Two things are the most exciting for near term transformation of space capability
Spiderfab and Spacex reusable rockets.
Here is the Spiderfab update.
Improving and testing reliability and a lot of engineering would be needed to get to 100 kilometer structures.
Making 6U cubesat trusselator to put out 50 meter trusses and make truss of trusses from several
They are using Baxter robot to work with trusselators.
Babak Saif, NASA GSFC - A Gravitational Wave Detector Based on an Atom Interferometer