BIG problems with Ares I - "the stick"

[mikeemmert]

<blockquote><font class="small">In reply to:</font><hr /><p>Surplus H2 is present in the SSME exhaust, burns in the (lower) atmosphere, and does not contribute to the thrust of the vehicle.<p><hr /></p></p></blockquote>The surplus hydrogen in an SSME has left the vicinity of the vehicle, wheras excess hydrogen in an aerospike is still adjacent to the nozzle.<blockquote><font class="small">In reply to:</font><hr /><p>I don't see how this effect would help an aero-spike unit either.<p><hr /></p></p></blockquote>How would you know? There haven't been sufficient tests on an aerospike engine. They get the project 95% completed, even get the hardware made, then cancel the program before the first test ever takes flight! This happened with NASP, the X-33, LASRE, and some other projects.<br />

 

[JonClarke]

My understanding of the the history is things generally start off being about right, end up significanctly over, and then end up being what they should be again.<br /><br />Again, I think this is a mountain out of a mole hill in the the longer term, driven mainly by various agenda amongst the space spectator industry (which is most of us here, myself included.<br /><br />I do not think this is politicising the discussion, which is something uneccessary, but pointing out the obvious.<br /><br />Jon <br /> <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>

 

[bpfeifer]

"Most spacecraft and aircraft are overweight early in their development. I really don't see much to be alarmed at, long term. of course the engineers whose job it is to fix the problem can't be so complacent, but that's what they are paid tro do."<br /><br />AND<br /><br />"Most spacecrafts and rockets tend to UNDER ESTIMATE weight early in their design, and add more weight as a result. Haven't you've heard of phase of "... weight growth.. cost growth..." as a result? "<br /><br />I'm not sure how the weight changed during the design process, but Collumbia was much heavier than the follow on Shuttles. Perhapse later Ares will also benefit from weight reduction. <br /><br />Also, I've head on this list both those saying the stick is under powered, and those saying that's inaccurate. No-one has yet put the numbers on the table to prove one way or the other. It's fine to endlessly discuss unprovable aguments, but isn't data available on the stick?<br /> <div class="Discussion_UserSignature"> Brian J. Pfeifer http://sabletower.wordpress.com<br /> The Dogsoldier Codex http://www.lulu.com/sabletower<br /> </div>

 

[vogon13]

Compare the mass of a hydrogen atom moving out the exhaust of an aerospike engine with the <i>stationary</i> oxygen atom in the atmopshere it is reacting with.<br /><br />One of Newton's little laws (you know, the action/reaction one) ain't gonna work for you here. <br /><br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[mikeemmert]

<blockquote><font class="small">In reply to:</font><hr /><p>Compare the mass of a hydrogen atom moving out the exhaust of an aerospike engine with the stationary oxygen atom in the atmopshere it is reacting with.<p><hr /></p></p></blockquote>If you mix hydrogen and air in a stoichiometric ratio and ignite it, a shock wave forms which initially moves out at mach 3. This slows down as it intercepts air.<br /><br />OK, you know how a shaped charge works? A large fireball moves out, and due to the geometry of the charge, a jet forms which can move 5 times faster than the shock wave.<br /><br />I know about this phenomenon because it was discussed extensively in <i>The Secret History of the Atomic Bomb</i> by Anthony Cave Brown and <i>The Making of the Atomic Bomb</i> by Richard Rhodes (sp?). Sorry to go outside engines for resources. Here's the Wikipedia article on shaped charges.<br /><br />Reading it and comparing it with the linkless material shows I will have to explain it better.<br /><br />Imagine a ring of explosive (hydrogen/air mixture). This is detonated. The outside of the ring moves out at mach 3. However, notice that the inside of the ring is pinched. It's energy is concentrated. By the time you reach the center, the energy of the explosion is highly concentrated. Jets form moving in opposite directions that travel much faster than the outside shock wave. Try drawing this scenario with arrows moving in from the ring, and you see the arrows converging together.<br /><br />Now, move the exploding ring foreward at over mach 3. Notice that the freshly created explosion is <i>ahead</i> of the still expanding ring created shortly before. So it pushes the fireball back. However, Newton's third law must be satisfied, as a result, a jet of smaller mass forms which must move foreward; since it's mass is smaller, it must move faster than that which is moving backwards. The energy is divided equally betwee

 

[geminivi]

Nasa has seen fit to respond to the blog rumors, and specifically NasaDeathWatch story about the problems in Ares I. While not a rocket expert, Nasa old hand or in anyway associated with space flight, common sense tells me that Mike Griffin is no fool. Only a fool would bid the capsule contract knowing their ride can't get to the proper orbit. <br /><br /><br />Here's the link<br />http://www.spaceref.com/news/viewsr.html?pid=22553

 

[moonmadness]

NASA Internal Memo From Constellation Program Manager Jeff Hanley <br /><br />STATUS REPORT<br />Date Released: Monday, November 13, 2006<br />Source: Johnson Space Center<br /><br /> <br /><br />From: Hanley, Jeffrey M. (JSC-ZA) <br />Sent: Monday, November 13, 2006 3:54 PM<br />Subject: FW: NASA Encounters Problems With Ares 1 Launch Vehicle Design <br /><br />All, between articles like this one (see below) and the wave of 'better ideas' for architecture that have waded into recent notoriety, I thought it was time to level set folks on where things stand - and - dispel these rumors and hearsay surrounding the "issue" of the Ares 1 performance and overall implications to the architecture. <br /><br />In summary, many who carp from the sidelines do not seem to understand the systems engineering process. They instead want to sensationalize any issue to whatever end or preferred outcome they wish. So be it, that is the world we live in. <br /><br />So where are we today, specifically on the issue of what the launch vehicle can lift and what the Orion is allowed to weigh? <br /><br />First, the latest set of analyses indicate that the Ares I can lift 58 klbm to the program-specified injection point of -30 x 100 nmi. This number PROTECTS worst case propulsion performance on the first and second stage. <br /><br />This compares favorably to the requirement that we specified for the Ares I to inject 52.1 klbm. <br /><br />The Orion team is working to a control mass of NGT 48.4 klbm. They in turn carry margin within that allocation ranging between approximately 10-20% for mass growth as the design process proceeds. <br /><br />Further, we have been fairly conservative on the amount of propellant we will load in the Orion Service Module for the lunar missions. <br /><br />Both the Ares I performance and the Orion control mass are 'watch items' on our list of top program risks. This is NORMAL for any such development effort ... mass delivered to space has been and will always be a source of risk for <div class="Discussion_UserSignature"> <p>I'm not a rocket scientist, but I do play one on the TV in my mind.</p> </div>

 

[vogon13]

The shaped charge analogy is inoperative due to the speed differential of the fuel, and the ambient atmosphere. Shaped charges don't work this way.<br /><br />Additionally, the vehicle has burned fuel to loft the surplus H2, and the surplus H2 dilutes the exothermic reactants, weakening the reaction that thrusts the vehicle.<br /><br /><br />Your assertion boils down to the vehicle pulling itself upward via it's own bootstraps.<br /><br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[propforce]

<blockquote><font class="small">In reply to:</font><hr /><p>[JonClark said...] "Most spacecraft and aircraft are overweight early in their development. I really don't see much to be alarmed at, long term. of course the engineers whose job it is to fix the problem can't be so complacent, but that's what they are paid tro do." <br /><br />AND <br /><br />[Propforce said...] "Most spacecrafts and rockets tend to UNDER ESTIMATE weight early in their design, and add more weight as a result. Haven't you've heard of phase of "... weight growth.. cost growth..." as a result? " <br /><br />I'm not sure how the weight changed during the design process, but Collumbia was much heavier than the follow on Shuttles. Perhapse later Ares will also benefit from weight reduction. <p><hr /></p></p></blockquote><br /><br />My point was about when a design is still "conceptual and on-paper", as the Stick is now, versus after it is built.<br /><blockquote><font class="small">In reply to:</font><hr /><p>Also, I've head on this list both those saying the stick is under powered, and those saying that's inaccurate. No-one has yet put the numbers on the table to prove one way or the other. It's fine to endlessly discuss unprovable aguments, but isn't data available on the stick? <p><hr /></p></p></blockquote> <br /><br />The SRB on the Stick is not "... under powered...". It has enough thrust to get off the ground. Actually it may have a little too much thrust. As the design is right now, it springs off the pad at 1.7g acceleration. Ideally, we would like to see more like 1.3~1.4.<br /><br />What the SRB lacks is enough propellant to deliver the vehicle to the right velocity before its burn-out. That was the same problem with the original Shuttle 4-segment SRB (called RSRM), so they upgraded it to a 5-segment SRB (called FSB) which would cost an additional $3 billions to make according to its manufacturer, ATK. But since they can not increase the diameter of the SRB, I think because the original tooling is lost or <div class="Discussion_UserSignature"> </div>

 

[tomnackid]

Actually they can't increase the SRB diameter because the segments are already the maximum size that can be transported by rail from land locked Utah. Also the Air Force was originally planning to launch shuttles from Vandenburg--where there is no barge access. The alternative proposed by Thiokol's rival Aerojet was to build a SRB factory onsite at KSC (which would have resulted in single piece SRBs with no joints--ah well) but after the Air Force was pressured in to signing on to STS it would mean building another factory at Vandenburg or anywhere else they need to launch shuttle from. <br /><br />building rockets is more than just the rocket equation! Its geography, politics, economics, defense...and I'm sure a lot more!

 

[propforce]

<blockquote><font class="small">In reply to:</font><hr /><p>Actually they can't increase the SRB diameter because the segments are already the maximum size that can be transported by rail from land locked Utah. <p><hr /></p></p></blockquote><br />If that's the ONLY reason, then find another way of transporting it. If Lockheed can trassport its 5.2m diameter rocket <i>(edit: payload fairing size is 5.2m) </i> from the <i>LANDLOCKED Colorado</i>, why can't they do the same from Utah? <br /><br />Need to think outside the box sometimes.<br /><br /><blockquote><font class="small">In reply to:</font><hr /><p>Also the Air Force was originally planning to launch shuttles from Vandenburg--where there is no barge access.<p><hr /></p></p></blockquote><br />There's a barge access NOW! Why is that? Perhaps someone did think outside of box?<br /><br /><blockquote><font class="small">In reply to:</font><hr /><p>building rockets is more than just the rocket equation! Its geography, politics, economics, defense...and I'm sure a lot more! <p><hr /></p></p></blockquote><br /><br />Oh I can assure you it's a lot more. If you read my posts at all, you'd realize that. <br /><br /> <div class="Discussion_UserSignature"> </div>

 

[vulture2]

The other difficulty I see is with facility and operating costs, which as with the Shuttle are largely ignored. Integrating the segmented SRBs is time-consuming, expensive, and hazardous. One of the primary motivations for the SRB-based CLV design was to utilize the existing infrastructure, but in reality the cost of maintaining the existing complex infrastructure, the VAB, MLPs, crawlers, and pad, is hurting the Shuttle. The EELVs have vastly simpler processing flows and support facilities. And having a dedicated vehicle for the CEV with no other customers will result in a low flight rate and increase per-flight cost. <br /><br />I do not see any launch vehicles around the world that use segmented solids except the Ariane V, and those are less than half the size of the SRBs. The only common application for large solids is for military missiles that have to be stored ready to launch, and those have relatively small payloads and are not segmented.

 

[propforce]

<blockquote><font class="small">In reply to:</font><hr /><p>"...If that's the ONLY reason, then find another way of transporting it...." <br /><br />Such as? <br /><br />The existing SRB is slightly smaller diameter than the Atlas, but it is loaded, Atlas is empty. <br /><br />One segment would push the C-5 Galaxy past its limits for weight and with no spare clearance on size. <br /><br />Truck? Even as an escorted oversize load that is a lot of weight, times 5 units for one flight. There are still a lot of old bridges.... Dropping a quarter million pounds of explosive through one of them wouldn't be very popular. <p><hr /></p></p></blockquote><br /><br />Dig a canal from Utah to the Pacific Ocean ! <img src="/images/icons/laugh.gif" /> But seriously, if we're able to build a trans-Alaska pipeline, interstate highway systems, the Hoover Dam, etc. You guys will need a little more imagination if you want to dabble in the access to space business !<br /><br />I think Lockheed uses the Anotov AN 245? Can't recalled if either the name nor the number is correct. CRS ya know! <img src="/images/icons/rolleyes.gif" /> <br /><br />Speaking of cargo transporter, have you seen the modified Boeing 747 freighter to transport 787 fuselarges?<br /><br />The SRB is only 3.2m diameter I'd believe <i>(Edit: it's 3.85m)</i>. I don't know what the C-5 payload size or weight limit is. But for crying out loud, use 2 ~3 transporters if you have to. Afterall, how often do you think we will launch the CLV? Once, maybe twice a year?<br /><br />BTW, the solid propellant motors do not "explode" easily. You can drop them from a truck and even the sparks would not be able to ignite them.<br /><br /><br /><br /><br /><br />Think outside the box, Newsie! <img src="/images/icons/smile.gif" /><br /><br /> <div class="Discussion_UserSignature"> </div>

 

[propforce]

<blockquote><font class="small">In reply to:</font><hr /><p>The other difficulty I see is with facility and operating costs, which as with the Shuttle are largely ignored. Integrating the segmented SRBs is time-consuming, expensive, and hazardous. One of the primary motivations for the SRB-based CLV design was to utilize the existing infrastructure, but in reality the cost of maintaining the existing complex infrastructure, the VAB, MLPs, crawlers, and pad, is hurting the Shuttle. The EELVs have vastly simpler processing flows and support facilities. And having a dedicated vehicle for the CEV with no other customers will result in a low flight rate and increase per-flight cost. <br /><br />I do not see any launch vehicles around the world that use segmented solids except the Ariane V, and those are less than half the size of the SRBs. The only common application for large solids is for military missiles that have to be stored ready to launch, and those have relatively small payloads and are not segmented. <p><hr /></p></p></blockquote><br /><br />Good post! Someone who understands operational issues <img src="/images/icons/smile.gif" /><br /><br /><br /> <div class="Discussion_UserSignature"> </div>

 

[rocketman5000]

>At some point the review board will freeze the design and say, "cut metal!" <br /><br /> No they won't, it will be glue composite!!!

 

[jschaef5]

How hard would it be to modify the railway to be a little bit wider? I'm guessing it might be cheaper than buying or renting or redesigning an airplane to carry it or any other method. <div class="Discussion_UserSignature"> </div>

 

[christine16]

hope thi is just a bad joke, cause I wana see US on Moon

 

[erioladastra]

"Nasa has seen fit to respond to the blog rumors, and specifically NasaDeathWatch story about the problems in Ares I. While not a rocket expert, Nasa old hand or in anyway associated with space flight, common sense tells me that Mike Griffin is no fool."<br /><br />Well firstm NASA did not respond, they sent an internal memo to folks. Of course, perhaps they knew it would end up on the web <img src="/images/icons/smile.gif" /><br /><br />But you and some other posters are correct that a few loud folks with little data or axes to grind can shape the debate. And of course, when the momen has past, they are not accountable. Don't froget, it was NASA watch that had it on direct info from Griffin that the Shuttle would never actually fly again. I didn't see any followup on this on NASAWATCH! <img src="/images/icons/smile.gif" />

 

[tomnackid]

propforce: <br /><br />why are you getting so combative? I was simpley pointing out why the SRB segments are the size they are. As for thinking outside the box a giant, segmented solid rocket that could be transported anywhere by rail WAS thinking outside the box back in the 1970s! I don't think any other country has solid rockets as large and sphisticaed as the US's. Anyway NASA continues to say that there is no problem withe the Ares I performance so the question is moot. I'll continue to belive the officail sources until I see some real evidence that Ares I can't do the job. The whole point of Ares I is to create a crew launcher with a single first stage engine. Yes Ares I is far from the most efficicient design but so far it is the ONLY concept that launches a CEV with a single first stage engine and a single second stage engine. "Fewer engines = fewer problems" is NASA's montra for Constellation. We can argue wether or not that is a valid assumption or not.

 

[halman]

erioladastra,<br /><br />As I understand it, the perceived problems with the Ares 'stick' is that the Crew Exploration Vehicle (which is actually a capsule and a service module, right?) is too heavy for the the stick to launch into orbit. From what I have read, the CEV is supposed to go from Low Earth Orbit to the surface of the Moon, and then return. This means that the CEV would have to be designed to do 4 primary jobs, those being; 1.) crew launch capsule, 2.) crew transit capsule for Moon flight, 3.) crew landing and launch capsule on Moon, and 4.) crew return capsule to Earth. Or is there a seperate Moon transport vehicle which is not currently in the news?<br /><br />Whatever happened to using a space station as a base for Lunar expeditions? If we are going to be active in space for the long term, shouldn't we have a base of operations there, where we can assemble, maintain, and modify exploration vehicles? Why isn't the International Space Station going to be used for the lunar exploration missions? Is it in the wrong orbit, or is it just because it doesn't belong to us?<br /><br />Back in the 1960's, the process of going to the Moon seemed so simple; You build a rocket to put people in space, and then you build a bigger rocket to put cargo in space. Then you send people to space to assemble the parts you send up on the big rocket, so that you have a space station. Then, you use the big rocket to send up parts for a Lunar Shuttle, that goes from the space station to the Moon, as well as fuel for the Lunar Shuttle. Then you test the Lunar Shuttle, until you are sure that it is working right, and then you go to the Moon. Over and over again, until you have a base on the Moon.<br /><br />What is the current plan? <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>

 

[montmein69]

>As I understand it, the perceived problems with the Ares <br /> />'stick' is that the Crew Exploration Vehicle (which is actually<br /> /> a capsule and a service module, right?) is too heavy for the<br /> /> the stick to launch into orbit.<br /><br />A man-rated Ares 5 could do the job because for a Moon or Mars mission more and more payload is always needed ...isn't it ? (two Ares 5 in fact : one for the freight, the second for both crew and freight)<br /><br />A low coast (hem ....hem ...) Ares 1 is useful only for a crew in LEO mission ... but it seems - in NASA project - that it could be the job for Xprize and its Falcon ????<br /><br />I can't understand where is the logic to give founding for private access in LEO (for ISS crew access or whatever) if there is no confidence in such a solution ? <br /><br />On the other hand if XPrize can't do the job (Falcon 1 is still grounded) ... or only in the next century ... Why give them founding ???? <div class="Discussion_UserSignature"> </div>

 

[mrmorris]

<font color="yellow">"I can't understand where is the logic to give founding for private access in LEO (for ISS crew access or whatever) if there is no confidence in such a solution ? "</font><br /><br />At the moment, the COTS contract for the ISS is resupply <b>only</b>. Crew rotation may be added in the future, but this is far from assured. NASA isn't *confident* that either SpaceX or Kistler will be able to do even the resupply. However, if either (or both) <b>are</b> succcessful, NASA stands to save billions. They are essentially gambling that by spending half-a-billion now, they'll save multi-billions later. NASA would be ecstatic for the SpaceX Dragon crew module to take over crew rotation to the ISS, leaving them free to pay for CEV flights only for lunar missions. However, at this stage of the game, <b>depending</b> on that happening would be stupid.<br /><br /><font color="yellow">"On the other hand if XPrize can't do the job (Falcon 1 is still grounded)..."</font><br /><br />I assume by 'X-Prize' you mean 'SpaceX', despite the fact that the two have nothing in common except the letter 'X ' (and 'E' and 'P', of course). For less than $100 million, Elon designed & built two distinct engines and a rocket and launched it. Mind you it was unsuccsessful, but it launched. By contrast, Kistler was $600 million in debt when they went into bankruptcy, despite having bought existing engines and never having gotten anywhere close to a launch. What SpaceX has done is impressive, even *with* the first-launch failure.

 

[edkyle98]

"As I understand it, the perceived problems with the Ares 'stick' is that the Crew Exploration Vehicle (which is actually a capsule and a service module, right?) is too heavy for the the stick to launch into orbit."<br /><br />According to Program Manager Jeff Hanley, Ares I is on track to be able to haul 26 tonnes to the Orion deployment orbit, and Orion is on track to weigh no more than 22 tonnes. <br /><br /> - Ed Kyle

 

[bitbanger]

<blockquote><font class="small">In reply to:</font><hr /><p>"...If that's the ONLY reason, then find another way of transporting it...."<br /><br />Such as?<p><hr /></p></p></blockquote><br /><br />Maybe it's time to reconsider airships.<br />

 

[PistolPete]

<blockquote><font class="small">In reply to:</font><hr /><p>From what I have read, the CEV is supposed to go from Low Earth Orbit to the surface of the Moon, and then return. This means that the CEV would have to be designed to do 4 primary jobs, those being; 1.) crew launch capsule, 2.) crew transit capsule for Moon flight, 3.) crew landing and launch capsule on Moon, and 4.) crew return capsule to Earth. Or is there a seperate Moon transport vehicle which is not currently in the news?<p><hr /></p></p></blockquote><br />Yes there is a separate lander and it actually has been in the news. Althought because the contract for the LSAM (or Lunar Surface Access Module, as it's currently being called) isn't up for grabs yet it hasn't made much news. However it did make the cover of both Popular Science (or Mechanics, I can't remember which), and the Smithsonian Air & Space magazine a few months ago.<br /><br />Here's a link for it at Astronautix.com <div class="Discussion_UserSignature"> <p> </p><p><em>So, again we are defeated. This victory belongs to the farmers, not us.</em></p><p><strong>-Kambei Shimada from the movie Seven Samurai</strong></p> </div>