FAQ for
Space Men (1960) More at IMDbPro »

Watch Assignment: Outer Space, aka Space Men (1960), on:

archive.org on here

And Pub-D-Hub classic film channel, a Roku Channel has it on streaming video

No major distributor has released it, but several small companies have. This film seems to be in the public domain, which means any distributor can legally sell copies without paying royalties. Beware. Some small distributors market copies of public domain films with poor picture and sound. Others are more reputable and deliver good transfers of the best available prints. Shop around.

You can begin your search here at Amazon.com.