Solar Orbiter closes in on the Sun for its first big reveal
ESA/NASA's Solar Orbiter made its first close pass in mid-June, and its first imagery is due for release later this month.
Solar Orbiter has been quietly doing its job since launching back in February, and now it’s finally at the point where we get to see what it’s actually capable of. In mid-June, the ESA/NASA spacecraft made its first close approach to the Sun, swinging in to about 77 million kilometers — roughly half the distance between Earth and the Sun. That’s the closest any of its instruments have gotten to our star so far, and it’s the moment mission scientists have been building toward for months.
The instrument everyone’s watching is the Extreme Ultraviolet Imager, or EUI, which is designed to capture the Sun’s outer atmosphere in wavelengths our eyes can’t see. Extreme ultraviolet light reveals structure in the corona that’s invisible in ordinary visible-light images — loops of plasma, bright active regions, and the finer filamentary structure that’s thought to feed the solar wind. Solar Orbiter isn’t the first mission to look at the Sun in EUV, but getting this close, this early in the mission, means the resolution on these first images should be notably sharp.
Why the close pass matters
Solar Orbiter’s whole mission design is built around repeated close passes, using gravity assists from Venus to gradually tilt its orbit out of the ecliptic plane over the next few years. Eventually it’ll get views of the Sun’s poles that we’ve simply never had before — no other mission has managed a proper look at the solar poles from this kind of vantage point. This first pass isn’t at the mission’s minimum distance (that comes later, and the orbit tightens over time), but it’s close enough to serve as a real shakedown for the imaging suite under actual solar-heat conditions, which is no small thing given the spacecraft has to survive temperatures nobody puts a camera through casually.
What’s got me interested is less the distance record and more the timing. ESA has said the first-look imagery from this pass should become public later in July, and that’s a pretty quick turnaround for a spacecraft that’s still early in its commissioning phase. If the EUI data comes back clean, it’ll be a good sign that the rest of the ten-instrument payload — coronagraphs, magnetometers, particle detectors — is similarly on track heading into the tighter passes ahead.
It’s also worth remembering this mission is meant to work in tandem with Parker Solar Probe, which flies much closer to the Sun but without cameras pointed directly at it (Parker’s shield doesn’t allow that kind of direct solar imaging at close range). Solar Orbiter is the one built to actually photograph the Sun up close, repeatedly, over years. So this first EUV release, however it looks, is really just the opening frame of what should be a long and increasingly detailed film.
I’ll be watching for the actual images later this month. Given how much anticipation there’s been around this pass, they’d better be good.