This is hardware for controlling the final lowering of NASA's Mars Science
Laboratory rover to the surface of Mars from the spacecraft's hovering,
rocket-powered descent stage.
The photo shows the bridle device assembly, which is about two-thirds of a
meter, or 2 feet, from end to end, and has two main parts. The cylinder on
the left is the descent brake. On the right is the bridle assembly,
including a spool of nylon and Vectran cords that will be attached to the
rover.
When pyrotechnic bolts fire to sever the rigid connection between the
rover and the descent stage, gravity will pull the tethered rover away
from the descent stage. The bridle or tether, attached to three points on
the rover, will unspool from the bridle assembly, beginning from the
larger-diameter portion of the spool at far right. The rotation rate of
the assembly, hence the descent rate of the rover, will be governed by the
descent brake. Inside the housing of that brake are gear boxes and banks
of mechanical resistors engineered to prevent the bridle from spooling out
too quickly or too slowly. The length of the bridle will allow the rover
to be lowered about 7.5 meters (25 feet) while still tethered to the
descent stage.
The Starsys division of SpaceDev Inc., Poway, Calif., provided the descent
brake. NASA's Jet Propulsion Laboratory, Pasadena, Calif., built the
bridle assembly. Vectran is a product of Kuraray Co. Ltd., Tokyo. JPL, a
division of the California Institute of Technology, manages the Mars
Science Laboratory Project for the NASA Science Mission Directorate,
Washington.