BBC TV – How Satellites Rule Our World

They are constantly circling hundreds of miles above our heads, driving our daily lives – yet we barely give satellites a second thought. Satellite engineer Dr. Maggie Aderin-Pocock Ph.D., MBE wants to change all that. She wants to make us realise and appreciate what these unsung heroes of the modern world have done for us.

Maggie reveals how satellites have revolutionised exploration, communication, location-finding and spying. She discovers how they have transformed not only the way we see our planet but our understanding of the dangers within it, like volcanoes and earthquakes. Plus, she discovers the jaw-dropping power of the technology used by satellites to make our lives run smoothly.

The final 8 minutes of the show covers CubeSats and features Peter Shaw of the amateur radio STRaND smartphone satellite project.

‘In Orbit: How Satellites Rule Our World’ was broadcast on BBC 2 at 2100 BST (2000 UT) on Sunday, March 25 and is available to watch on the web at

It is understoood that this broadcast could be blocked in certain countries. A way around this may be to use a Proxy Server or software such as Expat Shield.

Dr. Maggie Aderin-Pocock Ph.D., MBE

UK Amateur Radio Smartphone CubeSat STRaND-1

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

UK Amateur Radio Smartphone CubeSat STRaND-1

The International Amateur Radio Union satellite frequency coordination panel has agreed a frequency of 437.575 MHz for the UK satellite STRaND-1.

Some of the SSTL STRaND-1 Project Team, from Left to Right: Bob Dyer, Nick Holt, Dale Mellor, Mark Brenchley, Shaun Kenyon, Jonathan Gebbie, Rupert Taylor, Rosie Linehan, James Parsons, Andy Schofield

STRaND-1 will carry an Android Smartphone and plans to use data rates of 9k6 or 19k2 bps for the AX.25 packet radio downlink. A software-based speech synthesiser will be included to pay homage to the UOSAT family of satellites.

The 3U CubeSat measures 30 by 10 by 10 cm and weighs 4 kg. Unlike previous CubeSats it will feature full 3-axis control with the attitude an orbit control system comprising a nano-magnetorquer, nano-reaction wheels, GPS receiver, 8 pulse plasma thrusters and a butane thruster.

STRaND stands for Surrey Training, Research and Nanosatellite Demonstration and the programme is intended to be a long-term arrangement between the space company SSTL and academic researchers at the Surrey Space Centre (SSC), with STRaND-1 the first of a long line of STRaND nanosatellites.

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