Uncrewed Systems Technology 051 l Primoco One 150 l Power management l Ocius Bluebottle USV l Steel E-Motive robotaxi l UAVs insight l Xponential 2023 p Issue 51 Aug/Sept 2023 art 2 l Aant Farm TPR72 l Servos l Tampa Deep Sea Barracuda AUV

10 August/September 2023 | Uncrewed Systems Technology NASA is launching a quartet of six-unit (6U) CubeSats into orbit to test swarm technologies (writes Nick Flaherty). Swarms of autonomous spacecraft promise to change the way NASA conducts science and exploration missions, but those operating a long way from Earth have to carry out functions on their own, owing to the time delay in communicating with ground stations and potential comms disruptions. Autonomy allows a mission to continue though, even when comms with the spacecraft are temporarily disrupted. It also allows the swarms to change behaviour to observe unexpected or rare phenomena. The project, called Starling, will see the CubeSats positioned about 355 miles above Earth and spaced about 40 miles apart. This is to demonstrate the ability to fly together autonomously while keeping track of each other’s relative positions and trajectories. The satellites will also demonstrate the ability to plan and execute activities as a group, without guidance from mission controllers, including responding to new information from onboard sensors. The project has a number of elements. In Reconfiguration and Orbit Maintenance Experiments Onboard (ROMEO) tests, cluster flight control software will initially operate in shadow mode, autonomously planning manoeuvres while the CubeSats are controlled from the ground. Once validated, ROMEO will demonstrate execution of swarm maintenance manoeuvres from aboard the spacecraft without ground intervention. The Starling Formation-Flying Optical Experiment will use commercial cameras to measure the position of stars so that each spacecraft can determine its own orientation relative to the stars. A navigation algorithm uses this orientation data and star tracker images to visually detect and track the other three craft. The Distributed Spacecraft Autonomy (DSA) experiment will use the dualband GPS receivers on the CubeSats to measure the density of atmospheric regions. Each orbiting CubeSat constantly changes position relative to the atmospheric phenomenon and the GPS satellites, requiring changes to the monitoring strategy in response to observations. Onboard DSA software will autonomously coordinate the selection of the best GPS signals across all spacecraft, to accurately capture regions of higher or lower ionospheric density. This is accomplished by first sharing information over a crosslink network to maintain a consistent state, then selecting the GPS signals to prioritise and share in the future. The CubeSats will also demonstrate creating and maintaining a Mobile Ad-hoc Network (MANET) which automatically adjusts to changing conditions using two-way S-band crosslink radios/ antennas. If one comms node fails, the network automatically reconfigures to maintain full communication capabilities for the other craft in the swarm. The CubeSats will be in a Sunsynchronous orbit around the Earth. These are nearly polar orbits that allow a satellite to consistently see the same amount of sunlight each orbit and therefore generate the same amount of power with its solar panels. The CubeSats were provided by Blue Canyon Technologies, in Colorado, which is also providing mission operations support. Rocket Lab USA is providing launch and integration services, and the payloads come from Stanford University’s Space Rendezvous Lab, Emergent Space Technologies in Maryland, CesiumAstro in Texas and L3Harris Technologies in Florida. Space vehicles In-orbit swarming test In the NASA project, four CubeSats will orbit the Earth at about 355 miles