Starling 1, 2, 3, 4

Starling [Blue Canyon Technologies]

NASA’s Starling mission is a multi-CubeSat mission to demonstrate autonomous swarm technologies. It's mission is advancing the readiness of various technologies for cooperative groups of spacecraft – also known as distributed missions, clusters, or swarms. Starling will demonstrate technologies to enable multipoint science data collection by several small spacecraft flying in swarms.

The six-month mission will use four CubeSats in low-Earth orbit to test four technologies that let spacecraft operate in a synchronized manner without resources from the ground. The technologies will advance the following capabilities.

• Swarm maneuver planning and execution
• Communications networking
• Relative navigation
• Autonomous coordination between spacecraft

The Starling mission will test whether the technologies work as expected, what their limitations are, and what developments are still needed for CubeSat swarms to be successful.

The four 6-unit CubeSats will fly in a Sun-synchronous orbit more than 300 miles above Earth and no more than 170 miles apart from each other. The spacecraft will fly in two formations. First, they will begin in line, or in-train, like a string of pearls. Then, the CubeSats will move out of the in-train configuration and into a set of stable relative orbits known as passive safety ellipses.

During the two flying formations, the following four technologies will be tested.

• Reconfiguration and Orbit Maintenance Experiments Onboard (ROMEO): In each phase, cluster flight control software will initially operate in shadow mode, autonomously planning maneuvers while the CubeSats are controlled from the ground. Once validated, ROMEO will demonstrate execution of swarm maintenance maneuvers from aboard the spacecraft without ground intervention. The performance of those maneuvers will then be evaluated.
• Mobile Ad-hoc Network (MANET): The CubeSats will be able to communicate with each other via two-way S-band crosslink radios/antennas, adapting a ground-based network protocol for reliable space communication across any spacecraft node within the swarm. If one spacecraft communications node fails, the communications route automatically reconfigures to maintain full communication capabilities for the remaining operational swarm of spacecraft.
• Starling Formation-Flying Optical Experiment (StarFOX): Using commercial star trackers, which are onboard cameras that measure the position of stars, each spacecraft determines its own orientation relative to the stars. An advanced navigation algorithm utilizes this orientation data and star tracker images to visually detect and track the other three spacecraft within the swarm to perform relative-position knowledge tests. The goal is for each spacecraft to achieve onboard awareness of its location as well as the location of the other three spacecraft.
• Distributed Spacecraft Autonomy (DSA): This experiment will demonstrate autonomous monitoring of Earth’s ionosphere, the layer between our atmosphere and the beginning of space, with a spacecraft swarm. This is intended as a representative measurement to demonstrate autonomous reactive operations for future missions. Starling’s dual-band GPS receivers are used to measure the density of atmospheric regions. Each orbiting Starling spacecraft constantly changes position relative to the atmospheric phenomenon and the GPS satellites. Therefore, the most interesting source of information changes over time, requiring changes to the monitoring strategy in response to observations. DSA onboard software will autonomously coordinate the selection of the best GPS signals, across all Starling spacecraft, to accurately capture regions of higher or lower ionospheric density. This is accomplished by first sharing information over the crosslink network to maintain a consistent state, then selecting the GPS signals to prioritize and share in the future. The ability to evaluate data as it is collected, balance promising observations with coverage to ensure other interesting information is not missed, and autonomously coordinate measurements, is an enabling technology for future science missions.

Starling was selected in 2020 by NASA's CubeSat Launch Initiative (CSLI) to be launched as part of the ELaNa program. Launch wass planned for mid 2022 on a shared Firefly-Alpha. Due to delays and uncertainties, the mission was moved to a Rocket Lab Electron KS launch in 3Q 2023.