Tag Archives: SSTL

Apr 20 2012

CubeSats: good things come in small packages

CubeSats may be small but they have big ambitions. Credit: Aalborg University

CubeSats may be small but they have big ambitions. Credit: Aalborg University

By Ben Gilliland
For the vast majority of Earth’s history it had but one satellite – the Moon – but that all changed in 1957 when, on October 4, the Soviet Union launched the first artificial satellite into Earth’s orbit.Sputnik-1 was a 58cm (23 inch) sphere that contained two 1-watt radio transmitters and three batteries (two for powering the radios and one to power a cooling fan). The 83kg aluminum sphere emitted radio signals that were transmitted back to Earth via four 2.4m-2.9m “whip” antenna.

Its radio did little more than beep at Earth, but its signal was picked up by amateur “ham radio” enthusiasts all over the world.

In many ways, Sputnik was not just the world’s first satellite, it was also the first “people’s satellite” – anyone with suitable radio equipment could listen to the plucky little satellite as, for 22 days, it whizzed around the globe at 29,000km/h (18,000mph).

Sputnik-1 kick-started the space race and the satellite industry, but was really little more than a transmitter that beeped. Credit: NASA

Sputnik-1 kick-started the space race and the satellite industry, but was really little more than a transmitter that beeped. Credit: NASA

America’s first satellite was even smaller. Launched on January 31, 1958, and weighing in at just 14kg, Explorer-1 boasted several scientific instruments including a cosmic ray detector, five temperature sensors and micrometeor detectors.But satellites didn’t stay small, simple and accessible for very long.

As they increased in complexity, so they increased in size. From the size of a beach ball, satellites were soon the size of a family cars, then buses and (in the case of the International Space Station) the size of a football field.

With increased size and complexity came increased costs.
It can take a decade and hundreds of millions of pounds to develop an Earth observation satellite – but that is just the tip of the financial iceberg. Launching a satellite weighing several tonnes into orbit can cost between £30million and £250million ($50million to $400million) and just paying for the radio bandwidth needed to get your information back to Earth can cost up to £1million ($1.6million) a year. That’s not taking into account the cost of ground operations and maintenance of the satellite.

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Mar 7 2012

UK Space Agency boost for tomorrow’s tiny space tech.

Sixteen UK space labs and companies are set to benefit from the latest round of the UK Space Agency’s National Space Technology Programme (NSTP) which will spur innovation in the fast-moving area of space technology known as ‘cubesats’.Artist's impression of a CubeSat. Credit: AMSAT-UK.

Artist’s impression of a CubeSat.
Credit: AMSAT-UK.

Cubesats are tiny, low-cost spacecraft – weighing only a few kilos – which can be launched ‘piggy-back’ on larger spacecraft. Many of today’s cubesats are proving to be great educational projects helping students hone practical skills in building and operating satellites. However, with advances in technology, many experts believe they will also be used for cutting-edge science or operational uses in the future.

The UK is already the world leader in small satellites through Surrey Satellite Technology Ltd (SSTL). Ten years ago, SSTL benefited from UK government investment helping it to grow into a world-class company. Today, the UK Space Agency is following the same road to space innovation by supporting cubesat technology. Already, UKube-1 – a sophisticated nanosat with an imager, scientific and educational payloads – is being built by leading cubesat company Clyde Space Ltd. in Scotland.

Now, eleven new research projects supported by £310k of grants from the National Space Technology Programme (PDF, 18 Kb)  will drive the next steps in British cubesat know-how.

“It’s going to be exciting to see what emerges”

Dr Chris Castelli, programme manager at the UK Space Agency explains: “We received 30 proposals to our recent competition and have now selected the best ones to fund. We’ve got a great range of ideas – from new technology such as wireless on-board monitoring and tiny thrusters to give cubesats their own manoeuvring capability; to practical uses such as bioscience and space-weather monitoring. All these ideas will feed into our thinking for a successor to UKube-1, which we hope to select in 2013. It’s going to be exciting to see what emerges.”

Cubesats represent only one part of the Agency’s innovation agenda which also encompasses giant communications satellites such as Alphasat and the exploration of the Universe through missions such as Herschel and Planck.

UK Space Agency logo
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

Oct 31 2011

Android App to Fly on STRaND-1 Smartphone Satellite

When a competion was run to find Apps  to fly on the Smartphone CubeSat STRaND-1 one of the wining entries was an App which was a spin-off of the work done by the AMSAT-UK FUNcube team. See the story at:

http://www.blackpepper.co.uk/posts/android-app-to-fly-on-strand-1-nanosat-mission/

A detailed article on STRaND-1 appeared in a recent edition of the newsletter OSCAR News published by AMSAT-UK. It can be downloaded from http://www.uk.amsat.org/on_193_final.pdf

The video of a presentation on STRaND-1 is at http://www.batc.tv/vod/Strand.flv

Join AMSAT-UK online at http://tinyurl.com/JoinAMSAT-UK/

 

 

Oct 3 2011

Surrey to start making radar satellites.

The distinctive shape is a consequence of the radar antenna underneath and the solar panel on top

The distinctive shape is a consequence of the radar antenna underneath and the solar panel on top

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Sep 7 2011

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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