Very quick and easy way to collect Unknown Fragments required to unlock Professor Palin. Travel to System: HIP 17403 Moon: A 4 A Coords: -34.98, -141.41. This is one of the Alien crash sites discovered ages ago. Ignore the "Crashed Vessel" POI that appears in the Navigation panel as you approach this moon, it's buggy and points to a blank location miles from the site. Go to the exact coordinates I've given above instead. The site is against the side of the small impact mountain at the centre of the large crater that the coordinates take you to.
At this site there are three Unknown fragments lying on the ground and two Unknown Artefacts too. Shoot the artefacts and they'll disintegrate into an additional Unknown Fragment yielding 5 UFs in total. Collect the UFs in your SRV, they each count as 3 items in your materials inventory, so that's 15 UFs. Now just mode swap from Open to Solo or vice-versa to cause all items to re-spawn. You can very easily collect 30 unknown fragments in less than 10 minutes on the surface and it's guaranteed, no RNG crap!

The only thing that can go wrong is if you visit the site in Open shortly after someone else has harvested all the items. In this case simply switch into Solo straight away.