3 ms·

> So they completely beta tested this landing system on earth right? That is not possible. Some things like gravity and atmospheric pressure/density cannot be

by Achshar 14y ago

> So they completely beta tested this landing system on earth right? That is not possible. Some things like gravity and atmospheric pressure/density cannot be replicated in the scale required to test here on earth. They have to rely on testing in parts and in some cases on calculations and data from previous visits and landings.

ck2 14y ago
Mars has LESS pressure. So the landing would be easier here, so it should have been tested? I find it impossible to believe it wasn't tested all together as a unit and just connecting individually tested parts. Kind of strange they would not share such a video, which if made by a government entity is public domain anyway.
- maaku 14y ago
  No. Mars having less atmosphere is exactly the point. Such an entry system hitting Earth's atmosphere would be like slamming into a brick wall--it wouldn't survive. And the greater density air on Earth would make the sky crane segment completely unstable. Not to mention that Earth's gravity is simply too large--components of the system would be crushed under their own weight. Believe it, because it's true.
  - AngryParsley 14y ago
    I don't know about most of your points, but the components being crushed under their own weight doesn't seem right. The probe was built in Earth gravity and had to undergo 4-5G of acceleration during launch. Also, it's going to experience 13G of deceleration when entering the Martian atmosphere.
- Achshar 14y ago
  > Mars has LESS pressure. So the landing would be easier here, so it should have been tested? No, having less atmosphere is a disadvantage in this case. This means just parachute wont work. Hence the whole sky crane thing. There is no feasible way to test the whole EDL (entry, descend, landing) phase here on this planet because simulating entry into mars's thin atmosphere is not possible out of computer simulations and whiteboards.
- fhars 14y ago
  No need to test on earth as it would certainly fail. The crane probably couldn't even lift its own weight on earth with its almost three times higher gravity.

by Achshar 14y ago

ck2 14y ago

Mars has LESS pressure. So the landing would be easier here, so it should have been tested? I find it impossible to believe it wasn't tested all together as a unit and just connecting individually tested parts. Kind of strange they would not share such a video, which if made by a government entity is public domain anyway.

maaku 14y ago
No. Mars having less atmosphere is exactly the point. Such an entry system hitting Earth's atmosphere would be like slamming into a brick wall--it wouldn't survive. And the greater density air on Earth would make the sky crane segment completely unstable. Not to mention that Earth's gravity is simply too large--components of the system would be crushed under their own weight. Believe it, because it's true.
- AngryParsley 14y ago
  I don't know about most of your points, but the components being crushed under their own weight doesn't seem right. The probe was built in Earth gravity and had to undergo 4-5G of acceleration during launch. Also, it's going to experience 13G of deceleration when entering the Martian atmosphere.
Achshar 14y ago
> Mars has LESS pressure. So the landing would be easier here, so it should have been tested? No, having less atmosphere is a disadvantage in this case. This means just parachute wont work. Hence the whole sky crane thing. There is no feasible way to test the whole EDL (entry, descend, landing) phase here on this planet because simulating entry into mars's thin atmosphere is not possible out of computer simulations and whiteboards.
fhars 14y ago
No need to test on earth as it would certainly fail. The crane probably couldn't even lift its own weight on earth with its almost three times higher gravity.