SOURCE : vox.com
NASA’s New Horizons spacecraft is about to show us an alien world for the first time. At precisely 7:49 am ET on Tuesday, the probe will become the first spacecraft to fly by Pluto.
New Horizons has been en route for nine years, traveling more than 3 billion miles. The flyby will be over in a matter of minutes, as the probe frantically takes hundreds of photos and collects data on Pluto’s atmosphere, geology, and moons. All this data will be enormously valuable to scientists as they seek to understand our solar system and how it formed billions of years ago.
More than anything, this mission is about broadening our horizons — taking in just a little bit more of the impossibly vast universe we live in.
1) We’ve never seen Pluto before
Pluto feels familiar. It’s easy to imagine the small, frigid rock, millions of miles from the sun and covered in ice.
But what you’re picturing in your head when you think about Pluto is probably an artist’s illustration. Until very recently, we didn’t even know exactly what color it was — and the best photos we had of Pluto looked like this:
New Horizons is going to change that in a very big way. Already, as it’s closed in on Pluto, it’s given us way better photos than ever before:
Pluto (right) and its moon Charon, as seen by New Horizons on July 11. (NASA-JHUAPL-SWRI)
The high-resolution photos to come will give us detailed topographical maps, just like those provided by the satellites that orbit Earth. They could reveal mountains, ice caps, volcanoes, or even an ocean of liquid water under the ice. “Who knows what kind of bizarre things we’ll find up close?” Stern said.
2) This mission will remind you how vast space really is
Earth, as seen by the Voyager spacecraft, from more than 4 billion miles away.
We spend our entire lives on the surface of Earth — so it’s hard to really grasp how far away Pluto truly is from us.
But as an analogy, think of Earth as a basketball. By comparison, Pluto would be a little larger than a golf ball. But if you wanted to keep the scale constant, you’d have to put that golf ball incredibly far away: 50 to 80 miles (depending on its location in orbit). This mission, like many activities in space, is a good reminder of how vast our corner of the universe is — and how absurdly tiny our entire earthly realm of experience is by comparison.
And it’s not just the size of space that boggles the mind. It’s also the timescale on which everything occurs. Pluto takes 248 Earth years to orbit the sun. To put it another way, the entirety of US history has occurred during a single Plutonian orbit.
3) We won’t get many more missions like this for a while
There’s a mission to Europa planned, but it won’t reach the moon for a decade or more.
The past few decades have been filled with all sorts of fascinating missions to the planets, moons, asteroids, and comets of our solar system — uncrewed probes sent every few years, run by trained scientists, and supported by government funding.
But the sad truth is that this era is largely drawing to a close. As David W. Brown writes in an article on the dark future of American space exploration, “There is nothing budgeted in the pipeline to take its place. Yesterday invested in today. But we are not investing in tomorrow.”
This is the result of cutbacks to NASA’s planetary exploration budget. The OSIRIS-REx probe will launch next year, to travel to an asteroid and bring back a sample, but it won’t return until 2023. Meanwhile, a mission to Jupiter’s moon Europa is in the works, but it likely won’t be launched until 2025 at the earliest, and wouldn’t reach Europa until the 2030s.
In other words: Enjoy this brief flyby. It’s going to be a while before any NASA probe visits a new world.
4)This is a staggering technological achievement
t’s hard to appreciate just how difficult it is to send a spacecraft to Pluto. But think of it this way: because it’s so incredibly far away, it took New Horizons nine years to cover the 3-billion-mile trip there — which means the craft is using decade-old technology, traveling a route that was calculated years ago.
New Horizons’ trajectory through the solar system.
Despite this, NASA engineers managed to get the tiny probe — about the size and shape of a grand piano — to an incredibly precise spot in space, using Jupiter’s gravity as a slingshot to accelerate it outward and a few thruster burns over the years to keep the probe on track.
Along the way, they had to worry about potentially damaging debris nearby Pluto — as well as a scary software glitch this past weekend, which was, thankfully, resolved. Now New Horizons is going to fly within 7,750 miles of Pluto, coming closer than its moons.
Because New Horizons is traveling at such a high speed (about 31,000 miles per hour) and can’t slow down, the flyby will be over in a matter of minutes — fording it to collect all its data in a tiny window of time.
And receiving all that data is another huge challenge. Because New Horizons is so far away, it takes about 4.5 hours for any data it sends back to reach Earth. And the signal is so faint that NASA has to use 200-foot-wide radio dishes (one each in Australia, California, and Spain) to pick it up. This means an extremely low rate of data transmission: about 1 kilobit per second, more than 50 times slower than a 56k modem from the ’90s. It takes more than 42 minutes for New Horizons to fully transmit an image that’s 1024 pixels wide.
If you haven’t been paying attention so far, now’s the time to start. This is a really big deal.
