NASA’s IceCube, a tiny satellite deployed from the International Space Station (ISS) in May 2017, has created the first global map of ice clouds.
The ice clouds are considered key variables in climate and weather models. Like other clouds, they also absorb/reflect the Sun’s energy and affect the heat emission from Earth into space. Ice clouds are formed with small particles high in the atmosphere. When these particles absorb moisture, they become heavier and bigger in size. Eventually, they melt to form rain drops (although some ice crystals also stay in the air).
For researchers, it has always been a highly difficult (and uncertain) task to measure atmospheric ice on a global scale. Small ice particles inside the clouds are too opaque for visible and infrared sensors to penetrate, which means satellites fail to detect the amount of these particles. To overcome this limitation, NASA installed a sub-millimeter radiometer (developed by Virginia Diodes Inc., of Charlottesville, Virginia, under a NASA Small Business Innovative Research contract) in IceCube to bridge missing sensitivity between microwave and infrared wavelengths. According to NASA, this radiometer can measure critical atmospheric cloud ice properties at altitudes between 3-9 miles (5 Km-15 Km).
“With IceCube, scientists now have a working sub millimeter radiometer system in space at a commercial price,” said Dong Wu, a scientist and IceCube principal investigator at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
“More importantly, it provides a global view on Earth’s cloud-ice distribution.”
IceCube weighs 10 pounds and is about the size of a loaf of bread. It is equipped with deployable solar arrays, a deployable UHF communications antenna, and three-axis attitude control. The funding for the mission came from NASA’s Earth Science Technology Office’s (ESTO) In-Space Validation of Earth Science Technologies (InVEST) program and NASA’s Science Mission Directorate CubeSat Initiative.
IceCube was originally planned as a 30-day technology-demonstration mission, but it is still operating satisfactorily in low-Earth orbit.
According to Dong Wu, IceCube principal investigator at NASA’s Goddard Space Flight Center in the US, IceCube is providing data that’s “good enough to do some real science.”
“The hard part about developing the CubeSat is making the commercial parts durable in space. We bought commercial components for IceCube and spent a lot of time testing the components making sure each part worked.” said Tom Johnson, Goddard’s Small Satellite manager stationed at NASA’s Wallops Flight Facility in Virginia.
Johnson revealed that this mission was expanded because of its low cost and outstanding results. The team downloads the data eight to 10 times a week. The satellite is also able to hold data for a couple of weeks.
IceCube is expected to continue functioning for about a year before making a reentry into the Earth’s atmosphere and eventually burning up in the atmosphere.