NASA responds to Ares I thrust-oscillation issue

docm · Jan 17, 2008

http://www.spaceref.com/news/viewnews.html?id=1266 Cutting through the doubletalk & newspeak these are the most pertinent paragraphs IMO; <blockquote>In reply to:<hr />> After the Ares I system design review in late October 2007, thrust oscillation was identified as a risk by the Ares Project and assigned a risk of four-by-five (out of five-by-five) on the NASA risk matrix.NASA uses the risk matrix as a way to track the probability that a risk may manifest itself and the overall impact if the risk does manifest itself. Risks are scored from 1 (low) to 5 (high) for both probability and overall impact. The thrust oscillation risk is not directly associated with launch vehicle performance or first-stage development. The thrust oscillation risk is associated with the integrated stack, meaning the assembled Ares I first stage, upper stage and Orion crew vehicle.Ares I performance is tracked on a monthly basis, and Ares I consistently has met its performance requirements with margin. /> Because it is early in the process, NASA is still working to characterize the potential impact, assess design feasibilities and formulate a plan to address the technical analysis on the thrust oscillation issue. Therefore, NASA has not held a formal briefing for congressional staff or Government Accountability Office staff but has been open about this issue since first learning about it. Thrust oscillation is a new engineering challenge to the developers of Ares - but a challenge very similar to many NASA encountered during the Apollo Program and development of the space shuttle. Every time NASA faces an engineering challenge - and it faces many</blockquote> <div class="Discussion_UserSignature"> </div>

no_way · Jan 18, 2008

the entire article doesnt say much, except that maybe something more coherent will be said in march.

docm · Jan 18, 2008

That's why I said "doubletalk & newspeak". The important part to me is that this problem has risen to a 4x4 level in their matrix. Given that these oscillations are endemic to solids, and this 5 seg design in particular, it'll take some fancy footwork to damp them before they hit the upper stages. <div class="Discussion_UserSignature"> </div>

no_way · Jan 18, 2008

In related news, dates slip away faster than real time can catch up http://www.nasaspaceflight.com/content/?cid=5335 http://rocketsandsuch.blogspot.com/2008/01/slip-sliding-away.html

radarredux · Jan 18, 2008

> In related news, dates slip away faster than real time can catch up/i> Sigh... and the drum beat just keeps going on. <img src="/images/icons/frown.gif" />

docm · Jan 18, 2008

This short-shifting of test flights/components is going to bite them in the arse. So much for closing the gap without extending the shuttle into the next decade, 'cause Ares/Orion's never going to make it at this rate. I sure hope SpaceX gets the Dragon up to speed on schedule. <div class="Discussion_UserSignature"> </div>

MeteorWayne · Jan 18, 2008

"I sure hope SpaceX gets the Dragon up to speed on schedule. " Amen!! I feel that is our best hope for the immediate (decadish) future. <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

radarredux · Jan 18, 2008

From NASA's response: /> NASA's analysis backs up the fact that the Ares family enables the safest, least expensive launch architecture to meet requirements for missions to the International Space Station, the moon and Mars. /i> I've read a couple of times that part of NASA's strategy was to have a considerable amount of costs and risks to the constellation program go into Ares I. For example, Ares V will also have the same 5-element stack as Ares I, so a significant amount of the Ares V development costs will be addressed during Ares I development. And ultimately, NASA wants a pretty big HLV for the Lunar missions in order to minimize costs for a Mars mission. I'm just not so sure I am buying the argument anymore. And it seems to me that Constellation is starting to face more political risks and technical risks. None of the likely presidential candidates have come out and endorsed the Constellation program (NASA's biggest, most visible, and probably most important program), and Obama (who I think at this point has the greatest chance of becoming President) has even announced he wants to cut back funding for it. From NASA's response: /> This activity culminated with release of the Exploration Systems Architecture Study in 2005. Since then, the baseline architecture has been improved to decrease life cycle costs significantly./i> I am having some troubles seeing how they have brought costs down. It seems like every time we turn around there is another delay and increase in costs. Maybe what they meant to say was, "Soon after ESAS was announced expected costs spiked up, but since we have decreased the costs from that spike by reducing capabilities of the system." From NASA's response: /> NASA is not contemplating alternatives to the current approach./i>

docm · Jan 18, 2008

More fallout; http://www.space.com/news/080118-nasa-new-rocket-shake.html <blockquote>In reply to:<hr />WASHINGTON (AP) - NASA is wrestling with a potentially dangerous problem in a spacecraft, this time in a moon rocket that hasn't even been built yet. Engineers are concerned that the new rocket meant to replace the space shuttle and send astronauts on their way to the moon could shake violently during the first few minutes of flight, possibly destroying the entire vehicle. "They know it's a real problem,'' said Carnegie Mellon University engineering professor Paul Fischbeck, who has consulted on risk issues with NASA in the past. "This thing is going to shake apart the whole structure, and they've got to solve it.'' If not corrected, the shaking would arise from the powerful first stage of the Ares I rocket, which will lift the Orion crew capsule into orbit. /> The shaking problem, which is common to solid rocket boosters, involves pulses of added acceleration caused by gas vortices in the rocket similar to the wake that develops behind a fast-moving boat, said Arenas, who has researched vibration and space-launch issues. Those vortices happen to match the natural vibrating frequencies of the motor's combustion chamber, and the combination causes the shaking. Senior managers were told of the findings last fall, but NASA did not talk about them publicly until the AP filed a Freedom of Information Act request earlier this month and the watchdog Web site Nasawatch.com submitted detailed engineering-oriented questions. The response to those questions, given to both Nasawatch and AP, were shared with outside experts, who judged it a serious problem. NASA engineers characterized the shaking as being in what the agency considers the ''red zone''</blockquote> <div class="Discussion_UserSignature"> </div>

windnwar · Jan 19, 2008

I truly hope we get a new administrator soon with the sense to look at the Direct proposal before Griffin starts tearing things down that can't be put back. Ares 1 is looking like a great way to kill Astronauts while costing an arm and a leg. I fully expect the 1x flight to come apart in flight unless they cheat the test. Heres hoping good things for SpaceX so we have somebody to buy rides from. <div class="Discussion_UserSignature"> ""Only two things are infinite, the universe and human stupidity, and I'm not sure about the former." --Albert Einstein" </div>

docm · Jan 19, 2008

1x (which looks to be delayed) probably won't fall apart because its SRB is a 'normal' 4 segment and not the new 5 segment. Vibrate it will, but apparently not as much and as long as the interstage holds together it should be OK. Of course this begs the question "why do a test with mostly non-flight hardware?" In one of his more lucid moments jimfromnsf had the perfect answer: PR. It is 90% to show the politicians and news media something they can touch that simulates progress. <div class="Discussion_UserSignature"> </div>

holmec · Jan 19, 2008

That one made the radio news here in STL. <div class="Discussion_UserSignature"> "SCE to AUX" - John Aaron, curiosity pays off </div>

radarredux · Jan 19, 2008

>> "Of course this begs the question "why do a test with mostly non-flight hardware?" /> Apparently the ONLY reason for this test is public relations./i> Which isn't entirely a bad thing. Program managers, venture capitalists, and other sponsors of work like to see demos and other evidence of progress in terms they can understand. And similarly, they often use these demos to "sell" the effort to other people (e.g., their bosses, potential customers, etc.). In academia there is the saying "Publish or perish". In the R&D community there is a similar saying, "Demo or die". During the drought years you need to keep people enthusiastic about the program. Personally, however, I think LRO is going to be the best means for motivating the troops, Congress, and the citizens. I also think robotic landers could play an incredibly valuable role in keeping these groups enthusiastic and engaged until humans can set foot on the stage.

vt_hokie · Jan 19, 2008

Why waste money trying to solve a problem that doesn't need to be solved? Why put precious resources into trying to make a strap-on solid booster into a first stage when existing liquid fueled engines can do the job?

vt_hokie · Jan 19, 2008

So, what are the options for the fix for something like this? Added mass in the form of some sort of damper that will further reduce the already inadequate Ares I performance, I would imagine!

docm · Jan 19, 2008

"1x (which looks to be delayed)" I do not think it will be delayed. Do you have a link that saids it will be? I mistyped 1x, meaning to type 1y. Of course 1x is a straw-man test anyhow and the "real deal" 1y has been delayed by a year. At any rate here's the article; http://www.nasaspaceflight.com/content/?cid=5335 the chart.... and a quote from the article; <blockquote>In reply to:<hr />$700m gap threatens major delays to Ares test flights/development Following a NASA Constellation budget review - which found the program has a short term deficit of $700m - managers have presented a re-aligned development and test flight schedule, in an attempt to protect Orion's debut mission to the ISS in 2015. Among numerous changes, Ares I-Y is to be delayed by a year, Orion's 1-3 are delayed between nine and three months, while Ares V's lunar mission debut with Orion 13 will now be an unmanned fly-by. /> <hr /></blockquote> <div class="Discussion_UserSignature"> </div>

steve82 · Jan 19, 2008

"It's highly likely to happen and if it does, it's a disaster,'' said Fischbeck, an expert in engineering risks." A little overdramatic, I think. My employer sent me up to Carnegie-Mellon a few years back for a course that they were supposed to be the world's foremost authority on. I found them to be overly pedagogical and condescending, aside from being totally ignorant of what's actually going on in the field as far as NASA projects were concerned. I'm not saying there is no problem with the thrust oscillations, NASA has known about it is working on it. I just think it's way too early to be going around predicting disaster like that. It's also irresponsible of the media, and especially Keith Cowing, to try to present it as some sort of dark conspiracy by NASA and their PAO to cover up the truth when PAO can't release details of engineering analyses that haven't even been delivered to NASA yet.

radarredux · Jan 20, 2008

So what will be the final costs? In other words, assume that NASA can compensate enough for the vibrations to move forward on Ares I. But would this require all components in the command module and the capsule to be hardened against greater vibrations than expected? If so, does this increase costs and weight?

windnwar · Jan 20, 2008

I would imagine it'll either cost weight or cost isp performance if the fix is to modify the fuel grain somehow, something i'd expect will reduce the grains efficiency. Either way it means that something else is going to have to go to make up for it. Last figures I saw, it was about 3-4 metric tons less payload to orbit then Delta IV heavy can do, and those numbers were before this issue came to light. Add to that the fact the Delta IV doesn't shake its cargo to pieces and I'd say we really aren't getting our money's worth. <div class="Discussion_UserSignature"> ""Only two things are infinite, the universe and human stupidity, and I'm not sure about the former." --Albert Einstein" </div>

bobblebob · Jan 20, 2008

Ive not really been following the progess of Ares I apart from a few articles ive read here and there. So basically Ares is overbudget, not as powerful as expected and at the moment wont lift anything into space as it would probably explode if it did? In other words a total enginnering disaster at present?

holmec · Jan 20, 2008

<blockquote>In reply to:<hr />Added mass<hr /></blockquote> You really think that would work? Mass to dampen doesn't make sense to me. Why not just make the switch to liquid? It would seem to solve some problems. I remember a few months back when we watched a Soyuz takeoff live, even in the cabin. The comment was made how smooth the ride was compared to STS. Switching to all liquid for ARES I could make the ride smooth which can only be beneficial to crew and equipment. <div class="Discussion_UserSignature"> "SCE to AUX" - John Aaron, curiosity pays off </div>

j05h · Jan 20, 2008

> Why not just make the switch to liquid? It would seem to solve some problems. Ares I is a mediocre solution looking for a problem. Delta, Atlas, eventually Falcon are the way to go. If Atlas was good enough for John Glenn, it should be good enough for Dr. Griffin. The entire premise of Ares is on shaky ground. Or thrust-oscillating ground. Scott Horowitz and ATK should be charged with a false bill of sale, IMHO. This project started promising an existing (4seg, SSME) system and is evolving into a new, underperforming and dangerous rocket. On top of that, they are pulling critical systems out of Orion to make up for AresI shortcomings - while EELV has margins. Yes, watch Soyuz launch video, here's Charles Simonyi's launch: http://youtube.com/watch?v=ya91BbkNZ3I Josh <div class="Discussion_UserSignature"> <div align="center">We need a first generation of pioneers. </div> </div>

radarredux · Jan 20, 2008

> Why not just make the switch to liquid? It would seem to solve some problems./i> "just make a switch" is an awfully big statement. At this point, I am for it, but there will be huge costs to pay. Politically there will be a lot of questions about NASA wasting all the money that has already gone into Ares I and doubts about whether they can be entrusted with more money. There may be time lost as the whole process needs to start again for a new booster (Delta, Atlas, whatever). Then there will be the inevitable lawsuits from ATK for contract cancellations. Then there will be the questions of how this affects development of Ares V (which currently plans to use the 5-segment boosters of Ares I).

windnwar · Jan 20, 2008

Watching that launch and the toy he has hanging above him barely swaying at all during the ride, even the booklet he's holding barely moves at all. That is an exceptionally smooth ride compared to anything i've seen on STS. Ares is going to be like being put in an industrial shake table! <div class="Discussion_UserSignature"> ""Only two things are infinite, the universe and human stupidity, and I'm not sure about the former." --Albert Einstein" </div>

radarredux · Jan 20, 2008

> Watching that launch and the toy he has hanging above him barely swaying at all during the ride/i> Holy cow, that was a smooth flight. Even if NASA gets the vibrations down to something acceptable for Ares I, it is going to be embarrassing to have the U.S.'s access to LEO look like a car riding on square wheels.

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