How nasa landed rovers on mars in brief?

Question

i want to know how nasa landed their rovers on mars and the technology involved in brief concept

Answer 1

Working backwards.

The rovers land in a tetrahedral container whose lids open in such a way that it will flip rightside up no matter how it ends up.  This lets the rover roll off the track and begin its mission.  You only need strong enough panels and strong enough motors to push it upright.

The landing container is dropped from a short height and lands on the balloon-shaped landing bags filled with gas that absorb the shock of touchdown.  The lander bounces along the surface to a stop.  The technology here is the fabric that can withstand abrasion without popping like a balloon.

The lander is carried to that low altitude by a parachute whose shrouds disconnect at a predetermine height; the chute and its equipment are carried away by a solid-rocket motor assembly that also abruptly slows its descent.  This is a technique used by Russian drops of equipment via parachute on Earth.  Just before the payload hits the ground, the rockets high up on the parachute shrouds fire, slowing the payload rapidly so its landing isn't so hard.

So while the large parachute manages most of the descent, previously a drogue parachute (a small, high-speed parachute) provided the initial slowing and proper orientation of the spacecraft.  It is deployed after the spacecraft has undergone most of the aerodynamic heating of entry, hiding behind an aeroshell -- not too different from sky-surfing.  The drogue is a very familiar concept, and it is "reefed" (i.e., the size of its opening adjusted) by reefing shrouds attached to ordinary servos.  Aeroshells are a matter of careful thermal and mechanical design accompanied by advanced materials that are light, strong, and retain those properties while hot.

And it all begins with a separation from an orbiter and a de-orbit engine burn, much as the space shuttle or the Russian Soyuz capsules do.

Answer 2

Pathfinder lander landed with the aid of parachutes that deployed to slow its descent and then airbags which surrounded the rover to absorb the impact of hitting the ground. Spirit and Opportunity used the same technology, only with reinforced/doubled airbags.

The most recent rover (Phoenix) also used a parachute to slow its descent rate, but instead of airbags it used thrusters/rocket motors for its final descent and it landed on legs (much like the lunar modules did back in the day). Phoenix was just too big/heavy for the airbags to work.

Here is additional info about the Spirit and Opportunity landing technology:

http://marsrovers.nasa.gov/technology/is...

Here is Phoenix's site - if you poke around, you will probably find more info there:

http://www.jpl.nasa.gov/news/phoenix/mai...