Ares I Thrust Oscillation mitigation - the current state of play

[Zachstar]

Source: NASASpaceflight.com

"Thrust Oscillation is a recognized characteristic of solid rocket motors - in Ares I's case, the five segment first stage - with concerns arising when pressure oscillations drive resonant modes in the vehicle structure. It is not clear as to exactly how bad the TO numbers are, due to lack of flight data."

"Last year, preliminary structural analyses on Ares I indicated that a potential resonant concern resulted in high dynamic G force levels in the upper stage, and more importantly, in the Orion capsule - a serious threat to the health of the astronauts during ascent. "

"The analysis status at the time of the opening findings noted 'initial preliminary assessment of the element impacts of 'conservative' loads indicated 'RED' status for crew, Service Module structure and the Upper Stage Main Propulsion System. At this point, Thrust Oscillation officially became the number one concern for the new vehicle. "

"This issue has a long path in front of it before it can no longer be described as a major concern for the vehicle."

Read more: http://www.nasaspaceflight.com/content/?cid=5394

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I know this is a bit complicated but try to understand. Bush and NASA touted this new program that was designed to keep many shuttle jobs (For political purposes of course) While leading on some sort of plan to return to the moon.

In my view the rockets that were touted as "Safe, Simple, Soon" was completely playing the American people and now we got a rocket that unless fixed will never be man rated. Therefore unless COTS works there will be no US manned spaceflight (Unless by purchasing seats on Russian spacecraft) after the Shuttle retires.

So we got this rocket that has already lost so much performance and shuttle heritage that the Orion crew capsule has had to go to amazing measures to keep the mass down and yet do more to get the craft to Orbit.

Let us be clear. As it stands now it is almost a golden target for a budget cut that will end any chance we have of returning to the moon in the 2020 timeframe.

There is another solution one created outside of NASA and is picking up support. I hope you will note it to Congress and the presidential candidates so that we have a real chance of building a viable system.

http://www.directlauncher.com/

http://en.wikipedia.org/wiki/DIRECT

[angrycarpenter]

1. Politics not practicality will determine the next step.

Conservatives hate the space program. Many would be happy to see NASA fail and be closed down.

They could turn the assembly building into the G Bush library. Maybe it is big enough to hold his ego.

[Ian David]

2. You have no idea how many arguments I've gotten in over this.

Just the other day, I was at the drive-thru window getting coffee, when the subject of pressure oscillations drive resonant modes came up during our brief discussion. The girl working the window was clearly not understand how bad the TO numbers were, but I had to explain to her that we'd need more flight data.

[Tesha]

4. That's just TO bad, y'know? (NT)

[A HERETIC I AM]

5. I hate it when that happens. n/t

[Tesha]

3. We might as well out-source this to the Chinese (or the ESA) as well.

Multi-segment solid fuel rockets have been the bane of the
manned space program since aty least the Challenger.

It's a shame the military forced those early "extra lift"
changes to the Space Shuttle that then forced the incorporation
of the SRBs. We'd probably be far ahead, technologically, of
where we are today if the Space Shuttle had remained a true
single-stage-to-orbit vehicle.

Tesha

[Ian David]

6. Plus, the SRBs are the most polluting of the shuttle's components, aren't they? n/t

[Tesha]

7. By definition, yes.

If the main engines are burning just LOX and LH₂, then
by definition, their only output is steam (although I
suppose some NO_x is evolved right near the
exhaust streams. But the exhaust from the SRBs is nasty.

Tesha

[Zachstar]

8. There is no comparason tho.

The use of solid rockets is very limited so the amount of pollution they spew is small in comparason with even the most basic polluting factory.

[Tesha]

9. The question was in regards to the Space Shuttle.

So unless you consider the manufacturing and recycling
processes of the Shuttle's components, the SRBs are the
clear winner.

Tesha