Astra Rocket 3.3 liftoff
Astra's Rocket 3.3 could be seen tipping briefly seconds after engine ignition. The vehicle moved sideways for nearly 20 seconds ascending, but failed about two minutes later. Credit: Astra/ webcast

WASHINGTON — Small launch vehicle company Astra has identified the cause of an August launch failure and says it will make its next attempt as soon as late this month.

In an Oct. 12 statement, Astra said the Aug. 28 launch of a Rocket 3.3 vehicle, designated LV0006, failed because propellants leaked from a supply system and ignited, disabling one of the rocket’s five first-stage engines less than one second after liftoff.

“The issue we encountered was something we hadn’t seen before,” Benjamin Lyon, executive vice president and chief engineer of Astra, said in a blog post about the investigation. A quick-disconnect system, designed to seal shut when lines feeding RP-1 fuel and liquid oxygen into the rocket disconnect at liftoff, instead allowed the propellants to leak into an enclosed space between the rocket and its launch platform.

“Those propellants were ignited by the engine exhaust, causing an over-pressure event that severed the connection to the electronics that control the fuel pump, shutting down the engine less than one second after liftoff,” he wrote.

With only four engines operating, the rocket hovered just off the ground, drifting away from the launch tower until it had burned off enough propellant to make it light enough to ascend under its reduced thrust. The vehicle reached max-Q, or maximum dynamic pressure, but the mission terminated shortly thereafter.

Astra says it’s made several changes to correct the problem on future launches. It modified the propellant connections to reduce the risk of leaks, and changed the locations of the propellant interfaces so that even if there are leaks, fuel and oxidizer won’t mix. The company also updated verification processes. “Together, we believe these changes significantly reduce the likelihood of seeing a similar event in the future,” Lyon wrote.

With those changes in place, Astra said it’s ready to proceed with the launch of its next vehicle, LV0007. That launch, the second of two under a U.S. Space Force contract and designated STP-27AD2, is scheduled for launch in one of two windows. The first window is from Oct. 27 to 31, while the second runs Nov. 5 to 12. The launch will take place from Kodiak Island, Alaska, the location of the company’s three previous orbital launch attempts.

There had been speculation in recent days that Astra was preparing for a new launch attempt based on the publication of a temporary flight restriction (TFR) Oct. 7 by the Federal Aviation Administration, restricting airspace in the vicinity of the Kodiak launch site for “space operations.” However, that TFR begins Oct. 19 and runs through Oct. 29, and is configured differently than TFRs for previous Astra launches there.

The upcoming launch will be the fourth orbital launch attempt for Astra, which failed to reach orbit on its first three launches but came close on its second, in December 2020. Lyon said that the August launch verified changes made after the second launch, including a closed-loop propellant control system to better manage propellants and avoid an early engine shutdown like that on the second launch.

The August launch also demonstrated improved guidance, navigation and control (GNC) software. That revised code, Lyon wrote, “was on full display in this launch when the rocket course-corrected after tipping sideways, making us all very happy with our GNC.”

Astra did not reveal launch plans beyond its next launch. However, at an Oct. 5 online meeting of the Small Payload Ride Share Association, an Astra official, Tom Williams, said the company would launch later this year from a second location that he did not identify but “we will hopefully announce shortly.” A leading candidate for that second site is Kennedy Space Center’s Launch Complex 48, a multi-user pad intended for small launch vehicles like Astra’s that require minimal infrastructure.

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...