Workshop support is now available in a 'beta' build of Race The Sun.
For players who'd like to join in, here's how:
1. Opt into the beta, in the game properties (see 'betas' tab)
2. Join the following beta group for access to workshop:
http://steamcommunity.com/groups/rts_workshop
Please use the community forums here for feedback:
http://steamcommunity.com/app/253030/discussions