I used three on a newly colonized planet, in succession from the use artifact page under the planet, yet the planet only advanced one day?
I exited the planet and went back, still only one day advance.

The Time Vortex only does a one days push in time. Having 5 to max out the planet at once is cool (used three once on a planet hehe).

That's the point though... I used 3 and only got 1 days push

If you use the direct contact option, we can credit the other 2 back into your cargo.