Taters, the Space Laser Cat



“Everyone loves Taters.” 

–Ryan Rogalin, Jet Propulsion Laboratory

In our current understanding of the cosmos, nothing travels faster than light. All the incarnations of the electromagnetic spectrum move at 299,792,458 meters per second in a vacuum, which is approximately 186,000 miles per second or 671 million miles per hour. That’s some serious speed. The circumference of the Earth is just under 25,000 miles, meaning a photon would circle our planet in 0.13 seconds. The scale of the universe becomes sobering when we realize the fastest item in existence still requires eons to zoom from place to place. Light from our star takes more than eight minutes to hit our planet; light from the sun takes 2 hours and 40 minutes to hit Uranus. The closest star – Proxima Centauri – is 4.24 light years away. If we could accelerate to the speed of light, an entire Olympic cycle would transpire before we got there. The fastest object humans have ever created – NASA’s Parker Solar Probe – almost hits 400,000 miles per hour. That figure is 0.05% of the speed of light. We have a long way to go if we want to bridge the great distances of the universe.

Despite the rapidity of light, it’s not fast enough for practical purposes even on our more pedestrian, solar-system scales. For example, Voyager 1 and 2, which have crossed the heliopause and entered deep space, utilize radio to communicate with Earth. Radio, being a part of light’s electromagnetic spectrum, is as fast as anything can be, yet it takes nearly a day for messages to reach the craft from home or vice versa. This lag is well worth the boon of information we’ve received from the probes but makes any communication that might require finesse or timeliness a difficulty. Thankfully, with the Voyagers, we don’t need to send many emergency communiques. Radio frequencies are fantastic for sending music or voice data on Earth, where they can reach automobiles or cellular phones nearly instantaneously. They are also rather robust for talking with hunks of metal outside the solar system, given we don’t need to transmit critical info. It’s cheap, it’s fast, and we have centuries of experience with the medium.

Radio has a cosmic downside, however. It’s fast, but its bandwidth is limited. The different types of light all have varying frequencies, despite the same speed. The frequency of radio waves is about the size of a skyscraper, which seems large for something as ethereal as light. Gamma rays, on the other hand, have frequencies on the scale of atomic nuclei. Though light all travels at the same speed, a higher frequency translates into more energy. Get hit with a radio wave and nothing happens; take a bunch of gamma rays and you might as well stick your head in a particle accelerator.

The electromagnetic spectrum - graphic from NASA

How does this frequency pedantry affect communication in space? 

Though radio, visible light, x-rays, and gamma rays all travel at the same speed, their differing frequencies mean we can transmit different amounts of data at that same speed. Because radio waves have the longest wavelengths, they can send the smallest amount of information at light speed. We refer to this attribute as bandwidth. Think of it this way: you have trains that can roll at the speed of light. Radio waves send one train. Gamma rays would send 10 quadrillion trains at the same time. Each train can carry new information, so the gamma rays would impart far more data at the same speed.

NASA scientists believe we’re reaching the upper limits of the effectiveness of radio’s bandwidth.  We can beam music to the space station with no problem with radio’s bandwidth, but, when the necessary information involves complex telemetry or video, its functionality effectively ceases. Why does this bandwidth matter? The messages we send Voyager in deep space might not matter much, but the data we communicate to a human mission to Mars, for example, would matter quite a bit. The information we would need to flash to such a mission contains too much data for radio.

Unfortunately, we can’t currently use gamma rays to send information. NASA looked for a usable upgrade to radio waves. Enter lasers!

A telescope using lasers - photo by Ghizzi Panizza

Light Amplification by Stimulated Emission of Radiation is a coherent stream of visible light. Lasers are fantastic candidates for communication in space for two reasons: their coherence allows them to be focused on specific locations and the frequency of visible light is much higher than that of radio waves.

NASA launched (literally, haha) the Deep Space Optical Communications experiment to test the ability of lasers to revolutionize chatting in space. The technology went up with the Psyche mission, an orbiter with the main task of studying the eponymous asteroid that sits in the belt between Mars and Jupiter. This mission was a fantastic choice to sample the technology because its location mimics a potential flight to Mars.

In December, NASA decided to test the system. What would be the best way to do so?

The answer, of course, is kitties!

The ultra-high-definition video above features a feline named Taters, who is the companion of a worker at the Jet Propulsion Laboratory. To keep the video somewhat on brand, Taters plays with the greatest of all cat toys: a laser.

From 19 million miles away, the laser sent the video to Earth in two minutes. Of course, that’s the same time it would take radio to make the transmission. The laser, however, did so at 267 megabits per second, more than 100 times greater than radio waves could. To make many of us on Earth jealous, too, that speed is better than a lot of broadband plans.

Scientist Ryan Rogalin noted, “In fact, after receiving the video at Palomar, it was sent to JPL over the internet, and that connection was slower than the signal coming from deep space. JPL’s DesignLab did an amazing job helping us showcase this technology – everyone loves Taters.”

The lasers imparted more information than the cat video, of course, but Taters was the star.

NASA's cheat sheet on the info beamed from Psyche

Space exploration is a serious business, but injecting a bit of fun with a cat is great medicine for researchers in the weeds. Mascots such as Taters can also keep the public engaged with space, which seems to have lost the allure of the public.

We’ve long utilized lasers to bounce light to the moon and back, but DSOC is pushing the boundaries of laser technology. One day, we might be able to send a video to a human standing on the surface of an alien world. That footage could include mission-critical information.

Or it might feature Taters.

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