ScienceCasts: Mars Landing Sky Show

[ music ]
Mars Landing Sky Show.
Presented by Science at NASA.
Every time NASA lands a rover on Mars -
or even makes the attempt -
it is cause for celebration.
On August 5th, the heavens themselves are
aligning to mark the event.
Only a few hours before the Mars Science Lab spacecraft
reaches the red planet and drops Curiosity on a
hair-raising descent, mission planners have dubbed the
"seven minutes of terror," Mars itself will put on a
special show in the sunset skies of Earth: Together with
Saturn and Spica (a blue giant star in the constellation
Virgo), the Red Planet will form a "Martian Triangle"
visible from almost all parts of our planet.
Go outside after sunset on August 5th and look west where
the setting sun has just disappeared.
As soon as the sky fades to black, a triangle of
first-magnitude lights will pop out of the twilight.
The vertices are Mars, Saturn, and Spica.
Together, they form an equilateral triangle about 5 degrees
on each side.
This means you could hide the Martian Triangle behind your
outstretched palm.
It would also fit comfortably inside the bowl of the Big Dipper.
The tightness of the triangle makes it extra eye-catching.
The three objects are very different: Mars is a small rocky
planet relatively close to Earth; Saturn is a ringed gas
giant halfway across the solar system; Spica is a massive
binary star on the other side of our galactic spiral arm.
Nevertheless, they shine with the same intensity as seen
from Earth.
On the scale of astronomical brightness, all three are
ranked first magnitude.
This makes them easy to see with the unaided eye.
Not long after the Martian Triangle follows the sun below
the horizon, the real action begins: At approximately 10:30
pm PDT, Curiosity's entry capsule will slam into the upper
atmosphere of Mars raising temperatures around the heat
shield to 2100 degrees Celsius, more than twice as hot as
basaltic lava.
What happens next seems almost unbelievable.
Because Curiosity is so much bigger and heavier than any
previous rover, old ways of landing such as air bags
wouldn't work.
Mission planners had to come up with something
new and unorthodox.
Reporter Scott Gold of the LA Times described it this way:
"In the time it takes to drive to the grocery store, the
spacecraft will change shape like a toy Transformer six
times, slowing down from 13,000 mph to 1.7 mph while using
76 pyrotechnic devices, ropes, knives and the largest
supersonic parachute ever built." At the end of the
maneuver, a "Sky Crane" gently lowers the rover onto the
floor of Gale Crater.
If the rover survives the hair-raising descent and lands
intact as planned, it will mark the beginning of an
extraordinary mission of discovery.
Bristling with the most advanced sensors ever sent to Mars,
the one-ton rover will spend the next two years (at least)
finding out whether one of the most intriguing places in
the solar system ever offered an environment favorable for
microscopic life.
Let's just say, it's a good reason to go stand outside
under the stars.
After the Martian Triangle sets, go inside and turn on NASA
TV for the Mars landing itself.
The real show is about to begin.
The NASA portal for Mars can be found at www.nasa.gov/mars.
For additional news about Mars - as seen from your backyard
and Curiosity's - visit science.nasa.gov.