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The world of space science has treated us to some cool revelations in the past couple of weeks, and to fans of all things extraterrestrial like us, they're both pretty exciting.  One has to do with how people will get to space in the future, and the other is teaching us more about how our solar system was like in the distant past.  

So first, there's a new spaceship out there!  Unveiled in a ceremony on February 19th, it's called the VSS Unity, the name chosen by Stephen Hawking, and it's the latest version of Virgin Galactic's space tourism vehicle SpaceShipTwo.  The previous version of SpaceShipTwo known as the VSS Enterprise was lost in the October 2014 crash that killed one of its test pilots, Michael Alsbury.  

So Unity is designed to incorporate the lessons the company learned from that accident and hopefully make sure that nothing like that ever happens again.  Mainly, that involved adding a particular fail-safe.  The SpaceShipTwo system gets to space with the help of WhiteKnightTwo, a plane that is basically its mothership.  The plane carries the spaceship to a certain height and releases it.  Then, the ship uses rocket power to get above 100 kilometers, the point where passengers are officially in space.  The flights are designed so that space tourists get to experience a few minutes of weightlessness, then head back to Earth, which involves a tricky glide back down through the atmosphere.  

To help the ship slow down on its way home, SpaceShipTwo has what's known as a feathering system--when the ship re-enters the atmosphere, the wings and tail tilt upward to help it slow down, and that's what went wrong with the Enterprise back in 2014.  The feathering system is only supposed to be activated after the engines had stopped firing, when the ship is already going a little more slowly, but on the day of the crash, one of the pilots unlocked the feathering system too early and the Enterprise broke apart.  So one of the main changes to the new ship is that even if a pilot tries to unlock the feathering system at the wrong time, the computer system will make sure that they won't be able to.  

The Unity isn't quite ready to fly yet, though.  The ship still needs to go through all kinds of ground testing to make sure the components work together properly, then the next major step will be the glide tests, where the ship is released by WhiteKnightTwo and glides to a landing without firing its rockets.  If all goes well with the ground and glide test, the Unity will be ready for the final stage of testing, where it'll use rocket power to test flights that go higher and higher and eventually reach space.  After that, it might start ferrying some of the 700 people who have already signed up for the $250,000 flight, but there's no word yet on how long testing is expected to take, and it sounds like the Virgin Galactic team isn't in any kind of rush, which makes sense.  This is spaceflight, where we reach great distances by taking many, many small steps.

The other reveal of the week came on February 18, which also happens to be the 86th anniversary of Pluto's discovery by American astronomer, Clyde Tombaugh.  To celebrate, NASA released photos of Pluto's largest move, Charon.  The agency also announced that it's looking more and more like Charon had a subsurface ocean of liquid water.  Yes!  Even on the remotest fringes of the solar system!  These days, Charon is very, very cold, like, more than 200 degrees below zero, so there's almost definitely no liquid water sloshing around in there now, but there probably used to be sources of heat inside Charon.  For example, radioactive elements that would have generated heat as they decayed.  If it once had a liquid ocean that eventually froze, that would explain a lot about the moon, mainly its cracks.  The area highlighted in this picture, known as Serenity Chasma, is a series of chasms up to 7 kilometers deep.  Compare that to the Grand Canyon, which is about 1.5 kilometers deep.  Plus, Charon's a lot smaller than Earth, only about 1200 kilometers wide, so it's an incredibly deep gouge compared to the moon's size.  Mission scientists think that the chasms probably formed as the liquid ocean froze and expanded, cracking the surface, which means that there's yet another world in our solar system that might have once had an ocean of liquid water. 

Thanks for watching this episode of SciShow Space News, and thanks especially to our Patrons on Patreon, who help make this show possible.  If you want to help us keep making episodes like this, you can go to Patreon.com/SciShow, or you can join us on the SciShow channel Wednesday, March 2nd for our 12 hour livestream, and don't forget to go to YouTube.com/SciShowSpace and subscribe.

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