NASA is currently in the middle of building its next big rocket, the Space Launch System, which the agency hopes to use to send people into deep space and on to Mars someday. But before it can do all that, the SLS has to prove itself in the form of a test flight. That mission — scheduled for 2018 — will take NASA's uncrewed Orion spacecraft around the far side of the Moon. Toting the Orion may be the primary goal of the trip, but the SLS will have some extra room for other technologies — so it's going to take up to 13 small satellites along for the ride.

NASA announced today what seven of those miniaturized satellites — called CubeSats — will look like. CubeSats are a type of research satellite, usually not much heavier than a couple pounds, that are fairly easy to build for space-based science and exploration. Since the test flight will take the Orion close to the Moon, many of the probes are designed to do close-up analysis of the lunar surface. A CubeSat called SkyFire will do a flyby of the Moon, collecting data with onboard sensors. And a satellite called the Lunar Flashlight will use a laser to map water ice at the lunar south pole.

An artist rendering of the Lunar Flashlight. (NASA)

A couple of the CubeSats will be tasked with learning more about the deep space environment. A Near-Earth Asteroid Scout will visit and study an asteroid that's in Earth's neighborhood. And a satellite called the BioSentinel will carry yeast cells into space, to give researchers a better understanding of how deep space radiation affects living organisms. This knowledge will be particularly helpful if NASA wants to send humans to the Red Planet; astronauts will have to pass through a lot of radiation-filled space to get there, and NASA needs to know how that exposure will affect the human body.

The SLS still has room for more payloads on its test flight. Three of the remaining satellites will come from international space partners, and an additional three will be decided through NASA's Cube Quest Challenge — a competition that challenges participants to design and create their own space-worthy CubeSats.

With the announcement of these satellites, the first planned flight of the SLS is starting to take shape — though it's still two years away. But beyond that flight, the SLS's future is blurry. The first crewed flight of the rocket is scheduled for no later than 2023, though NASA says it is working toward a launch date of 2021. NASA was also recently given more money to accelerate production of a second version of the rocket, which may complicate the SLS's upcoming mission timeline.