• NRL's Christoph Englert examines the prototype Michelson interferometer (MIGHTI) being developed at NRL for flight on NASA's ICON mission.
     NRL's Christoph Englert examines the prototype Michelson interferometer (MIGHTI) being developed at NRL for flight on NASA's ICON mission.

NASA's ICON Mission a Go for 2017

January 6, 2015
By Sandra Jontz
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When NASA’s Pegasus rocket lifts off in June 2017, it will carry scientific equipment and technology that might help researchers better understand space variations that contribute to disruptions in communications equipment, radar and Global Positioning Systems here on Earth.

NASA’s Ionospheric Connection Explorer (ICON) mission will study what happens in Earth’s upper atmosphere and the connections to environmental conditions on the planet, says Thomas Immel, ICON mission lead with the University of California, Berkeley’s Space Sciences Laboratory.

“[The ionosphere] shows day-to-day, hour-to-hour variability that we have never understood,” Immel says.

At times, at lower latitudes on the Earth, it can become so dense that the ionosphere becomes unstable. “At low latitudes, the density of the ionosphere is often high enough to cause larger GPS errors and geospace errors than we see at middle latitude,” he says. “But during geomagnetic storms, a great deal of that plasma’s density grows, and it can extend over places like the United States, and indeed, reduces or eliminates the availability of geopositioning systems.”

The U.S. Naval Research Laboratory (NRL) will send an instrument designed to study the Earth's thermosphere. The Michelson Interferometer for Global High-resolution Thermospheric Imaging (MIGHTI) aboard the satellite will measure neutral winds and temperatures in the Earth’s low latitude thermosphere using the Doppler Asymmetric Spatial Heterodyne (DASH) spectroscopy technique.  

The ICON scientists will rely on data provided by the Deep Space Climate Observatory (DSCOVR), scheduled for launch aboard the SpaceX Falcon 9 on January 23, which will give weather forecasters reliable and continuous measurements of solar wind speeds and provide advance warning of impending dangers of volatile sun activity. It is slated to replace NASA’s aged Advanced Composition Explorer (ACE), launched in 1997 and operating a decade past its design life.

“That hour of warning that we get … is important operationally, but also important for studying events long after they occur,” Immel says. “We need to understand those inputs as best we can if we’re going to characterize and make predictions of what similar events might occur to the ionosphere. … DSCOVR will allow us to understand the best we can the inputs we’re getting from the sun that ICON will observe.”

Roughly one month post launch—what scientists call the 30-day check out—researchers will be able to begin their science mission, Immel says. ICON currently is slated to be a two-year mission, but if all goes well, conceivably could be extended to at least a decade.

If they can better understand what causes atmospheric variations, scientists might be able to make better predictions on when capabilities on Earth might suffer impacts, he says.

“Say you’re flying from Africa to South America and you want to use geopositioning along the way. What’s the likelihood that you’re going to face an outage during say, a nighttime flight? Right now, it’s anyone’s guess. What’s the ionosphere going to be like over South America tomorrow? That’s a really good question.”

The scientists’ aim is to answer that question. “We don’t have the capability to make that prediction. …  Having that would be outstanding.”

“We see rainy seasons on the Earth that are reflected as seasons in the ionosphere,” he continues. “What are the key drivers of that? Where is the interaction taking place? Why do we have sort of ‘rainy’ seasons in space? Of course, there is no rain, but it varies with the rainy season in the tropics.”

The scientists first began working on dreaming of a space mission in 2007, a year after Immel and collaborators published some of the first research papers showing atmospheric seasonal variations and relations to conditions in the tropics, he says. Their first solicitation to NASA in 2008 was not selected. But a repurposed proposal submitted in 2011 was.

ICON is an Explorer-class mission, managed at NASA's Goddard Space Flight Center in Greenbelt, Maryland. The spacecraft is being built by Orbital Sciences Corporation in Dulles, Virginia. 

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