|Each DVD carries nearly four million Mars
enthusiasts’ names collected by NASA. Each DVD also
includes engaging designs leading to other activities.
Each rover will photograph and return to Earth a picture
of each DVD disk of names as they rest on the Martian
|The DVD is made of silica glass rather than
plastic so that it can withstand the high temperatures
necessary to sterilize it of Earth microbes before it
is sent to the Martian surface. Also, the silica glass
has a much longer lifetime than typical commercial DVDs—in
fact, the silica glass DVD could last more than 500 years.
The DVD will remain on the lander as a time capsule for
a future generation.
||The entire assembly, which weighs 69 grams,
has been subjected to a battery of tests designed to simulate
the extreme environmental conditions of the journey to
Mars: temperature cycling from 125 to 60 degrees Celsius,
exposure to vacuum, high-speed random vibration, and shocks
of 4,000 times the acceleration of Earth’s gravity.