Deep Six is a space station outside of the jump gate base 8 systems. The Jam-1 star system is only accessible with a Hyperdrive attached to a ship.
A class 1 ship (Turtle or Hornet) with a class 1 Hyperdrive is usually the first ship one would use to initially visit the Jam-1 system. Such a ship will have 8 tons of cargo space and use 4 tons of hydrogen to get from Vulcan space to Jam-1 space, leaving 4 tons for cargo. The Gas Giant at Jam-1 has ample hydrogen to skim for your return flight. Alternatively, if you are away from the jump gate systems without hydrogen to get back, you can use the 'Emergency Jump' button in the map (press M) to return you to Ceres.
Your first visit to Jam-1 is part of the Susan Steele storyline missions. You will be searching for a trail of space wreckage from the coordinates provided by Susan. Deep Six is not known to your computer the first time you visit Jam-1 and will not show up on your autopilot until all the wreckage is salvaged for the mission.
You will not be able to dock at Deep Six, but you will have access to a Contracts Board (similar to Janus A). To advance the storyline, select "Take a note back to Ceres for Jessica Steele" from the Contracts Board.
The contracts offered at this Contracts Board have higher rewards than those offered in the base 8 systems due to its remoteness. A larger ship with equivalent larger Hyperdrive would be very lucrative.