Final testing is under way for a craft that stirs excitement at NASA. After 60 years of dreaming, planning and hard work, the space agency and engineers from a Maryland university recently unveiled the Parker Solar Probe -- an unmanned device that will fly closer to the sun than anything launched from Earth ever has. In this context, mind you, closer doesn't mean what it usually does. The craft will use Venus' gravity like a slingshot to orbit the sun 24 times -- coming within 4 million miles of the sun's superheated surface. (Yes, that's considered “close.”)

Its launch from Cape Canaveral in Florida aboard a Delta IV rocket, tentatively planned for July 31, will send Parker on a data-gathering trip lasting seven years and costing $1.5 billion. The sun is the only star we can study this way. The more we know about it, the more we can understand how life on Earth developed with help from that source of light and heat. "Every measurement we make is a potential discovery," says project scientist Nour Raouafi. Nicky Fox, a female engineer at Johns Hopkins University who works at the Goddard Space Flight Center in Greenbelt, Md., adds: "We can go up and visit our own neighbor, and kind of better understand stars throughout the universe. . . . The sun is central to our everyday life. It isn't just a point in the sky. Obviously, it gives us light and heat, and it enables us to be alive on this planet, but it also has all these mysteries."

The 1,400-pound spacecraft, made of titanium and aluminum and about the size of a small car, will be protected from solar heat by a series of four-and-a-half inch thick carbon panels. It's expected to endure temperatures of about 2,500 degrees, while equipment inside gets no warmer than 80 degrees. While orbiting at 450,000 miles per hour – you read that right – the probe will travel through the sun's corona, usually seen only during a total solar eclipse. Researchers hope for clues about why the corona is 300 times hotter than the sun's surface. They also want to learn more about solar wind – energized particles hurled from the sun at millions of miles per hour. That phenomenon can affect our planet's magnetic field, cause destructive power surges and damage satellites.

NASA says: "It is the coolest, hottest mission under the sun. It's going to explain to us how a star works. . . . Until you actually go out, you have no idea quite how hot it is out there or how windy it is or what the conditions are like." – Nicky Fox, project scientist

Craft's creator: The Parker Solar Probe is designed and built by Johns Hopkins University's Applied Physics Laboratory in Laurel, Md.

Engineer says: "To be experiencing this and seeing it all come together, it's indescribable, to be honest." – Betsy Congdon, mechanical engineer at Johns Hopkins