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SpaceX has done it again! It's landed the first stage of a Falcon 9 rocket and the Dragon capsule has returned from the ISS. Now, what's next for New Horizons? It has its sights set an another tiny world in the Kuiper Belt.

Hosted by: Hank Green

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New Horizons


[Intro plays]

Hank: About a week ago, SpaceX CEO Elon Musk celebrated some pretty great news with a casual tweet: “May need to increase size of rocket storage hangar.” Why might the storage hangar need more room? Because on May 6th, SpaceX landed the first stage of a Falcon 9 rocket on a drone ship! Again!

This landing was even more difficult to pull off than their successful landing last month, after the rocket had been used to launch a Dragon capsule to the International Space Station. That’s because last week’s mission involved launching a Japanese communications satellite to a higher orbit than the Dragon. The farther destination meant that this first stage rocket descended to Earth at a much higher velocity and temperature, making it harder to safely maneuver and land. But they did it!

Another successful landing means that SpaceX is one step closer to developing a launch system that’s reliable and reusable -- which would make spaceflight a lot cheaper in general. And these Falcon 9 rockets aren’t the only things coming back from space. That Dragon capsule that SpaceX sent up to the ISS in last month’s launch? This past Wednesday, it came back to Earth with around 1700 kilograms of science experiments and other cargo.

Some of that cargo includes biological samples from crew members, like the last batch from Scott Kelly’s year-long mission that ended in March. There are also plant samples from an experiment called Plant Gravity Sensing, which is studying how plants figure out where to grow roots and stalks. The capsule even has a group of 20 mice onboard! These mice are part of the Rodent Research study, which aims to learn more about how bones and skeletal muscles weaken in space. The mice were sent up with this capsule last month, and now they’re coming back. Hopefully, studying the effects of their time in space will help protect future astronauts.

And speaking of the future: The New Horizons probe that visited Pluto last July is off to... even newer horizons. This spring, the New Horizons mission team at the Johns Hopkins Applied Physics Laboratory in Maryland submitted official extended mission plans. Which means that New Horizons has an official new target! Pending NASA’s approval, of course.

The probe’s next stop is a small, icy world in the Kuiper Belt called 2014 MU69. And buzzing past it could tell scientists a lot about the early days of the solar system. Scientists have been eyeing MU69 for a while. Back in 2011 -- when New Horizons was still four years away from Pluto -- researchers were already searching for a next target in the Kuiper belt using ground-based telescopes. But all of their potential options were too far away -- New Horizons would need more fuel or a different flight path to do a successful flyby.

Then, in 2014, they found a few reachable candidates using the Hubble Space Telescope -- including the medium-sized MU69, which became their top choice in August 2015. By studying these Kuiper Belt Objects, scientists think they can learn more about the beginnings of our solar system 4.6 billion years ago, because these icy bodies are kind of like time capsules.--they’re still very similar to how they were in those early, planet-forming days. So studying these objects can help researchers learn a lot more about our solar system’s past.

MU69 is about 45 kilometers in diameter, and about a billion kilometers away from Pluto. And the plan is for New Horizons to fly as close, or even closer than it did to Pluto. Which should get us some fantastic images, as well as other data that will tell scientists about things like the geology, atmosphere, and surface properties of the tiny world that we can’t observe accurately from far away.

Even though the official proposal is still awaiting NASA’s final approval -- which will probably happen sometime this fall -- New Horizons is already on its way to MU69. The probe made a couple of well-timed maneuvers last October and November to shift its trajectory toward 2014 MU69. If all goes well, New Horizons should be making the flyby on New Year’s Day, 2019. And! It’ll only need to use about 35% of its remaining fuel to get there. So once we get deeper into the Kuiper Belt... who knows where it’ll visit next?

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