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Sending electronics in to space has always been a costly affair.The reason being that regular silicon based processors like the ones you use in your computers cannot function in the extreme climates of space.The electronics therefore have to be heavily shielded or have a temperate controlled environment to house the delicate circuitry.
Now,a project led by the Georgia Institute of Technology has developed a novel approach to space electronics that could change how space vehicles and instruments are designed.
The new capabilities are based on silicon-germanium (SiGe) technology,which can produce electronics that are highly resistant to both wide temperature variations and space radiation.
THE OLD METHOD
The conventional approach to protecting space electronics was developed in the 1960s,involves bulky metal boxes that shield devices from radiation and temperature extremes.
Designers must place most electronics in a protected,temperature controlled central location and then connect them via long and heavy cables to sensors or other external devices.
SiGe alloys combine silicon,the most common microchip material,with germanium at nanoscale dimensions.The result is a robust material that offers important gains in toughness,speed and flexibility.
That robustness is crucial to chips ability to function in space without bulky radiation shields or large,power-hungry temperature control devices.Compared to conventional approaches,SiGe electronics can provide major reductions in weight,size,complexity,power and cost,as well as increased reliability and adaptability.
SHEDDING THE WEIGHT
By eliminating the need for most shielding and special cables,silicongermanium technology helps reduce the single biggest problem in space launches weight.
Moreover,robust SiGe circuits can be placed wherever designers want,which helps eliminate data errors caused by the lengthy wiring.
For instance,the Mars Exploration Rovers,which are no bigger than a golf cart,use several kilometres of cable that lead into a warm box, said Andrew Keys,chief technologist at NASA.
If we can move most of those electronics out to where the sensors are on the robots extremities,that will reduce cabling,weight,complexity and energy use significantly.
The teams overall task was to develop an end-to-end solution for NASA a tested infrastructure that includes everything needed to design and build extreme-environment electronics for space missions, said John Cressler,team leader for the project.
The silicon-germanium electronics developed has been shown to function reliably throughout that entire plus-120 to minus-180 degrees Celsius range.It is also highly resistant or immune to various types of radiation found in space.
Other space-oriented companies are also pursuing the new silicongermanium technology,Cressler said.But NASA,he explained,wants the intellectual-property barriers to the tech to be low so that it can be used widely.The idea is to make this infrastructure available to all interested parties.That way it could be used for any electronics assembly an instrument,a spacecraft,an orbital platform,lunar-surface applications,Titan missions wherever it can be helpful.
A paper on the project findings will appear in IEEE Transactions on Device and Materials Reliability.
| Georgia Tech Professor John Cressler displays a functional prototype device developed for NASA using silicon-germanium microchips.The device,a 16-channel sensor interface,has been tested successfully in simulated space environments |