Chasing the secrets of the sun

  • Article by: AMINA KHAN , Los Angeles Times
  • Updated: March 17, 2012 - 5:02 PM

An experiment-packed satellite will soon go up-close-and-personal with our own star.

LOS ANGELES

The chest-high rack of electronics Justin Kasper is assembling in a Massachusetts office park will fit in a shoe box before he's done.

It won't be much to look at -- a few inches across, shaped rather like a coffee cup attached to a Kindle -- but to Kasper, it'll serve as eyes across nearly 100 million miles of space.

In less than seven years, that cup will be journeying to the center of the solar system to scoop up bits of the sun.

"This really has been a life's dream," said Kasper, of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass.

In 2018, NASA is scheduled to launch a spacecraft from Cape Canaveral Air Force Station in Florida to fly, Icarus-like, dangerously close to our star.

Fitted with a select set of instruments, Solar Probe Plus will address two questions that solar physicists have tussled with for decades: How does the corona, that ghostly, spiked halo seen during a total solar eclipse, heat to more than 1 million degrees, far hotter than the sun's surface? And what powers the solar wind, the stream of charged particles that flows from the corona?

An up-close look at the sun may ultimately help scientists predict solar flares, as well as coronal mass ejections -- "solar storms" like those launched at Earth two weeks ago. These events send a barrage of high-energy particles crashing against Earth's magnetic field, at times disabling satellites, wiping out power grids, forcing airlines to reroute flights and potentially exposing astronauts to fatal doses of radiation.

Scientists have sent probes to the solar system's edge, but never so near its heart. Coming within 3.7 million miles of the sun's surface -- 25 times closer than Earth -- the 1,350-pound unmanned spacecraft will heat to 2,600 degrees Fahrenheit and endure 512 times the sunlight of vessels orbiting Earth.

The mission "will undoubtedly have impact on our ideas about how life operates throughout the universe -- if life does operate throughout the universe -- how our planet evolved and how we're going to contend with the further exploration of space," said Richard Fisher, director of NASA's heliophysics division.

Half a century in the making, with an estimated price tag of $1.2 billion and barely 88 pounds allotted to experimental hardware, the project spawned fierce competition among heliophysicists for a piece of the action.

In September 2010, Kasper learned that his proposal to count the electrons, protons and helium ions in the solar wind had won one of five coveted spots.

Other proposals approved will map the sun's electric and magnetic fields; pick up radio and shock waves passing through the plasma; and take detailed, three-dimensional images of the corona.

Other spacecraft have ventured toward the sun before: In 1976 the Helios 2 mission came within 27 million miles. The European Space Agency plans to launch a solar orbiter in 2017 that will come as close as 26 million miles.

But Solar Probe Plus, to be built by the Johns Hopkins University Applied Physics Laboratory, is more ambitious by far, venturing seven times closer.

The latest plans call for the spacecraft to do a number of flybys of Venus and then settle into orbit around the sun.

The mission has its shortfalls. There will be no coronal dust detector, which would have helped reveal the composition of dust floating in the corona. More important to some, there will be no instrument to analyze rare, heavy elements in the solar wind, which could have helped show where individual gusts originate.

But even those who are disappointed still enthuse about the wealth of insight Solar Probe Plus will bring.

"We're sad we're on the sidelines on this one, but that's what we have to live with," said Eberhard Moebius, a space scientist at the University of New Hampshire whose experiment didn't make the cut. "It's still the most exciting mission in our field."

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