Astra completes investigation and schedules next orbital launch attempt
Astra has completed the investigation into the terminated launch of LV0006 in August 2021. A… The post Astra completes investigation and schedules next orbital launch attempt appeared first on NASASpaceFlight.com.
Astra has completed the investigation into the terminated launch of LV0006 in August 2021. A propellant leak caused an engine failure at liftoff, resulting in insufficient thrust to achieve orbit. Design changes have been implemented to address the anomaly for Astra’s next rocket, LV0007.
The launch window for LV0007 opens on October 27 and continues through October 31. Additional launch opportunities are available from November 5 to November 12.
LV0006 Investigation Results
On August 28, Astra conducted a test flight of Rocket 3.3, the latest version of their small satellite launch vehicle. Designated LV0006, the rocket ignited all five of its Delphin first stage engines and lifted off from the Pacific Spaceport Complex in Kodiak, Alaska.
During liftoff, kerosene fuel and liquid oxygen both leaked from the propellant supply system adjacent to the rocket. This system is designed to quickly disconnect and seal when the rocket launches. When LV0006 lifted off, these leaked propellants mixed and became trapped beneath the interface between the rocket and the ground equipment.
These mixed propellants were subsequently ignited by the exhaust of the first stage engines, which caused an over-pressurization that severed the electrical connection which controls the fuel pump. This caused the shutdown of one Delphin on the first stage less than one second after liftoff.
Reviewing flight data and video, two things are very clear – 1) An engine shut down right after launch 2) Everything that happened next made me incredibly proud of our team. Space may be hard, but like this rocket, we are not giving up. #AdAstra pic.twitter.com/2g3n812EaW
— Chris Kemp (@Kemp) August 29, 2021
This shutdown created an asymmetrical thrust, which caused the vehicle to tip sideways and slide away from the launch pad. The four remaining engines gimballed to straighten the rocket, but with only four engines worth of thrust so early in the flight, reaching orbit was not possible.Astra Updates
After two and a half minutes, the vehicle had cleared the pad, but deviated significantly from its planned trajectory, prompting the termination of thrust on the remaining engines and the end of the flight.
There were a couple of prior upgrades to the Rocket 3 series which were validated by the flight of LV0006. When LV0005, the one and only Rocket 3.2 to fly, fell just short of achieving orbit in December 2020, a propellant mixture management issue was to blame. For LV0006, Astra implemented closed-loop control of the vehicle’s propellants, and this system performed nominally during launch.
Additionally, the software loaded into the rocket’s Guidance, Navigation, and Control (GNC) system was updated with new code and algorithms after Rocket 3.2. The GNC system proved its worth with LV0006, correcting for asymmetrical thrust at liftoff and achieving two and a half minutes of flight.
As with all test flights, a wealth of other thermal and acoustic data was also collected for analysis and future improvements to Astra launch vehicles.
“Data from the two-and-a-half-minute flight provided valuable insights that we have incorporated into LV0007 and future launch vehicles,” said Chris Kemp, Founder, Chairman, and CEO of Astra. “Our team is looking forward to returning to flight and learning more about our launch system – consistent with our launch and learn philosophy.”
Following the investigation, multiple corrective actions have been taken to prevent this type of anomaly from occurring again. First, the locations of the ground equipment interfaces which feed fuel and oxidizer to the rocket have been moved. Now, even if both propellants do leak, they will no longer mix with one another.
In order to prevent leaks from developing in the first place, the propellant supply system has been modified and re-qualified. This includes removing the cover which created the confined space which trapped the mixed propellants on LV0006.
Finally, verification processes for designs and operations were both improved. With the implementation of these changes, Astra is now targeting another orbital launch attempt this month.
Future Astra launch schedule
LV0007 is the second Rocket 3.3 vehicle and will make Astra’s next orbital launch attempt. Like Astra’s previous test flights, the mission will be conducted from the Pacific Spaceport Complex in Kodiak, Alaska. Also, like LV0006, the mission will carry a test payload for the United States Space Force’s Space Test Program, a mission designated STP-27AD2.
The launch window for LV0007 consists of two segments. The first stretches from October 27 to October 31, and the second from November 5 to November 12. Should additional time be needed to conduct the launch, Astra would coordinate a new launch window with the range.
LV0007 will be Astra’s fourth orbital launch attempt, building on two suborbital test flights with Rocket 1 and Rocket 2, a ground failure with Rocket 3.0, and failed orbital launches with Rocket 3.1, 3.2, and the first 3.3 (LV0006). Successfully achieving orbit will set the stage for Astra to begin delivering customer satellites to orbit, including payloads for the US Space Force and NASA.
While plans are subject to change pending the results of LV0007’s flight, Astra’s Thomas Williams stated during the Small Payload Ride Share Association Symposium this month that the company’s second launch site will debut later this year. Astra is planning to utilize many launch sites, combined with high rocket production cadence, to provide daily access to orbit.
(Lead photo of LV0006 on the pad in Kodiak – via Astra)
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