Inside a 2,900-square-foot cleanroom at Southwest Research Institute, two workers lean over a table assembling hardware for a satellite with a delicate job: docking with other spacecraft and transferring fuel while both hurtle through space at 7,000 miles per hour.
SwRI has been tasked with building the satellite — formally the Astroscale Prototype Servicer for Refueling (APS-R) also known as “Provisioner” — as part of a $25 million project funded by the U.S. Space Force (USSF) and led by Colorado-based aerospace company Astroscale U.S.
SwRI is responsible for building and testing the spacecraft before it’s shipped off for launch.
The project fits the Space Force’s push toward “dynamic space operations,” making U.S. satellites, which are limited in mobility by how much fuel they can carry, more maneuverable and better able to avoid threats, according to National Defense Magazine.
Roughly the size of a gas pump, the satellite will sit 22,236 miles above Earth’s equator waiting to bring fuel to compatible spacecraft in the planet’s orbit. Basically the AAA roadside assistance of space, as SwRI research and development manager Scott Sutherland puts it.
The goal is to extend the lifespan of spacecraft, which are currently limited by how much fuel they can carry on their missions.
SwRI engineers and technicians are building the satellite inside of the nonprofit research institute’s 74,000-square-foot Space Systems Integration Facility, where it will also undergo rigorous testing to prepare it for the harsh environment beyond Earth’s atmosphere.
Provisioner is one of the most complicated spacecraft the institute has built, said Michael McLelland, SwRI’s vice president of research and development.
Two dancing bullets
The satellite’s guts are spread throughout the cleanroom: its black box, which contains the spacecraft’s brain, the solar arrays that power it and all of the complex hardware that will allow it to dock and refuel other spacecraft.
Engineers and technicians wear white coveralls and hair nets under the bright sterile lights of the cleanroom, a specialized environment that minimizes dust and other contaminants that can interfere with sensitive space instrumentation.
Once in space, the plan is for the satellite to remain in one spot above Earth’s equator in geostationary orbit, matching the spin of the planet. It will access a separate fuel depot in orbit that contains hydrazine propellant and then rendezvous with compatible spacecraft, carefully docking with them before transferring fuel.
“Think about two bullets trying to do a dance and touch each other,” McLelland said. “You’re trying to maneuver and hit it where it’s gonna be, not where it’s at. And you can’t crash into it, because people get really mad when you break their spacecraft.”
Joseph Alexander, the systems engineer for APS-R, said that the satellite will be assembled and ready to be shipped off for launch in about three months.
Before that, though, it will undergo extensive tests next door in the environmental testing facility.
Preparing for space
Satellites orbiting Earth experience a wide range of temperatures, sometimes simultaneously, losing heat to cold deep space and absorbing intense unfiltered sunlight.
“In the old days,” McLelland explained, “we would put [spacecraft] in rotisserie mode and just let it spin to keep it even.”
But many modern satellites are not designed to rotate like the older ones, requiring extensive measures to ensure heat balance by engineers.
To ensure APS-R and other spacecraft are up for the challenge, SwRI places them into its thermal vacuum chamber, which simulates the vacuum of space and can be cranked up to 180 degrees and as low as -150 degrees Fahrenheit, Sutherland said.
Engineers also place hot and cold plates within the chamber to simulate simultaneous temperature gradients.
The satellite will also undergo testing to ensure it’s compatible with its launch vehicle, which will carry it out of the planet’s atmosphere.
Larger spacecraft are also blasted with sound waves in the institute’s acoustic chamber to simulate launch vibrations and noise on the spacecraft’s instruments.
“When we get the next stack of speakers in… we’ll actually break the world record for the loudest digital sound made,” McLelland said. “It’s exactly like the launch. It sounds just like being on the pad. You can feel it.”
SwRI — a nonprofit research institute founded by San Antonio philanthropist Tom Slick in 1947 — plays a specialized role in the aerospace industry, often putting its weight behind a smaller number of unique missions and hard challenges for government and commercial clients.
“The big industry is all too expensive,” Sutherland said. “SwRI’s really good at those hard, challenging projects. We won’t mass produce 50, 60, 70, spacecraft in a line production — our engineers and scientists really enjoy the challenge of different mission sets every single time.”
