1. Space Shuttle Relative Navigation Sensors Upgrade Jim Lamoreux NASA/JSC 5/22/02

2. Shuttle Relative Navigation Sensors for Rendezvous, Proximity Operations, & Docking: Star Trackers (ST) Ku-Band Rendezvous Radar (Integrated with TDRS Communication System) – Skin tracks 23 sq m target from 22 nmi; ISS from 100 nmi – Measures Rng, Doppler Rng Rate, Brg, Brg Rate Trajectory Control Sensor (TCS) – Measures Rng, Rng Rate, Brg to retroreflectors on ISS for approach and docking Hand-Held Lidar (HHL) – Rng, Rng Rate to skin reflection Closed Circuit TV (CCTV) with subtended angle overlays Crew Optical Alignment Sight (COAS) Shuttle Rel Nav Sensors Upgrade

4. Typical Shuttle-ISS Rendezvous Profile Shuttle Rel Nav Sensors Upgrade

5. Shuttle-ISS Braking Gates and Proximity Operations Shuttle Rel Nav Sensors Upgrade

6. Shuttle-ISS Separation and Fly-Around Shuttle Rel Nav Sensors Upgrade

7. Rendezvous Sensor Priority Matrix Shuttle Rel Nav Sensors Upgrade RangePrime SensorBackups >140,000 ft-Z Star Tracker -Y Star Tracker Wait for Radar <140,000 ft Day Radar-Z Star Tracker (while target < 8 arcmin) -Y Star Tracker (while target < 8 arcmin) COAS <140,000 ft Night Radar-Z Star Tracker -Y Star Tracker COAS

8. Prox Ops Sensor Priority Matrix (ISS) Shuttle Rel Nav Sensors Upgrade RangePrime SensorBackups 5000 - 600 ftTCSRadarHHLSubtended angles charts (Visual) 600 - 3 ftTCSHHLCCTV and Overlay 3 ft - DockTCSCCTV and Overlay

9. Prox Ops Sensor Priority Matrix (Non-ISS) Shuttle Rel Nav Sensors Upgrade RangePrime SensorBackups 5000 - 100 ft or loss of lock RadarTCS (If available) HHLSubtended angles charts (Visual) 250 (or Radar break lock) - Grapple HHLTCS (If available) Camera Triangulation 35 ft - GrappleEnd Effector Camera TCS (If available) Camera Triangulation

10. Ku-Band Radar/Comm System and TCS supportability problems are predicted due to a growing shortage of spare parts and unavailability due to obsolescence. Initial assessments (1999): TCS not supportable beyond 2008, but parts available to built more units. Ku-Band Radar/Comm System not supportable beyond 2005; Need to develop replacement. Shuttle Rel Nav Sensors Upgrade

11. Initial Efforts for Ku-Band Radar/Comm Upgrade: Employed QFD tool to identify and prioritize requirements. Separate comm and radar systems for simultaneous use Eliminate antenna deployment (crit 1) Eliminate existing radar problems (e.g., range ambiguity beyond 22 nmi) and unused functions (e.g., angle rate measurement) Enhance sensor capabilities if cost effective Consider single sensor to replace rendezvous radar and TCS Employ dual redundancy to eliminate training and crew workload required for single-string radar failure. Obtained radar/lidar developer info via RFI’s and site visits, collaborated with JPL regarding lidar developments for automated rendezvous, docking, and landing for DS4 comet sample return. Established target costs and risks in design-to-cost exercise. Developed concept of operations, program and system requirements documents. Shuttle Rel Nav Sensors Upgrade

12. Architecture changed by Shuttle Program (8/01): Abandon separate tracking and comm plan. Functionally duplicate existing Ku-band integrated radar/comm system and retain legacy vehicle interfaces to minimize cost. Radar upgrade terminated by Shuttle Program (2/02) Reassessment of supportability problems, risks, and costs indicated problems are less severe and are manageable to at least 2012 if KSC repair capabilities are improved. Business case no longer supports radar/comm upgrade. Upgrade documentation archived for possible future use (COD, PRD, SRD, Specs, IDD, etc). Shuttle Rel Nav Sensors Upgrade

13. Concluding Remarks Information generated for Space Shuttle relative navigation sensor upgrade will be valuable for future vehicle developments. For a new reusable launch vehicle, for which sensor interfaces are not already established, a single sensor type that can support rendezvous, proximity operations, docking/capture, and possibly landing may be attractive. Shuttle Rel Nav Sensors Upgrade