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What went wrong with SpaceX's Falcon 9 on September 1st? And an update on our old friend Philae!

Learn more about Last June's Explosion:
Learn more about Philae:

Hosted by: Caitlin Hofmeister

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Caitlin: The last few weeks have reminded the world that space exploration can involve more drama and suspense than an HBO series. On September 1st, a SpaceX Falcon 9 rocket exploded during a routine test, and, the company still isn’t sure why.

Two days before it was set to launch a satellite into orbit, the Falcon 9 was on the launch pad at NASA’s Kennedy Space Center in Florida, preparing for what’s known as a static fire test. It’s used to test a rocket’s engines before launch to make sure everything's working properly. Normally, the rocket is strapped to the launch pad and fueled, and the engines are fired for a few seconds. Then the engines are shut down, and the rocket is considered ready for launch.

This time, things weren’t so simple. While the rocket was being fueled for the test, it suddenly exploded, destroying the rocket and the $200 million satellite it carried. The satellite, called Amos-6, was owned by the Israeli company Spacecom, and Facebook was going to use it to bring Internet to regions of Africa. SpaceX has had a lot of recent successes with their booster landings, but they’ve experienced failure before.

Last June, a Falcon 9 exploded while carrying $100 million worth of cargo for NASA. But with that accident, SpaceX was able to find the problem and fix it. This time, they still have no idea what caused the issue. When the fireball happened, the engines were shut off, and there seems to have been no other source of heat that would have ignited it. SpaceX CEO Elon Musk is calling this the most complicated disaster they’ve ever had, and he’s even asked that anyone with pictures or videos of the explosion send them to SpaceX to help their investigation.

Even though there’s no official answer yet, there are a few ideas. SpaceX uses rocket fuel that’s made of extremely cold liquid oxygen and kerosene, which, when they mix, cause an explosion. And the problem started around the rocket’s upper-stage oxygen tank, so there could have been an issue with fueling. Also, there was a quiet bang just before the rocket caught on fire, so something could have hit it.

It’s also possible that the welding burst on a seam or a joint broke on a strut, but the rocket’s sensors aren’t showing evidence of that. Whatever it was, SpaceX will need to identify the problem before they fly again, and their upcoming launches have been put on hold for now. But hopefully, they’ll figure out what happened soon and get Falcon 9s back on the launch pad.

Meanwhile, we’ve solved a big mystery when it comes to another spacecraft that didn’t quite work the way it was supposed to: The story of Philae, the first spacecraft to land on a comet, finally has a happy ending! In 2014, Philae landed on the comet 67P, or Churyumov-Gerasimenko, after 10 years of traveling. Philae was meant to grab onto the comet using harpoons, so it would stick the landing. But the harpoons didn’t work properly, so Philae bounced twice during landing and ended up in an unknown, dark location somewhere on the comet.

No light meant no power to its solar panels, so Philae’s battery died after just three days. It did manage to conduct some great research in those three days, including the first ever picture from a comet’s surface, but after that, the historic mission seemed to be over. Then, in summer 2015, Philae came back to life! Because the comet’s orbit was bringing it closer to the sun, Philae’s solar panels got a little more light in June and July.

This gave the lander enough power to communicate with Rosetta, its partner spacecraft in orbit around 67P, and ping short bursts about its operational status before going quiet again in July. But those tiny bits of data weren’t enough to tell us exactly where Philae was — and without knowing its location, it was hard to put context to the data it sent us in November.

Since the mission is scheduled to end later this month, many thought the lander was lost for good. That is, until last week! Philae, we found you! Scientists just finished processing images from OSIRIS, a high-resolution camera on Rosetta, and spotted Philae hiding in a crevice. So now we officially know where it landed. The data Philae gathered is the most detailed look we’ve ever had at a comet, so being able to trace it to a specific location means our research is more exact and more useful in the long run.

We’re not going to be able to wake it up or anything, but still — it’s nice to know where the little spacecraft went. And even though Philae is done with its mission, Rosetta has one last task! After 12 years in space, Rosetta is at the end of its life, and it’s traveling farther away from the sun every day, meaning solar power is harder to come by.

But the ESA has given Rosetta one final mission. On September 30th, the orbiter will descend to the surface of the comet and take close-up, high-res images for its scientific send-off. It won’t explode or anything once it hits the surface — the comet’s gravity is too low for that. But communications will officially shut down, and the mission will come to the end.

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