RE: Perseverance Lander minutes away from Mars.
February 18, 2021 at 5:19 pm
(This post was last modified: February 18, 2021 at 5:40 pm by HappySkeptic.)
Spacecraft can make course corrections. Even if the math is perfect, the various engine burns aren't. The last correction would've been two days ago, and an orbital insertion burn was likely done hours before touchdown.
Calculating spacecraft trajectories is fairly easy math for computers to solve. It is a minimization problem. The mechanics are largely Newtonian, and with a minimum of fuel, determine a trajectory. Now, doing it before computers -- that would be tough!
Gravity assist on more complex missions makes these calculations really fun. The spacecraft gains most of the angular momentum of the planet it is slingshots around, plus the spacecraft gains extra speed for burns done within the gravity well (compared to outside the well).
Calculating spacecraft trajectories is fairly easy math for computers to solve. It is a minimization problem. The mechanics are largely Newtonian, and with a minimum of fuel, determine a trajectory. Now, doing it before computers -- that would be tough!
Gravity assist on more complex missions makes these calculations really fun. The spacecraft gains most of the angular momentum of the planet it is slingshots around, plus the spacecraft gains extra speed for burns done within the gravity well (compared to outside the well).
