Early Saturday morning in Florida, a bit after 3:30 a.m., a massive rocket carrying a 1,500 pound probe bound for the Sun stood ready on the launchpad. With four minutes left in the countdown, a few engineers called a 'No go'—part of the system wasn't 100 percent ready for launch. The countdown stopped. No one was taking any chances with this mission. Around an hour after the original launch time of 3:31 a.m., the launch was scrubbed.
Long before dawn on Sunday, the Delta IV Heavy rocket stood ready again. This is the second most powerful rocket in operation, bested only by SpaceX's Falcon Heavy. This time, as the engineers ran through their last checklists, all systems were go—and the spacecraft was ready to sail toward the Sun.
Witnessing the launch of the Parker Solar Probe was its namesake, Eugene Parker. The mission is the only one in NASA history to be named after a researcher while they were still alive.
In 1958, Parker wrote a paper proposing the existence of the solar wind—plasma streaming outward from our host star. His theory wasn't vindicated until NASA's first planetary mission, Mariner 2.
It will take seven years for the Parker Solar Probe to reach its ultimate destination, an orbit nearly 4 million miles from the Sun's surface—exposed to its blistering heat, and closer than any other spacecraft has ever gotten. The probe is well-equipped for the scorching proximity, but getting [close enough to take detailed measurements of the outermost layer of the star takes careful planning.
During the seven-year voyage, the probe will slingshot around Venus seven times, losing much of the sideways momentum it started the trip with (remember, Earth is moving around the Sun at 67,000 miles per hour, so anything coming from our planet has to account for that as it heads out into space.) But while it slows its sideways momentum, it will start going faster along its own path, eventually accelerating to 430,000 miles per hour—faster than any spacecraft before—as it makes its closest approach to our nearest star.
Its first few weeks will start more slowly. Now that it's safely launched and on its way, the spacecraft will start deploying its antenna and other instruments. It will cruise by Venus for the first time in October. By November it will reach within 15 million miles of the Sun, closer than any other spacecraft has ever gotten.
Just after the launch, Parker was interviewed on NASA live and asked how he was feeling about the launch. He replied: “All I can say is, wow, here we go! We're in for some learning over the next few years.”
