Returned to Sender —

Rocket Lab says recovered booster in “good condition,” some parts will re-fly

“Our team has already started working on upgrades for future recovery missions.”

Rocket Lab successfully launched its "Return to Sender" mission 10 days ago. Then, for the first time, the company attempted to recover the Electron booster's first stage from the ocean after this launch, and now Rocket Lab has provided a preliminary assessment of the vehicle's condition.

In summary, the company said in an update on its website, "We couldn't have asked for a better outcome of our first recovery attempt and the team is thrilled." The rocket came back in such good condition, the company added, "We will re-qualify and re-fly some components."

The November 20 flight marked the first time Rocket Lab has fished an Electron out of the Pacific Ocean. The rocket was picked up in the waters off the coast of New Zealand, where the small booster launches from. Founder Peter Beck said the company wanted to assess the health of the first stage—and make necessary modifications to heat-shield and flight software—before going to the final step of catching the Electron rocket midair with a helicopter.

Although they had conducted a number of tests before this mission, the company's engineers weren't entirely sure what they would get back after the Electron rocket experienced temperatures in excess of 2,400°C and speeds of 2.35km/s during its descent.

Video of Electron first-stage separation.

To accommodate this turbulent environment as Electron screamed back through the atmosphere, Rocket Lab added reaction-control-system thrusters to reorient the first stage for re-entry. A parachute system was also added to slow its descent lower in the atmosphere.

So how did the rocket's heat shield withstand these conditions?

"The stage held up remarkably well," the company said. "The carbon composite structure was completely intact. As expected, the heat shield on the base of the stage suffered some heat damage during re-entry. It was never designed for this load case, but before we strengthen the heat shield we wanted to see just how much heat it could take unchanged. With a wealth of data on this now, our team has already started working on upgrades for future recovery missions."

What the news release does not say is how well the rocket's engine section, with its nine Rutherford engines, fared during re-entry. Neither has the company released photos of the engine section itself. This suggests there is still significant work to be done to protect this area during re-entry.

“Data is great”

However, it seems likely that Rocket Lab will get there. The company's engineers are now inspecting and analyzing "every inch" of the recovered first stage so that they can refine its recovery systems ahead of the next attempt. This will not take place on Rocket Lab's next launch—the "Owl's Night Begins" mission for Synspective, a Japanese Earth-imaging company, due to launch as soon as December 12.

Rather, Rocket Lab says it will wait to launch another recovery mission in early 2021. It will not attempt a retrieval by helicopter this time, either. The goal is to collect more data. "One set of data is great, but we’re a conservative bunch and want to validate everything a second time before we move to the next phase of recovery," the company said.

By recovering and re-flying the first stage of a vertically launched rocket, Rocket Lab is seeking to become only the second company to do so—following the lead of SpaceX and its Falcon 9 rocket. Rocket Lab has now flown 16 Electron missions. In December 2015, SpaceX successfully landed a Falcon 9 rocket for the first time on its 20th launch of a Falcon 9 rocket.

Listing image by Rocket Lab

Channel Ars Technica