A camera on board NASA’s Curiosity rover has taken the first
photographs from the surface of the planet Mars of a 1909 Lincoln,
V.D.B. cent the vehicle carries.
The Lincoln cent is part of a calibration target for Curiosity’s
Mars Hand Lens Imager. The first images of the target and the cent
were taken on Sept. 9, during the 34th Martian day, or sol, of
Curiosity’s work on Mars, according to NASA.
“Part of Curiosity’s left-front and center wheels and a patch of
Martian ground are also visible” in one of the images, according to NASA.
The cent included as part of the calibration target “is a nod to
geologists’ tradition of placing a coin or other object of known scale
as a size reference in close-up photographs of rocks, and it gives the
public a familiar object for perceiving size easily when it will be
viewed by MAHLI on Mars,” according to a press release. The coin used
for the target was purchased by Mars Hand Lens Imager (or MAHLI)
principal investigator Kenneth Edgett, of Malin Space Science Systems,
San Diego. Edgett told Coin World in February that he considers
himself an “amateur” coin collector.
Edgett decided to use a 1909 Lincoln, V.D.B. cent for special reasons.
“Originally the Curiosity rover was going to launch in 2009, and
so I had planned all along to use a 1909 cent in celebration of the
centennial of the Lincoln cent,” he said Feb. 7. “I could not use one
of the four 2009 cents because we had to commit to the design and
materials (i.e., the 1909 is brass, 2009 is mostly zinc) in 2008. When
the launch was delayed to 2011, we still went forward with the 1909
cent because we already had it in-hand.”
In February, Edgett explained the practice of geologists using
something like a coin when taking photographs on Earth: “When a
geologist takes pictures of rock outcrops she is studying, she wants
an object of known scale in the photographs. If it is a whole cliff
face, she’ll ask a person to stand in the shot. If it is a view from a
meter or so away, she might use a rock hammer. If it is a close-up, as
the MAHLI can take, she might pull something small out of her pocket.
Like a penny.”
According to NASA, the camera that took the photographs is in the
turret of tools at the end of Curiosity’s robotic arm. “Its
calibration target is on the rover body near the base of the arm. The
Sol 34 imaging by MAHLI was part of a week-long set of activities for
characterizing the movement of the arm in Mars conditions. MAHLI has
adjustable focus. The camera took two images with the same pointing:
one with the calibration target in focus and one with the wheel and
Martian ground in focus. The view here combines in-focus portions from
these shots,” according to NASA.
In addition to the Lincoln cent, the calibration target for the
MAHLI instrument includes color references, a metric bar graphic and a
stair-step pattern for depth calibration.
“The new MAHLI images show that the calibration target has a
coating of Martian dust on it. This is unsurprising — the target was
facing directly toward the plume of dust stirred up by the sky crane’s
descent engines during the final phase of the 6 August 2012 landing,”
according to NASA.
Future images of the Lincoln cent will allow NASA scientists and
coin collectors to monitor any changes to the cent, including toning,
as it sits exposed to the elements. While coins have been carried
aboard other NASA spacecraft as parts of instrument packages, this is
the first time that a coin can be monitored while it rests on the
surface of another planet.
“The main purpose of Curiosity’s MAHLI camera is to acquire
close-up, high-resolution views of rocks and soil at the rover’s Gale
Crater field site. The camera is capable of focusing on any target at
distances of about 0.8 inch (2.1 centimeters) to infinity, providing
versatility for other uses,” according to NASA. ■