Rocket Lab, the world’s most prominent dedicated small satellite launcher, has made significant headway on plans to recover and reuse the booster stage of its Electron rocket, meaning that SpaceX’s reusable Falcon rockets could finally have company.
Recovering a booster is perhaps where all similarities end, however. While the SpaceX Falcon 9 gracefully guides itself back for a controlled landing on an ocean-going drone ship or land-based landing zone, Rocket Lab’s Electron booster will be snagged straight out of the air by a helicopter with a grappling hook.
Recently, Rocket Lab completed what the company called “a major step forward” in plans to achieve full booster recoverability with the successful completion of a “mid-air recovery” test. The test occurred over the open ocean near New Zealand and featured what was identified as an “Electron first stage test article.” One helicopter released the test article at a low altitude – around 2.5km (8,000ft) – and a nearby second helicopter, outfitted with a specially designed grappling hook, swooped in and snatched it out of the sky as it plummeted toward the ocean.
Rocket Lab’s recovery efforts did not simply begin with dropping a rocket-shaped test article from a helicopter. Long before ever attempting to catch a test article falling through the sky, the company had to ensure that the first stage of the Electron booster could even survive the return trip. Rocket Lab CEO and founder, Peter Beck, referred to it as punching through the wall which best summarizes the conditions that the first stage encounters upon re-entry through on the Earth’s dense atmosphere.
The company’s tenth successful launch dubbed “Running Out of Fingers” in December of 2019 was not only successful because it delivered and deployed the payload, but it was also the first time that Electron’s first stage first made it safely through the wall intact. Unlike SpaceX’s Falcon 9 that slows during descent with a series of engine burns, Rocket Lab’s Electron orients itself for the right “angle of attack” to slow down during re-entry.
The first stage of Electron has undergone a number of block upgrades to enable re-entry in one piece. The tenth mission featured the use of the upgraded Electron booster equipped with guidance and navigation hardware, as well as, a reaction control system (RCS) to gently control and reorient the first-stage during re-entry. The RCS was able to keep the booster adequately oriented and slowed it to under 900 kilometers per hour (560mph) for a controlled sea-level impact. The following eleventh mission dubbed “Birds of a Feather” in February 2020, also featured a successful controlled descent of the upgraded Electron first stage.
The final step in slowing the Electron down enough to be recovered by a grappling hook suspended by a helicopter was to develop and test a parachute system. Beck posted a teaser of the prototype parachute on Twitter in early February promising low altitude drop tests to follow soon after. Rocket Lab stated that the successful “mid-air recovery” test occurred weeks prior to the now mandated “Safer at Home” orders given in New Zealand amid the global COVID-19 pandemic.
As reported by Michael Sheetz of CNBC, Rocket Lab will continue to test recovery efforts on an undisclosed mission scheduled for later this year. That test will exercise Electron’s RCS block upgrades and parachute system to a greater extent to slow the booster to a point of survivability upon impact with the water – a speed of about 8kilometers per hour (5mph).
Like SpaceX, Rocket Lab targets a reduction of launch costs and an increase in launch capabilities with full first-stage reusability. The dedicated launcher of small satellites also strives to further open access to space for the rapidly expanding small satellite market.
Currently, Rocket Lab has two operational launch pads, one on New Zealand’s Mahia Penninsula and another at the Mid-Atlantic Regional Spaceport at NASA’s Wallops Flight Facility in Virginia. Later this year a second location on New Zealand’s Mahia Penninsula will come online drastically increasing Rocket Lab’s launching capabilities.
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