Catching a falling rocket with a helicopter more complex than it sounds, says Rocket Lab
And it should know – having just failed to catch one
Private launch outfit Rocket Lab has again failed to catch one of its Electron launcher's first stages with a helicopter as it floated back to Earth.
"Bringing a rocket back from space is a challenging task and capturing it mid-air with a helicopter is as complex as it sounds," said Rocket Lab founder and CEO, Peter Beck. "The chances for success are much smaller than those for failure because many complex factors must perfectly align."
Rocket Lab's Electron can carry 300kg to low Earth orbit and has over 30 successful launches to its name. But the craft is not re-usable because its first stage either splashes down into the ocean – which rather makes a mess of its engines – or burns up on re-entry. Rocket Lab has recovered Electron boosters, and has successfully recovered and restored one engine for terrestrial firing tests.
To make Electron reusable, the company hopes to catch Electrons as they float to Earth beneath a parachute.
That plan requires the use of Sikorsky S-92 helicopter that's more than capable of carrying the 1,000kg booster.
But catching it is another matter.
As Rocket Lab staff explained during the live-streamed video (see below) of the mission: "Between the main parachute deployment and the time it would take Electron to reach the ocean, our pilots have about ten minutes to complete the catch. Within that time our pilots need to control the Sikorsky, balance the swing of the hook underneath while it's attached to the helicopter's line, hook up precisely to Electron’s parachute line, and then secure the rocket beneath them for the journey back."
Sadly, on this occasion, a brief loss of telemetry from Electron's first stage during re-entry meant the catch wasn't attempted. And fair enough, given that the Sikorsky crew clearly need to be very confident they know the rocket isn't going to whack them out of the sky.
Rocket Lab does not consider the mission a failure, because it was able to recover the booster from the Pacific Ocean east of New Zealand.
"We are proud to have successfully recovered our fifth rocket from the ocean now and we look forward to another mid-air capture attempt in future as we work toward making Electron a reusable rocket," Beck said.
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The CEO is happier about the main job of this mission: launching a satellite called MATS (Mesospheric Airglow/Aerosol Tomography and Spectroscopy) for the Swedish space agency.
MATS's job is to investigate waves in the atmosphere and their impact on Earth's climate. The satellite does that by studying variations in the light that oxygen molecules emit at an altitude of 100 kilometers.
The satellite went aloft without incident and now occupies a 585km circular orbit, making it the 152nd orbiter successfully launched by Rocket Lab. ®