Shooting beyond the stars
USU’s Space Dynamics Laboratory is preparing to propose a new program that would build on the success of the Wide-field Infrared Survey Explorer satellite program in partnership with NASA.
After being in hibernation for almost two years, NASA has granted the reactivation and renewed use of the WISE satellite, which had its entire payload developed at SDL.
“It is a wonderful opportunity to reuse our assets,” said Amy Mainzer, the principal investigator of the renewed project at NASA’s Jet Propulsion Lab.
According to Mainzer, the WISE satellite was put into orbit December 2009. It had an initial run of 10 months with the liquid hydrogen supply that kept the instrumentation cooled being exhausted during that time. Instead of being decommissioned, NASA decided to put the satellite into hibernation. With the satellite still functional, the JPL received the reactivation authorization last August.
If all goes well, the satellite will be able to extend its original lifetime well into 2017, Mainzer said. The renewed project will be known as the Near-Earth Object Wide-field Infrared Survey Explorer.
According Mainzer, all looks good so far in the recalibration process. At the current rate of recalibration, conservative estimates for the satellite to be prepared for data collection are for the end of March.
When discussing the importance of this program, Shane Larson, a research associate professor of astronomy working jointly with Northwestern University and USU, said, “The game is about cataloging.”
From an astronomer’s perspective, the importance of the both the WISE and NEOWISE programs, is its ability to look at the universe in infrared wavelengths, according to Larson. Infrared is light that doesn’t have enough energy to be seen by the human eye.
To view in the infrared, satellites need to be kept extremely cold, according to Larson. The WISE satellite was kept cooled with a cryostat using liquid hydrogen, which stays a liquid at temperatures just above absolute zero, or -460 degrees Fahrenheit. The cryostat was part of the payload developed at the Space Dynamics Laboratory.
Larson said some items in space can only be observed through the use of infrared instruments. Some of the objects are known as dark asteroids, and there could be many in close orbit to Earth.
One such object was the meteor that struck Chelyabinsk, Russia back in February 2013. The airburst from the meteor’s explosion injured close to 15,000 people and damaged more than 7,000 buildings.
According to Larson, events like this occur regularly. By charting out the orbits using the WISE and NEOWISE programs, it will be easier to predict when and where these events occur.
Once recalibration is finished, the data collected will aid in predicting such events. According to Mainzer, the reason that recalibration will take until at least March comes from the fact that the satellite needs to finish lowering to its operational temperature. In hibernation, the satellite was pointed toward Earth for half of its orbit. This is a problem because Earth radiates heat at temperatures around 300 degrees above absolute zero, which is just more than 200 degrees warmer than the operational temperature.
“It would be just like looking at stars during daylight,” Mainzer said, speaking about this problem.
Once the satellite finishes recalibration, it will operate at a relatively warmer temperature; 75 degrees above absolute zero, Mainzer said. It will continue to collect data in the infrared to look for objects in space that would have near-Earth orbits.
Both Mainzer and Larson are optimistic about the information that will be collected from the NEOWISE program. Mainzer said JPL and SDL are working together to put another camera into space within the next few years.
New technology has been developed to keep the camera operating at temperatures warmer than the equipment used by the WISE satellite, Mainzer said. It would serve as a stepping stone toward having a more comprehensive understanding of this part of the universe.
In order to learn more about the program, Mainzer encourages those interested to check out the program’s website at neowise.ipac.caltech.edu, or contact her via twitter @AmyMainzer.
-david.berg@aggiemail.usu.edu