NASA’s Mars Science Laboratory made international headlines last month when its Curiosity rover made a successful landing on the red planet’s Gale Crater. Launched on November 26th, 2011, Curiosity traveled over 350 million miles to touch down just 1.5 miles away from its target on August 6th, 2012. Equipped with a scientifically advanced payload specifically tailored to explore the Martian environment, NASA set out eight specific goals for this automobile-sized rover. According to the NASA Jet Propulsion Laboratory (JPL) stationed at the California Institute of Technology, Curiosity is expected to:
- Determine the nature and inventory of organic carbon compounds
- Inventory the chemical building blocks of life (carbon, hydrogen, nitrogen, oxygen, phosphorous, and sulfur)
- Identify features that may represent the effects of biological processes
- Investigate the chemical, isotopic, and mineralogical composition of the [M]artian surface and near-surface geological materials
- Interpret the processes that have formed and modified rocks and soils
- Assess long-timescale (i.e., 4-billion-year) atmospheric evolution processes
- Determine present state, distribution, and cycling of water and carbon dioxide
- Characterize the broad spectrum of surface radiation, including galactic cosmic radiation, solar proton events, and secondary neutrons
To achieve these mandates, NASA equipped Curiosity with an array of sampling, testing, and image-acquiring gadgets that can then be sent millions of miles back to earth for analysis. As such, Curiosity has to utilize a variety of Big Data technologies to extrapolate large amounts of information to send back to a variety of labs on Earth. Here’s a look at just a few of Curiosity’s gadgets as outlined by JPL:
Traveler Eyes; Navigation Cameras (or, “NavCams”)
- Main Function: Aid in autonomous navigation
- Grayscale: cover red wavelengths centered at ~650 nanometers
- Image Size: 1,024 by 1,024 pixels
- Image Resolution: 0.82 milliradians per pixel
- Focal Length: in focus from 20 inches (0.5 meter) to infinity
- Focal Ratio and Field of View: fixed-aperture f/12 and 45° square; field of view is similar to a 37-mm lens on a 35mm camera
Human Eyes; Mast Camera (or, “MastCam”)
- Main Function: Color Stereo Imaging
- Image Size: 1600 X 1200 pixels
- Image Resolution: 2.9 inches (7.4 centimeters) per pixel at a distance of about six-tenths of a mile (1 kilometer) and about 0.006 inch (150 microns) per pixel at a distance of 6.6 feet (2 meters)
- Left Eye (Mastcam-34): 450 microns/pixel at ~6.5-foot (2-meter) distance; 22 centimeters/pixel at ~.6 miles (1 kilometer)
- Right Eye (Mastcam-100): ~150 microns/pixel at ~6.5-foot (2-meter) distance; 7.4 centimeters/pixel scale at ~.6 miles (1 kilometer)
- Focal Length: in focus from about 6 feet (2.1 meters), the nearest view of the surface, to infinity
- Left Eye: ~34 mm
- Right Eye: ~100 mm
- Focal Ratio and Field of View:
- Memory: 8 Gigabyte memory allows several hours of HD video or 5,500+ raw frames to be stored (e.g., a full-scale mosaic of 360° x 80° imaged in 3 science color filters with at least 20% overlap between images)
- HD Video: 10 frames per second
Laser Eyes; Chemistry Camera (or, “ChemCam”)
- Main Function: Analyze Chemical Composition
- Telescope: focuses laser and camera
- Remote Micro-Imager: one of Curiosity’s “eyes,” captures detailed images of the area illuminated by the laser beam
- Laser: vaporizes rock surfaces, creating a plasma of their component gases
- Spectrometer: three spectrographs divide the plasma light into wavelengths for chemical analysis
“Magnifying Eye” Mars Hand Lens Imager (MAHLI)
- Main Function: Microscopic Imaging
- Image Size: up to 1600 X 1200 pixels with auto-focus
- Image Resolution: possibility of 13.9 microns/pixel
- Focal Length: in focus from 18.3 mm at the closest working distance to 21.3 mm at infinity
- Focal Ratio and Field of View: from f/9.8 and 34° to f/8.5 and 39.4°
- Memory: 8 Gigabyte flash memory storage; 128 megabyte synchronous dynamic random access memory (SDRAM); HD Video: 720p
- Other: first sends back thumbnails so scientists can select best images to send back to Earth
“Weather Detector” Rover Environmental Monitoring Station (REMS)
- Main Function: Weather Station
- UV sensor on the rover deck (“back”) about 1.5 meters above ground level
- pressure sensor inside the rover body and connected to the external atmosphere via a tube that exits the rover body through a small opening with protection against dust deposition
- Capability: Designed to survive a -130 °C to +70 °C temperature range and minimize power consumption for operation
- Measurements: autonomously record at least 5 minutes of data at 1 Hz each hour, every sol (Martian day), for all sensors (i.e., total baseline of two hours per sol); maximum of three hours of operation per sol allows a continuous block of monitoring time if desired
Curiosity has 17 other camera systems, hi-tech robotic arms, and an array of sensors that can analyze and store data on surface dust, gases, liquids, and even detect hazards before encountering them (called “HazCams”). NASA reported that Curiosity is equipped with just 2GB of flash memory. And while that seems small for an agency like NASA, PCMag notes that, “2GB is eight times as much as previous Mars rovers, Spirit and Opportunity, had on board.” And all of this has to be built within a shell that can be transported to Mars and then resist heavy Martian radiation. PCMag continues:
“Curiosity’s computer chip also got a speed boost over its younger siblings. It clocks at up to 200 megahertz, 10 times the clock of the Spirit and Opportunity computers. There’s also 256MB of RAM and 256KB of electrically erasable programmable read-only memory in Curiosity’s calculating engine.”
While many in the tech community wondered why the common iPhone came equipped with better cameras than what is found on Curiosity, the answer lies in the wonder and perils of Big Data. When engineers began building Curiosity, 2003-era cameras were rather state-of-the-art. But even more than this, Curiosity’s distance from Earth makes larger megapixel cameras rather unnecessary. Because the rover is so far away, Curiosity requires little more than a 2-megapixel camera. According to NASA engineers, fewer megapixels translate into more images that are good enough—for now—to continue Martian research. Low pixilation also allows NASA to transmit more data (and thus more images) back to Earth since Curiosity can only send about 250mb of information each day. For a research-based institution, it is obvious why NASA would opt for more images at lower quality than fewer images at a higher resolution.
Nevertheless, like many Big Data acquiring businesses back home on Earth, Curiosity has its own Big Data dilemma. While organizations around the planet struggle to acquire and analyze petabytes of data, Curiosity struggles to acquire, store, and then transmit data sizes that are taken for granted back on Earth. And that is what makes this interplanetary Big Data adventure so interesting. Curiosity’s Big Data problem means that the rover has to acquire and store enough information before releasing 250mb each day over a 350 million mile distance. But why is the distance such a problem? According to the American Institute of Aeronautics and Astronautics (AIAA), “communicating directly between Earth and Mars requires large amounts of power since the radio signals have to penetrate the Martian atmosphere, traverse millions of miles of deep space, and then reach a ground station through the Earth’s atmosphere. The Curiosity rover has limited power and its signals received on Earth are very weak, noisy and convey data at a low rate of delivery.”
Exactly how does Curiosity send its data? Through a series of intricate satellite positioning and mind-boggling international cooperation, Curiosity sends data back to the Earth by a serious of older technologies placed in orbit by humans and (slightly) newer global political agreements and international scientific standards.
The AIAA states:
“Some of the rover’s scientific data, including images of the surface of Mars collected by Curiosity’s 17 onboard cameras, are sent directly to and from Earth via NASA’s Deep Space Network (DSN) of large ground antennas. However, once Curiosity becomes fully operational most of the scientific and engineering data will be transferred via relay satellites that are in orbit around Mars. These are primarily the Mars Reconnaissance Orbiter (MRO) and the Mars Odyssey (ODY) spacecraft. The MSL Mars-Earth communications systems are using internationally-agreed space data communications standards to enable reliable transmission of the expected rich data sets to be gathered by Curiosity. These standards were developed by a team of international space data communication specialists collaborating within the Consultative Committee for Space Data Systems (CCSDS). Use of internationally-agreed upon standards reduce cost and risk to space missions, and also offer rich ‘cross-support’ capabilities to collaborate since key data interfaces are inherently interoperable.”
More specifically, the data standards used for Curiosity’s transmission mandate that data be sent “through weak-signal relay or direct-to-Earth space links, in addition to the cross-support capability of using the European Space Agency’s (ESA) Mars Express Orbiter which relays to and from Earth via ESA’s deep space tracking network, ESTRACK.”
And while it is absent from most commercial media, a large part of the Curiosity mission is setting the groundwork to one day transfer more data at a higher rate in the future. The AIAA states:
“The MSL [Mars Science Laboratory] mission will demonstrate new Adaptive Data Rate (ADR) data return technology over Prox-1, which allows for up to an average 50% greater telemetry return over the life of the mission by monitoring the signal strength between the MRO and Curiosity and then adapting the rover’s data transmission rate to maximize the throughput. In addition, Prox-1 will be built into the UHF radio for the next NASA Mars orbiter called MAVEN, which is planned for launch in 2014, as well as the European Space Agency’s (ESA) 2016 orbiter, providing on-going mission-to-mission cross-support at Mars.”
Essentially, NASA’s Curiosity mission is integral to solving the Big Data problem now that there is a physical presence on Mars. Indeed, implicit in NASA’s overall desire in sending rovers to Mars is the larger desire to solve an interplanetary Big Data problem. DataDirect aptly notes:
“When we look at the Mars rover mission, it is an incredible use case for Big Data. Consider the vast amounts of data streaming from the Curiosity to the Jet Propulsion Lab in California, Los Alamos in New Mexico, and other labs around the world – from surface imagery to soil and rock chemical composition to atmospheric conditions to video diaries. All of this data is being captured within Hadoop file systems on Earth. Then begins the huge task of breaking down the data, analyzing it, and theorizing its meaning. […] This is an interplanetary Big Data scenario – it doesn’t get much bigger than that. As the trend towards greater usage of Hadoop drives greater needs for Big Connectivity, greater insights will be gained through better data gathering and analysis methods. Use cases like the Mars rover provide us with greater insight into how important Big Data connectivity and analytics are in the scientific community as well as to businesses – enabling us all to see further.”
As an undying human thirst to explore the universe shall never adequately be quenched, sure to arise are problems and hurdles that catalyze the development of technological innovations that seek to make things easier, faster, and more efficient. As the Big Data adventure continues to evolve here at home, it could be argued that it was inevitable for the trend to make its way into the outermost reaches of our galaxy. Indeed, it has found new breathing space atop the Martian crust, reporting back to us that the adventure is far from over.
