I came across this UA article from 2013, regarding their professor Andrei Lebed. http://uanews.arizona.edu/story/testing-einstein-s-e-mc2-in-outer-space The article is written for laymen, and I'm no expert myself, but it seems to suggest that there won't be any atomic absorption for hydrogen in flat spacetime, i.e. the microgravity of outer space. and I agree with the writer's opinion, the idea does sound really novel. What do you guys think of this?