I would like to understand how safe landing of a rover is achieved on mars or any other planet where the pressure is very low. Is it achieved by releasing gas from high pressure to low pressure. I assume the equal and opposite reaction of the escaping gas will be swinging in different directions. Then how do scientists manage to channelize the equal and opposite reaction in one single direction to achieve safe landing?
$\begingroup$
$\endgroup$
5
-
1$\begingroup$ I really don't understand what you are asking here. What does the title of your question have to do with landing a rover on Mars? Please edit for clarity. $\endgroup$– Organic MarbleCommented Sep 20, 2020 at 15:09
-
1$\begingroup$ Sure. I have edit my query now. Hope it coveys the question clearly now. $\endgroup$– MahenCommented Sep 20, 2020 at 15:21
-
1$\begingroup$ This seems to be an oddly obfuscated and roundabout way of asking how rocket engines control the direction of thrust. $\endgroup$– Christopher James HuffCommented Sep 20, 2020 at 18:59
-
$\begingroup$ Also see When things land on Mars what fraction of their velocity do they remove propulsively? and also What is the preferred orbital trajectory for a rover/lander to land on a body? and especially Why do you need a heat shield on Mars entry if the atmosphere is so thin? and this answer $\endgroup$– uhohCommented Sep 21, 2020 at 0:40
-
$\begingroup$ Another opportunity to re-view apod.nasa.gov/apod/ap120731.html "7 Minutes of Terror" ! $\endgroup$– DJohnMCommented Sep 21, 2020 at 16:33
Add a comment
|
1 Answer
$\begingroup$
$\endgroup$
5
To land any lander on the Moon one must fully use some kind of a rocket engine. These engines are characterized on Earth and the thrust is understood, and a careful trajectory is determined.
To land on Mars is quite a bit trickier, but uses less energy. Basically there is a 3 stage landing system for every US lander. The first is to use a heat shield to slow down using the atmosphere of Mars. The second is to use parachutes to get the velocity even lower. The final stage must be accomplished via rockets, similar to landing on the Moon, or airbags to further slow the speed down. These rocket engines are characterized in a similar way. We understand the atmosphere of Mars and have tested the rockets in similar conditions.
The gases do not escape randomly, but are very much in a specific direction. The flow is basically the same of any rocket launching, the tower of flame below them is mostly in a single direction. The atmosphere can affect how the flow happens after, but that flow won't directly affect the rocket.
answered Sep 20, 2020 at 16:36
-
$\begingroup$ Okk. So the same must be the way the Rocket booster landing of SpaceX works. $\endgroup$– MahenCommented Sep 20, 2020 at 16:49
-
$\begingroup$ SpaceX's landings don't use parachutes, except for the Dragon capsules. There are videos out there, look for "7 minutes of terror Mars" and you'll find them. $\endgroup$– PearsonArtPhoto ♦Commented Sep 20, 2020 at 19:15
-
2$\begingroup$ Note that the airbag landings also used a rocket braking stage. The rocket motors were attached to the payload by a tether, in a more primitive "skycrane" arrangement, and slowed the airbagged payload to a near-halt before it was released. The airbags just made it so high-precision rocket control wasn't needed. $\endgroup$ Commented Sep 20, 2020 at 20:42
-
$\begingroup$ Not to mention using thrusters near the ground, which has its own set of issues. $\endgroup$– PearsonArtPhoto ♦Commented Sep 20, 2020 at 21:42
-
$\begingroup$ I had a conflicting thought about Diffusion and what Pearson said "The gases do not escape randomly, but are very much in a specific direction". $\endgroup$– MahenCommented Sep 21, 2020 at 5:12