Ares “delay” puts NASA on the back foot - January 23, 2008
Last week AP and NasaWatch broke the news that engineers were worried Ares, the replacement for the shuttle, could shake itself to pieces in the first few minutes of flight. “They know it’s a real problem. This thing is going to shake apart the whole structure, and they’ve got to solve it,” AP was told by Paul Fischbeck, of Carnegie Mellon University, who analysed risks for NASA in the past.
According to AP, acceleration pulses from gas vortices in the solid rocket booster powering the Ares launcher match the natural frequencies of the motor’s combustion chamber. This kind of resonance is bad – as any physics student shown footage of the Tacoma Narrows Bridge can testify. I don’t know if this is quite the same thing as the pogo oscillations that plagued the Saturn V rockets, but it sounds similar and it’s worth noting that Ares is nicknamed ‘The Stick’.
Later, NasaWatch got hold of a NASA memo that seemed to show that the Ares launch had been delayed by 12 months (blog post, memo). However Griffin has denied this. His slightly tetchy denial is rather convoluted but he says this is not a delay but a “re-phasing” of milestones (NasaWatch blog post). Clear on that?
Image: artist's rendition of an Ares I rocket on launch pad / NASA
Comments
Many of us in the physics field were aware of this problem from day 1, way back in September of 2005.
This vehicle design should have never even made it into the engineering phase. This whole situation is a complete embarrassment to the nation.
Posted by: Thomas Lee Elifritz | January 24, 2008 05:54 AM
Many of us in the physics field were aware of this problem from day 1...
A similar situation occurs with the shorter Shuttle SRBs. However, the External Tank's close proximity dampens these oscillations and prevents this mechanism from having a deleterious effect on the vehicle. Not having the luxury of a large liquid damper, the most probable solution to the Ares 1 problem is the addition of mass. Of course, this is not what the concept needs, since it is already sway over its mass budget.
When will NASA admit that this is an impractical approach? I think we all know that the only thing keeping it alive is Griffin's infatuation with the concept.
Posted by: The People | January 24, 2008 11:01 AM
I first heard about this problem from a biologist about 3 years ago - the expected oscillations (not just g's but variations in g's) of "The Stick" were large enough to dislodge astronaut brains and other vital organs, even if the rocket could survive. Has anyone asked Griffin about this?
Posted by: Mike | January 24, 2008 05:09 PM
This is a fertility rite for the intellectually sterile. 90% of initial information is usually wrong! Ares is rapidly becoming the Godess of Stupidity. We went to the Moon with slide rules, wild budgets, and a bunch of dreamers. Now we have multi-tasked ourselves to the point where we cannot design a vehicle to get us back until 2020 or beyond. We are driven by a budget that cannot be "plused up" as there aint no money, and the dreamers are bean counters who cause engineers to change their minds 360 degrees every day. It is time NASA be disbanded and the USAF take over. They can do no worse, and we can quit pretending NASA is not a test bed for them anyway.
Posted by: Thomas Napton | January 24, 2008 07:45 PM
this story was on NASASpaceFlight.com before anywhere else, as per usual, and based on an actual presentation, not just a memo.
http://www.nasaspaceflight.com/content/?cid=5335
Posted by: Tony NASA | January 25, 2008 02:07 AM
There is a better way of going to and from earth orbit and it is right under NASAs nose. See the web site-- www.us-spaceplanesystems.com
Posted by: Chief Designer | January 25, 2008 02:28 AM
Perhaps it was never intended to fly. Certainly the option of a "shuttle-derived" system was more palatable to the companies/constituents/lobbyists for which the shuttle program was a long term golden goose. Perhaps shuttle-derived designs (with plenty of design changes over time) keep companies making money after the program was shut down. (Not that I’m against them making money…if we are going to get something out of it.)
Another component may be that shutting down STS without naming a follow on program was politically unfeasible (despite a lack of public support, I don't think many mainstream politicians want to be remembered in the history books for putting the kibosh on US manned spaceflight.)
Perhaps a final outcome of 1) a few extra years of $$$ for shuttle contractors, 2) an elimination of manned spaceflight without much ado, and 3) no politician being saddled with the blame (such a situation would make it easy to blame nameless/faceless engineers that the general public is already suspicious of) is what Ares is all about (by design or by chance.)
Or not...
Posted by: Bill | January 25, 2008 09:28 PM
I don't understand why we don't just improve & modernize the existing Space Shuttle system. It's a proven system, we've got lots of experience running it, and a redesigned Shuttle2 would be safer, cheaper to operate, and fits the original phased transportation system (earth-to-space station, earth orbit to lunar orbit, lunar lander & eventual lunar base) that we've invested so heavily in. Bush and his plan simply doesn't make sense and is destined to fail, just like everything else he touches.
Posted by: Dave G | January 26, 2008 09:49 PM
I don't understand why we don't just improve & modernize the existing Space Shuttle system.
It is far too expensive to operate, especially at the low flight rates projected for ESAS. Granted, at those low flight rates the entire effort is difficult to justify anyway. If it were really worth sending people into space, it would be worth doing it on a larger scale. The timidity of the plan betrays it.
Posted by: Paul F. Dietz | January 29, 2008 12:03 AM
The shuttle system was designed to support some 30 to 40 flights per year. We've never come near that. Given reality, it makes sense to retire the Shuttle. I belive that there was political pressure to use SOME part of the shuttle, hence the 1st stage solid. There appear to be problems with this approach. My suggestion would be to keep the CEV and 2nd stage elements and replace the 1st stage solid with an EELV derived 1st stage.
Posted by: Tom Nicolaides | January 29, 2008 03:27 PM
I just don't get it. You'd think that with all the "brainiacs" working on Ares that they would at least be able to pool their brain cells and figure a way to make it work without shaking the whole structure and collapsing it.
Posted by: Ares | October 5, 2009 09:44 PM