Tuesday, October 30, 2018

SPACECRAFT MAKES RECORD CLOSE-APPROACH TO THE SUN

NASA's Parker Solar Probe is now closer to the sun than any other spacecraft in history, shattering the previous record of 26.6 million miles set by the Helios 2 spacecraft in 1976. The probe is now well inside the orbit of Mercury.

"It's a proud moment for our team," says Project Manager Andy Driesman of the Johns Hopkins Applied Physics Laboratory.




Count to 3. Parker just broke the record again. The spacecraft is accelerating sunward for the mission's first perihelion on Nov. 5th. At closest approach, the solar disk will seem 6 times wider than it does on Earth as the probe is hit by "brutal heat and radiation" (NASA's words). Parker's carbon-composite heat shield is expected to heat up to a sizzling 2000 deg. F.

Parker's prime mission is to investigate the origin of the solar wind--a project best done uncomfortably close to the star. Parker will trace the solar wind back to its source and find out how it escapes the sun's gravity and magnetic confinement.

Russell Howard of the Naval Research Laboratory expects to learn a lot from this encounter. "We might detect magnetic islands in the solar wind, which have been theoretically predicted. And if a CME (solar explosion) happens or a comet passes through the sun's atmosphere while we are so nearby, it could be spectacular."



Howard is the principal investigator for WISPR, the probe's wide-field camera system. WISPR can actually see the solar wind, allowing it to image clouds and shock waves as they approach and pass the spacecraft. Other sensors on the spacecraft will sample the structures that WISPR sees, making measurements of particles and fields that researchers can use to test competing theories.
"We lose communication with the spacecraft during the perihelion period which begins next week," notes Howard. "This is because there isn't sufficient power to drive both the instruments and the transmitter. The first dump of data will occur in early December." Stay tuned for that.

Parker will plunge toward the sun 24 more times in the next 8 years, breaking many records en route. Here's the timeline.

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