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NASA says adding springs won't affect rocket performance

NASA's aging space shuttle fleet is set to retire in 2010. Once the shuttles retire, getting America's into space will require a new vehicle. Rather than a large and complex vehicle like the space shuttle, NASA has opted to go with a rocket called Ares I.

NASA says it expects the Ares I rocket to meet its publicly stated deadline of March 2015. Internally, NASA had hoped that the Ares I and its Orion crew capsule would be ready for flights beginning in September 2013. According to New Scientist, that internal date has slipped from September 2013 to September 2014.

The change of NASA's internal best-case scenario date from 2013 to 2014 is partly because of budgetary issues that have made budgets tight for 2009 and 2010. Another significant reason for the delay in the Ares I rocket is due to safety concerns that have been raised by the media. According to New Scientist, a report from the US Government Accountability Office has called attention on potential safety issues of the Ares I rocket that could create vibrations, potentially destroying the rocket and possibly killing the crew.

The possibility of vibrations come from a chance that fuel could burn unevenly inside the Ares I rocket, which could cause vibrations that build up to catastrophic levels. NASA officials now report that they have found a solution to the potential vibration problem. The space agencey says it will use to mass dampers to cancel out potential vibrations that could lead to catastrophic failure.

NASA's Jeff Hanley described the system in a teleconference as "big springs at the base of the rocket". The springs would have sensors that monitor the rocket vibrations and adjust their behavior to counteract the vibrations produced by the rocket.

However, Stephen Metschan, an engineer promoting an alternative to Ares I called Direct 2.0, worries about the safety of such a system. Metschan's concern is that if this spring system were to malfunction during lunch the entire vehicle and its crew could be lost.

Other NASA engineers are also working on an additional alternative to the Ares I called Jupiter.

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Springs....
By Moishe on 8/12/2008 4:23:50 PM , Rating: 5
Sounds so low-tech. They probably know what they're talking about. If this is the case, why hasn't this been a problem in past rockets?

I hope a problem during lunch wouldn't cause death though. They REALLY oughta get better NASA cafeteria food if that's the case.




RE: Springs....
By noxipoo on 8/12/2008 4:31:08 PM , Rating: 2
Maybe they are serving tomatoes or jalapeno peppers during lunch that may cause the entire crew to be lost? It would of been hilarious if the spring was to save fuel by springing the rocket up during it's lunch.


RE: Springs....
By randomly on 8/12/2008 7:31:52 PM , Rating: 2
The problem stems from the fact that the ARES I entire first stage is a solid rocket, not liquid fueled. They wanted to use a Shuttle SRB for the first stage to cut costs, but then it turned out it was too small so they had to increase it's size to 5 segments from the original 4, which greatly increases development costs. They may have to increase the size again.

Some analysis yielded shaking as bad as 4G which would be so severe as to kill the crew. It's going to be a real struggle to reduce the shaking below 1/4 G which is the limit where astronauts can see and read the control panels and operate controls effectively.

The DIRECT 2 approach seems more reasonable, with lower costs and less risk, but it's going to be next to impossible for NASA to consider a different design at this point due to politics and contractor pressures.


RE: Springs....
By masher2 (blog) on 8/12/2008 8:23:11 PM , Rating: 3
> "but it's going to be next to impossible for NASA to consider a different design at this point due to politics and contractor pressures."

Which is why I believe ARES is likely to be as large a failure as the Space Shuttle. Yes, it gave us a few extra capabilities, but its primary design goal was to drastically reduce launch costs, complexity, and turnaround time...yet the old Saturn V equals or beats it in all these areas.


RE: Springs....
By hellokeith on 8/13/2008 12:59:51 AM , Rating: 2
"Large failure" is not how I would describe the Shuttle program. The heavy-payload-lifting + large crew compliment --> earth orbit really makes the Shuttle a magnificent and unique (perhaps the most unique ever) man-made machine. And really it wasn't until recently with computer/robotic advances that space station resupply became possible with traditional rockets. So that's 20-30 years of a set of duties that only the Shuttle could accomplish.

I won't argue that it is a very expensive bureaucracy, but this is driven as much or more by D.C. politics (which NASA cannot control) as by engineering issues.

As far as ARES goes, I'm unsure where you are coming from to make such a bold prediction. If that assumption is bureaucracy-driven, then it really doesn't matter what implementation NASA chooses.. the red-tape is built-in. Imagine if they tried a 100% new design!!!


RE: Springs....
By randomly on 8/13/2008 2:04:08 AM , Rating: 1
He said 'as large a failure as the shuttle'. I would have to agree with him. The shuttle with two total vehicle losses, 14 astronauts killed, enormous cost overruns, and program delays reaching not into just years but decades. The total cost of the program is staggering.

They wanted it to do everything, but it was too complicated, too fragile, too expensive to build, maintain, and launch. The shuttle is not an economical launch vehicle for any satellite, and it's been a long time since it carried anything but ISS pieces. If it weren't for the international obligations of the space station the shuttle would have been scrapped many years ago.

The only really unique ability of the shuttle was the capability to return large cargo on re-entry. All the other capabilities could have been accomplished via cheaper, safer, and more efficient approaches.

The shuttle is a neat piece of hardware, but that design decision was extremely costly for the US and has delayed our space efforts by at least a decade if not more. Advanced engineering dictated by congress and politics is just a recipe for disaster.


RE: Springs....
By jabber on 8/13/2008 6:06:00 AM , Rating: 2
I bet some of those long gone/retired Saturn rocket guys would have spotted that one pretty quick.

Probably a bit of a brain drain at NASA when you go 20+ years between major launch vehicle initiatives. Probably few left from the early shuttle days let alone Apollo.

Lot of guys there now I bet, that design and innovate using only Powerpoint! Dear o Dear.

I wish them luck anyway.


RE: Springs....
By artbronze on 8/12/2008 9:34:38 PM , Rating: 2
Yes the cafeteria really does suck at the Cape but we don't think the food has reached the fatal stage yet. It just gives management gas.


RE: Springs....
By Paratus on 8/13/2008 12:37:23 AM , Rating: 2
This wasn't a problem with the shuttle due to location of the SRBs on the side of the stack as well as the extra mass from the tank acting as a damper.

There are several options to fix this and the spring mass dampers are just one solution or part of one solution.


RE: Springs....
By techfuzz on 8/15/2008 8:45:46 AM , Rating: 2
quote:
Sounds so low-tech. They probably know what they're talking about. If this is the case, why hasn't this been a problem in past rockets?

It has been a problem before. The Saturn V rockets also had this problem. The same solution was used back then, basically they installed giant shock absorbers.


mass damper=\=springs
By herm0016 on 8/12/2008 7:03:14 PM , Rating: 2
mass damper =\= "big spring" mass dampers are much different than springs. I do not think the the GAO has the technical know how to dictate design changes. this is just another political move to cut nasa funding even more.




RE: mass damper=\=springs
By masher2 (blog) on 8/13/2008 10:26:32 AM , Rating: 2
> "mass damper =\= "big spring" mass dampers are much different than springs."

Eh? A mass damper is just a damped harmonic oscillator, i.e. a spring with a weight on it. Even in those cases where a damper isn't a mechanical spring, it's still mathematically modelled as one.


RE: mass damper=\=springs
By Jimbo1234 on 8/13/2008 2:06:38 PM , Rating: 2
Correct, but the title is a bit misleading. When I see the word spring, I think of a coil spring.

A tuned mass damper has the same natural frequency as the object that is exhibiting the resonance. The idea is that the energy will go into damper not the important object. It is modeled as a spring but doesn't have to be one.

Although, technically you could call everything a spring.

And the title is incorrect in another manner. "NASA Considers Springs to Dampen Vibrations on Ares I Rocket" does not make sense. "Dampen" should be "Damp." To dampen is to make something wet. Vibrations are damped (e.g. tuned mass damper not dampener, damped natural frequency not dampened natural frequency, etc.).


RE: mass damper=\=springs
By masher2 (blog) on 8/13/2008 2:57:49 PM , Rating: 2
No, because the ARES mass damper *is* a spring system.

quote:
The system weight is classed as 1000 lbm, which consists of rails and springs under the top plate of the parachute platform on the First Stage. The active system would require a control system and associated battery power supply - all located under the aeroshell that houses the drogue parachute.

The passive system has a rail attachment on the forward skirt extension of the First Stage providing lateral support. Damping would be provided by springs attached through the ancillary ring.

http://www.nasaspaceflight.com/content/?cid=5413


America's lunch to mass (sic, sic, sic)
By Den on 8/12/2008 5:15:02 PM , Rating: 5
"getting America's into space"
"it will use to mass dampers to cancel out"
"malfunction during lunch" (already mentioned above)
Three strikes, I'm out :)




Abort system
By hellokeith on 8/12/2008 6:50:16 PM , Rating: 2
The crew capsule has an abort disconnect system. This is one of the reasons NASA is going back to a man-on-top design. Anything goes wrong, the abort eject system is fired, and the crew capsule is separated and distanced from the Ares rocket. Parachute opens up, and the crew get a nice ride down to the ocean for safe pickup. You can watch the abort rocket test video on the NASA site right now.

My point is, this whole vibration thing is much to do about nothing.




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