Since NASA's Mars Science Laboratory (MSL) rover Curiosity landed on the red planet, each sol (a Martian "day") of the mission sees a flood of new photographs from Aeolis Palus -- the plain inside Gale Crater where Curiosity landed on Aug. 5. In September 2012, mission controllers sent the command for Curiosity to flip open the dust cap in front of the robotic arm-mounted Mars Hand Lens Imager (MAHLI). Until that point, the semi-transparent dust cap only allowed MAHLI to make out fuzzy shapes -- although it did a great job imaging Curiosity's "head" and it is also famous for capturing Curiosity's first color photograph. But since the true clarity of MAHLI has been unleashed, we've been treated to some of the most high-resolution views of the rover, Martian landscape and, most importantly, we've seen exactly what MAHLI was designed to do: Look closely at Mars rocks and dirt, assembling geological evidence of potential past habitability of Mars.
The Business End
Curiosity is armed with 17 cameras and MAHLI is designed to capture close-up photos of geological samples and formations as the rover explores. MAHLI was designed and built by Malin Space Science Systems and is analogous to a geologist's hand lens -- only a lot more sophisticated. Its high-resolution system can focus and magnify objects as small as 12.5 micrometers (that's smaller than the width of a human hair!). This photograph captured by the rover's Mastcam shows the MAHLI lens (with dust cap in place) in the center of the end of Curiosity's instrument-laden robotic arm.
To aid its studies, MAHLI is equipped with four LEDs to light up the imager's samples.
The first photograph to be returned from MAHLI without the dust cover in place was received on Sol 33 (Sept. 8) of Curiosity's mission. Shown here is a view of the ground immediately in front of the rover. Although this photo was a test, mission scientists were able to do a very preliminary study of the large "pebble" at the bottom of the picture: "Notice that the ground immediately around that pebble has less dust visible (more gravel exposed) than in other parts of the image. The presence of the pebble may have affected the wind in a way that preferentially removes dust from the surface around it," they wrote.
How Did Lincoln Help MAHLI?
On Sol 34 (Sept. 9), MAHLI was aimed at Curiosity's calibration target. This target is intended to color balance the instrument and provide a "standard" for mission scientists to refer to. The 1909 Lincoln penny was provided by MAHLI's principal investigatory Ken Edgett. Using a penny as a calibration target is a nod to geologists' tradition of placing a coin or some other object of known scale as a size reference in close-up photographs of rocks, says the MSL mission site.
Although MAHLI will be used to examine microscopic scales, it is showing its prowess at generating some spectacular high-definition views of the rover. Shown here is a mosaic of Curiosity's three left-side dusty wheels.
Hazard Avoidance Cameras
Hazard Avoidance Cameras, or Hazcams, have become "standard issue" for the last three rovers to land on Mars. Mounted on the front and back of rovers Opportunity, Spirit and Curiosity, these small cameras provide invaluable information about the terrain and potential hazards surrounding the rovers. These cameras are not scientific cameras -- they are engineering cameras. Shown here, MAHLI has imaged the four front Hazcams on Curiosity. Interestingly, it was these cameras who returned Curiosity's first dusty image after touch down in August.
Using the flexibility of the robotic arm, MAHLI was able to check the underside of Curiosity. As the camera can focus on objects from 0.8 inch (2.1 centimeters) to infinity, MAHLI has incredible versatility allowing mission controllers to focus on the very small features of Mars to checking the health of the rover to viewing the impressive vistas beyond.
In October 2012, the Internet was abuzz with speculation about a "mystery object" lying beneath the rover during digging operations at "Rocknest." Sadly, after studying the translucent object, mission scientists deduced that it wasn't anything native to the alien environment, it was actually a piece of plastic that had fallen from Curiosity. Yes, Curiosity is littering the red planet.
The MAHLI camera was very attentive while Curiosity dug trenches in the Mars soil at "Rocknest."
In early 2013, MAHLI snapped another curious photo. This time, after driving to a rocky outcrop at a location dubbed "Yellowknife," the camera picked out what appeared to be some kind of organic-looking object embedded in the rock. Nope, it's not a Mars "flower" -- more likely it's a concentration of minerals.
In what has become an iconic photo of Curiosity, MAHLI was commanded to capture dozens of high-resolution pictures of the rover. Like an "arms length" shot you may have in your Facebook profile, Curiosity did the same, composing a mosaic of pics taken with its outstretched robotic arm.
Curiosity Cleans Up!
The Mars rover isn't only a scientific superstar, it also has a talent for cleaning. This circular pattern on a Mars rock was brushed aside by Curiosity's Dust Removal Tool (DRT), helping the rover carry out analysis of the rock surface beneath the layer of dirt.
Scientists this week began assessing what may be the most important part of an upcoming mission to look for life on Mars: location, location, location.
Europe’s ExoMars rover, slated for launch in 2018, will be the most focused and ambitious attempt to find evidence of past or present life on Mars since NASA’s Viking expeditions four decades ago.
ExoMars’ planners aren’t starting from scratch, however. Recent findings from NASA’s Mars Science Laboratory Curiosity mission, for example, indicate that ExoMars may not have drill down very deep -- or perhaps not at all -- to collect viable samples for analysis.
ExoMars will carry a drill capable of burrowing up to 6.6 feet (2 meters) into the planet’s surface. Scientists figure that at that depth, organic materials -- if they exist -- would be shielded from the onslaught of damaging radiation that constantly pummels the planet.
“One of the things that Curiosity has been able to do is understand that not all surfaces on Mars are created equal and have equal ages,” California Institute of Technology geologist John Grotzinger, who leads the rover’s science team, told Discovery News.
Last year, researchers discovered that Mars’ winds sometimes do the digging for them, exposing relatively fresh rocks at the base of scarps.
“One result from MSL that may be useful is that the depth (to collect samples) maybe less than 2 meters,” ExoMars project manager Vincenzo Giorgio told Discovery News. “We can definitely accommodate that.”
“If it turns out that drilling is complicated and inefficient, you can save that capability for when you need it the most,” Grotzinger added.
Unlike ExoMars, Curiosity was not designed to look for life directly. Instead, it is assessing if a region of Mars, known as Gale Crater, has or ever had the necessary ingredients and environments to support life.
A self-portrait of NASA's Mars rover Curiosity combines dozens of exposures taken by the rover's Mars Hand Lens Imager (MAHLI) during the 177th Martian day, or sol, of Curiosity's work on Mars (Feb. 3, 2013) at the "John Klein" drill site.NASA/JPL-Caltech
Within months of Curiosity’s August 2012 landing, scientists learned that the answer was “Yes.” The rover now is on its way to assess the habitability of other sites and figure out how any organic material could have been preserved.
Even if life never took hold on Mars, the planet should have a rich stew of organic material from crashing comets and asteroids.
By the time ExoMars managers choose a landing site in 2016 or 2017, they may have even more guidance from Curiosity.
“We’re not just after water anymore,” Grotzinger said. “Now we’re honing in on the right kind of habitable environments. Then, we have to have (the right instruments) to know which subset of those habitable environments might contain the organic goodies.
“I think each time we do this, we’re getting more sophisticated. We’re getting a better understanding. But it’s also a much tougher question each time,” Grotzinger said.
In addition to data from Curiosity, sister rovers Opportunity and Spirit, and past landers, scientists will use imagery and chemical analysis from Europe’s Mars Express, NASA’s Mars Reconnaissance Orbiter and other Mars-orbiting satellites to assess prospective landing sites for ExoMars.
Scientists met in Madrid this week to begin considering eight potential landing sites, all near Mars’ equator. They hope to winnow the candidates’ list to four by June or July.