Ares I-X Launch Scrub: Can You Say "Triboelectrification"

Written by Nancy Atkinson

The test flight for the Ares I-X rocket was scrubbed on Tuesday after repeated delays which included weather, a stuck cover on a probe, a cargo ship straying into the launch hazard zone, weather, and weather.

“We had some opportunities, but just couldn’t get there,” launch test director Jeff Spaulding said to the team. “Weather didn’t cooperate.” The biggest issue with weather was the launch commit criteria of avoiding possible static discharge called “triboelectrification” created by the outer coating of the rocket as it flies through cloud vapor or precipitation that is colder than -10 degrees C (14 deg. F). This static electricity could disrupt the transmission of flight test data from the rocket, one of the main reasons for the test.

Sunset at Launch Pad 39B at NASA's Kennedy Space Center. Credit: NASA/Kim Shiflett

The launch window opens at 8 am EDT (1200 GMT) on Wednesday.

The 5-hole probe on the top of the Ares I-X rocket. Credit: NASA

On Tuesday, when the weather improved enough to remove the 5-hole probe cover, then came a problem with removing it. This difficulty was not anticipated.

“After hundreds of tests with the probe, that’s the first time we’ve seen that failure mode,” said NASA engineer Jon Cowart on NASA TV. On Twitter, a NASA engineer shared that they gave the pad crew the recommendation to pull the lanyard attached to the cover “as hard as you can.” It worked.

Then came a cargo ship that entered the hazard area in offshore waters. The ship was notified and it turned around quickly.

But by that time the weather had deteriorated. Good on their word that they could quickly restart the countdown clock, the launch team tried several times to coordinate a hole in the clouds with acceptable (less than 20 knots) ground and upper level winds. It was a roller coaster of “go” and “no-go,” but ultimately the weather cards never fell into the fight configuration to allow the launch to take place.

Tomorrow the weather is better but not great. The chance of unacceptable conditions drops to 40% no go for Wednesday, as opposed to 60% no go today. Forecasters predict somewhat quieter winds at ground level, upper level winds are expected to be lighter and clouds will be decreasing, with more breaks in the clouds.

The test flight will last six minutes from liftoff to splashdown, with the Ares I-X reaching a maximum altitude of 46,000 km (153,000 feet) and a top velocity more than 4.7 times the speed of sound.