Mars atmospheric entry

[5] Viking Program era researchers were the true pioneers of this technology, and development had to be restarted after decades of neglect.

More specifically, NASA is carrying out thermal imaging infrared sensor data-gathering studies of the SpaceX booster controlled-descent tests that are currently, as of 2014[update], underway.

[8] The research team is particularly interested in the 70–40-kilometer (43–25 mi) altitude range of the SpaceX "reentry burn" on the Falcon 9 Earth-entry tests as this is the "powered flight through the Mars-relevant retropulsion regime" that models Mars entry and descent conditions,[9] although SpaceX is of course interested also in the final engine burn and lower velocity retropropulsive landing as well since that is a critical technology for their reusable booster development program which they hope to use for Mars landings in the 2020s.

Curiosity's EDL team releases a timeline for mission milestones (depicted in this artist's concept) surrounding the landing of the Mars rover.

Concept art of a Mars lander as it approaches the surface, illustrating how identifying a safe landing spot is a concern.

HiRISE image from Mars Reconnaissance Orbiter of NASA Perseverance rover/ Ingenuity helicopter ( Mars 2020 Mission ) descending via parachute on February 18, 2021.
Video of descent and touchdown of Perseverance
NASA thermal imagery of the SpaceX controlled-descent test of a Falcon 9 first stage from stage separation onward, on 21 September 2014 . Includes footage of "powered flight through the Mars-relevant retropropulsion regime", beginning at 1:20 in the video.
The inset frames show how the lander's descent imaging system is identifying hazards (NASA, 1990)