Material science and manufacturing are two that have always seemed interesting to me, particularly monocrystalline stuff like semiconductors, optics, and metallurgy.

There's a lot of fundamental science to be done in space; some forms of crystal are much easier to grow, chemical reactions and biological interactions etc. etc. For reference, it wasn't long ago NASA was trying to figure out if spiders could form webs in space.

This is an old idea, dating back to at least the 1940s. Many experiments have already been done in microgravity environments.

In the 1960s, they used sounding rockets to do experiments on how molten metals solidify in microgravity, with manufacturing applications in mind.

In the 1970s, they ran experiments, also on sounding rockets, on melting and solidifying materials without letting them touch a container: https://ntrs.nasa.gov/citations/19840059952

More recently, many microgravity experiments have been performed on the International Space Station. Experiments were done on protein crystal growth aboard the ISS in 2000, just a couple of years after it was launched. (I think it took some time to get the experimental facilities up and running.)

Another experiment on the

Here’s an assortment of links on the subject, starting with a good overview:

https://www.nasa.gov/missions/station/applications-within-re...

https://issnationallab.org/research-and-science/space-resear...

https://www.nasa.gov/missions/station/the-benefits-of-microg...

https://ntrs.nasa.gov/citations/20200001550

https://ntrs.nasa.gov/citations/20150023126

https://asmedigitalcollection.asme.org/manufacturingscience/...

ZBLAN manufacturing

https://www.nasa.gov/missions/station/iss-research/optical-f... https://thedailypost.digital/how-microgravity-made-zblan-cou...