Into the Infinite: NASA's Starling Mission and the Satellite Swarm

In July, NASA will launch a team of four six-unit (6U)-sized CubeSats into Earth's orbit to explore their ability to cooperate autonomously, without real-time updates from mission control. This robotic team of small satellites aims to test essential technologies for future deep space missions, where complex and autonomous spacecraft will play a crucial role.

The Starling mission will see the CubeSats flying in two formations, testing technologies that pave the way for future cooperative endeavours in deep space science. Positioned approximately 355 miles above Earth and spaced about 40 miles apart, the mission is set to last at least six months.

Roger Hunter, program manager for NASA's Small Spacecraft Technology program, highlighted the significance of Starling, emphasizing that its capabilities for autonomous command and control in small spacecraft swarms will enhance NASA's abilities for future science and exploration missions.

Starling will focus on testing four key capabilities: autonomously maneuvering to maintain group cohesion, establishing an adaptable communications network among spacecraft, tracking each other's relative positions, and responding to new information from onboard sensors by autonomously executing new activities. In essence, Starling aims to create a swarm of small satellites functioning as an autonomous community, capable of collaborative responses to their environment and task completion. This mission represents a significant step forward in advancing NASA's capabilities for future space exploration.

NASA's Starling mission marks a significant step in advancing the readiness of technologies crucial for cooperative groups of spacecraft, often referred to as distributed missions, clusters, or swarms. This innovative initiative aims to demonstrate the feasibility of multipoint science data collection by multiple small spacecraft operating collaboratively in swarms. Over the course of a six-month mission, Starling will utilize four CubeSats positioned in low-Earth orbit to rigorously test four key technologies. These technologies are designed to empower spacecraft to operate in a synchronized manner without relying on resources from ground control, pushing the boundaries of autonomous space exploration.

The focus of the Starling mission encompasses testing the following technologies:

1. Swarm Maneuver Planning and Execution: Evaluating the capability of spacecraft to plan and execute maneuvers in a coordinated and synchronized manner within the swarm.
2. Communications Networking: Advancing technologies that establish efficient and adaptable communication networks among spacecraft within the swarm, enabling seamless information exchange.
3. Relative Navigation: Assessing the ability of spacecraft to precisely determine and maintain their relative positions within the swarm, a crucial aspect for coordinated operations.
4. Autonomous Coordination Between Spacecraft: Testing the autonomous coordination capabilities between individual spacecraft within the swarm, ensuring they can respond to changing conditions and operate in a harmonized manner.

The primary goal of the Starling mission is to validate the functionality of these cutting-edge technologies, identify potential limitations, and pinpoint areas that require further development. By conducting these comprehensive tests, NASA aims to gain a detailed understanding of the capabilities and challenges associated with CubeSat swarms, paving the way for future successful missions in space exploration.

Enhanced Autonomy Revolutionizes Swarm Missions: Distributed spacecraft offer a unique advantage by collectively pursuing objectives. The integration of autonomy into these missions empowers them to act collaboratively with minimal ground oversight. Autonomy ensures mission continuity during periods of limited communication with ground control due to distance or location. Spacecraft swarms operating at considerable distances from Earth necessitate greater autonomy, given the inherent delays in communicating with ground stations.

Assembling satellites into a swarm requires orchestrating multiple maneuvers for each spacecraft. Managing these operations from the ground becomes impractical as the swarm's size grows or communication delays increase. The Starling mission is pioneering technologies that traditionally relied on ground-oriented operations but are now transitioning to operate autonomously onboard each spacecraft.

Autonomous operation within a spacecraft swarm is pivotal for making distributed spacecraft missions cost-effective and highly scalable. Starling marks the initial stride in developing a novel mission architecture that could eventually enable autonomous swarms with numerous spacecraft, even at considerable distances from Earth.

Swarm technologies represent a transformative approach to scientific measurements in space, offering the capability to gather data from multiple points, establish self-healing communication networks, and operate spacecraft systems independently of constant Earth communication. The inherent redundancy in a swarm of spacecraft enhances resilience, making the team robust against individual failures or malfunctions, as each spacecraft can compensate for the others.

In Starling's maiden mission, a suite of four cutting-edge technologies will undergo testing. The first technology, ROMEO (Reconfiguration and Orbit Maintenance Experiments Onboard), focuses on testing software designed to autonomously plan and execute maneuvers without direct input from operators. During the Starling mission, ROMEO will enable the satellites to fly in a clustered formation, autonomously planning and executing trajectories.

The mission also incorporates a Mobile Ad-hoc Network (MANET), a communications system comprising wirelessly linked devices that autonomously route data based on network conditions. Analogous to Earth's mesh Wi-Fi systems, Starling's spacecraft feature crosslink radios allowing communication within the swarm. The onboard MANET software will determine the optimal route for traffic through the satellite network, and the mission aims to demonstrate the system's ability to automatically create and maintain a network in space over time.

Each CubeSat in the Starling mission is equipped with "star tracker" sensors traditionally used for orientation. In this unique application, called StarFOX (Starling Formation-Flying Optical Experiment), these sensors not only track stars but also pick up light from nearby swarm spacecraft. Specialized software then utilizes this information to monitor the entire swarm, allowing the backdrop of stars to serve as a celestial tether keeping the swarm together. This innovative use of common spacecraft sensors demonstrates the adaptability and ingenuity required for successful swarm missions in space.

The culmination of the Starling mission brings to the forefront the groundbreaking Distributed Spacecraft Autonomy (DSA) experiment, showcasing the remarkable capability of a swarm of spacecraft to autonomously collect and analyze scientific data onboard while optimizing collaborative data collection responses. In this advanced phase, the satellites are entrusted with monitoring Earth's ionosphere, a critical segment of the upper atmosphere. If one satellite detects an intriguing phenomenon, it communicates with others in the swarm, enabling them to observe the same event. This autonomous responsiveness enhances the efficiency of science data collection, laying the foundation for numerous future NASA science missions.

Post the successful completion of its primary mission, Starling will transition into a collaboration with SpaceX's Starlink satellite constellation. This partnership aims to test and refine advanced space traffic management techniques for autonomous spacecraft operated by different organizations. Through the sharing of trajectory intentions, NASA and SpaceX will showcase an automated system ensuring the safe operation of both satellite sets in relative proximity within low-Earth orbit.

The subsequent iteration, Starling 1.5, emerges as a foundational step in comprehending the intricacies of space traffic management. According to Roger Hunter, the mission manager, this phase is instrumental in establishing the "rules of the road" for coordinating spacecraft in space.

The role of robotics in exploration, whether crewed or un crewed, remains pivotal. The networked, autonomous, and coordinated operation of satellites and spacecraft signifies NASA's commitment to advancing humanity's reach and conducting more profound scientific endeavours than ever before. The Starling project, led by NASA Ames, receives support from NASA's Small Spacecraft Technology program, Blue Canyon Technologies for spacecraft design and manufacturing, and Rocket Lab USA, Inc. for launch and integration services. Additionally, partners contributing to Starling's payload experiments include Stanford University's Space Rendezvous Lab, Emergent Space Technologies, Cesium Astro, and L3Harris Technologies, with funding support from NASA's Game Changing Development program within the Space Technology Mission Directorate (STMD).

1. Reconfiguration and Orbit Maintenance Experiments Onboard (ROMEO): ROMEO is designed to enhance the autonomy of the CubeSats by introducing cluster flight control software. Initially operating in shadow mode, this software autonomously plans maneuvers while the CubeSats are ground-controlled. Once validated, ROMEO will showcase the execution of swarm maintenance maneuvers directly from aboard the spacecraft without ground intervention. The performance of these maneuvers will undergo thorough evaluation, marking a significant advancement in autonomous spacecraft operations.
2. Mobile Ad-hoc Network (MANET): The MANET experiment focuses on enabling communication among CubeSats through two-way S-band crosslink radios/antennas. Adapting a ground-based network protocol, this system ensures reliable space communication across any spacecraft node within the swarm. In the event of a communication node failure, the system automatically reconfigures the communications route, preserving full communication capabilities for the operational swarm of spacecraft. MANET thus exemplifies an adaptive and resilient communication network.
3. Starling Formation-Flying Optical Experiment (StarFOX): Utilizing commercial star trackers, each spacecraft autonomously determines its orientation relative to the stars. An advanced navigation algorithm employs this orientation data and star tracker images to visually detect and track the other three spacecraft within the swarm, conducting relative-position knowledge tests. The objective is for each spacecraft to achieve onboard awareness of its location and that of the other three spacecraft. StarFOX showcases the precision of relative-position determination through innovative use of star trackers.
4. Distributed Spacecraft Autonomy (DSA): DSA aims to demonstrate the autonomous monitoring of Earth's ionosphere with a spacecraft swarm. This experiment employs dual-band GPS receivers on Starling spacecraft to measure atmospheric density. The constant change in position relative to atmospheric phenomena and GPS satellites necessitates adaptive monitoring strategies. DSA's onboard software autonomously coordinates the selection of optimal GPS signals across all Starling spacecraft, ensuring accurate capture of regions with varying ionospheric density. This technology enables real-time data evaluation, balancing promising observations with coverage to prevent overlooking other significant information. DSA is a crucial enabling technology for future science missions, showcasing the autonomy needed for dynamic and responsive data collection in space.

Collaborators and Contributors

• NASA's Small Spacecraft Technology program, operating under the Space Technology Mission Directorate, is the primary funder and manager of the Starling mission.
• NASA's Ames Research Center in Silicon Valley, California, spearheads the Starling project, offering expertise in payload avionics, software development, spacecraft integration and testing, and mission operations.
• Blue Canyon Technologies, based in Boulder, Colorado, is responsible for the design and manufacturing of spacecraft buses, along with providing crucial mission operations support.
• Emergent Space Technologies, located in Laurel, Maryland, contributes the cluster flight application software essential for the ROMEO experiment.
• Cesium Astro, headquartered in Austin, Texas, is a key partner providing crosslink radios and antennas integral to the success of the MANET experiment.
• Stanford University's Space Rendezvous Lab, situated in Stanford, California, is actively involved in the development of the StarFOX experiment, showcasing their expertise in cutting-edge space technologies.
• NASA's Game Changing Development program, part of the Space Technology Mission Directorate, provides vital funding for the Distributed Spacecraft Autonomy (DSA) experiment.
• Rocket Lab USA, Inc., based in Long Beach, California, plays a crucial role in the Starling mission by providing top-tier launch and integration services.
• L3Harris Technologies, Inc., located in Melbourne, Florida, contributes ground software support, focusing on spacecraft navigation and maneuver planning, showcasing their expertise in advanced space technologies.

NASA's exploration of space isn't just about reaching new heights; it's about unlocking the mysteries of the cosmos, pushing the boundaries of human knowledge, and inspiring generations to dream beyond the stars. In every orbit, every mission, and every discovery, NASA ignites the spark of curiosity that fuels our collective journey into the vast unknown.