Perseverance Lander minutes away from Mars.

[Brian37]

A-fucking-men.

Nail biting to watch. Can't wait to see the first images.

[HappySkeptic]

Wait, did anyone see Capricorn One?

[BrianSoddingBoru4]

3.03 minutes
Therefore, a light shining from the surface of Mars would take the following amount of time to reach Earth (or vice versa): Closest possible approach: 182 seconds, or 3.03 minutes. Closest recorded approach: 187 seconds, or 3.11 minutes. Farthest approach: 1,342 seconds, or 22.4 minutes.Nov 14, 2017

How Long Does It Take to Get to Mars? | Space

https://www.space.com/24701-how-long-doe...%20minutes

WOW! That is f-ing fast. I was just watching the news and they were saying Mars has a 40 minute longer day than earth. I find it amazing that they have to work out all that math to time everything down to the second to land that thing. They were reporting too, that the mission will have it land in an ancient riverbed in an attempt to try to find signs of prior life.

Landing a machine on Mars safely has been compared - not unreasonably - to shooting a bird in flight when you can't see the bird and all you have to go on are reports about where it was the last time someone looked at it.

Boru

[Brian37]

WOW! That is f-ing fast. I was just watching the news and they were saying Mars has a 40 minute longer day than earth. I find it amazing that they have to work out all that math to time everything down to the second to land that thing. They were reporting too, that the mission will have it land in an ancient riverbed in an attempt to try to find signs of prior life.

Landing a machine on Mars safely has been compared - not unreasonably - to shooting a bird in flight when you can't see the bird and all you have to go on are reports about where it was the last time someone looked at it.

Boru

It is amazing that the math, like even GPS on earth keeps track of an object, but his type of thing is far more complex because of timing and distance. 

If you ever heard of "back timing" in radio stations playing LP, it is the math of figuring out when to start the next song before the song playing ends. This is a billion times more planning and timing ahead. Absolutely amazing what goes into figuring these things out.

[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).

[Brian37]

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 is slingshots around, plus the spacecraft gains extra speed for burns done within the gravity well (compared to outside the well).

Computers certainly have replaced human labor with things like this, but it took a buildup of all sorts of sciences that humans figured out to be able to write the code and programs and build the rockets and rovers to make this moment possible.

100 years ago computers were literally a system of on off switches with light bulbs taking up gym sized rooms. It is amazing to me that we have gone from that to a laptop replacing that. 

And, it would not surprise me one bit if we find the building blocks of life on Mars.

[zebo-the-fat]

The lander took pictures of the surface, compared them with it's internal map and adjusted it's course to correctly land in the correct place... all on it's own, no help from Earth because of the time lag. That's clever!

[BrianSoddingBoru4]

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 is slingshots around, plus the spacecraft gains extra speed for burns done within the gravity well (compared to outside the well).

Computers certainly have replaced human labor with things like this, but it took a buildup of all sorts of sciences that humans figured out to be able to write the code and programs and build the rockets and rovers to make this moment possible.

100 years ago computers were literally a system of on off switches with light bulbs taking up gym sized rooms. It is amazing to me that we have gone from that to a laptop replacing that. 

And, it would not surprise me one bit if we find the building blocks of life on Mars.

Actually, the vast majority of computers in the 1920s looked like this:

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Boru

[The Valkyrie]

Another amazing accomplishment.

[AFTT47]

If I'm not mistaken, we are in a record string of consecutive successes landing on Mars.

Mars is a deceptively challenging target to land on. It has an atmosphere which is thick enough to be a problem (requiring a heat shield) but not thick enough to be much of a help slowing down. Prior to the current string of successful landings, the success rate was only about 50%. We (the Americans) seem to have it licked now.