- Number 323 |
- October 25, 2010
Idaho scientist prepares to power up Mars mission
Steve Johnson, director of the
INL Space Nuclear Systems
and Technology Division, with
the Multi-Mission Radioisotope
that will power the 2011 Mars
Scientific Laboratory mission.
A rocket scientist isn't what you expect to find in the deserts of southern Idaho, but that's what Steve Johnson is.
As director of the Space Nuclear Systems and Technology Division at DOE's Idaho National Laboratory, Johnson oversaw the fueling and testing of both the new Mars rover's power source and its predecessor for the 2006 Pluto New Horizons mission. Both Radioisotope Thermoelectric Generators (RTGs) were assembled at INL's Space & Security Power Systems (SSPS) facility.
RTGs use radioisotope decay to generate heat and electricity for space missions. They can supply low amounts of electric power for well over a decade. Space mission RTGs have to withstand the heavy vibrations and dramatic temperature changes of launch and operate for many years afterward without any maintenance or refueling.
Johnson oversees rigorous testing at SSPS — including shaking on the facility's vibration table and checking for steady power rates and magnetic field generation that could interfere with instruments. The Multi-Mission RTG (MMRTG) for the new Mars rover had to be redesigned and tested for the ability to generate power both in the cold vacuum of space and on a planetary surface.
The MMRTG and the New Horizons RTG were both fueled and flight tested at SPSS. The MMRTG was ready for the original 2009 launch window. It is waiting out the delay in air-conditioned storage that siphons off the heat it is producing; you can't switch off the decay of a radioisotope.
Meanwhile, the Space Nuclear team has already started work on the 2015 Advanced Stirling Radioisotope Generator (ASRG). Johnson also has a hobby to help keep him occupied. He carves wood burls, abnormal tree growths that are usually the result of some environmental stress. Their odd shape and fast growth make for interesting and beautiful grain patterns. Larger burls can be cut and sanded to make tables or benches, while smaller pieces can be made into bowls, utensils or cribbage boards.But Johnson won't have much time for woodcarving, since training for the Mars launch began in September. In June, the team will haul the MMRTG down to Florida and take shifts through the launch window, sometime between Thanksgiving and Christmas.
Submitted by DOE's Idaho National Laboratory