Tracking down the “missing” carbon from the martian atmosphere

Mars is blanketed by a mostly carbon dioxide atmosphere—one that is far too thin to prevent large amounts of water on the surface of the planet from subliming or evaporating. But many researchers have suggested that the planet was once shrouded in an atmosphere many times thicker than Earth’s. For decades that left the question, “Where did all the carbon go?”

Now scientists from Caltech and JPL think they have a possible answer. The team suggests that 3.8 billion years ago, Mars might have had only a moderately dense atmosphere. The researchers have identified a photochemical process that could have helped such an early atmosphere evolve into the current thin one without creating the problem of “missing” carbon.

“With this new mechanism, everything that we know about the martian atmosphere can now be pieced together into a consistent picture of its evolution,”says Renyu Hu, a postdoctoral scholar at JPL, a visitor in planetary science at Caltech, and lead author on the paper that appeared in Nature Communications.

When considering how the early atmosphere might have transitioned to its current state, there are two possible mechanisms for the removal of excess carbon dioxide (CO2). Either the CO2 was incorporated into minerals in rocks called carbonates or it was lost to space.

A separate study coauthored by Bethany Ehlmann, assistant professor of planetary science at Caltech, used data from several Mars-orbiting satellites to inventory carbonate rocks, showing that there are not enough carbonates in the upper crust to contain the missing carbon from a very thick early atmosphere.

To study the escape-to-space scenario, scientists examined the ratio of carbon-12 and carbon-13, two stable isotopes of the element carbon that have the same number of protons in their nuclei but different numbers of neutrons, and thus different masses. Comparing measurements from martian meteorites to those recently collected by NASA’s Curiosity rover, they found that the atmosphere is unusually enriched in carbon-13. To explain that, they describe a mechanism involving a photochemical cascade that produces carbon atoms that have enough energy to escape the atmosphere, and they show that carbon-12 is far more likely to escape than carbon-13.

“With this mechanism, we can describe an evolutionary scenario for Mars that makes sense of the apparent carbon budget, with no missing processes or reservoirs,” says Ehlmann, who is also a coauthor on the Hu study.

Photo credit: NASA/JPL-Caltech/Univ. of Arizona

Gecko’s Trick Makes for No-Slip Grip (+)

In the Fall 2015 issue of E&S, we examined how the tiny hairs on gecko feet exploit attractive forces—called van der Waals forces —between temporary electric dipoles to create adhesion.

We also noted that JPL engineer Aaron Parness and colleagues have used that concept to create a material made of synthetic hairs much thinner than a human hair. They hope to use the material to develop a gecko-inspired gripping technology to manipulate objects in space. A four-minute video, Crazy Engineering: Gecko Gripper, highlights some of their work—as well as some charming geckos.

In addition, JPL recently posted an artist’s conception of a project in progress—a creation called LEMUR (Limbed Excursion Mechanical Utility Robot) that might one day use Parness’s technology to inspect and maintain installations on the International Space Station.

Get A Grip

The same forces that give gecko feet their uncanny ability to stick to just about anything may soon help scientists collect space trash. Geckos use tiny hairs that exploit electrostatic attractive forces, called van der Waals forces, for temporary adhesion. Now, researchers at JPL are working on gripping tools inspired by the tiny lizards that might one day be used to grab onto objects in space, like debris or defunct satellites.

“The reliability of van der Waals forces, even in severe environments, makes them particularly useful for space applications,” say Aaron Parness, a JPL robotics researcher who is the principal investigator for the grippers. Recent experiments during brief periods of weightlessness on a test flight showed that the grippers could seize a 20-pound cube as it floated, as well as get a firm hold on a researcher wearing a vest made of spacecraft material panels. The current device, made of adhesive pads, is handheld by researchers during tests, but the long-term goal is to integrate the grippers into a robotic arm.


Earlier this year, a scientific instrument dubbed SPIDER landed in a remote region of Antarctica. Conceived of and built by an international team of scientists, the instrument was launched on a balloon from McMurdo Station on New Year’s Day. Caltech and JPL designed, fabricated, and tested the six refracting telescopes the instrument used to map the thermal afterglow of the Big Bang, also known as the cosmic microwave background (CMB). SPIDER’s goal: to search the CMB for the signal of inflation, an explosive event that, in the first fraction of an instant after the birth of our universe, blew the observable cosmos up from a volume smaller than a single atom. The instrument appears to have performed well during its flight, says Jamie Bock, head of the SPIDER receiver team at Caltech and JPL. “Of course, we won’t know everything until we get the full data back as part of the instrument recovery.”

Photo of SPIDER afloat over Antarctica courtesy of SPIDER team

RoboSimian to the Rescue (+)

In our Summer 2015 article Robots to the Rescue, we wrote about RoboSimian—JPL’s entry into the Defense Advanced Research Projects Agency (DARPA) Robotics Challenge—and how its JPL, Caltech, and UC Santa Barbara creators prepared it for the contest.

The competition, motivated by the radiation dangers posed to response crews at Japan’s Fukushima Daiichi nuclear power plant after a tsunami struck in 2011, challenged teams to design a robot that can perform many of the same emergency procedures as a human rescue worker.

This year’s Robotics Challenge featured robots designed and built by 23 teams from around the world and culminated with a final round of physical tests in June that challenged the robots’ dexterity and mobility. This 90-second JPL video of the robot’s-eye view of the action shows RoboSimian driving a vehicle, clearing debris, opening doors, and even cutting through walls when instructed by a human operator. For its efforts, it snagged a fifth-place finish.

Sisir Karumanchi, a robotics expert and member of the JPL RoboSimian team, hailed the competition as “a seminal event in the field of robotics, with multiple teams demonstrating significant advances in human-robot communications, perception, motion planning, and control of robots for field use.”

Robots to the Rescue

When disasters strike, first responders—often highly trained emergency medical staff—risk their lives to rescue victims and secure damaged structures. However, an apelike robot named RoboSimian could one day provide a safer alternative.

RoboSimian is JPL’s entry in the Defense Advanced Research Projects Agency (DARPA) Robotics Challenge. The competition, motivated by the radiation dangers posed to response crews at Japan’s Fukushima Daiichi nuclear power station after a tsunami struck in 2011, challenges teams to design a robot that can perform many of the same emergency procedures as a human rescue worker.

Composed of researchers from JPL, Caltech, and UC Santa Barbara, the RoboSimian team crafted a machine featuring four equally strong and dexterous limbs that allow the robot to drive a vehicle, climb over debris, turn valves, and even cut through walls when instructed by a human operator. At the final competition this June in Pomona, RoboSimian’s performances on these tasks will be judged against at least 10 other competitors. Scoring will also include the competitors’ performance during a surprise task that won’t be revealed until the day of the competition.

Although robotic rescue workers might seem outlandish now, the reality might be closer than we think. Several previous DARPA challenges of the last decade—in which Caltech and JPL have both participated—led directly to advancements in the driverless car technologies that are being explored today.

Photo courtesy of JPL-Caltech

JPL—The Suicide Squad’s First Mission (+)

"Suicide Squad" members, from left: Rudolph Schott, Amo Smith, Frank Malina, Ed Forman, and Jack Parsons.
“Suicide Squad” members, from left: Rudolph Schott, Amo Smith, Frank Malina, Ed Forman, and Jack Parsons.
Photo courtesy JPL

“The Rocketmen” video, one chapter in a documentary series about the early days of JPL, focuses on the origin of the rocketry pioneers known on campus as the “Suicide Squad” for their dangerous experiments.

The group was highlighted in the Spring 2014 issue of E&S in an article titled “Launch Points,” and JPL’s three-minute video offers even more interesting details about it.

The video covers the group’s first rocket motor test in 1936, conducted in a remote part of the Arroyo Seco on Halloween. JPL historian Erik Conway notes onscreen that the initial efforts fizzled when the fuse sputtered out. “On the fourth try, the motor ignited and the oxygen line whipped around, started shooting fire, and they all ran away,” Conway says, adding that the group considered the experiment a success in part because “they learned a number of things not to do.”

Blasts from the Past (+)

Our “Launch Points” article about JPL’s origins and history focused on some of its most important milestones. Magazine space considerations, however, meant that we had to omit many other equally interesting and noteworthy stories.Space_Suit_1.tif

Luckily, JPL, in its own version of Throwback Thursday, posts an archival photo and caption each month on its website highlighting events that range from historically significant to scientifically important to just plain quirky.

Among our favorites is the photo chosen for July 2010, which features engineer Allyn B. “Hap” Hazard in a 1960 image wearing a space suit he designed. The photo appeared in Life and other magazines at the time.

Launch Points: The Ultimate JPL Walkabout

As JPL has grown and has continued to expand its role in space exploration, the number of buildings on its 177-acre site has increased in tandem. All of the facilities are assigned a number according to the order in which they were built. Buildings 1 through 10 no longer exist, so Building 11, constructed in 1943, is the oldest on JPL’s campus. Building 349, the Arroyo Parking Structure, is the newest.

In 2012, JPL graphic designer Luke Johnson decided to go on a tour of the buildings in numerical order. The walk that he thought he might complete in an afternoon ended up taking him on a 52.2-mile hike over four days. After his walkabout, he collaborated with a team of designers to create a map that is handed out to all new JPL hires. [Click here to download a PDF of the map].

It includes highlights about what can be found in various buildings on campus. For example, the atomic clock housed in Building 298 is one of the world’s most stable clocks.

Click here for more of JPL’s origin story…

Photo: JPL/NASA/Caltech

Launch Points: Mission: Communication

When engineers at JPL first started considering how to bring data back from planetary spacecraft in 1958, the first thing they did was ask Caltech astronomer John Bolton for a survey of the state of the art in radio telescope technology. They knew that in order to track spacecraft, they were going to be seeking relatively faint signals from space—just the type of thing radio astronomers were doing. Bolton had just written a paper on the topic that had not yet been published and was able to immediately provide the engineers with the information they needed to start piecing together a network that could help them track and keep in touch with spacecraft continuously as Earth continued to rotate.

Today, JPL operates what is known as the Deep Space Network (DSN), with locations near Madrid, Spain; near Canberra, Australia; and at Goldstone, California. With multiple antennas at each location, the DSN supports all interplanetary spacecraft missions and some Earth-orbiting missions, providing a crucial link between Earth and our robotic emissaries in space.

Click here for more JPL origin stories…

Photo: Courtesy NASA/JPL/Caltech

Launch Points: Got There First

Since its serendipitous yet second-place showing in the satellite space race set JPL on its current course of planetary missions, the lab has seen a lot of firsts. These missions, designed, built, and managed by JPL, propelled inaugural visits to Venus, Mars, Neptune, Uranus, and interstellar space.

Click here for more of JPL’s origin story…

Photo of Mariner 2: Courtesy NASA/JPL

Launch Points: The First Close-Up of Mars

In July 1965, JPL and the world were anxiously awaiting the first close-up image of the Red Planet, which would be delivered by Mariner 4. The spacecraft flew by Mars on July 15 and started transmitting the pictures it took the next day at a frustratingly slow rate of eight and a third bits per second. Once the data had been received, the image still had to be processed. Getting impatient with the image-processing process, members of the Mariner team started stapling to the wall strips of data related to one of the transmitted images, and coloring them by hand based on the brightness values of the pixels. That paint-by-number creation hangs today in Building 186 and is known as the “first image of Mars.”

Click here for more of JPL’s origin story…

Photo: Courtesy NASA/JPL/Caltech