An EDL System. An ice cream cone shaped aeroshell. The thin atmosphere of Mars.
(Erik Bailey)
The main purpose of EDL [Entry, Descent and Landing] is to take a spacecraft that is traveling at 12,500 miles an hour and bring it to a screeching halt in a soft way, in a very short amount of time.(music)
(Ben Cichy)
When we enter the martian atmosphere, we’re 70 miles above the surface of Mars – and our lander is safely tucked inside what we call an “aeroshell.”(Erik Bailey)
It looks kind of like an ice cream cone, more or less.(Ben Cichy)
And on the front of it is this heat shield — this saucer-looking thing that has about a half inch of what’s essentially cork on the front of it, which is our heat shield. Now this is really special cork, and this cork is what’s going to protect us from the violent atmospheric entry that we’re about to experience.(Rob Grover)
Friction really starts to build up on the spacecraft, and we use the friction when it’s flying through the atmosphere to our advantage, to slow us down.
NASA’s Phoenix Mars Lander was configured with an EDL system designed for its entry, descent and landing upon Mars. The configuration of the EDL system was similar to that of the Mars 2001 Lander, which served as an archetype for the Phoenix. Phoenix’s EDL was enhanced and modified to fit the objectives of its mission, and ultimately land the Phoenix on the north pole of Mars, a first feat for interplanetary exploration.
As described in the Vodcast, the EDL system was designed to decelerate the Phoenix, traveling at 12,500 miles per hour. The EDL had to curb the mission in order for Phoenix to enter the thin atmosphere of Mars. At 13,000 miles per hour, Phoenix entered the Martian atmosphere and used friction to further reduce its speed. With Phoenix descending towards the Martian surface at a relatively high rate, an aeroshell and heat shield were employed in order to harness and protect the mission from becoming inflamed. Protected by the aeroshell and heat shield, the mission plummeted towards the Martian surface.
(Erik Bailey)
The outside can get almost as hot as the surface of the Sun.(Rob Grover)
The temperature of the heat shield will reach 2600 degrees Fahrenheit.(music)
(Erik Bailey)
But the inside doesn’t get very hot: it probably gets about room temperature.
To further decrease Phoenix’s speed, its parachute was deployed. However, the parachute deployed seven seconds later than anticipated. When the parachute deployed, the lander’s speed reduced, causing the heat shield to detach. When the shield detached, the landing radar activated and the gear extended. With its legs extended, Phoenix continued to plunge through Mars’s atmospheric layers until it came within approximately .6 miles of the surface…
The success of the Phoenix’s entry and descent upon Martian soil is greatly due to the configuration of the EDL system.
(Ben Cichy)
EDL is this immense, technically challenging problem. It’s about getting a spacecraft that’s hurtling through deep space, and using all this bag of tricks to somehow figure out how to get it down to the surface of Mars at zero miles an hour. It’s this immensely exciting and challenging problem.
References
Robinson Family Aerospace Mission 