A helicopter successfully played catch with a rocket’s descending first stage Monday in Rocket Lab USA's first attempt to recover an Electron launch vehicle’s booster in mid-air.
In the test, a Sikorsky S-92 helicopter lowered a hook at the end of a cable to snag the first stage as it fell at a rate of 22mph under its primary parachute. The cable successfully caught a line hanging from a smaller drogue chute and Rocket Lab’s mission control center erupted with cheers.
Shortly after, however, the helicopter pilots decided they were experiencing loads outside of their mission criteria and elected to stop the test early, jettisoning the rocket to resume its parachute fall to the ocean. A distinct “aww” could be heard on the stream from mission control. (Fast forward to 52 minutes and 25 seconds in the video below for the launch.)
“A little bit wetter than we’d hoped,” Rocket Lab CEO and founder Peter Beck said of that booster’s condition in a press call late Monday night before rating the test overall “incredibly successful.”
He emphasized the difficulty of the test, which saw the stage reach suborbital space before reentering the atmosphere. The flight profile allowed about 10 minutes for the helicopter to match speeds with the booster and get its cable to pluck the drogue line. “It’s kind of like Ghostbusters in a way; you want those two lines to cross,” he explained.
Mid-air retrieval is not a new concept, for example, the National Reconnaissance Office’s CORONA series of spy satellites sent back film in re-entry capsules caught by Air Force planes. However, they involved much smaller objects than a one-ton carbon-composite rocket stage with nine kerosene-fueled engines.
After the early jettison of the Electron booster, Rocket Lab’s recovery ship retrieved the stage for analysis on shore. Beck said in the call that even if the pilots had seen no issues hauling the booster (which is well below its five-ton lifting capacity), they probably would have dropped the stage into the water beside the boat to make things a little safer.
The rest of the Electron launch from Rocket Lab’s facility on New Zealand’s North Island proceeded satisfactorily, with its second stage lofting 34 small satellites.
First successfully launched in 2018, Electron can deliver 661 pounds to low Earth orbit; far less than SpaceX’s Falcon 9 and other larger rockets, but enough for the growing popularity of smaller object launches such as cubesats. Last year, the company completed five launches, second among US launch operators after SpaceX’s unprecedented 31 Falcon 9 missions.
Reusability will help lower Rocket Lab’s costs–Beck said 80% involve the first stage–as it moves towards starting launches at a new Wallops Island, Virginia facility at which it also plans to build, fly and land its larger, also reusable Neutron rocket.