APL Space Weather Watchers Ready for Follow-on Iridium Data Buy
WASHINGTON — A team at the Johns Hopkins University Applied Physics Laboratory that has been usingmobile communications satellites for the past four years to keep tabs on potentially disruptive space weather is close to securing a grant for continued observations by the 66-satellite Iridium Next constellation the McLean, Virginia, company plans to deploy between 2015 and 2017.
It will be the second phase of APL’s Active Magnetosphere and Planetary Electrodynamics Response Experiment, or Ampere, which started in 2008, about 10 years after Iridium Communications deployed its present constellation of 66 satellites in low Earth orbit.
Ampere project scientists use the satellites’ magnetometers — non-science-grade instruments Iridium uses to help keep the communications satellites pointed at the right spot — to measure the agitating effects of solar winds on so-called Birkeland electrical currents that flow between the ionosphere and low Earth orbit.
Funding for Ampere 2, which would initially continue observations using the existing Iridium constellation, should arrive in the form of a National Science Foundation grant “in late summer or early fall of next year,” Ampere Principal Investigator Brian Anderson said in a July 25 phone interview. Anderson’s team at APL, which consists of himself and two co-investigators, applied for a five-year follow-on grant this year.
“[The National Science Foundation] is proceeding with sponsorship of that, and all we’re doing is finishing off the budgets and getting it signed off,” Anderson told SpaceNews.
Anderson declined to say how much funding APL is seeking for Ampere 2, but he said the scope of work would be similar to that performed under a five-year, $4 million grant that ran out in May 2013. For the first two years of the Ampere project, Anderson’s APL-based team worked with Iridium and Boeing Space Operations and Ground Systems, which operates the constellation from Leesburg, Virginia, on software changes that enabled the Iridium satellites to collect and transmit the desired magnetometer readings at least once every 30 seconds.
Such frequent readings from the Iridium magnetometers have been flowing to the Ampere team 24 hours a day since 2010, and improved magnetometers slated for use on Iridium Next should allow even more frequent and precise sampling, Anderson said.
Birkeland currents, which are responsible for the dancing, green auroras sometimes visible from the ground at higher latitudes, flare up when they are bombarded with charged particles ejected by the sun during so-called coronal mass ejections.
“There’s a whole host of near-Earth space environment effects that are tied to these currents,” Anderson said. “The acceleration of the Earth’s radiation belt, heating of the upper atmosphere, widespread interruptions in radio frequency communications, which disturbs large ground networks.”
When they flare up, Birkeland currents can also create drag on low-orbiting spacecraft, forcing operators to burn fuel to keep the satellites in their intended orbits.
Birkland flare-ups on Earth’s dayside take about 40 minutes to ripple over to the night side, Anderson said. With that sort of lead time, satellite operators could prevent headaches by postponing orbital maneuvers or software uploads when a bad geomagnetic storm is about to hit.
But for all of its promise, APL’s current arrangement with Iridium is not really a model for the sort of space weather early warning system Anderson says government and commercial satellite operators should want.
Creating a space weather warning system that could operate 24 hours a day would take “a different tier of resources” than what the National Science Foundation, a science-focused agency without a specific mandate to tackle the space weather problem, could afford to give for Ampere, Anderson said.
Moreover, given the expense of staffing a round-the-clock space weather warning center with redundant power, computing and personnel, a data-buy approach like Ampere’s is a logical consideration for future systems, Anderson believes. “If someone were to try to do Ampere with their own satellites and their own infrastructure, their cost would be a hundred times to a thousands times more than was required to do this,” he said. “We were able to achieve something that never would have been possible otherwise.”