concept vehicle configuration
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Hubble Space Telescope Program -- Robotic Servicing Mission Concept Review
1051304_MW_HSTRoboticConcept.ppt
LOGO.049
Goddard Space Flight Center Concept Vehicle Configuration
Deorbit Module (DM)
Ejection Module (EM)
Hubble RoboticVehicle
Robotic Module
V1
V2
V3
Hubble Space Telescope Program -- Robotic Servicing Mission Concept Review
2051304_MW_HSTRoboticConcept.ppt
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Goddard Space Flight Center Conduit Deploy
Deploy Conduit and Latch onto the HST Handrails/Structure
– Conduit provides 1553 Bus connection from RSUs attached to WFC3 to 486 Computer located in Bay 1 and electrical connections between HST SA3 Diode Boxes and new batteries
Hubble Space Telescope Program -- Robotic Servicing Mission Concept Review
3051304_MW_HSTRoboticConcept.ppt
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Goddard Space Flight Center
Arm Characteristics:– Grapple Arm end effector captures HST Grapple
Fixture (GF)– 7 joints, 8” diameter to null differential rates upon
capture– Closed loop vision system to track GF target
without an operator in event of LOS– Open loop positioning error less than 1.5” and 2
degrees for berthing to HRV
Grapple Arm Task 1: HST Capture/Berthing
Large end effector capture envelope and high arm tip speed permits:– Relaxed requirement on HRV tracking errors with
respect to HST at rendezvous– High confidence of capture even if HST is rolling
since arm can track HST
Hubble Space Telescope Program -- Robotic Servicing Mission Concept Review
4051304_MW_HSTRoboticConcept.ppt
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Goddard Space Flight Center
1. HRV approaches HST and holds at 7m range
2. Arm assumes ‘Ready to Capture’ pose
3. HRV positions HST GF in ‘Capture Box’, arm acquires GF target
4. When position/orientation meets “Ready to Capture” conditions, HRV triggers arm to Capture and turns off thrusters
5. Arm tracks GF target with EE camera and closed loop vision processing/servo’ing
6. EE captures HST GF and brings HST to near rest, brakes applied
7. HRV thrusters enabled and combined vehicle stabilized
Approach vector and standoff distance may be selected from a variety of options
HST Capture Sequence
Hubble Space Telescope Program -- Robotic Servicing Mission Concept Review
5051304_MW_HSTRoboticConcept.ppt
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Goddard Space Flight Center EM Equipment Breakdown
Propulsion system
– ‘TDRSS’ program Hydrazine tanks (4)
• Used for HRV pursuit & docking, and during EM deorbit
– Pressurant (‘blow-down’) tanks (2)
– Valves, filters, plumbing, regulators, heaters, etc. (not shown)
(Note that EM bulkhead at tank mounting flange level blocks view of lower half of tanks)
Hubble Space Telescope Program -- Robotic Servicing Mission Concept Review
6051304_MW_HSTRoboticConcept.ppt
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Goddard Space Flight Center EM Equipment Breakdown
GN&C system, cont:
– IMU’s (2)
– Magnetometers (2)
– Torquer bars (3)
• Mounted along X,Y,& Z axes
– Momentum wheels (4)
• Mounted in pyramid pattern
Mag Torquer bars
Several of the listed items are not shown in these views. There is radiator panel mounting space to accommodate all the items listed.
Hubble Space Telescope Program -- Robotic Servicing Mission Concept Review
7051304_MW_HSTRoboticConcept.ppt
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Goddard Space Flight Center EM Equipment Breakdown
GN&C system:
– Horizon sensors (2)
– Star trackers / celestial nav (2)
– Coarse Sun Sensors (8)
• 1 each on fwd & aft ends, 6 distributed around DM-end, on L-brackets facing radially out.
– (GPS antennae – also on next slide)
Hubble Space Telescope Program -- Robotic Servicing Mission Concept Review
8051304_MW_HSTRoboticConcept.ppt
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Goddard Space Flight Center Simulated Performance Results
Hubble Space Telescope Program -- Robotic Servicing Mission Concept Review
9051304_MW_HSTRoboticConcept.ppt
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Goddard Space Flight Center Capture Approach Candidates1. Baseline Approach
• Point relative navigation sensors at one of the HST grapple fixtures
• Most conceptually straightforward approach for a grapple capture
• Mismatch in HST/HRV inertia properties result in torque and momentum storage requirements which exceed reaction wheel capabilities
2. “Sideways” Approach• Make minor HRV axis nominally parallel with
HST minor axis• Torque and momentum storage requirements
reduced to within reaction wheel capabilities• Requires repackaging of relative navigation
sensor suite 3. Aft End Approach
• Applicable to both grapple and direct docking capture methods
• Matches HST/HRV minor axes• Avoids potential sources of interference (i.e.
HST”s high gain antenna and solar arrays)• Control analysis pending
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