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Iridium merges science with communications mission

Posted: August 18, 2010

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Working under a U.S. government grant, researchers are calling upon the Iridium satellite constellation for the first real-time global space weather observations from low Earth orbit.

Artist's concept of an Iridium satellite. Credit: Iridium
Led by the Johns Hopkins University Applied Physics Laboratory, the new space weather research program will help forecasters predict the onset of sun-triggered geomagnetic storms that could cause power outages and communications blackouts.

"This milestone brings us one step closer to accurate space weather forecasts around the Earth," said Brian Anderson, the program's chief scientist at the Applied Physics Laboratory. "Solar storms can disrupt satellite service and damage telecommunications networks, cause power grid blackouts and even endanger high-altitude aircraft."

Designed for mobile communications, Iridium satellites orbit about 500 miles above Earth and cover the entire globe. The space weather application is the first time the fleet has been employed on a secondary scientific mission, according to the Johns Hopkins University.

The Iridium fleet's 66 existing satellites have already demonstrated continuous space weather observations around the world at 100 times greater sampling density than previously possible, according to a joint statement released Wednesday.

Funded by a $4 million National Science Foundation grant, the first public release of space weather products is scheduled for the fourth quarter of 2010, the statement said.

The program is called the Active Magnetosphere and Planetary Electrodynamics Response Experiment, or AMPERE for short.

"AMPERE is a hugely exciting and novel project that brings the best of university scientists together with commercial space assets and industry engineering expertise to open a new window on our home planet's response to solar activity," said Therese Jorgensen, program director at NSF.

Boeing Co. introduced a new data stream for magnetic field data from sensors already aboard Iridium satellites, giving scientists nearly instant access to space weather information.

Officials say the satellites broadcast data every two to 20 seconds for analysis within minutes. Previous data were collected every three minutes and received by scientists the next day.

Boeing manages Iridium's satellite constellation and will process and package space weather products for the AMPERE program.

Anderson said the AMPERE program is well-timed as activity on the sun picks up after an extended quiet period known as solar minimum.

"The next wave of solar storms will occur over the next three to five years and recent solar activity is just the beginning of a long, stormy space weather season," Anderson said. "The timing for AMPERE is just right because we need this system both to help us understand how solar storms disturb the space environment and to develop reliable monitoring and forecasts of major space weather storms."

The Iridium Next constellation will begin launching in 2015 to replace the company's current fleet, which launched between 1997 and 2002.

Iridium is seeking partners for hosted payload opportunities on the next-generation satellites.

Each spacecraft will have space for 110 pounds of instrumentation, at least 50 watts of continuous on-orbit power and a communications rate of a megabyte per second.

Iridium is in discussions with military and civil government agencies for space situational awareness and Earth observation opportunities in the hosted payload program.

A company spokesperson said Wednesday that Iridium expects to announce secondary payloads on the new satellites by the end of 2011.