# Presentation: 280530

## The Petite Amateur Navy Satellite(PANSAT) Hitchhiker Ejectable

- The Petite Amateur Navy Satellite(PANSAT) Hitchhiker Ejectable

- Sept. 1999

## STS-95 Payload Bay

## STS-95 Launch

## 23 hours, 26 minutes later . . . 

## PANSAT Deployed

## PANSAT Hitchhiker Ejectable

- Introduction
- Design Requirements and Issues
- PANSAT Testing
- Payload Safety
- Lessons Learned
- Conclusion

## Introduction

- Hands-on space system development for officer students
- Global, digital message-relay
- Spread spectrum modulation
- Amateur radio involvement

## Introduction

- Designed and built at NPS
- 50 theses published
- Used in laboratory instruction at NPS
- Facilities installed to support spacecraft development
- Subsystem testing at NPS
- Integration and system-level testing at NASA/GSFC

## Design Requirements

- Spacecraft Bus
- Shuttle secondary payload as baseline
- 150 lbs total weight (max.)
- NASA Hitchhiker requirements
- Simple Design
- No propulsion
- No attitude control
- Development and testing at NPS
- Communications with NPS ground station
- 2-Year mission life

## 19-inch diam. (max.)
21.8-inch height (from separation plane)
CG envelope:  1.27 cm (0.5-inch) radius from CL and 26.03 cm (10.25-inches) from separation plane

- 19-inch diam. (max.)
- 21.8-inch height (from separation plane)
- CG envelope:  1.27 cm (0.5-inch) radius from CL and 26.03 cm (10.25-inches) from separation plane

- Payload Envelope

- Mr. Daniel Sakoda, Naval Postgraduate School

- 1999 Shuttle Small Payloads Project Office Symposium

## Hitchhiker Ejectable Requirements

- Design Limit Loads (analysis alone)
- Factor-of-safety of 2.0 times limit loads for yield
- Factor-of-safety of 2.6 times limit loads for ultimate failure

## PANSAT

- Expanded
- View

- Mr. Daniel Sakoda, Naval Postgraduate School

- 1999 Shuttle Small Payloads Project Office Symposium

## PANSAT Block Diagram

## Spacecraft Design

- Subsystems
- Communications payload
- Modem
- RF Section & Antennas
- Digital control subsystem (DCS)
- Processor board
- Temperature multiplexer
- Data storage modules (memory)
- Electrical power subsystem (EPS)
- Mechanical & Structure subsystem

## Design Issues

- Hitchhiker Payload
- Trade reliability for safety
- Microswitches (3 single-points-of-failure in series)
- RF timer circuit
- Trade capability for safety
- Ensure compatibility of materials
- Low out-gassing materials
- Fracture-resistant structural materials

## PANSAT Testing

- Subsystem environmental test at NPS
- Random vibration
- Thermal-vacuum cycling
- System-level vibration at NASA/GSFC
- Random vibe each axis
- Vibration level:  8.2 grms
- Functional testing

## PANSAT Testing

- Mass properties test
- C.G. location determination
- Within 1/16 inch of analytical
- Moments of inertia on two axes

## Payload Safety

- Familiarize with Hitchhiker *Customer Accommodations and Requirements Specification* (CARS) and other documents
- Design to remove safety hazards
- Removal of hazard
- Inhibits (including payload operations)
- PANSAT safety issues
- Batteries
- Radio frequency (RF) emissions
- Structure

## PANSAT Battery

- Compliant with *Manned Space Vehicle Battery Safety Handbook, (NASA/JSC)*
- Battery construction
- Teflon-coated interior of housing
- Glass wool packing
- Dry Nitrogen purge of housing
- PRV in line with sub-micron filter
- Thermal cutouts

## PANSAT Battery

- Fully discharged at integration
- Microswitches inhibit charging - “dead in the can”

## Safety Inhibits

- Microswitches applicable prior to ejection
- Non-operational while in canister
- (2) series-connected on power leg of solar panel power bus
- (1) in-line on the ground leg of solar panel power bus
- 15-second timer added for post-separation
- Inhibits transmission
- Enabled after safe distance from orbiter

## Structure Subsystem

- Al-6061-T6
- Finite Element Analysis (FEA) verified through modal test
- High margins of safety
- Structural strength
- Low-risk classification for fracture
- Spacecraft weight not a problem

- Load-Bearing Structure

## Lessons Learned

- Learn by doing:  Hands-on experience invaluable in educational process
- Design with safety in mind
- Design to test:  *see paper by J. Horning*
- Recycle test setups
- Recycle test procedures
- Emphasize rigorous testing at subsystem level

## Satellite Performance

## Satellite Performance

- Telemetry data
- Solar panel currents (8)
- Battery status (temperature, on-line, charge, etc.)
- Spacecraft temperatures
- On-orbit operations
- RF state reset
- Telemetry processing
- Determination of software updates

## Aug. ‘99 Solar Eclipse

## Aug. ‘99 Solar Eclipse

- 11 August 1999

## For more information . . .

- http://www.sp.nps.navy.mil/pansat