Argus: SLU Core Bus Operational TestSteve Massey, Tyler Olson, Joe Kirwen, Wesley Gardner

SHOT IIPost-Launch Presentation

July 1st, 2012

Senior Design Critical Design Review 2

Argus / SCARAB: Mission OverviewThe Argus spacecraft is designed to utilize the SCARAB bus to support a radiation monitoring payload designed by Vanderbilt University in order to improve predictive models of the effect of radiation on small scale electronicsThe balloon payload was designed to test the SCARAB bus managing multiple payloads in a space-like environment.

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Expectations

• We expected to receive data from each radio within the first 20 minutes of flight.

• We expected to be able to receive sensor data when prompted.

• We expected seamless interaction between the radiation modeling payload and the SCB which will end in time-tagged event data saved to flash memory

• We expected some interesting pictures

Pre-Flight Notes

We determined Friday night that the EPS was incapable of holding enough charge to operated the payload for more than a few minutes

We incorporated a secondary battery pack of 8 AA batteries and a 12 V USB converter to power the payload through the CDH USB line.

Post-Flight Analysis

Attempts to pick up Beacon and UHF data immediately after launch were unsuccessful.Initial inspection of the payload on recovery showed that the USB line had been dislodged sometime during the flight, disconnecting the battery pack.Analysis of the flight data showed that the flight computer was on for the first 38 minutes.

Post-Flight Analysis (continued)

While the battery pack supplied enough power to activate the flight computer, it could not provide enough current to operate both the 5 and 3.3 V buses, meaning neither payload was activated

Post-Flight Analysis: Good News

The CDH subsystem performed flawlessly up until the USB power cable was disconnectedWhen we realized the EPS would not perform reliably, we were able to come up with a possible solution within the deadline

Senior Design Critical Design Review 8

Post-Flight Lessons

Flatsat tests before leaving St. Louis showed that both payloads were operational: had the EPS not failed, we would likely have completed all of our objectivesRevisions to our current component tracking and testing system are necessary to prevent future anomalies of system critical hardware

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