Mariner 4: Mars seen directly
Mariner 4: Mars seen directly
Mariner 4 was a deep-space flyby mission sent to obtain the first photographs of another planet from deep space and collect scientific measurements. During its close approach on 15 July 1965, it replaced romantic speculation about Mars with evidence: the planet appeared ancient, cold, heavily cratered, and hostile rather than a plausible home for imagined civilizations.[1][2][3]
Its television camera returned 21 complete images and 22 lines of a twenty-second image, taken through red and green filters. Those photographs revealed widespread cratering and a Moon-like, ancient surface, turning Mars from a canvas for conjecture into a physical world that could be observed and assessed.[4][5]
Measurements that changed the landing problem
Mariner 4 also used radio occultation. In plain language, this meant that Earth observed the spacecraft's radio signal as Mariner 4 passed behind Mars, so the signal traveled through the planet's atmosphere; changes in the signal revealed atmospheric conditions. The measurements showed that Mars had a very thin atmosphere and very low surface pressure.[6]
- The atmosphere was too thin for parachutes alone to provide a dependable descent, so future landers would require retro-rockets as well as parachutes.[7]
- Daytime surface temperatures were about -100 degrees Celsius, reinforcing the picture of an extremely cold environment.[8]
- Together, the photographs and measurements presented Mars as an ancient, cratered, cold, and hostile world, sharply displacing earlier romantic expectations with direct evidence.[9][10]
Créez votre compte pour conserver cette réponse et la reprendre plus tard.
Examinons les alternatives :
- Modifier la requête.
- Démarrer une nouvelle conversation.
- Supprimer des sources (si elles ont été ajoutées manuellement).