There was a lot of traffic to and from space last week, with a splashdown and a launch happening within a day of each other.    First, there was the return of the DRAGON capsule, which you might remember was carried into space by the rocket that SpaceX tried -- and failed -- to land on a floating ocean platform back in January.   DRAGON came home after about a month at the International Space Station, splashing down in the Pacific Ocean with 1600 kilograms of cargo.    Some of it was just trash and old equipment, but the capsule also delivered the results of several experiments that astronauts have been working on in the ISS.   Among their results? A plastic ratchet wrench, and a few preserved fish.   Now, a plastic wrench may not sound like all that big a deal, but this is a very special wrench.    It’s the first object to be designed on Earth, and then have its specifications sent to the ISS to be 3-D printed.    The wrench returned with 19 other tools that were printed in space, but it was the only object that wasn’t pre-programmed into the printer before it was sent to the station.   Since all 20 tools were built in microgravity, they’re going to be put through a battery of tests to see if they hold up as well as parts that are 3-D printed on Earth.    NASA’s goal here is to eventually be able to send astronauts designs for parts that they can print on the fly, which would be especially important on long missions to, say, Mars.    Then there’s the fish.    These are zebrafish, which are kind of freaky-looking, but they're actually a fantastic choice for studying the muscle degeneration that astronauts often experience in orbit.   For starters, you can see through their skin. It’s one thing to study muscle tissue under a microscope, but it’s quite another to actually see it in action.    Also, the zebrafish genome has been completely sequenced, so researchers can figure out what changes that they observe in the fish might be related to their genetics.    A few zebrafish were already returned to Earth alive, but these fish stayed on and have since died, so they were chemically preserved for the trip back.   The hope is that by studying how muscles degenerated in the fish, researchers will be better able to stop the same thing from happening in astronauts while they're in orbit.     Now, while the DRAGON capsule was coming back from space, the a new deep-space observatory -- a mission over fifteen years in the making -- was just heading out.    DSCOVR is going to occupy a fixed point between Earth and the Sun, where it can monitor space weather, especially the solar wind.   Sudden bursts of solar wind can cause magnetic storms that have the potential to knock out things like GPS communications and cell phone service.   But, by measuring the flow of charged particles from the sun and changes in the wind’s magnetic field, DSCOVR will be able to warn us of these storms up to an hour in advance, so we can better prepare for them.   And the observatory’s got another purpose, too: It’s carrying an instrument called NISTAR, which will detect how much energy Earth reflects back into space.   This means that, for the first time, we’ll know how much of the sun’s radiation is getting trapped by the atmosphere -- which will be crucial for understanding climate change.   While a lot of global warming research is focused on measuring its effects -- like, the fact that 2014 was the warmest year on record -- DSCOVR will be able to tell us how much solar energy is actually sticking around and heating up the planet.   Finally, while you’re looking up at the sky this week, if you're in the Northern hemisphere, be sure to take a look at the Moon at dusk on Saturday, February 21st.    Or more accurately, slightly below it and to the right. The Moon will be a very thin crescent, so if you’re having trouble finding it, look west-southwest.   You should be able to see what looks like a bright point of light, and if you look more closely, you might see another one next to it.    Neither of these will be twinkling, because they aren’t stars: They’re planets.    What you’ll be seeing is Mars and Venus in conjunction, meaning that their orbits will line up so that they’ll appear at their closest, from our perspective on Earth.    The planets will actually be so close together that it might be hard to tell them apart with the naked eye, because Venus will look about a hundred times brighter than Mars.    But if you have a pair of binoculars handy and it’s a clear night, you’ll be able to see both.   The two planets haven’t been this close together since 2008 and won’t be again until 2017.    So, enjoy the view.   Thanks for joining me for Sci Show Space News.  Don’t forget to go to youtube.com/scishowspace and subscribe!