Safeguarding the Three Corner Sat Constellation By Stephen Levin-Stankevich Stephen Nauman

Mission Overview Joint project between the University of Colorado, Arizona State University, New Mexico State University, and AFRL. Demonstration of formation flying. Stereoscopic imaging to determine cloud heights. Demonstrate capabilities of innovative artificial intelligence software, CASPER, developed by JPL.

Mission Requirement The mission should demonstrate constellation autonomy by using SCL. The on-board system shall perform constraint and rule checking. The mission shall use SAMMI as the ground station user interface.

Autonomous Safeguarding SCL Stores each h&s set in database. Rules can react to faults in the h&s. Real-time analyses of system values for constraint checking CASPER Analyzes resources before starting a task. Continuously re- evaluates the schedule. Avoids conflicts with locked resources.

SCL Overview A scripting language used to carry out tasks that require many flight software commands to the hardware. Contains a database for each satellite that carries the most recent health and status. Performs continuous rule checking for analysis of satellite’s health.

SCL Rules Rules are a reaction to an event that already occurred on satellite. Allow for solutions to failure mode effects. Autonomous safeguarding of satellite Rule change_master Subsystemnone Categorypower Activationyes Continuousno if volt_batt <= 10.5 and master_sv = satellite_name_sv then --give master duties to diff. Sat. execute schedule_change_master in 1 tick end change_master

SCL Constraints Constraints allow for prevention of faults on the satellite. function reject_crosslink dest_sat if dest_sat = 1 or dest_sat = 2 or dest_sat = 3 then if isl_mode_sv = 0 then rtedebug "cannot send via crosslink because out of isl mode" return yes end if return no end reject_crosslink

Constellation Commanding One satellite is designated as master and controls the other two designated as slaves. CASPER runs on the master only. SCL controls each slave autonomously.

What is SAMMI? SAMMI is a GUI that allows the mission operator to control and monitor the Satellite. SAMMI consists of: –The main page: Monitor all three satellites at once. –Three master pages: Monitor all the sub-systems of each satellite. –The subsystem pages: Display all the values retrieved from the health and status –The plots: Will plot the h&s values over time.

What will SAMMI do? Retrieve data from the health and status package sent by the satellite. –It will display these values on the screen with a sensor that will determine if they are within nominal ranges. –A history of these values can also be displayed in a graph. Retrieve data from STK and tell the user when the satellite will be in range of a ground station. Interface with SCL, so the user will be able to issue commands from the SAMMI master page. The user will be able to find and see the problems easily.

Summary SCL will provide autonomous safeguarding of the satellite Rules will continuously monitor sensors and states to protect the satellite SAMMI will allow quick error detection and analyses on the ground.

Acknowledgements Colorado Space Grant Consortium Air Force Research Laboratories University of Colorado Space Grant Staff –Dave Beckwith –Elaine Hansen –Chris Koehler –Elaine Hansen