Most Hollywood films use computer-generated imagery
, also known as "cgi" to create special effects such as explosions, large crowd scenes, natural disasters, monsters and more. Prior to the development of sophisticated computer technology and the growth of this art form, movie effects were done with models, prosthetics or editing in post production. The ability of computer generated imagery to imitate realistic phenomena is impressive and although it can be very expensive to create a large amount of such material (because it requires many skilled artists and technicians), most larger budget studio movies in Hollywood use these effects now because they have become fairly standard for the industry.
The special effects in Martian are no exception; the film uses a vast amount of special effects technology to portray the space capsule's flight, crash and movement, as well as the landscape of the planet. Creating realistic effects requires studying the actual events carefully, so artists and designers would have looked at a great deal of footage of space travel and space program missions.