Comments on: NASA to Install "Shock Absorbers" to Mitigate Thrust Oscillation http://www.universetoday.com/2008/08/19/nasa-to-install-shock-absorbers-to-mitigate-thrust-oscillation/ Space and astronomy news Sun, 8 Nov 2009 10:14:11 -0600 http://wordpress.org/?v=2.8.5 hourly 1 By: Kevin M. http://www.universetoday.com/2008/08/19/nasa-to-install-shock-absorbers-to-mitigate-thrust-oscillation/comment-page-1/#comment-30362 Kevin M. Fri, 22 Aug 2008 18:40:38 +0000 http://www.universetoday.com/?p=17040#comment-30362 The problem is in trying to retro-fit a new component (orion) onto an old one (the boosters) to save money. The eveidence of our eyes alone tell us that this design is unstable - the boosters are not wide enough to handle the resonances that will be caused by the wider Orion capsule, which will wobble like the top of a cat-tail. Just like a building, the base must be wider than the top to be truly stable - but NASA seems to be ignoring common-sense physics. I look for an early flight to have the Orion simply snap off on launch. I feel sorry for the astronauts being suckered into flying in this contraption. Interestingly, this design perfectly reflects the fragile American ecnonomy - increasingly unsound at its foundation, with ambitions of vainglory far bigger than we can any longer support.. The problem is in trying to retro-fit a new component (orion) onto an old one (the boosters) to save money. The eveidence of our eyes alone tell us that this design is unstable – the boosters are not wide enough to handle the resonances that will be caused by the wider Orion capsule, which will wobble like the top of a cat-tail. Just like a building, the base must be wider than the top to be truly stable – but NASA seems to be ignoring common-sense physics. I look for an early flight to have the Orion simply snap off on launch. I feel sorry for the astronauts being suckered into flying in this contraption. Interestingly, this design perfectly reflects the fragile American ecnonomy – increasingly unsound at its foundation, with ambitions of vainglory far bigger than we can any longer support..

]]> By: btw http://www.universetoday.com/2008/08/19/nasa-to-install-shock-absorbers-to-mitigate-thrust-oscillation/comment-page-1/#comment-30301 btw Fri, 22 Aug 2008 09:37:35 +0000 http://www.universetoday.com/?p=17040#comment-30301 This reminds me of a software bug in the old DBase 3+. After writing a program for awhile, a bug would pop up that that the company could not ftix, so there was an added "feature" that one had to employ to keep the program from deteriorating into pablum. They tried to pawn it off as a feature, but really it was just extra dead weight. This reminds me of a software bug in the old DBase 3+. After writing a program for awhile, a bug would pop up that that the company could not ftix, so there was an added "feature" that one had to employ to keep the program from deteriorating into pablum. They tried to pawn it off as a feature, but really it was just extra dead weight.

]]> By: Nancy Atkinson http://www.universetoday.com/2008/08/19/nasa-to-install-shock-absorbers-to-mitigate-thrust-oscillation/comment-page-1/#comment-30196 Nancy Atkinson Thu, 21 Aug 2008 12:10:44 +0000 http://www.universetoday.com/?p=17040#comment-30196 Sili- The weight of the actuators is about 1,400 lbs, but the engineers and managers have been holding about 8,000 lbs of performance margin in reserve to handle unexpected problems that might come up. Jeremy- They thought about just putting special springs on the seats to take care of it, but decided to damp out the entire rocket so it wouldn't affect performance or cause some other unknown problem. Nancy Sili-
The weight of the actuators is about 1,400 lbs, but the engineers and managers have been holding about 8,000 lbs of performance margin in reserve to handle unexpected problems that might come up.

Jeremy-
They thought about just putting special springs on the seats to take care of it, but decided to damp out the entire rocket so it wouldn't affect performance
or cause some other unknown problem.
Nancy

]]> By: Bravehart http://www.universetoday.com/2008/08/19/nasa-to-install-shock-absorbers-to-mitigate-thrust-oscillation/comment-page-1/#comment-30151 Bravehart Thu, 21 Aug 2008 02:54:15 +0000 http://www.universetoday.com/?p=17040#comment-30151 Reading the commentary, is somewhat dishartening. Changing or altering an osilation frequency is no laughing matter. It requires an understanding of the materials and the dynamics of the structure. In order to reduce weight, the booster is not rigid enough to counter the schock waves. My suggestion would be to simply add open ended pipes along side the booster for reenforgement and airo dynamics. True, it will increase the weight only minimal but none the less. The advantage of this suggestion, when dampers are added on the bottom of each pipe, they will function in 3 way's.Altered frequency, reduction of vibration and they also function as a limited steering mechanism. At leased 6 or more pipes are required, aero dynamics testing will determine the actual number. My preliminairy calculations said 6 as a minimum. There is a drawback to this, it will increase noise! But this is only during the time from takeoff to stratosphere, which is only 6 minutes. Even leaniary half pipes can do, but then the number of 6 will increase. Maybe NASA will look in to this alternative? Reducing the "G" forces is a whole different ball game, and as an ex fighter jog, I know what it feels like! But I will not offer a suggestion to that it is still classified. Reading the commentary, is somewhat
dishartening. Changing or altering an osilation frequency is no laughing matter.
It requires an understanding of the materials
and the dynamics of the structure. In order
to reduce weight, the booster is not rigid enough to counter the schock waves. My
suggestion would be to simply add open ended pipes along side the booster for reenforgement and airo dynamics. True, it will
increase the weight only minimal but none
the less. The advantage of this suggestion,
when dampers are added on the bottom of
each pipe, they will function in 3 way's.Altered frequency, reduction of vibration and they also function as a limited steering mechanism. At leased 6 or more pipes are
required, aero dynamics testing will determine the actual number. My preliminairy
calculations said 6 as a minimum. There is
a drawback to this, it will increase noise! But
this is only during the time from takeoff to
stratosphere, which is only 6 minutes.
Even leaniary half pipes can do, but then the number of 6 will increase. Maybe NASA will look in to this alternative? Reducing the "G" forces is a whole different ball game, and
as an ex fighter jog, I know what it feels like!
But I will not offer a suggestion to that it is
still classified.

]]> By: Sili http://www.universetoday.com/2008/08/19/nasa-to-install-shock-absorbers-to-mitigate-thrust-oscillation/comment-page-1/#comment-30092 Sili Wed, 20 Aug 2008 17:24:31 +0000 http://www.universetoday.com/?p=17040#comment-30092 Sounds awefully heavy. Wouldn't it be better (for some value of "better") to design the solid booster shells in such a way that they resonance frequencies either aren't reached or are less bothersome? Make sure sure they're 'out of tune' so to speak. Sounds awefully heavy.

Wouldn't it be better (for some value of "better") to design the solid booster shells in such a way that they resonance frequencies either aren't reached or are less bothersome? Make sure sure they're 'out of tune' so to speak.

]]> By: Jeremy C http://www.universetoday.com/2008/08/19/nasa-to-install-shock-absorbers-to-mitigate-thrust-oscillation/comment-page-1/#comment-30063 Jeremy C Wed, 20 Aug 2008 15:35:11 +0000 http://www.universetoday.com/?p=17040#comment-30063 Why not damp the vibrations in the capsule. It just seems a whole lot simpler to give the rocket passengers (aka astronauts) waterbeds and dampen the dashboard mountings then try to muck about with mission critical systems. This seems like the curse of engineers the world over coming into play: "If it works, it doesn't have enough features." Why not damp the vibrations in the capsule. It just seems a whole lot simpler to give the rocket passengers (aka astronauts) waterbeds and dampen the dashboard mountings then try to muck about with mission critical systems.

This seems like the curse of engineers the world over coming into play: "If it works, it doesn't have enough features."

]]> By: Torbjörn Larsson, OM http://www.universetoday.com/2008/08/19/nasa-to-install-shock-absorbers-to-mitigate-thrust-oscillation/comment-page-1/#comment-30056 Torbjörn Larsson, OM Wed, 20 Aug 2008 14:58:35 +0000 http://www.universetoday.com/?p=17040#comment-30056 <blockquote> They are using something that was not designed to fly like this. </blockquote> Agreed, and when I noted the continuing adjustments over at the Bad Astronomer I got an interesting tale in reply that the history goes back to IIRC the Romans (standardized road for military reasons (?), standardized wagon wheel base, standardized [sort of, I suspect] train base, standardized bridge clearance, and, finally) deciding the transport width of the SRBs. My reaction was, and still is, that it is choosing economics over safety. But if they can handle it despite the bad feelings the iterations and kludges leave an interested bystander with, it's nothing for me to nitpick on. Btw, if it was an actual organ pipe there would be easier methods to change its resonance behavior. But I suspect more drastic measures here would detract even more as regards safety and development time.

They are using something that was not designed to fly like this.

Agreed, and when I noted the continuing adjustments over at the Bad Astronomer I got an interesting tale in reply that the history goes back to IIRC the Romans (standardized road for military reasons (?), standardized wagon wheel base, standardized [sort of, I suspect] train base, standardized bridge clearance, and, finally) deciding the transport width of the SRBs.

My reaction was, and still is, that it is choosing economics over safety. But if they can handle it despite the bad feelings the iterations and kludges leave an interested bystander with, it's nothing for me to nitpick on.

Btw, if it was an actual organ pipe there would be easier methods to change its resonance behavior. But I suspect more drastic measures here would detract even more as regards safety and development time.

]]> By: R2K http://www.universetoday.com/2008/08/19/nasa-to-install-shock-absorbers-to-mitigate-thrust-oscillation/comment-page-1/#comment-30051 R2K Wed, 20 Aug 2008 14:26:52 +0000 http://www.universetoday.com/?p=17040#comment-30051 More time, more money, more risk. Why not add em! Throw in a hot tub while you are at it to let passengers relax their pogo injured bodies after. More time, more money, more risk.

Why not add em!

Throw in a hot tub while you are at it to let passengers relax their pogo injured bodies after.

]]> By: JAG http://www.universetoday.com/2008/08/19/nasa-to-install-shock-absorbers-to-mitigate-thrust-oscillation/comment-page-1/#comment-30047 JAG Wed, 20 Aug 2008 14:08:21 +0000 http://www.universetoday.com/?p=17040#comment-30047 Why add actuators and all kinds of things that could work imperfectly, 5 seconds of vibration? I'd rather deal with that. Although I guess with the level of tech in this new "kebab" might as well make the whole ride plush Why add actuators and all kinds of things that could work imperfectly, 5 seconds of vibration? I'd rather deal with that. Although I guess with the level of tech in this new "kebab" might as well make the whole ride plush

]]> By: von Dawson's Express http://www.universetoday.com/2008/08/19/nasa-to-install-shock-absorbers-to-mitigate-thrust-oscillation/comment-page-1/#comment-30032 von Dawson's Express Wed, 20 Aug 2008 12:20:13 +0000 http://www.universetoday.com/?p=17040#comment-30032 Ares 1 with Orion looks like a Kebab, it looks awful, the old adage, 'if it looks right, it is right' is so true. The 2nd Saturn V problem was a pogo effect caused by the propellents and oxident, this thins a solid and is a different thing. They are using something that was not designed to fly like this. Ares 1 with Orion looks like a Kebab, it looks awful, the old adage, 'if it looks right, it is right' is so true.

The 2nd Saturn V problem was a pogo effect caused by the propellents and oxident, this thins a solid and is a different thing. They are using something that was not designed to fly like this.

]]> By: Tyler Durden http://www.universetoday.com/2008/08/19/nasa-to-install-shock-absorbers-to-mitigate-thrust-oscillation/comment-page-1/#comment-29984 Tyler Durden Tue, 19 Aug 2008 23:29:34 +0000 http://www.universetoday.com/?p=17040#comment-29984 (and emasculating a giant phallic symbol no less!) (and emasculating a giant phallic symbol no less!)

]]> By: Tyler Durden http://www.universetoday.com/2008/08/19/nasa-to-install-shock-absorbers-to-mitigate-thrust-oscillation/comment-page-1/#comment-29983 Tyler Durden Tue, 19 Aug 2008 23:29:05 +0000 http://www.universetoday.com/?p=17040#comment-29983 They're putting a skirt on their rockets? Talk about emasculating. They're putting a skirt on their rockets?

Talk about emasculating.

]]> By: Aodhhan http://www.universetoday.com/2008/08/19/nasa-to-install-shock-absorbers-to-mitigate-thrust-oscillation/comment-page-1/#comment-29977 Aodhhan Tue, 19 Aug 2008 22:02:06 +0000 http://www.universetoday.com/?p=17040#comment-29977 This was actually experienced during the 2nd launch of the Saturn V rocket test back in the 60s. Something which didn't occur during the initial launch. Luckily it occured before we added astronauts to the top of it. It was solved by adding "shock" dampeners on the first stage. This was actually experienced during the 2nd launch of the Saturn V rocket test back in the 60s. Something which didn't occur during the initial launch. Luckily it occured before we added astronauts to the top of it. It was solved by adding "shock" dampeners on the first stage.

]]> By: Tim http://www.universetoday.com/2008/08/19/nasa-to-install-shock-absorbers-to-mitigate-thrust-oscillation/comment-page-1/#comment-29975 Tim Tue, 19 Aug 2008 21:36:25 +0000 http://www.universetoday.com/?p=17040#comment-29975 Commander! Inertial dampers are failing! (sort of) Commander! Inertial dampers are failing! (sort of)

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