Entry, Descent, and Landing Technologies
A Major Improvement in Landing Accuracy
It's hard to land on Mars, and even harder to land a rover close to its prime scientific target. Previous rovers have landed in the general vicinity of areas targeted for study, but precious weeks and months can be used up just traveling to a prime target. The Mars 2020 mission team is working on a strategy to put the rover on the ground closer to its prime target than was ever before possible. The Range Trigger technology reduces the size of the landing ellipse (an oval-shaped landing area target) by more than 50%. The smaller ellipse size allows the mission team to land at some sites where a larger ellipse would be too risky given they would include more hazards on the surface. That gives scientists access to more high priority sites with environments that could have supported past microbial life.
Range Trigger - It's All About Timing
The key to the new precision landing technique is choosing the right moment to pull the "trigger" that releases the spacecraft's parachute. "Range Trigger" is the name of the technique that Mars 2020 uses to time the parachute's deployment. Earlier missions deployed their parachutes as early as possible after the spacecraft reached a desired velocity. Instead of deploying as early as possible, Mars 2020's Range Trigger deploys the parachute based on the spacecraft's position relative to the desired landing target. That means the parachute could be deployed early or later depending on how close it is to its desired target. If the spacecraft were going to overshoot the landing target, the parachute would be deployed earlier. If it were going to fall short of the target, the parachute would be deployed later, after the spacecraft flew a little closer to its target.
Shaving Time Off the Commute
The Range Trigger strategy could deliver the Mars 2020 Perseverance rover a few miles closer to the exact spot in the landing area that scientists most want to study. It could shave off as much as a year from the rover's commute to its prime work site.Another potential advantage of testing the Range Trigger is that it would reduce the risk of any future Mars Sample Return mission, because it would help that mission land closer to samples cached on the surface.
Improving Models of the Martian Atmosphere for Robotic and Future Human Missions to Mars.
MEDLI2 is a next-generation sensor suite for entry, descent, and landing (EDL). MEDLI2 collects temperature and pressure measurements on the heat shield and afterbody during EDL.
MEDLI2 is based on an instrument flown on NASA's Mars Science Laboratory (MSL) mission. MEDLI stands for "MSL Entry, Descent, and Landing Instrumentation." The original only collected data from the heat shield. MEDLI2 can collect data from the heat shield and from the afterbody as well.This data helps engineers validate their models for designing future entry, descent, and landing systems. Entry, descent, and landing is one of the most challenging times in any landed Mars mission. Atmospheric data from MEDLI2 and MEDA, the rover's surface weather station, can help scientists and engineers understand atmospheric density and winds. The studies are critical for reducing risks to both robotic and future human missions to Mars.
Entry, Descent, and Landing (EDL) Cameras and Microphone
Unprecedented Visibility into Mars Landings
Mars 2020 has a suite of cameras that can help engineers understand what is happening during one of the riskiest parts of the mission: entry, descent, and landing. The Perseverance rover is based heavily on Curiosity's successful mission design, but Mars 2020 adds multiple descent cameras to the spacecraft design.
The camera suite includes: parachute "up look" cameras, a descent-stage "down look" camera, a rover "up look" camera, and a rover "down look" camera. The Mars 2020 EDL system also includes a microphone to capture sounds during EDL, such as the firing of descent engines.