Student Space Systems Fabrication Lab, College of Engineering, University of Michigan
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Supporters 		Tethered SATellite Testbed (TSATT)

Introduction

Next-generation space mission capabilities include numerous concepts that depend on either rendezvous operations or precision formation flying, such as multi-spacecraft formations, close proximity operations, and automated rendezvous and docking.  Current approaches to validate technologies necessary to enable such capabilities involve costly and complex flight demonstrations (e.g., NASA’s DART mission).  Such demonstrations are high risk in nature because they must simultaneously implement many unproven technologies, including sensors as well as approach and docking algorithms.  These in-flight demonstrations must account for missed approach and collision avoidance scenarios while demanding a complete understanding of failure modes and effects in providing redundancy in critical areas.  In addition, with the two crafts in different orbits, there is a necessary need for real-time management as they drift apart.

The University of Michigan’s Student Space Systems Fabrication Laboratory (S3FL), in collaboration with Tethers Unlimited Inc. (TUI), is currently designing a tethered nanosatellite mission called TSATT (Tethered SATellite Testbed).  The purpose of TSATT is to validate the following concept: tethered satellite systems offer a simpler and less expensive approach for validating rendezvous and formation flying sensors and algorithms by decoupling these technologies from the hardware needed for spacecraft maneuvering and reducing the need for detailed real-time management.  Unlike validation approaches utilizing free-flying spacecraft, requirements on TSATT and its subsystems can be greatly simplified due to the natural ability of a tethered system to control its relative position.  By utilizing a variable length tether deployer and retriever, sensor performance at multiple, controlled nanosatellite separation distances can be tested.
tsatt
Artistic Conception of TSATT in orbit.

TSATT is being designed to demonstrate a new, lower-cost method to:
  • Validate rendezvous and formation flying (sensor) technologies
    • Traditional approach requires (costly) free-flying spacecraft, but these missions run risks of collision and orbital debris generation (e.g. DART)
  • Provide close-flying (reconfigurable) spacecraft for long periods (months to years)
    • TSATT provides well-defined close-flying nanosat targets for ground visual, lidar, or radar observations and training
    • Reconfigurable tether length and system rotation (tether libration)
delta II
TSATT as Delta II secondary payload

Quick Facts
  • TSATT - two tethered nano-spacecraft (~ 30 kg)
  • Max tether length - 10’s of meters to ~1 km
  • Retractable to multiple shorter distances
  • Orbit: LEO (300-800 km, any inclination)
  • CUSTOMER PAYLOAD OPTIONS AVAILABLE - Please contact S3FL


For more information, please contact our office (2028 Space Research Building, 2455 Hayward St, Ann Arbor, MI 48109) at 734.936.0511, or email s3fl-info at umich dot edu