Other mistake: Clay Lacy is listed as Lear Jet Pilot twice in the credits. The first time it's listed with the Property Master/2nd Prop Man/Transportation Coordinator. Then later it's listed with Production Auditor/Bookkeeper/Lead Man.
Factual error: A round-trip voyage between Mars and Earth would take about two years. Although the movie's timeline is compressed, from when the astronauts supposedly leave Earth to them supposedly returning (and dying) and then Caulfield rescuing Brubaker, the entire plot implausibly takes place in only eight months. It is mentioned at the memorial that they "left" Earth eight months earlier. The military memorial is held at least a month after the "tragedy" so that would mean they made the trip in seven months, which is impossible. The film is not set in the future when technology would be more advanced.
Chosen answer: It's never stated in the film, however, as the astronauts have been declared officially dead and therefore cannot ever be allowed to contact anybody, they were most likely executed as soon as they were captured.
Tailkinker ★