What to Know
NASA's Parker probe will venture closer to the sun than any other spacecraft
Saturday's launch attempt encountered a series of snags and controllers delayed the launch after running out of time
When deployed, scientists hope Parker with gather information on our star and shed light on others out in space
A last-minute technical problem Saturday delayed NASA's unprecedented flight to the sun.
The early morning launch countdown was halted with just one minute, 55 seconds remaining, keeping the Delta IV rocket on its pad with the Parker Solar Probe.
Rocket maker United Launch Alliance said it would try again Sunday, provided the helium-pressure issue can be resolved quickly. As soon as the red pressure alarm for the gaseous helium system went off, a launch controller ordered, "Hold, hold, hold."
Once on its way, the Parker probe will venture closer to our star than any other spacecraft. The $1.5 million mission is already a week late because of rocket issues. Saturday's launch attempt encountered a series of snags; in the end, controllers ran out of time.
Thousands of spectators gathered in the middle of the night to witness the launch, including the University of Chicago astrophysicist for whom the spacecraft is named. Eugene Parker predicted the existence of solar wind 60 years ago. He's now 91 and eager to see the solar probe soar. He plans to stick around at least another few days.
Here's why the Parker spacecraft is so tough and why scientists are so hot for this first-of-its-kind mission:
Parker's lightweight heat shield is just 4 ½ inches (11 centimeters) thick. But it can withstand 2,500 degrees Fahrenheit (1,370 degrees Celsius) as well as extreme radiation, thanks to its high-tech carbon. Although the corona reaches millions of degrees, it's a wispy, tenuous, environment and so the spacecraft won't need to endure such severe temperatures. The 8-foot (2.4-meter) shield will face the sun during the close solar encounters, shading the science instruments in the back and keeping them humming at a cool 80 degrees Fahrenheit (27 degrees Celsius). As one scientist notes, this is a shield Captain America would envy.
SEVEN YEARS IN HOT PURSUIT
The spacecraft's path to the sun runs past Venus. It will fly by our solar system's hottest planet seven times over seven years, using the gravity of Venus to shrink its own oval orbit and draw increasingly closer to the sun. The first Venus flyby is in October, followed by the first dip into the sun's corona in November. There will be 24 orbits between Venus and the sun, with the final three putting Parker closest to the sun — just 3.8 million miles (6 million kilometers) out — in 2024 and 2025. That's a scant 4 percent of the 93 million miles (150 million kilometers) between Earth and the sun.
The records will start falling as soon as Parker takes its first run past the sun.. The current close-to-the-sun champ, NASA's former Helios 2, got within 27 million miles (43 million kilometers) in 1976. Parker will come within 15.5 million miles (25 million kilometers) in November and then start beating its own record. During its closest solar approaches, the spacecraft will hurtle through the corona at 430,000 mph (690 kph), setting a speed record.
Our yellow dwarf star is, in many ways, a mystery. The outreaching corona is hundreds of times hotter than the sun's actual surface, confounding scientists. In addition, physicists don't know what's driving the solar wind, the supersonic stream of charged particles constantly blasting away from the sun. By being right in the thick of it, Parker should provide some answers, shedding light not only on our star but the billions of others out there.
PARKER THE MAN
Sixty years ago, a young astrophysicist at the University of Chicago, Eugene Parker, proposed the existence of solar wind. Many were skeptical and told him to read up on it first "so you don't make these killer mistakes," he recalls. Vindication came with NASA's Mariner 2 spacecraft in 1962. Parker is now 91 years old and at Cape Canaveral with his family to witness his first launch — a Delta IV Heavy rocket with the spacecraft bearing his name. It's the first time NASA has named a spacecraft after someone who's still alive. In an interview with The Associated Press on Thursday, Parker noted from a publicity standpoint, "it absolutely wipes out everything else" in his career. "At my age, it gets fatiguing. But of course, I enjoy it."