KIRTLAND AIR FORCE BASE, N.M. — Radiation-resistant computers developed here by
the Air Force Research Laboratory (AFRL) helped not only steer one of NASA’s
Mars Exploration Rovers to the red planet last week, they also guided it to a
safe and spectacular landing on Mar’s rocky surface. Another landing is
scheduled for later in the month.
AFRL’s Rad6000 32-bit microprocessors, manufactured for the Air Force by BAE
systems, controlled the spacecraft during its flight from Earth. The tiny
microchips will also orchestrate the Rovers — named Spirit and Opportunity —
as they move about the planet searching for signs that water might once have
existed on our neighbor.
"NASA chose AFRL microprocessors because they are proven reliable, rugged, and
fully compatible with their systems," said Creigh Gordon, an engineer assigned
to the AFRL’s Space Vehicles Directorate.
These computers can withstand the harsh radiation environment of space and
operate reliably over long-term missions. They control all data stream telemetry
between the spacecraft and controllers on the ground.
The Rad6000 was not only the world’s first radiation-hardened 32-bit
microprocessor; it was also the most complex, containing more than one million
transistors. And transistors run the show.
Like neural connections in the human brain, transistors inside computer chips
help manage the flow of electrical energy by directing it through a maze of
silicon-based circuits. Transistors act like switches at electronic junctions to
speed electrons to their intended destinations so that desired spacecraft and
rover functions can be performed.
Constant bombardment by radiation, however, generates unwanted electrical
charges inside transistors, building to the point that the transistor, or
switch, can no longer control the electron flow. Consequently, overcharged
transistors shut down, and failed electronics mean dead missions and the loss of
hundreds of millions of dollars. Much of AFRL’s work in electronic spacecraft
components prevents such losses.
"Through our efforts within the Space Vehicles Directorate, the Air Force has
made significant investments into radiation hardening fabrication technologies
and the space electronics based on them," said Gordon. "Contractors such as BAE
Systems and others now have the ability to manufacture such devices, which
results in better products for us, NASA, the Defense Department, as well as the
commercial customer," he added.
Before AFRL researchers stepped in a few years ago, Gordon explained, the
Defense Department and NASA paid from $50 million to $100 million for each
processor in development and manufacturing costs. Now, after AFRL involvement,
the price of a typical processing module dropped to between $500 thousand and $2
million and is available as off-the-shelf hardware.
As a direct result, microprocessor performance has improved a hundredfold.
"That’s an additional value of a military laboratory helping to transform and
transfer technology to military and civilian users — it maximizes taxpayer
investment," Gordon said.
"By creating new circuit designs and the processes by which they are
constructed, using different materials, and by building-in safeguards such as
back-up subsystems, the Air Force-industry team has also significantly increased
the life span for spacecraft missions by making electronic systems such as
microprocessors more resilient to the catastrophic effects of radiation," said
Gordon.
More than 60 Air Force, Defense Department, NASA, and commercial space systems
are now using this technology and better than 90 percent of satellites launched
today rely on radiation-hardened processors developed by AFRL’s Space Vehicles
Directorate.
