It's a short story about two astronauts who land on a planet. They think they see green hills, flowers, breathable air. Despite the warnings coming from their base, one of them removes his helmet. At the base they see his head explode, but the second astronaut sees his companion running free and happy, inviting him to take off his helmet too and join him. Torn between his companion's entreaties and his superiors' warnings, the second astronaut finally gives in to the delusion and takes off his helmet.
What short story is it? Who is the author?