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avoided mishap and continues to
operate. In 2014, it beat Lunokhod
2’s distance record, and by August
2015 it had completed the marathon
distance of 26.4 miles (42.45 km).
This was no mean feat on a planet
located some hundreds of millions
of miles from Earth.
Curiosity needed
Spirit and Opportunity were
equipped with the latest detectors;
including a microscope for imaging
mineral structures and a grinding
tool for accessing samples from
the interiors of rocks.
However, Curiosity, the next
rover to arrive on the planet in
August 2012, carried instruments
that not only studied the geology
of Mars but also looked for
biosignatures—the organic
substances that would indicate
whether Mars once harbored life.
These included the SAM or Sample
Analysis at Mars device, which
vaporized samples of ground rock to
reveal their chemicals. In addition,
the rover monitored radiation levels
to see whether the planet would be
safe for future human colonization.
Considerably larger than
previous rovers, Curiosity was
delivered to Mars in an unusual
way. During the landing phase of
the mission, the radio delay (causedEXPLORING MARS
by the sheer distance from Earth)
was 14 minutes, and the journey
through the atmosphere to the
surface would take just seven—all
on autopilot (not remotely controlled
from Earth). This created “seven
minutes of terror”: the engineers
on Earth knew that by the time a
signal arrived informing them that
Curiosity had entered the Martian
atmosphere, the rover would
already have been on the ground
for seven minutes—and would be
operational or smashed to pieces.Safe landing
As Curiosity’s landing craft moved
through the upper atmosphere,
its heat shield glowed with heat,
while rockets adjusted the descentIn the “Kimberley” formation
on Mars, photographed by Curiosity,
strata indicate a flow of water. In the
distance is Mount Sharp, named after
US geologist Robert P. Sharp in 2012.The Seven Minutes of Terror
has turned into the Seven
Minutes of Triumph.
John Grunsfeld
NASA associate administrator