rfoshaug

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<blockquote><font class="small">In reply to:</font><hr /><p>Saturn V the MOST SUCCESSFUL launch vehicle & launch program in the U.S. history has 5 engines on its first stage, with a 100% SUCCESSFUL launches. <p><hr /></p></p></blockquote><br /><br />That's not entirely true. First of all, there were only 13 Saturn V launches - quite a small statistical foundation to claim it was a safe rocket. It's like those claiming that the Concorde was the safest aircraft in the world because it had never crashed. Then one went down and it was the <i>least</i> safe commercial airliner in the world, statistically speaking.<br /><br />Secondly, the second Saturn V flight, the unmanned Apollo 6 was technically very close to count as a launch failure. It wasn't a catastrophic failure, but if it had been a manned lunar mission, they wouldn't have gone to the moon because of the launch vehicle. It also came quite close to tearing itself apart.<br /><br />From the Wikipedia article on Apollo 6:<br /><br /> <font color="yellow"><br />Two minutes into the flight, the rocket experienced severe Pogo oscillations for about 30 seconds. </font><br /><br />And then:<font color="yellow"><br />In part due to the pogo, the spacecraft adaptor that attached the CSM and mockup of the Lunar Module to the rocket started to have some structural problems. Airborne cameras recorded several pieces falling off it at T+133.<br /><br />After the first stage was jettisoned at the end of its task, the S-II second stage began to experience its own problems. Engine Number Two (it had five) had performance problems from 206 to 319 seconds after liftoff and then at 412 seconds shut down all together. Then two seconds later Engine Number Three shut down as well. The onboard computer was able to compensate and the stage burned for 58 more seconds than normal. Even so the S-IVB third stage also had to burn for 29 seconds longer than usual. </font><br /> <div class="Discussion_UserSignature"> <p><font color="#ff9900">----------------------------------</font></p><p><font color="#ff9900">My minds have many opinions</font></p> </div>
 
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halman

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rfoshuag,<br /><br /><br />"Saturn V was a good rocket and a large rocket, but it was not necessarily the perfect rocket. People often make the safety comparison to the Shuttle, claiming that Saturn V was safer since nobody lost their lives in one. But if NASA had launched 115 Saturn V's, my feeling is that at least one would have been lost, maybe more."<br /><br />People often also ignore the fact that both shuttle loses were the result of management decisions to fly when there was a considerable risk of losing the vehicle. I would say that Challenger was almost certain to experience problems with the Solid Rocket Boosters, due to the overnight low temperatures of 28 degrees F. on the pad. And at least one other orbiter had returned with a good sized hole in a leading edge carbon-carbon fiber panel, the result of what was known to be strikes from the foam on the External Tank, before the Columbia incident. Instead of putting launches on hold until the problem was fixed, it was decided to keep flying and hope for the best. To me, that is like saying a car is unsafe after someone drives it into a brick wall at 70 mph and destroys the vehicle. <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>
 
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rocketman5000

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Its interesting to note that most consider less engines on a rocket to be safer and more engines on a airplane to be safer. SpaceX not included.<br /><br />I think this all stems back to issues similiar to those that destroyed the Soviet N1 moon rockets. Assuming that you don't get resonation in the propulsion system. (a problem that should be analytically solveable using modern fluid dynamic software) Multiple engines give you more redundancy. How many times has the Shuttle shut down an engine and still flown a successful mission? You can still obtain the same total impulse if you burn less engines longer. If you have to shutdown your solitary engine I hope you have a backup plan allow for crew escape.<br /><br />The safety of a system ultimately lies in how well was it designed and how long it has flown. If problems are identified when flown and fixed (unlike the shuttle) The system should become safer the longer it flys. The Soyuz program is testimate to this method. <br /><br />If you wish to have a rocket with more launch capacity an incremental improvement can be made to the rocket Through incremental improvements your launcher can gain performance AND retain its safety record.
 
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