MARS SCIENCE LABORATORY

The Mars Science Laboratory (MSL) mission—along with its rover, Curiosity—is part of NASA’s Mars Exploration Program. The Mars Exploration Program is a long-term program focusing on the robotic exploration of the red planet. Curiosity was designed to determine the planet’s habitability and to determine if Mars ever had an environment that was able to support small life forms (microbes). The Mars Science Laboratory mission landed on Mars in August 2012. [1]

Science Payload

The Curiosity rover explores Gale Crater and acquires rock, soil, and air samples for onboard analysis. It hosts an advanced kit of 10 science instruments that play an important role with regard to the Mars Science Laboratory mission. These instruments are used to acquire information about the geology, atmosphere, environmental conditions, and potential biosignatures on Mars. It hunts for special rocks that formed in water and/or have signs of organics. The rover is equipped with 17 cameras, a laser to vaporize and study small pinpoint spots of rocks at a distance, and a drill to collect powdered rock samples. Curiosity analyzes powdered samples drilled from rocks, and also measures the chemical fingerprints present in different rocks and soils to determine their composition and history, especially their past interactions with water. [2] Mars Science Laboratory carries:

Cameras:

  • Mast Camera (Mastcam)
  • Mars Hand Lens Imager (MAHLI)
  • MARS Descent Imager (MARDI)

Spectrometers:

  • Alpha Particle X-Ray Spectrometer (APXS)
  • Chemistry & Camera (ChemCam)
  • Chemistry & Mineralogy X-Ray Diffraction/X-Ray Fluorescence Instrument (CheMin)
  • Sample Analysis at Mars (SAM) Instrument Suite

Radiation Detectors:

  • Radiation Assessment Detector (RAD)
  • Dynamic Albedo of Neutrons (DAN)

Environmental Sensors

  • Rover Environmental Monitoring Station (REMS)

Atmospheric Sensors

  • Mars Science Laboratory Entry Descent and Landing Instrument (MEDLI) [3]

Mission, Goals, and Objectives

Mars Science Laboratory landed at Gale Crater and the core mission is to assess whether Mars has ever had an environment capable of supporting microbial life.

The Mars Science Laboratory mission is part of a series of expeditions to the red planet that will help meet four main goals of the Mars Exploration Program:

  • Determine whether life ever arose on Mars
  • Characterize the climate of Mars
  • Characterize the geology of Mars
  • Prepare for human exploration [4]

Mars Science Laboratory has the following objectives:

Biological objectives:

  • 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

Geological and geochemical objectives:

  • Investigate the chemical, isotopic, and mineralogical composition of the Martian surface and near-surface geological materials
  • Interpret the processes that have formed and modified rocks and soils

Planetary process objectives:

  • Assess long-timescale atmospheric evolution processes
  • Determine present state, distribution, and cycling of water and carbon dioxide

Surface radiation objective:

  • Characterize the broad spectrum of surface radiation, including galactic cosmic radiation, solar proton events, and secondary neutrons [5]

Mission Team

The Mars Science Laboratory mission is led by a number of individuals affiliated with the NASA Jet Propulsion Laboratory, which is managed by Caltech in Pasadena, California, and involves almost 500 scientists from the U.S. and other countries around the world. [6] The MSL Science Team includes scientists affiliated with NASA Headquarters, University of Guelph, Los Alamos National Laboratory, NASA Ames Research Center, Space Research Institute (Russia), Malin Space Science Systems, Southwest Research Institute, Centro de Astrobiologia (Spain), and the NASA Goddard Space Flight Center. [7]

Exploration Environment

The MSL and Curiosity Rover are exploring a region on the surface of Mars known as Gale Crater. The mission specifically targets a mountain located in the middle of Gale Crater – Mount Sharp – which is taller than Mount Rainier in the state of Washington. No Mars mission has ever attempted to approach it until MSL, which placed the Curiosity rover at the foot of the mountain in August 2012. MSL utilized precision-landing innovations to land in the area of flat ground between the mountain and the crater’s rim that encircles it – too small a target for previous missions without precise landing capability.

Mount Sharp towers approximately 3 miles above the floor of Gale Crater. [8] Its origin is unknown; however it is not simply a rebound peak from the asteroid impact that created Gale Crater. While a rebound peak may lay at its very core, Mount Sharp has hundreds of flat-lying geological layers, each of which represents an environmental change in Mars’ history. The layers are stacked, younger on top of older, and then partially eroded away over the eons the mountain has existed.

Some of the lower layers of Mount Sharp could indicate that a lake historically existed within Gale Crater, or could be identified as sediments delivered by wind and then soaked by groundwater. Orbiters have previously mapped minerals in these layers that could indicate water was present at one time. The higher layers of Mount Sharp could be deposits of dust resulting from a “great drying-out” period on the planet. [9]

Mars has several other craters that contain mounds or mesas that may have formed in ways similar to Mount Sharp, some of which also rise above the rim of the crater, while many others remain filled, or buried by rock. Those formations that rise higher than the rims of the craters that encircle them present a mystery in the evolution of environmental conditions on Mars – one that the MSL mission hopes to begin to solve.

Launch, Journey, and Mission

The Mars Science Laboratory (MSL) spacecraft—which includes the Curiosity rover—began its mission with a launch aboard a United Launch Alliance Atlas V 541 rocket on November 26, 2011. The Atlas V lifted off from Space Launch Complex 41 on Cape Canaveral Air Force Station in Florida. The MSL spacecraft landed successfully on the floor of Gale Crater on August 6, 2012. [10]

The core phases of the MSL mission include:

  • Pre-launch activities (mission preparation, landing site selection, assembly and testing, and delivery of the spacecraft to Cape Canaveral)
  • Launch
  • Cruise (the voyage through space)
  • Approach
  • Entry, descent, and landing (the journal through the atmosphere of Mars, landing on the surface of the planet)
  • First drive (after landing, engineers conducted tests to ensure that the Curiosity rover was in a “safe state”)
  • Surface operations (learning about Mars through the use of the Curiosity rover). [11]

The mission is currently in the surface operations phase, which covers the rover’s time conducting scientific investigations at Gale Crater on Mars. While exploring Mars, the rover will collect, grind, distribute, and analyze approximately 70 samples of soil and rock. [12] NASA's Curiosity Mars rover has seen a lot since Aug. 5, 2012, when it first set its wheels inside the 96-mile-wide (154-kilometer-wide) basin of Gale Crater. As of August 2020, Curiosity has since journeyed more than 14 miles (23 kilometers), drilling 26 rock samples and scooping six soil samples along the way. Analysis has revealed that ancient Mars was indeed suitable for life. Studying the textures and compositions of ancient rock strata is helping scientists piece together how the Martian climate changed over time, losing its lakes and streams until it became the cold desert it is today. [13]

Recent Discoveries

In October 2020, it was reported that the sample collected from NASA’s Curiosity rover’s latest drill hole, “Groken,” were delivered to CheMin for detailed analyses in order to determine the composition of the nodules. The top priority is to do more CheMin analysis on the sample and improve the data before deciding whether to deliver the sample to SAM. In addition to CheMin, ChemCam and Mastcam are also being targeted on the area around the drill hole - on “Villians,” “Vond,” and “Clibberswick” - to support the investigation into the nodules by examining local variability. ChemCam is also taking more high resolution RMI images of the “Housedon Hill” area to help test hypotheses and inform direction to go in the Mt. Sharp sulfate unit. Given that Gale Crater is fully into the windy and dust storm season, Curiosity has been tasked with a lot of environmental observations. Atmospheric observations include standard Mastcam crater rim extinction, cloud movies, zenith movies, and taus (dust opacity measurements), as well as Navcam line of sight imaging, and a suprahorizon movie. [14]

It July 2020, NASA's Curiosity Mars rover started a road trip that will continue through to the fall across roughly a mile (1.6 kilometers) of terrain to ascend to the next section of the 3-mile-tall Martian (5-kilometer-tall) mountain, Mount Sharp. Curiosity's top speeds range between 82 and 328 feet (25 and100 meters) per hour, depending on the landscape. The rover's next stop is a part of the mountain called the "sulfate-bearing unit." Sulfates, like gypsum and Epsom salts, usually form around water as it evaporates, and they are yet another clue to how the climate and prospects for life changed nearly 3 billion years ago. In journeying to the "sulfate-bearing unit," Curiosity leaves behind Mount Sharp's "clay-bearing unit," which the robotic scientist had been investigating on the lower side of the mountain since early 2019. Scientists are interested in the watery environment that formed this clay and whether it could have supported ancient microbes. Curiosity is expected to reach Mount Sharp’s “sulfate-bearing unit” in early fall, although the science team could decide to stop it along the way to drill a sample or study any surprises it comes across. [15]

In September 2018 news, NASA’s Curiosity rover surveyed its surroundings on Mars, producing a 360-degree panorama of its location on Vera Rubin Ridge. The source speaks to NASA’s interest in studying the rocks of the Mars, and notes that the best way to discover why these rocks are so hard is to drill them into a powder for the rover's two internal laboratories. The lab scientists then analyze the rocks in an effort to reveal why they may be acting as “cement” on the ridge; enabling the regions to stand, despite wind erosion. The source notes that groundwater flowing through the ridge in the ancient past may have had a role in strengthening it, or perhaps acted as plumbing to distribute this wind-proofing "cement." The source further notes that much of the ridge contains hematite, a mineral that forms in water; leading scientist to question if there is sufficient variation in hematite that could lead to harder rocks. [16]

In September 2016, the Curiosity rover found evidence that chemistry in the surface material of Mars contributed to the makeup of its atmosphere over time. Efforts looked at the ratios of certain isotopes of xenon and krypton. The measurements provide evidence of an interesting process in which the rock and unconsolidated material on the planet’s surface have contributed to the xenon and krypton isotopic composition of the atmosphere in a dynamic way. [17]

In June 2016, the Curiosity rover found chemicals in Martian rocks that suggest the planet once had more oxygen in its atmosphere than it does currently. Researchers found high levels of manganese oxides by using a laser-firing instrument on the Curiosity rover. [18]

In June 2016, scientists discovered an unexpected mineral rock sample at Gale Crater on Mars. The Curiosity has been used to explore sedimentary rocks within the Gale Crater since August 2012. The rover collected rock and scientists detected a silica mineral called tridymite. Tridymite is associated with silicic volcanism, which is known on Earth, but was not thought to be present on Mars. The discovery of tridymite may have implications on how scientists think about the volcanic history of mars—as its presence suggests that Mars may have once had volcanoes that led to the presence of this mineral. [19]

Updated: October 2020, Diane M. Long