Friday, October 30, 2009

Ares I-X Flight Test Yields Few Feared Vibrations

NASA's slender Ares I-X rocket flew a rock-steady test flight allayed fears the vehicle might shake so violently that it could injure or kill astronauts, a program official said today.

Standing 327 feet tall, the skinny "single stick" performed a perfect flyaway maneuver at liftoff and cleared the tower at Kennedy Space Center's launch pad 39B without problems, and the first and second stages of the vehicle separated cleanly, the official said.

A parachute system failure and resulting damage to the rocket's first stage are being regarded as a "minor thing."

"The fact that it didn't work is not a problem. You've heard me say it over and over again: We want to find these things that are not quite working (right)," NASA Ares I-X Program Manager Bob Ess told reporters here at Kennedy Space Center. "That's why we did this test -- to see how everything would work."

NASA's Ares I-X slammed into the Atlantic Ocean and sustained significant damage Wednesday after its first-stage parachute recovery system failed to operate properly.

The pilot and drogue chutes deployed as expected. The three main parachutes -- each 150 feet wide and the largest of their type in the world -- inflated as intended during the first phase of a two-stage deployment. But then within seconds, one of the main chutes inexplicably deflated. Another only inflated partly during the second stage of deployment.

The failures resulted in a harder-than-anticipated “slap down” on the ocean surface.

Divers on the recovery team discovered a large dent on the casing of the four-segment shuttle solid rocket booster that powered the Ares I-X first stage. They also found a large crack in part of the casing on the uppermost segment of the booster and a fractured actuator bracket.

The $445 million Ares I-X flight test was designed to determine whether the tall-and-skinny rocket -- only 18 feet in diameter at its widest point -- could be controlled during the critical first two minutes of flight. Ess said the vehicle flew "rock steady."

"We have great confidence that they found a way to handle all the winds with this long skinny vehicle. It's not a problem for it," Ess said.

What's more, the vibrations induced during first-stage powered flight were significantly lower than projections based computer modeling and wind tunnel tests.

Some of those models and tests raised questions about a phenomenon called "thrust oscillation" -- vibrations induced as solid propellant within the rocket's casing is exhausted. Some feared the vibrations might be so severe that an Orion crew capsule atop an Ares I rocket might be damaged, or that astronauts onboard could be injured or killed.

Another concern was that vibrations could disable the rocket's flight-termination system, which is made up of small explosive devices that would enable range safety officers to deliberately destroy an errant Ares I before it could threaten populated areas around KSC.

Two Ares I-X sensors specifically designed to measure thrust oscillation beamed back data that indicated vibrations were minimal.

"It's only a preliminary look, but so far the oscillations look very small," Ess said. "There was very little there. At this point there is nothing that indicates that thrust oscillation was even a factor."

The finding joins a growing body of data that suggests thrust oscillation on the Ares I rocket, which will employ a five-segment solid rocket motor, will not be a significant problem.

Sensors flown on four-segment shuttle solid rocket motors over the past year have shown that vibrations on the Ares I first stage will be much lower that much feared.

The vibrations generated during a September test-firing of a five-segment solid rocket motor test were eight to 10 times less than design limits -- so low NASA and booster manufacturer ATK might not have to add extra dampers or shock absorbers to the Ares I rocket.

"A year ago, it was kind of doom-and-gloom for thrust oscillation," Ess said. "We instrumented shuttle flights. We've done ground tests, and now we've done this test. And we're just not seeing these (high) numbers in thrust oscillation."

The flight test Wednesday was the first in a series designed to certify the Ares I to fly U.S. astronauts on missions beyond Earth orbit.

A White House panel delivered a report earlier this month that outlined options that would cancel Ares I in favor of the development of commercial crew transportation systems.

President Obama is expected to chart a course for NASA in the next few months. Ess said the Ares I-X flight test proved something: "The Ares I concept really works," he said. "Surprise. Surprise."

ABOUT THE IMAGE: Click to enlarge the NASA image of the Ares I-X rocket blasting off from launch pad 39B at Kennedy Space Center on Wednesday. You can also click the enlarged version to see an even bigger, more detailed view. The image shows the deliberate "fly-away" maneuver performed at ignition as the rocket's bell-shaped nozzle was canted one degree. The maneuver was performed to ensure the exhaust plume from the rocket would not damage the Fixed Service Structure at the pad. Photo credit: NASA/Tony Gray and Tom Farra


Graham said...

Test and learn and incorporate those lessons thats what they've always done.They'll end up making a robust set of new hardware Ares 1 and Ares V fit to take astronaughts out into deep space again.

Keep on going Nasa some people are watching every test with great interest.

Anonymous said...

Great, Now lets get to work and get this going so we dont have to go "overseas" to get to space. Have NASA accelerate development of the escape system and crew module, those systems will be needed no matter what vehicle they ride on. Go NASA, Go ARES

Gaetano Marano said...


"vibrations" isn't the #1 problem of the Ares-1 compared with its (too high) costs:

and the weak upperstages' mass lifted by the REAL (5-segments SRB) Ares-1 version:


Anonymous said...

"The Ares I concept really works," he said. "Surprise. Surprise."

Surprise, surprise... not to those of us who have unwaveringly believed in the Ares I concept all along. Lots of people owe Messrs. Hanley, Cooke and Ess congratulations and apologies.

Anonymous said...

Um, excuse me but didn't the Ares 1X NOT have the extra booster segment that was anticipated to cause the resonance/vibration? Let's wait until (if) the extra segment booster is flown to slap ourselves on the back about what a great job NASA did.

Anonymous said...

With all Obama's problems and setbacks recently, he needs to confirm his plans for NASA, ASAP. I find the dithering only further damages his pre-election image. Ares 1-X was a success, money and time have been invested. So increase the funding or announce a new strategy Mr President!!

Anonymous said...

I agree with Mr. Marano. The problem isn't vibrations, it's the Constellation Program's lack of any strategic objective that justifies the extremely high cost of its obsolete throwaway technology.

I was at the meeting where our local politicos called for a letter writing campaign to get $3 billion. They all campaigned on platforms of cutting taxes and "shrinking government" regardless of consequences. Now here they are asking taxpayers in other parts of the country to pay higher taxes and send them here, so government can get bigger. And what practical benefits will the country get in return? They weren't able to name anything, except for jobs in their districts. Obviously other parts of the country will not be sympathetic.

We just launched 4 shuttles in five months, each with seven crew and up to 15 tons of cargo even to the high-inclination ISS orbit. The Ares will cause a gap of five years, after which KSC will have only two launches a year with four people and a few hundred pounds of cargo in a tiny capsule that will be pulled out of the ocean. Spaceships will never again land in Brevard County.

There are legitimate goals for human spaceflight, both research and tourism, but they are both sensitive to cost. The market has shown that there are a few people who will pay $20 million for a ride to LEO, but that's about the maximum. Only one person bought two tickets. The Ares/Orion will cost $250-$500M given that it will have to carry the overhead of the VAB, crawlers, MLPs, LC-39, and all the center infrastructure that gets charged to Shuttle. That's far too expensive for practical flight to LEO, and lunar flight will be a lot more expensive. It would be far more productive to keep the Shuttles flying.

graham said...

If you want to go into space you have to fund it it's simple really. The shuttle is too old now it's had it's day(and i have loved it).It's time to move on,the new vehicles will provide capability to do both LEO missions and DEEP SPACE missions. The orions not tiny it's 25% larger than an apollo era craft and designed for six crew, but will initially take four.

And the Ares V will be the largest heavy lift rocket ever built, capable of shooting some 80 tons into orbit.