[♪ INTRO] Space-age technology is supposed to be the best humanity has to offer.

But on May 6, 1965, something surprisingly mundane went into orbit around the

Earth: an aluminum sphere, just over one meter wide. And that was it. It could not take measurements. It could not communicate with scientists on the ground.

It was just…a hollow aluminum ball. But nearly six decades later, that hollow ball is still up there doing its job! Because you don’t always need bells, whistles, or antennas to be important.

Sometimes, you just need to be shiny…and really, really round. The Lincoln Calibration Sphere 1, or LCS-1, is exactly what it says on the tin. It is a sphere created by MIT’s Lincoln Laboratory for the purposes of calibration.

In other words, the lab’s engineers knew that it would be useful to have something in space with precisely known /consistent/ properties that they could test their scientific instruments on before pointing them at the thing they wanted to study. It is vitally important to calibrate your tools before taking any measurement, but it’s especially important if you’re investigating something new and have no other data to compare against. And by the 1960s, the field of astronomy had really opened up.

LCS was designed as a check on radar, which involves bouncing radio waves off an object to see how far away it is or what its surface looks like. After those radio reflections are captured by satellite dishes back on Earth, scientists can combine how much of the signal was reflected, how long it took to come back to Earth, and how it was twisted along the way to construct their view of any given target, whether it’s a spacecraft or a space rock. But to make sure that view is accurate, they need to know how the atmosphere and the dishes themselves affect the radio signal.

And that is where the LCS comes in. Scientists wanted a sphere because they needed it to look the same from every direction, and they wouldn’t have to worry about whether or not it was spinning and the radio waves were hitting differently shaped sides. If LCS were a cube, for instance, it would look bigger when viewed from the corner than face-on.

You’d have to know exactly how it was oriented at every moment in order to calibrate your instruments, since otherwise you wouldn’t know how big it should look. That sounds like a nightmare. For the same reason, LCS also needed to stay a consistent distance from the ground.

So its orbit was a nearly perfect circle, roughly 2,800 kilometers up. For comparison, that’s about five times farther away than the Hubble Space telescope hangs out. Finally, a couple identical spheres were left down here on Earth to compare how radio waves bounced off of them and confirm the signal quality that scientists were getting from space.

Now, LCS was not the first calibration sphere of its kind, but it was bigger and its orbit was more circular. That not only made LCS easier to see, it also meant the whole calibration process was less complicated. These calibration tools, they don’t usually make headlines.

As empty, smooth, shiny metal balls, they’re only flashy in the most literal sense. The world’s most boring disco balls. But because their whole purpose is to reflect light to keep other instruments on track, they make science possible.

Which is its own kind of party! All of the care and planning that went into designing LCS started paying off soon after it launched. In 1966, a pair of astronomers reported that they had used LCS to calibrate radar measurements of the Moon, revealing just how bumpy the surface is and what it’s made of.

Combined with on-site data collected by probes, LCS helped to prove that there were parts of the Moon that were actually safe for astronauts to land on! And it’s been helping ever since, giving scientists those crucial instrumental checks before they move on to bigger and more exciting targets. But LCS has experienced a little wear and tear.

For example, a study published in 2012 found that it’s not as shiny as it used to be, and the light it reflects gets brighter and dimmer in a predictable pattern. That suggests that the sphere is spinning, and that a bit of its surface has a mark or ding in it. Which isn’t a big surprise after spending more than half a century in space.

The James Webb Space Telescope got hit by debris a few months after it unfolded its mirrors. But this minor damage hasn’t stopped scientists from finding creative ways to use LCS-1 and its identical twin, LCS-4, which was launched in an 850-kilometer orbit in 1971. Astronomers have tracked the orbits of both spheres to measure how Earth’s atmosphere expands and contracts in response to how much light and matter the Sun is throwing out into space at any given moment.

For example, when this solar activity is more intense, it can inflate our atmosphere, placing more molecules in higher orbits. Worst case scenario, a satellite experiences so much drag as it flies through these extra molecules that it falls out of a stable orbit, and burns up in the atmosphere...or even collides with another. Since a calibration sphere’s orbit will slowly shift in response to any atmospheric changes, they’re a pretty handy tool to see what proper satellites will need to be able to handle when the Sun gets a little too excited.

Meanwhile, physicists, engineers, and Earth scientists alike have used LCS to learn how to track space debris…everything from rocket stages to wrenches… and model how it spreads out over time. Today, there are tens of thousands of pieces of debris orbiting the planet at more than 7 kilometers per second. A misplaced wrench traveling that fast could be bad news for satellites and astronauts alike if we can’t figure out where it is and where it’s headed.

And finally, LCS can be used in ways that dip its proverbial toes into the pool of science fiction! Back in the nineties, a pair of engineers proposed using calibration satellites as a check not on radar, but equipment pointing super powerful lasers into deep space. And what would those lasers be doing?

Oh, nothing too out there. Just taking advantage of the fact that light can very lightly push on things in order to push spacecraft into interplanetary, if not interstellar space. And in a way, it’s hard to imagine something more fitting for LCS.

This little, unpowered metal ball that NASA used to study the Moon could once again help propel another giant leap for humankind. So thanks to this unsung hero of space history, and an even bigger thanks to our Patreon patrons, who help us keep this channel running so we can bring to you the bizarre story of human progress. If you are out there thinking to yourself, “Hey, I’ve been meaning to sign up for that.

I should go to patreon.com/scishow right now!,” we definitely agree. You’re in for a real treat. [♪ OUTRO]