To unlock space you must have repaired Eden and built all 3 eden Airships. You need to research the tech that allows you to "activate eden" (In the Tech Hall - resource tab), once you've done that you will be able to enter the initial sector in space.
To be able to explore the first sector, you will need to set up your Airships for each of the four Factions worth of Gumballs at the same time. You can also add Robots and Clones to improve your total energy. Your energy will be significantly lower than in the Sky until you've done sufficient research. The 5th research tab which makes this possible is unlocked in the first space sector, M01.
The initial release for space brings one sector, more have been promised later in 2018 and following.
Each sector is divided into a 9x9 grid with subsectors, which must be cleared of their Fog of War. You can only clear one every few minutes, but you will find items in space to reduce this cooldown.
You'll find your satellite in sector M01, it's called Agares and can be upgraded using the Eden resources, as seen in the Energy Hall. It can be upgraded with no cooldown, but increasing resource costs.
- In Space Extra DMG dealt by all fleets +X, DMG taken by all fleets -X
Each resource has it's own level, and the total effect of all three is shown in your satellite page. No max level is known yet.