How this list is ranked
By likes — the count Bluesky shows on each feed's own page, which is the closest thing the network has to a public popularity signal. It rewards feeds that have been around a while, so a brand-new space feed can be excellent and still sit near the bottom.
A feed lands in this category if Bluesky's own feed search returns it for "space", or if its name says so outright. That means the list is generous rather than strict: some feeds here are only partly about space.
Adding one of these feeds
Open a feed above, follow the link through to bsky.app, and use the pin button on that page. It shows up as a tab on your home screen and you can drag it into whatever order you like. Feeds are free and opt-in — nothing is added to your account until you pin it.