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CU Boulder reaping reward of its (many) moments in the sun

Parker Solar Probe instrument features component from LASP

Artist’s concept of the Parker Solar Probe spacecraft approaching the sun. Launching in 2018, Parker Solar Probe will provide new data on solar activity and make critical contributions to our ability to forecast major space-weather events that impact life on Earth.
Artist’s concept of the Parker Solar Probe spacecraft approaching the sun. Launching in 2018, Parker Solar Probe will provide new data on solar activity and make critical contributions to our ability to forecast major space-weather events that impact life on Earth.

Scientists at the University of Colorado Boulder are already reaping the fruits of their participation in an ongoing space mission that is traveling faster and sailing closer to the sun than any spacecraft has traveled before.

Known as the Parker Solar Probe, the spacecraft has already completed three of 24 orbits around the sun, where it will have covered 96% of the distance from the Earth to the sun at the conclusion of its prime mission in 2025 — if it makes it that far.

Launched Aug. 12, 2018, the Parker Solar Probe’s four-instrument suite includes what is known as the FIELDS experiment, for which a team of CU Boulder scientists designed the signal processing board.

The purpose of the FIELDS experiment is to make direct measurements of electric and magnetic fields and waves, energy flux, absolute plasma density and electron temperature, spacecraft floating potential and density fluctuations and radio emissions.

Researcher David Malaspina, a space plasma physicist at CU Boulder’s Laboratory for Atmospheric and Space Physics, has been involved in the initiative since 2009 when he helped write the proposal in support of LASP’s participation in the project.

David Malaspina

“The Parker Solar Probe is a fundamental physics mission, to determine what drives the solar wind and what parts of the sun produce the different solar winds,” Malaspina said. “But ultimately, that can be used to improve our space weather predictions. The goal is fundamental physics, but the ultimate application is the improvement of those predictions.”

Space weather is how scientists refer to the changing conditions of the solar system, including the solar wind, with an emphasis on its impacts on and near the Earth, where solar storms can have dramatic effects on everything from spacecraft to cellphone service and planetary power grids.

Currently, said Malaspina, who is an assistant professor in CU Boulder’s Department of Astrophysical and Planetary Sciences, our ability to predict space weather is “at most three days, and with definitive accuracy, it’s about 45 minutes.”

“With the Parker Solar Probe, then you could have maybe even up to 13 days advance warning, as opposed to where we are now, which is 45 minutes,” Malaspina said. “That kind of warning it’s kind of like a storm warning — in the same way as the longer you know a hurricane is coming, the more you can do to prepare for it.”

‘An unprecedented view’

The solar probe mission is managed by NASA and the John Hopkins University Applied Physics Laboratory, and the University of California, Berkeley is the leader on the FIELDS experiment.

“Observing the sun up close rather than from a much greater distance is giving us an unprecedented view into important solar phenomena and how they affect us on Earth, and gives us new insights relevant to the understanding of active stars across galaxies,” said Thomas Zurbuchen, associate administrator for science at NASA, at a news conference. “It’s just the beginning of an incredibly exciting time for heliophysics with Parker at the vanguard of new discoveries.”

Scientists’ work will help unravel such questions as how the turbulent, gaseous region of space gets so hot, reaching temperatures of almost 1 million degrees Fahrenheit.

“How this is happening is basically unknown, especially in this region where the solar probe is traveling,” said Alexandros Chasapis, a research scientist at LASP who has worked on the mission, said in a statement. “We just didn’t have any data.”

The FIELDS team has published its first findings in recent days in the journal Nature, one of four papers sparked by the project to be newly published. Eventually, Malaspina said, as many as 60 papers could be generated by the solar probe.

So far, “One of the most interesting findings that FIELDS measurements have determined, the solar wind to the Earth is really turbulent, like a choppy sea. The expectation has been for a very long time that the closer you get, the choppier and choppier it would be, until you’re in a raging froth of sea,” Malaspina said.

But that is not the case.

“What we have found is the closer you get to the sun, the solar wind has two different modes. So half the time it is the choppy sea that was expected — the turbulence field is high, very turbulent region, but then it turns into something that’s like a perfectly calm lake, where almost all the fluctuations go away. The magnetic field is calm, until you pass another boundary and it will go back to being very turbulent and then back to a calm lake and choppy sea then calm. And this only happens very close to the sun.”

The spacecraft’s first orbits came within about 15 million miles of the sun. With the probe using close encounters with Venus to shed angular momentum, it steps closer to the sun every two-to-three orbits. Ultimately it will come as near as 3.83 million miles to the sun, which is seven times closer than any spacecraft has come before.

Also, it is flying faster than any spacecraft ever has, taking that distinction away from the previous record holder, the Boulder-based New Horizons mission past Pluto. In its first passes by the sun, it has hit 90 kilometers a second. At its fastest, it will touch 180 km per second, or about 400,000 mph.

Its one-of-a-kind heat shield can withstand temperatures up to 1,800 degrees Celsius. But eventually — and perhaps short of the planned 24th orbit in 2025 — it will succumb to the hostile environment it’s pioneering. Solar dust, and its impact, is another hazard it faces.

“Of course, every orbit is a gift,” Malaspina said. “One of the really big unknowns going into this mission is what the dust environment would be, since no spacecraft has ever visited this region there were no good measurements of what the environment would be. It was unknown.

“Everything was designed as conservatively as possible to survive it. And so far we have done really well. But there is always a possibility that it could end the mission. We’re happy to get” each orbit.