rApril 18 - 20, 2011 - Mechanical Engineering Statements The Oculus-ASR mission will: [MS-1] Provide calibration opportunities for ground-based observers at the Air Force Maui Optical
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Aerospace EnterpriseApril 2011 Principal Investigator: Dr. Brad King
Mission: Space Situational Awareness“Space Situational Awareness means knowing the location of every object orbiting the earth, active or inactive, big or small; and knowing why it is there, what it is doing right now, and what we think it will be doing in the future.”
– Lt. Col. Jim Shoemaker, USAF
•With increasing orbit altitude and decreasing telescope aperture, orbiting objects become unresolvable. •Most space objects are unresolvable from the ground.
Can we determine a satellite’s attitude and detect shape changes from the ground using only information gained from unresolved optical images?
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Mission Statements
The Oculus-ASR mission will:
[MS-1] Provide calibration opportunities for ground-based observers at the Air Force Maui Optical Site (AMOS) attempting to validate and/or anchor algorithms capable of determining spacecraft attitude and configuration using unresolved optical imagery.
[MS-2,3] *Provide data and images with two space imagers for their respective companies (Raytheon/SAIC).
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BareYellow Red
Blue
The “dot” of light contains spectral information
The color and brightness of the unresolved image varies depending on the satellite’s orientation with respect to the viewer and the sun.
It may be possible to determine the satellite’s attitude and/or spin rate by measuring the reflected light.
TLEsManeuverCommands
Euler Angles vs. timeImages of releasables
SpaceSegment
GroundSegment
Maneuver requests
Euler Angles vs. TimeImages of releasables
Ground Observations
MTU Ground Station
Air Force Maui Optical Site(and other AFRL ground-based
facilities)
AMOS Inputs: Attitude-state and maneuver requestsControl states will be scheduled for each overpass
AMOS Data Requirements: Euler angles vs.time for all overpasses and space-to-spaceimages of releasables during relevant overpasses.
Oculus-ASR Mission
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University Nanosatellite Prgm
• University Nanosatellite Program • Run by US Air Force• Spans 2 Yrs• … We won UNP-6 (!)
• Participating Schools• Cornell University• University of Central Florida• Montana State University• University of Hawaii at Manoa• Santa Clara University• Missouri University of Science and Technology• Michigan Technological University• University of Minnesota• Georgia Tech• Massachusetts Institute of Technology• Saint Louis University
What We Do
• Competition• Two-Year Competition Cycles• Student Built Satellite• Useful Mission• Limited Budget
• Previous Results• UN 3 – Third Place• UN 5 – Third Place
Spectral Characterization by AFRL
1/17/2011 UNP-6 FCR 11
Oculus-ASR can expose spectrally different materials to ground observers
Oculus-ASR will help provide the necessary data to calibrate instruments used to improve Space Situational Awareness and protect military and civilian space assets
Full calibration and verification of ASR telescopes can only be achieved by viewing an object orbiting Earth
FROST Characterization
Radiometric measurements of “closely spaced object” scenario as RSOs are deployed from Oculus-ASR
1/17/2011 UNP-6 FCR 12
Space-to-space images from Oculus-ASR of release events will be compared with ground imagery
Design: Requirements Verification
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Design: Requirements Verification
•Our RVM has ~300 Requirements•When All Requirements are met (Green), we are done.
• RVM Features:•Traceable Requirements•Mission Statement *Flowdown*•3 Status Levels (Green, Yellow, Red)
•Gates•Means of Status Change•Each *gate* requires documentation to pass•Documentation from defined test
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Project: Planning
•Project File – The overall plan•Includes deliverables, dependencies, timelines, and milestones•Communications – (Internal and External)
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Project: De-scope Options
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ID No. Description Consequences Flowdown benefits Critical issue(s) 1 June Gate 1 Sept Gate1 Eliminate PhotonMax
imagerInability to meet Requirement MS-2: ‘Provide data to Raytheon Missile Systems to assess change in PhotonMax EMCCD image quality over the duration of mission.’
• Decrease in spacecraft mass by XXX kg
• Simplification of OBDC box design
• Reduction of total data download requirement from XXX to XXX
• Elimination of potential thermal issue on imager TE cooler
• Mechanical integration of imager/lens and integration of PCI card with OBDC stack is incomplete
• Installation of camera software on imaging computer has not been attempted
• Camera/lens box and OBDC box with PCI supports machined
• Demonstrated basic functionality of camera software from flight computer
• Camera/lens and OBDC box pass component-level vibe test
2 Eliminate releasable sphere-sats
Inability to meet requirement M-8: ‘Provide ground viewing opportunities for monitoring the release of an RSO from the satellite.’
• Cost and complexity reduction by eliminating two Frangi-bolts.
• Initial release tests showed inconsistent fracture of Frangi-bolt
• New releasable mechanism completed and machined
• Successful and consistent release test data using spacecraft power control system
3 Eliminate reaction wheels
• Possible inability to meet S1-6 Goal: ‘Goal is to execute maneuvers described in GNC-XX-XXXX’
• Possible inability to maintain pointing accuracy for data downlink
• Decrease in spacecraft mass by XXX kg
• Reduction of control law complexity
• Possible elimination of OSCI board (?)
• Capability of spacecraft to perform intended maneuvers with only mag-torquers is unknown
• Reaction wheel lifetime is unknown
• Only one vibe test performed to date
• Use Simulinkmodel to verify that RWs are necessary to perform all maneuvers described in GNC-XX-XXXX
• Use Simulinkmodel to verify that RWs are required to maintain comm. pointing accuracy
If analyses show that RWs are required for comm. requirement then de-scope at 1 Sept. is not an option.
4 Eliminate SAIC imager Depending on Descope ID1 this could cause failure to meet MS-2: ‘Advance the technology of low-cost space imagers for nanosatellite-class vehicles by providing flight data from candidate technologies.’
Depending on Descope ID1 this could enable elimination of entire imaging computer
SAIC imager has never been operated at MTU since translator board has not been completed
Translator board complete and demonstrated with desktop computer
Imager and translator board successfully tested with flight computer
Components Verification
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Ground Operations
• Operations– Houghton, MI (operators)– Experimental or Amateur Licensing– NORAD ephemeris data for location
• Software– Nova Tracking Software– Ground station software partially written
• Ground Station Status– Design Phase– Collaboration with Husky Amateur Radio club
• Hardware– Primary Yaesu FT-857 Transceiver Kantronics KPC-9612+ TNC Modem UHF/VHF dual band Yagi, linear polarization– Secondary MicroHard MHX2420 2.4 GHz 24dBi parabolic dish, -3dB beam width ±
8° off bore sight, linear polarization
Path Forward
What is left to do?
Plenty.
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