Getting Closer

Although it won’t happen until the day after Christmas, a NASA spacecraft is ready to give something to the planet Venus: a bit of its orbital energy. That will allow the craft to move closer to its target: the Sun.

Parker Solar Probe is designed to study the Sun’s hot but thin outer atmosphere, known as the corona. It’ll also study the solar wind, and the Sun’s complex magnetic field.

To do all of that, though, it has to get close to the Sun, which is harder than you might think. It has to cancel out Earth’s orbital speed and fall toward the Sun, but not into it.

In fact, Parker will spend seven years reaching its target distance from the Sun. It’ll orbit the Sun 24 times over that period, and make a total of seven passes by Venus.

Those encounters allow the craft to refine its orbit. It transfers some of its orbital momentum to the planet, so it will drop closer to the Sun on each pass. In its current orbit, it takes 150 days to circle the Sun. After its Thursday encounter with Venus, though, the orbital period will drop to 130 days.

Parker Solar Probe has already passed closer to the Sun than any other craft — about 15 million miles. That’s about half the previous record. That’s allowing it to probe regions around the Sun that no one has seen before.

But that record is only the first of many. Parker Solar Probe will reach its target distance from the Sun in 2025 — less than four million miles from the surface of our star.

Script by Damond Benningfield