ARISSat-1 Critical Design Review Orlando, Feb 15, 2010 Control Panel Jerry Zdenek

Feb 15, 2010ARISSat-1 CDR2 Introduction Provides the Control of the Satellite and indicate Satellite Status Scope –Requirements –Design –Safety Considerations –Verification –Operations –Status

Feb 15, 2010ARISSat-1 CDR3 Requirements Compliant with all ISS safety requirements Provide an interface that an Astronaut in a pressure suit can control the satellite Indicate status of the Satellite Allow the system to be quickly shut down in case of a problem

Feb 15, 2010ARISSat-1 CDR4 Design Provide all timer functions equivalent to Suitsat-1 –One Power switch with LED status –Two Timer switches with LED status Same mechanical switch layout as Suitsat-1 Additional LEDs for Operational and Safety Verification Solve LED visibility problem reported by Astronauts Measure control panel temperature

Feb 15, 2010ARISSat-1 CDR5 Control Panel Front

Feb 15, 2010ARISSat-1 CDR6 Control Panel Assembly Flight units will have wires strain relieved

Feb 15, 2010ARISSat-1 CDR7 Design Interface Box –Switches and LEDs only –Nearly completely passive assembly Control circuitry on ICB Safety functions managed by ICB LED Brightness circuitry within Control Panel

Feb 15, 2010ARISSat-1 CDR8 LED Brightness Must balance two conflicting requirements –Minimize power usage –Good visibility to Astronauts, factoring in sun visor Solution: two different brightness modes –LEDs always on dimly (room visible) –If the first timer has not expired, run extra current through the LEDs for brightness –Using very high efficiency LEDs

Feb 15, 2010ARISSat-1 CDR9 Schematic – Timer Control

Feb 15, 2010ARISSat-1 CDR10 Schematic – Status LEDs

Feb 15, 2010ARISSat-1 CDR11 Safety Considerations Activation Switches –False activation due to switch contamination could create a safety hazard –Using APEM 12000X778 Switches to insure safety –Switches are designed for high-rel applications and is QPL certified to MIL-DTL and MIL-DTL-3950

Feb 15, 2010ARISSat-1 CDR12 Safety Considerations Access to switches –Metal Finger guards provided so that only one switch is activated at a time

Feb 15, 2010ARISSat-1 CDR13 Verification Improved design over Suitsat-1 –Switches are now operating with 50% design margin on wetting current –Suitsat-1 was operating outside spec Operating with both low and high voltage inputs In use during development testing of other systems Ran system at real time speed multiple times –Video Taped one run to verify specified timings

Feb 15, 2010ARISSat-1 CDR14 Operations Integral with ICB Safety Circuitry –Further details in ICB design review To Deploy: –Turn on 28V Power switch Verify LEDs in correct state –Turn on Timer 1 Switch Verify LEDs in correct state –Turn on Timer 2 State Verify LEDs in correct state Launch the satellite!

Feb 15, 2010ARISSat-1 CDR15 Status Design and Documentation Complete Electrical Testing complete Positioning of Thermistor inside box not defined yet Switch set up the same as Suitsat-1, so no operational problems expected Quantity of LEDs has been brought up as a training / ease of use issue Just need to assemble flight units!