American aerospace manufacturer and small satellite launch service provider Rocket Lab said on 9 December that it had flown a fully Autonomous Flight Termination System (AFTS) for the first time on an Electron launch vehicle, part of its reusable rocket program.
According to the company’s press release, the AFTS flown on the company’s most recent mission, ‘Running Out Of Fingers’, makes Rocket Lab one of only two US launch companies to have flown using an autonomous system.
AFTS is a GPS-aided, computer-controlled system designed to terminate an off-nominal flight, replacing traditional human-in-the-loop monitoring systems. It is crucial to increasing launch frequency and providing responsive launch capability, while maintaining high safety standards, Rocket Lab said.
In theory, it reduces the turnaround time between missions and provides greater schedule control by eliminating reliance on ground-assets and human flight termination operators.
‘Running Out Of Fingers’ hosted the first fully autonomous system on Electron, following four ‘shadow’ flights where the AFTS unit was flown on the vehicle for testing while traditional ground-based flight termination infrastructure remained in place. With the first fully autonomous mission now complete, Rocket Lab intends all future Electron missions to fly with the AFTS.
Flight termination systems are a vital part of launch operations. Traditionally, flight termination infrastructure is a ground-based system that involves a human making the decision to terminate a mission in the event of a launch vehicle straying from a pre-determined flight path.
By contrast, the AFTS is an independent, self-contained subsystem mounted on-board the Electron launch vehicle. It eliminates the need for a ground-based infrastructure by moving the flight termination function to the launch vehicle.
The system makes flight termination decisions autonomously by using redundant computers that track the launch vehicle using Global Positioning System and on-board sensors, combined with configurable software-based rules, that identify where the rocket can safely fly.
If a rocket goes off course the AFTS will issue a command to terminate the flight by shutting down the engines. The AFTS also delivers faster response times and improved monitoring as launch vehicle travels downrange, providing over-the-horizon tracking capabilities that are not limited by line-of-sight tracking such as that required by ground-based instrumentation at the launch site.
“The AFTS is yet another way Rocket Lab is innovating to increase the pace of launch and support responsive launch capability for small satellites,” Rocket Lab founder and CEO, Peter Beck, said in a statement.
“As we move to an autonomous system, I’d like to thank . . . White Sands Missile Range and Alaska Aerospace Corporation, who have provided ground-based flight termination system support for Electron missions since our first launch in 2017,” he added. “Their support has ensured the safety of every Electron mission and they have contributed to our record of mission success for customers.”
“I’m immensely proud of the team here at Rocket Lab that has made AFTS on Electron a reality,” Naomi Altman, Rocket Lab’s Avionics Manager and Project Lead for the AFTS program, added.
“For AFTS to be part of Electron’s 10th launch was the cherry on top of a monumental year for the whole team,” she said. “Reaching this milestone is also testament to the ongoing support of government agencies and contractors who worked closely with us to bring the AFTS online.”