At a Glance

The mission will bring the car-sized spacecraft within 4 millionmiles of the sun. The spacecraft will be forced to withstand heat and radiation unlikeany other spacecraft in history.The probe's 4.5-inch-thick carbon-composite shield can protect it from temperatures as high as 2,500 degrees Fahrenheit.

NASA's Parker Solar Probe is set to launch this weekend, a mission that will bring the car-sized spacecraft within 4 millionmiles of the sun.

A technical problem early Saturday delayed the launch at the last minute.

Now set to launch atop a United Launch Alliance Delta IV Heavy at 3:31 a.m. Sunday from the Kennedy Space Center in Florida, the spacecraft will within three months, according to a press release.

“Eight long years of hard work by countless engineers and scientists is finally paying off,” said Adam Szabo, the mission scientist for Parker Solar Probe at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

While 4 million miles might seem like a great distance, when talking about approaching the sun, it's definitely close enough.

At that distance, the probe will be able to studythe star's mysteriousatmosphere,solar windandits other unique properties butwill also be forced to withstand heat and radiation unlikeany other spacecraft in history.

“We’ll be going where no spacecraft has dared go before — within the corona of a star,” said project scientist Nicky Fox of the Johns Hopkins Applied Physics Lab. “With each orbit, we’ll be seeing new regions of the sun’s atmosphere and learning things about stellar mechanics that we’ve wanted to explore for decades.”

To withstand heat hot enough to , the 1,400-pound probe wasconstructed witha 4.5-inch-thick carbon-composite shield that canwithstand temperatures as high as 2,500 degrees Fahrenheit. Behind the shield, the probe will remain at a comfortable 85 degrees Fahrenheit.

During its 7-year mission, the probe will complete 24 orbits of the Sun, come within 3.8 million miles of the Sun’s surface at its closest approach and travel at speeds of up to 430,000 mph relative to the sun.

Expected complete it 93-million-mile journey to the sun in November, the probe will begin sending data back to NASA in December, according to the press release.

“For scientists like myself, the reward of the long, hard work will be the unique set of measurements returned by Parker,” said Szabo. “The solar corona is one of the last places in the solar system where no spacecraft has visited before. It gives me the sense of excitement of an explorer.”

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Should weather or other conditions prevent the early Sunday morning launch, NASA has a window that lasts until Aug. 23 to fire off its probe.

According to weather.com meteorologist Linda Lam,partly cloudy skies with a 40 percent chance of showers or thunderstorms are expected at the time of the launch.Temperatures in the mid-70s are expected, with light, southwest winds.