, Md. — A senior NASA space exploration official told an industry group here March 24 that a rocket vibration issue Ares 1 engineers have been wrestling with since last year presents less of a problem than previously feared.
Doug Cooke, NASA deputy associate administrator for exploration systems, told the Maryland Space Business Roundtable during the group’s monthly luncheon that intensive study of Ares 1’s so-called thrust oscillation issue has lessened the U.S. space agency’s concern that vibrations originating in the rocket’s solid-fueled main stage could grow to dangerous levels as the vibrations travel up the length of the rocket, potentially shaking the launcher apart in flight.
Cooke said that assessment, which moved thrust oscillation to the front burner for Ares officials, was based on “very preliminary calculations.”
NASA officials cautioned reporters early this year that the severity of the problem could recede by doing nothing more than taking a closer look at the simulations and analysis that yielded the unacceptable levels of vibration.
According to Cooke, that is indeed what has happened.
“We’ve gone through a lot of studies to put a finer point on it and have reduced it very significantly,” Cooke said. “We’re not completely finished, but it’s well within the ability to mitigate now between various design techniques that should not be disruptive to our overall efforts.”
Cooke’s comments came as NASA was preparing to release further details about the thrust oscillation issue the week of March 31.
Cooke also mentioned that NASA intends to instrument the solid-rocket boosters on an upcoming space shuttle flight to gain more thrust chamber pressure and accelerometer data that should prove useful to engineers working on Ares’ vibration issue. The main stage of the Ares 1 is essentially a larger version of the space shuttle’s solid-rocket boosters, or SRBs.
“We are going to get further data from ground testing SRBs. We are also going to instrument shuttle SRBs with thrust chamber pressures and accelerometers so we can better update our models on what’s actually happening,” Cooke said. “It turns out that in the past we have instrumented the shuttle SRBs with one of those at a time – either thrust pressures or accelerometers, but not both at the same time.”
NASA spokesman Grey Hautaluoma could not provide details March 25 on which upcoming shuttle mission would fly with the instrumented boosters, saying that the details were “still being worked.”