So, every day until today, the Space Mountain page on the
Disneyland website has said that it would be closed for refurbishment starting February 25.
Today, the wording changed, and it says "From February 25 to March 15, 2019, Space Mountain will be closed for refurbishment." I don't want to get my hopes up for Space Mountain next week, but I feel a bit more hopeful now. It seems like they wouldn't make the refurbishment more specific if the ride wasn't coming back before February 25th.
Of course, that could just be automated.
https://disneyland.disney.go.com/attractions/disneyland/space-mountain