Huygens Descent Control Sub-System (DCSS)

The Huygens spacecraft, which travelled to Titan on the Cassini spacecraft, consisted of a Descent Module inside a front shield and a back cover. The shield and cover protected the spacecraft from the harsh temperature and radiaion extremes of space during its seven year journey to Saturn. The spacecraft also experienced intense heat buildup from Titan's atmosphere as it slowed during entry.

As the spacecraft reached the top of Titan's atmosphere, it decelerated to 1,400 km/hr, 160km above the surface of Titan. A mortar from the back of the spacecraft fired, deploying a 2.6m diameter pilot parachute. The back cover then released along with the pilot chute which pulled it away from the descent module. Next an 8.3m diameter main parachute deployed. Once the spacecraft decelerated further, the front shield (which primarily protected from the heat of entry) released and fell away.

Using the main parachute, it would take Huygens six hours to reach the surface, which would have completely drained its batteries. So three pyrotechnics jettisoned the main parachute from the spacecraft after 15 minutes and deployed a smaller, 3m diameter stabilising drogue parachute, which allowed for a shorter descent time (two hours). Stability of Huygens was essential during this descent stage both to maintain the radio link and to allow the camera to take clear pictures of Titan's clouds and surface. Winds on Titan can reach up to 250km/hr so this was not an easy task.

The Huygens spacecraft, which travelled to Titan on the Cassini spacecraft, consisted of a Descent Module inside a front shield and a back cover. The shield and cover protected the spacecraft from the harsh temperature and radiaion extremes of space during its seven year journey to Saturn. The spacecraft also experienced intense heat buildup from Titan's atmosphere as it slowed during entry.

As the spacecraft reached the top of Titan's atmosphere, it decelerated to 1,400 km/hr, 160km above the surface of Titan. A mortar from the back of the spacecraft fired, deploying a 2.6m diameter pilot parachute. The back cover then released along with the pilot chute which pulled it away from the descent module. Next an 8.3m diameter main parachute deployed. Once the spacecraft decelerated further, the front shield (which primarily protected from the heat of entry) released and fell away.

Using the main parachute, it would take Huygens six hours to reach the surface, which would have completely drained its batteries. So three pyrotechnics jettisoned the main parachute from the spacecraft after 15 minutes and deployed a smaller, 3m diameter stabilising drogue parachute, which allowed for a shorter descent time (two hours). Stability of Huygens was essential during this descent stage both to maintain the radio link and to allow the camera to take clear pictures of Titan's clouds and surface. Winds on Titan can reach up to 250km/hr so this was not an easy task.