Android to go boldly in new satellite launch

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The challenge of getting a mobile signal in remote locations will be raised to new heights with the 2012 launch of a satellite with an electronic core consisting of an Android smartphone.

Surrey Satellite Technology (SSTL) and the University of Surrey will not be out of luck if they cannot get three bars in orbit, but they still have their fingers crossed that their experiment with common smartphone technology will work well enough to point the way to low-cost, high-performance commercial applications in a very small satellite built quickly from commercial off-the-shelf components.

According to STRaND-1 (Surrey Training, Research and Nanosatellite Demonstrator) system engineer Shaun Kenyon of SSTL, a mobile phone "is 90% of a satellite", with processor, radio, camera, motion sensor, etc already built in. Add solar panels and orientation control and you get to 100%, he says, based on a core component that costs less than $500.

Kenyon is not exaggerating. The Google Nexus One phone being used for STRaND includes a 5MP camera, 3-axis accelerometers, a magnetometer and compass, an FM radio receiver, microphone, light sensor and battery temperature sensor.

Plus, the phone's 1GHz processor with 512MB RAM is far meatier than most spacecraft, which can operate on 33MHz or so.

Thus, says Kenyon, the question arose, what could be done in space with such "brute force" processing power?

To find out, SSTL and the university's space engineering department, the Surrey Space Centre, ran a competition on Facebook to solicit ideas for phone apps that could be used to demonstrate in-orbit function.

Four were chosen, including one that will let members of the public visit a dedicated website and record screams, which will be played in orbit on the phone's speaker - and recorded by the phone's microphone, to test the theory expounded by the 1979 film Alien that, in space, "no one can hear you scream".

On the more scientific side are two applications to use the phone's camera to take pictures of the Earth and, via Google Earth, build a map of the planet.

A fourth will measure the local magnetic field using both the phone's and satellite's magnetometers, and compare the readings. The objective is to see if, in principle, such a simple spacecraft could measure oscillations in the upper atmosphere.

Another plan is to take advantage of the touch screen's sensitivity to charged particles. The phone, says Kenyon, is effectively a geiger counter and may be able to measure levels of space radiation.

NEW TECHNOLOGIES

Beyond the smartphone concepts, STRaND-1 will also test some new technologies developed by the Surrey Space Centre, including electric pulsed plasma thrusters, which give very small instantaneous thrusts for orientation control and will be a first on a very small satellite.

University of Surrey lecturer Chris Bridges, one of Kenyon's partners on the STRaND project, says the opportunity to fly the thrusters - the product of six years' work by one of the department's PhD students - illustrates the value of the partnership with SSTL, which got its start as a spin-off from the University 30 years ago.

The spacecraft will also test for the first time a Surrey-developed radio transceiver built around a radio chip that hasn't been used in space before.

And, STRaND-1 features an attitude determination system built by the University of Stellenbosch in South Africa. This consists of two wide angle cameras - one looks for the sun and the other looks for the horizon(s) of the Earth. Associated electronics turn these images into information on the direction STRaND-1 is pointing.

To back up the experimental equipment, STRaND-1 will also carry a GPS unit, a small "normal" thruster with very limited capability, magnetorquers - small coil electromagnets used to help point the satellite by reacting against the Earth's magnetic field - and reaction wheels, which are small metal wheels that spin up and down, used to help point the satellite.

The basic satellite is a three-unit CubeSat, a design standard set out by California Polytechnic State University based on 10cm x 10cm x 10cm units weighing no more than 1.33kg [see box].

The standard is important to developers as associated launch dispensers make it feasible to piggyback several units on a more standard payload. To keep launch costs manageable, STRaND-1 looks likely to piggyback on another mission early in 2012. A three-unit CubeSat like STRaND measures 34cm x 10cm x 10cm, and weighs less than 4kg.

If it works, and Kenyon readily admits it is a big "if", the team already has commercial applications in mind.

Meanwhile, the project is also unusual in its organisation. Kenyon, Bridges and eight colleagues are working in their own time, to keep costs down. SSTL and the University have each put up £35,000 ($55,000) to fund STRaND.

"It's a labour of love," Kenyon says, adding that it is exciting to bring an almost amateur scientist's ethos to one of the most complex engineering endeavours undertaken today.