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Earth has some new orbiters, and while one of them is vexing many scientists, another will help us learn more about our atmosphere.

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[♪ INTRO].

From an orbiting disco ball to a new NASA mission, there’s been lots of satellite news in the past week, some of it controversial, and some less so. First, the commercial spaceflight startup Rocket Lab had their second test launch last week, and it went really well.

They launched their rocket, adorably called Still Testing, from New Zealand, and it got all four of its satellites into orbit. Three were for industry or science, and one of them was just for fun. Well, fun for Rocket Lab, at least.

A lot of astronomers are pretty upset, because that fourth satellite is basically a disco ball. It’s called the Humanity Star, and it’s a geodesic sphere about a meter across with 65 highly reflective sides. It was designed to reflect sunlight back to Earth, and to be a flashing beacon brighter than any star we can see, apart from the Sun, of course.

It’ll only last about nine months, after which it’ll fall back to Earth and should burn up in the atmosphere. The idea behind it is to encourage people to think about their lives and humanity’s place in the universe. Which is neat, but some astronomers have argued that maybe this is really just a hunk of shiny space garbage.

After all, you could get that shared human experience by looking at the stars already there, or the moon, which is a satellite that reflects the sun. And more importantly, the Humanity Star will probably get in the way of scientific observations. See, there are already tons of satellites in space, and they frequently show up as long, white streaks through astronomers’ images.

But at least those satellites are typically useful, like for GPS or research. The Humanity Star, on the other hand, exists only to be seen. And it’s supposedly going to be a lot brighter than other satellites.

Part of the engineering inspiration behind the Star is the Iridium flare phenomenon, an unintentional byproduct of having satellites in space. Iridium is a telecommunications company with a network of very reflective satellites around Earth. When one of these satellites catches sunlight, the resulting flare is ridiculously bright, like, brighter than most things in the sky.

Iridium flares interfere with astronomical observations and, unfortunately, they’re pretty common, but at least they’re brief. But Rocket Lab took this one step further and built something that, in the eyes of some scientists, is designed to be as bright and inconvenient as Iridium flares all the time. So the Humanity Star is all fun and games, until it interferes with science.

But no matter how people feel about it, one thing’s for sure: Its parent company Rocket. Lab is doing some cool work. Someday, the company hopes to make 50 to 120 trips to space each year to launch satellites, more than any other organization.

And, maybe thankfully, most of those satellites will be practical. Meanwhile, last Thursday, NASA put a new satellite into orbit that’s definitely useful! It’s called GOLD, or Global-scale Observations of the Limb and Disk, and it’s expected to start doing science in mid-October.

Along with its partner satellite ICON, which should launch later this year,. GOLD will study Earth’s upper atmosphere, specifically, where the thermosphere and the ionosphere overlap. The thermosphere is a layer of our atmosphere that absorbs lots of heat from the Sun, keeping us comfy and not frozen to death.

It’s technically considered space, and it’s where the International Space Station lives. It’s made mainly of uncharged particles, and stretches from around 90 kilometers above the Earth up to 1000 kilometers. Meanwhile, the ionosphere is the region of the atmosphere where radiation from the Sun has knocked electrons off lots of atoms.

So it’s full of charged particles, or ions. And depending on the Sun’s conditions, it can stretch anywhere from 50 to 1000 kilometers above the Earth. The area where the thermosphere and ionosphere overlap is really dynamic, because it’s where two kinds of gas interact.

So there’s all kinds of stuff going on there. The thing is, we don’t know much about those interactions. Until now, they’ve been really hard to study, because satellites in the thermosphere tend to deorbit relatively quickly.

In general, we at least know that both space weather and Earth weather influence that region, so that will guide GOLD’s observations. During the day, GOLD will look at how the Sun affects this overlapping area, and how. Earth’s weather affects the thermosphere’s temperature and dynamics.

Then, at night, GOLD will look at the ionosphere. As this region moves around, unpredictable, dense pockets of ions can develop, and they can partially or completely disrupt radio transmissions to and from space. Which is not great, because that’s how we communicate with the ISS and get GPS signals.

So GOLD will study those pockets to help us better understand the interference, and maybe eventually compensate for it. Data from the satellite will also be used to calibrate models of the upper atmosphere. Since this area has been so hard to study directly, a lot of our understanding of what’s going on up there has come from models.

Lots of them are based directly on physical principles, but without data to confirm, we don’t really know how well they’re working. Using models and direct observations will allow us to do lots more research and better understand this environment. And it’s really important to figure out what’s going on there, because that’s where astronauts live!

And, for better or worse, where the Humanity Star now lives. And we want to keep these people and satellites safe! Well, definitely the people, and at least most of the satellites.

It depends on who you ask. Thanks for watching this episode of SciShow Space! If you’d like to keep learning about the universe with us, or if you want to write a disco song about space, let us know in the comments below, and go to and subscribe. [♪ OUTRO].