[Hank Green] It's official: American astronauts don't have to carpool anymore. Since the space shuttle program was mothballed in 2011, astronauts from the US have been hitching rides on Russian rockets. But on August 27th, NASA formally approved the design for its own rocket for human missions, and it's gonna be the biggest, most powerful ever built.

The Space Launch System, or SLS, is designed to carry the Orion spacecraft, and it could be ready to go as early as 2017. Or, at least, a version of it could be. It's a bit of a transformer. Its basic configuration is called Block I. It'll use four engines running on liquid hydrogen fuel, and two boosters that use a solid mixture of aluminum perchlorate. Just like the space shuttle, only about three times stronger. It'll be able to lift 70,000 kilograms, about 50,000 kilograms short of the old Saturn V's capacity. But that is just the basic configuration.

The plan is to use Block I on a test mission in three or four years to send an un-crewed Orion vessel on a trip around the moon and back. If all goes well, both on that mission and in NASA's budget, then Block I will send an Orion out again in 2021, this time to take four crew members to an asteroid that will have been sent into a lunar orbit. Then, in another decade or so, Block II will allow NASA to carry more and go even farther, including to Mars.

NASA hasn't specified the details of this phase, but it'll replace the shuttle-delivered engines of Block I with four engines of another design, and the SLS will reach its final height of 122 meters. With these modifications Block II will be able to boost a payload of 155,000 kilograms into near-earth orbit, or 130,000 kilograms into deep space, making it the most powerful rocket ever designed. It's slated to take up its first test flight in 2032, and hopefully NASA will have a cooler name for it by then.

  Another thing that we need to get better at is understanding sex in space. Seriously.

The fact is, we don't know what microgravity does to sperm and eggs and developing embryos, but if humans are going to be spending longer periods of time in space, maybe even colonizing distant worlds, we're gonna have to learn.

So to that end, Roscosmos, Russia's federal space agency, has been putting a lot of research into reproduction in space. On July 18th, they loaded a photon M4 satellite with a bunch of fruit flies and five geckos, four females and one male, housed in habitats with infrared cameras so scientists could watch how they mated. Then, upon returning to earth two months later, researchers were going to test any resulting eggs for abnormalities that might have resulted from microgravity, but unfortunately about a week after launch, Russia lost contact with the satellite, leading John Oliver to send out a memorable plea for help on the geckos's behalf.

On August 25th, the satellite returned to earth only to confirm John Oliver's worst fears; all five geckos were dead; the cause is still under investigation. The fruit flies returned home safely, however, and it appears that they bred successfully. So there's that.

But they and their fallen gecko comrades are not the first animals to have been sent into space for sex. In 2007, a Russian cockroach named Hope became the first animal to successfully give birth in space, with thirty-three precious babies. A handful of experiments aboard the ISS have looked at frog reproduction, and who knows what those tardigrades were up to when they were in orbit when their mission failed in 2012. But as far as terrestrial animals, there's still very little data. So rest in peace, gecko cosmonauts, I'm sure you gave it your all.

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