NASA Wants to Send the Fastest Spacecraft Ever Into the Sun

A project 60 years in the making will fill critical gaps in what we know about our stellar master.

Illustration of the Parker Solar Probe spacecraft approaching the sun.

Source: Johns Hopkins University Applied Physics Laboratory

NASA will launch a probe next year into the Sun’s outer atmosphere that’s expected to improve dramatically our understanding of  “space weather” and its risk to satellites, electrical grids, and telecommunications.

Eugene Parker
Source: The University of Chicago

Mission leaders gathered at the University of Chicago on Wednesday both to introduce the Space Probe Plus and to rechristen it the Parker Space Probe, in honor of Eugene Parker, the University of Chicago scientist who in 1958 hypothesized the existence of solar wind—an idea his contemporaries ridiculed until the Mariner 2 probe confirmed it a few  years later.

Despite decades of research, critical knowledge gaps remain that prevent scientists from being able to predict and track solar storms with the precision necessary to avoid low-probability, high-cost damage to technology. The probe will investigate two key questions about solar physics: How does the solar wind start? And why is the sun’s surface, at 10,000 degrees Fahrenheit, just a tiny fraction of the million-plus degree corona? “It’s like water flowing uphill,” said Nicola Fox, a professor at the Johns Hopkins University Applied Physics Laboratory where the probe is being assembled and tested. “It shouldn’t happen.”

The announcement is the first time NASA has ever named a mission after a living scientist—not a bad birthday present for Parker, who turns 90 on June 10. “Hooray for Solar Probe!” he said, at the conclusions of his remarks at the University of Chicago. 

The $1.5 billion mission was first proposed as the nation’s nascent space program was drawing up a to-do the list in the shadow of Russia’s successful launch of Sputnik in 1957. It has taken six decades of technical improvement to pull it off, in part because it’s an extreme project even by space exploration standards. The closest of Parker‘s planned seven approaches to the Sun, expected in mid-2025, will bring it within 4 million miles of the surface, or seven times closer than the 1974 Helios mission. At a top speed of 125 miles per second, it’ll be the fastest spacecraft in history.

Four suites of instruments will measure the Sun’s magnetic field, the solar wind’s speed, and the density and temperature of the particles that make it up. The instruments are protected from 2,500-degree heat by an engineering feat worthy of science fiction—a 4.5-inch carbon-composite shield that will keep the equipment near room temperature. 

Answering questions as fundamental as these will have the practical effect of improving space-weather prediction, an increasingly critical component of managing, and protecting, the increasing traffic jam in Earth orbit. Still, the probe is only the most recent tool to help scientists learn more about how the sun works and when it may hurl high-energy particles our way. 

The NOAA Space Weather Prediction Center in Boulder, Colorado.
Photographer: Joe Amon/The Denver Post via Getty Images

Space-weather monitoring in the U.S. is the responsibility of the National Oceanic and Atmospheric Administration. The Space Weather Prediction Center, based in Boulder, Colo., monitors solar activity from instruments both terrestrial and in orbit, including the Deep Space Climate Observatory, which circles the Sun a million miles from Earth and can give Earthlings an hour heads-up on how serious a solar eruption might be. It’s not much, but it’s better than nothing.

Shooting the new probe into orbit and accelerating it to ludicrous speeds will require the most powerful rocket currently at NASA’s disposal, United Launch Alliance’s Delta IV Heavy. The vehicle will have a rare third-stage, “just so we can achieve the incredible speed we need to be able to ‘surf’ around the Sun to take the critical data without getting pulled into the sun itself,” Nicola Fox, the Johns Hopkins professor, said in a statement. 

The launch window for the Parker Space Probe opens July 31, 2018, and closes 20 days later. In the seven years between launch and its 24th pass of the sun, the spacecraft will flip past Venus seven times, each time slowing a little bit, allowing a closer approach to the Sun. 

“Solar Probe is going to be the hottest fastest mission,” Fox said. “I like to call it the coolest hottest mission under the sun.” 

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