Tag Archives: PPT

May 29 2013

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 http://cusat.cornell.edu/docs/IARU/

CUSat http://cusat.cornell.edu/

IARU Amateur Satellite Frequency Coordination Status http://www.amsat.org.uk/iaru

Sep 9 2012

Plasma Powered Amateur Radio Satellite PROITERES Launched

The Japanese amateur radio satellite PROITERES was launched Sunday, September 9 at 0423 UT on PSLV-C21 from the Indian Space Research Organisation (ISRO) Satish Dhawan space centre. The satellite SPOT6 was on the same launch into a 654 km × 643 km, 98.28º inclination orbit. The rocket was fitted with the mini Redundant Strapdown Inertial Navigation System (mRESINS).

PROITERES was built by a team of students and faculty members of Osaka Institute of Technology (OIT) and the spacecraft aims to demonstrate powered flight using a Pulsed Plasma Thruster (PPT) engine.

Mike Rupprecht DK3WN reported hearing PROITERES, callsign JL3YZK, on 437.485 MHz at 07:36 UT.

Continue reading →

Jan 31 2012

Bright sparks redefine propulsion

CubeSats, like STRaND-1, are essential for the breakthrough of new technologies in the space industry. The relatively inexpensive CubeSat enables institutes and companies to test technologies and gain valuable flight heritage without risking millions (or even billions) of pounds of investment.

STRaND-1, the joint project between SSTL and the Surrey Space Centre (SSC), is one of these exciting experimental satellites and it’s not only its smartphone that makes it exceptional. Engineers at the Surrey Space Centre have also developed a unique mass and power saving plasma propulsion system to fly on the satellite. This system will be the first propulsive technology to provide very precise attitude control and pointing.

Pulsed Plasma Thruster flight hardware
Pulsed Plasma Thruster flight hardware

STRaND-1 will carry both a Resistojet and a Pulsed Plasma Thruster (PPT) module on board. The PPT will consist of eight micro thrusters; four located at the top of the satellite stack and four located at the bottom. The micro thrusters operate by discharging a discrete train of pulses. Each pulse is a plasma discharge that forms between two metal electrodes, much like a small lightning bolt or electrical spark. The spark erodes the metal from the electrodes and electromagnetics accelerate the eroded mass out of the nozzle, which produces thrust. This is known as the Lorentz force.

Surrey Space Centre has developed two ways of minimising mass and volume. Firstly, the electrodes which form the plasma discharge also function as the propellant. As metal is highly dense, more propellant can be stored in a smaller volume than that of conventional chemical propulsion systems. The total weight of the propellant for the whole STRaND-1 PPT system is just 10g.

Secondly, Surrey Space Centre’s novel discharge initiation system uses a mechanical contact trigger built out of a tiny piezoelectric motor only 5mm in length. This takes up less space than the conventional spark plug system which requires volume intensive circuitry.

The Pulsed Plasma Thruster module firing
The Pulsed Plasma Thruster module firing

Not only does SSC’s PPT module reduce mass and volume, it also uses less power than other propulsion systems. Between each pulse, energy is stored in a capacitor. This substantially reduces the power requirements for the thruster, making it perfect for small satellites such as STRaND-1. In fact, the power requirement for the system flying on STRaND-1 is only 1.5W, about the power needed to operate a bicycle light.

If successful, the STRaND-1 PPT will be the first propulsion system to provide full axis control on this class of satellite. Having an active propulsion system in orbit would open up new possibilities for future CubeSat missions like rendezvous and docking, and flyby inspection. The flight heritage and experience gained in using the PPT on STRaND-1 could then be transferred and scaled for other SSTL missions providing a low cost, mass and volume solution for future endeavours.

For updates on STRaND-1, visit the Facebook page or follow @SurreyNanosats on Twitter!

Read about STRaND-1 in a free sample issue of OSCAR News at http://www.uk.amsat.org/on_193_final.pdf