Spaceflight has fitted the first pair of green bipropellant thrusters created by in-space propulsion business Benchmark Space Systems on the Sherpa tug for deployment in January. Benchmark stated on December 21 that the Sherpa-LTC tug’s propulsion system had been fitted and fueled. The tug will be part of SpaceX Transporter-3 dedicated rideshare flight, which is set to deploy in mid-January and will deliver 13 payloads to various orbits.
Benchmark’s new Halcyon Avant thrusters are used in the system, which employs “green” propellants that are secure to handle. The thrusters outperform hydrogen peroxide monopropellant thrusters Benchmark, which were previously designed and flown on numerous satellites.
In an interview, Jake Teufert, Benchmark’s chief engineer, said, “We’re practically at par with the efficiency seen on legacy hypergolic systems,” such as those fueled by hydrazine and combined oxides of nitrogen. “Not only is it environmentally friendly, with all the benefits it entails, but we’re also winning the performance battle, so to speak.”
The company wouldn’t say how much thrust the system generates, but Teufert claimed the existing system had a specific impulse of 303 seconds, which is a measure of the propulsion efficiency. According to him, the company plans to boost that time to 315–320 seconds, making it “best in class” in comparison to other systems.
The system is powered by two very common propellants: high-test peroxide and hydrocarbon fuel. “With this system, one of the design objectives was to make it as adaptable and low-cost as feasible,” said Ryan McDevitt, Benchmark’s chief executive. “We’re using readily available propellants, and the magic happens on the thruster side.”
Teufert remarked, “It’s really extending the top of the line on hydrogen peroxide thruster design. To develop a modern peroxide thruster, we’re bringing 60 years of excellent practices and updating the state of the art. We’ve seen a lot of benefits from simply merging contemporary technology, production, and 60 years of industry heritage and lessons acquired.”
In a statement, Phil Bracken, who is the vice president in charge of the engineering at Spaceflight, said, “Benchmark’s revolutionary high-thrust technology will play a vital part in our first-ever multi-destination ridesharing mission. We built our Sherpa project to be modular so that we could use best-in-class propulsion systems to satisfy our customers’ unique launch requirements.”
Sherpa-LTE, a modified version of Spaceflight’s Sherpa tug that utilizes an electric propulsion system created by Apollo Fusion and flew for the first time in June, employs an electric propulsion system supplied by Apollo Fusion. The Sherpa-LTE is meant to maximize delta-V, or velocity change, for flights to geostationary orbit (GEO) and beyond, whilst the Sherpa-LTC is designed to offer higher thrust for quick transfers in the low Earth orbit (LEO).
A 2nd Halcyon Avant thruster system will be provided by Benchmark for a Sherpa-LTC mission that will launch later next year. According to McDevitt, his firm has seven missions in the works for 2022, with the prospect of increasing to ten to fifteen as more commercial and government clients sign up.
Benchmark has grown to 40 workers this year, both at its headquarters in Burlington, Vermont, and a test location in California, as a result of this business. As demand for the company’s thrusters develops, McDevitt predicts a 50 percent increase in headcount in 2022.