Curiosity rover's Mars Rock offers surprises

A rock on Mars being studied by NASA's Curiosity rover is unlike any Martian stone ever seen, and is surprisingly similar to an unusual, but well-known, kind of rock on Earth. This type of rock is the first of its kind encountered on Mars and is helping broaden scientists' understanding of how igneous rocks form, scientists said Thursday, Oct. 11. The rock, named "Jake Matijevic" in honor of a Curiosity mission team member who died in August, is a 16-inch-tall pyramid-shape specimen that Curiosity encountered at its landing spot in Mars' Gale Crater.

Curiosity, the centerpiece of the $2.5 billion Mars Science Laboratory Mission, touched down on the Red Planet Aug. 5 to learn whether Mars ever had the conditions necessary to support life. The Jake rock is being used as a calibration target for Curiosity to try out its suite of 10 science instruments on. 

In late September Curiosity used ChemCam and its Alpha Particle X-ray Spectrometer (APXS) to probe Jake's chemical composition. What they found was surprising. Jake appears to have higher concentrations of elements such as sodium, aluminum and potassium, and lower concentrations of magnesium, iron and nickel, than other igneous rocks studied on Mars.

While previously unknown on Mars, this type of chemical composition is seen in a rare but well-studied class of rocks on Earth. On Earth, such specimens are found on oceanic islands such as Hawaii and in other places. They are thought to form when interior rocks melt to form magma, which then rises toward the surface. As it rises, it cools, and parts of the material crystalize, preferentially selecting some elements while leaving a remainder of liquid magma that is enriched with the left-behind chemicals.

However, the researchers said it's too soon to know whether the Jake rock formed this same way.

Strange and shiny

Curiosity is about 65 days into its mission, and still testing out all of its equipment. The rover used its scoop tool to dig up Martian dirt for the first time earlier this week, and scientists saw a strange shiny object in photos of the scooped material. The find put a temporary halt on scooping activities while mission managers investigated the object. Scientists have since concluded that it is most likely a bit of plastic from the rover itself or its landing mechanism that fell off onto the ground during its entry, descent and landing (EDL) process.

Mission team members will continue investigating the debris, but they think it might be a piece of resistive heating material from the rover's exterior that was attached with adhesive, which might have come unstuck.

NASA's Curiosity all set to land on Mars

Curiosity, NASA’s one-ton roving vehicle, is scheduled to land on Mars early Monday. If all goes as planned, Curiosity and the Mars Science Laboratory will come to rest in Mars’ Gale crater. All Mars landers since 1997 have employed a system of airbags during landing. The airbags, inflating moments before landing, cushion the payload as it bounces across the Martian landscape before rolling to a stop. Not so with MSL — it’s too heavy for airbags.

An artist's conception of the sky crane gently lowering the Curiosity rover onto the surface of Mars.

Mars Science Laboratory will employ a heat shield, parachute and a rocket-powered disposable descent stage. Once it’s through protecting Mars Science Laboratory during its entry into Mars’ thin atmosphere, the heat shield separates shortly after the parachute deploys. Powered descent begins after releasing the parachute as eight rockets ignite on the descent stage, or “sky crane.” Shortly before touchdown the lander is lowered to the surface with lanyards. After touchdown the lanyards are cut and the sky crane flies off to a crash landing.

A similar plan was once considered in the early 1960s for the Apollo Moon-landing mission. A descent stage would have slowed the lunar module to a low hover then would separate, go off and crash. The “lunar crasher” concept was described as “dicey” by NASA engineer Caldwell Johnson and the idea was discarded. Seems the notion of intentionally crashing a piece of equipment near a soft landing site rubbed some engineers the wrong way. That is apparently no longer the case.

During August, two planets and a bright star form an ever-changing triangle low in the western sky. On Monday evening, they form an equilateral triangle. The triangle’s top point is the planet Saturn. The corners of the base are, from left to right, the star Spica and the planet Mars. Spica is the brightest star in the constellation Virgo and is 260 light-years away.

During the next few days, Mars continues eastward and passes between Saturn and Spica from Aug. 13-14. The trio is joined by the crescent moon on Aug. 21, posing for a unique group photo opportunity.