CUSAT Pulse Plasma Thruster Satellites

CUSat - Image credit Cornell University

CUSat – Image credit Cornell University

CUSAT is planning a SpaceX launch along with Cassiope and Dande, from Vandenberg into a 1500 by 325 km 80 degree inclination orbit. The satellite has a 2 watt packet radio transmitter and carries Pulse Plasma Thrusters (PPT) which can raise or lower the orbit.

Built by students at Cornell University CUSat-1/2 is a 45 kg space vehicle consisting of two functionally identical satellites that will launch together and separate in orbit. Image and positioning data will be downlinked using AX25 packet radio on 437 MHz. Cross linking between the two parts will also take place on 437 MHz.

Using centimeter accuracy carrier-phase differential GPS, the two satellites will perform autonomous relative navigation. One satellite will capture imagery of the other satellite and send these images to a ground station on Earth for the reconstruction of a 3-D model of the partner satellite.

Watch CUSat Spacecraft Mission

After launch and Launch Vehicle separation, the satellite will enter its initialization state. During initialize, the satellite will begin a self-check process to detect any malfunctioning systems. The satellite will then use Carrier-phase Differential GPS data to converge on an attitude estimate. CDGPS is a new technique for performing centimeter-level accurate position determination.

Once the attitude estimate for the satellite is determined, the satellite will use its on-board cameras to take images of the Earth, Moon, bright stars, and the ISON comet (C/2012 S1) which will be reaching perihelion in November 2013. If the team are able to take pictures bright stars, then they should be able to determine the attitude of the satellite to help verify the CDGPS estimate of the attitude. The satellite will then telemeter down mission data to the Ground Segment. This data consists of images, GPS data, Telemetry, and Command and Data Handling logs. The satellite maneuvers so that the antenna is always pointed towards the Ground Segment during data transfer.

After all the necessary pictures are taken, the CUSat team will perform test maneuvers using the pulse plasma thrusters. First, they will tilt the spin angular momentum. They do not want to change the magnitude, only the direction of this vector. Secondly, they will raise and lower our orbit of the satellite. In order to raise or lower the orbit, CUSat needs to fire its PPT thrusters in the direction, or against the direction of its velocity, respectively.

The frequencies are:
• CUSat-1   437.405 MHz
• CUSat-2   437.485 MHz
• Cross link 437.305 MHz

For more details see


IARU Amateur Satellite Frequency Coordination Status