This web page's content and links are no longer actively maintained. It is available for reference purposes only. NASA Official: David Skillman

About Simplesat

Simplesat is an Optical Microsatellite Experiment with David Skillman as the PI.


Satellite Characteristics

  • Mass: 52 kg
  • Size: 66 cm tall, 50 cm diameter
  • Telescope: 30 cm diameter optics, commercial CCD camera detector
  • Power: 10 watts orbit-average from solar cells mounted on body 14 amp-hr NiCd battery
  • Attitude: Three-axis stabilized, inertial pointing
  • Attitude, position, time sensor: Four channel GPS receiver
  • Pointing Control: via three reaction wheels
  • 1 degree via GPS,
  • 1 arcsec via star images from camera
  • Momentum control: Torque coils
  • Computer: commercial single board computers
  • Communications: 4800 baud to GSFC via ham radio equipment

Satellite Information

Downlink Radio Frequency: 400.965 MHz

Uplink Radio Frequency: 402.6 MHz

Downlink only over Goddard Space Flight Center (no beacon)

Unusual Characteristics:

  • no gyros
  • no earth sensors
  • no sun sensors
  • no star-trackers
  • no magnetometer
  • no optical cover
  • no detector cooling

Initial rate damping with hysteresis rods

  • reaction wheels driven by stepper motors
  • commercial CPUs (Octagon)
  • commercial NiCd batteries (Sanyo)
  • commercial telescope optics (Meade 12")
  • commercial CCD camera (Apogee)
  • modified commercial aircraft GPS unit (Trimble TANS-Vector)

all image data reduction done onboard

flight software written in Basic

130 temperature sensors on only two wires (DS1820)

electronics cards wire-wrapped