“As of October 2016, all methods of landing on Mars have required an aeroshell and parachute sequence for Mars atmospheric entry and descent, but after that there are three choices. A stationary lander can drop from the parachute back shell and ride retrorockets all the way down, but a rover cannot be burdened with rockets that serve no purpose after touchdown.
One method (for lighter rovers) is to enclose the rover in a tetrahedronal structure which in turn is enclosed in airbags. After the aeroshell drops off, the tetrahedron is lowered clear of the parachute back shell on a lanyard so that the airbags can inflate. Retrorockets on the back shell can slow descent. When it nears the ground, the tetrahedron is released to drop to the ground, using the airbags as shock absorbers. When it has come to rest, the tetrahedron opens to expose the rover.
If a rover is too heavy to use airbags, the retrorockets can be mounted on a sky crane. The sky crane drops from the parachute back shell and, as it nears the ground, the rover is lowered on a lanyard. When the rover touches ground, it cuts the lanyard so that the sky crane (with its rockets still firing) will crash well away from the rover.
For landers that are even heavier than the Curiosity rover (which required a 4.5 meter (15 feet) diameter aeroshell), engineers are developing a combination rigid-inflatable Low-Density Supersonic Decelerator that could be 8 meters (28 feet) in diameter. It would have to be accompanied by a proportionately larger parachute.”
“NASA’s Curiosity rover surveyed its surroundings on August 9, 2018, producing a 360-degree panorama of its current location on Mars’ Vera Rubin Ridge. The panorama includes skies darkened by a fading global dust storm and a view from the Mast Camera of the rover itself, revealing a thin layer of dust on Curiosity’s deck. In the foreground is the rover’s most recent drill target, named “Stoer” after a town in Scotland near where important discoveries about early life on Earth were made in lakebed sediments.”
“Volcanic activity, or volcanism, has played a significant role in the geologic evolution of Mars. Scientists have known since the Mariner 9 mission in 1972 that volcanic features cover large portions of the Martian surface. These features include extensive lava flows, vast lava plains, and the largest known volcanoes in the Solar System. Martian volcanic features range in age from Noachian (>3.7 billion years) to late Amazonian (< 500 million years), indicating that the planet has been volcanically active throughout its history, and some speculate it probably still is so today. Both Earth and Mars are large, differentiated planets built from similar chondritic materials. Many of the same magmatic processes that occur on Earth also occurred on Mars, and both planets are similar enough compositionally that the same names can be applied to their igneous rocks and minerals.
Volcanism is a process in which magma from a planet’s interior rises through the crust and erupts on the surface. The erupted materials consist of molten rock (lava), hot fragmental debris (tephra or ash), and gases. Volcanism is a principal way that planets release their internal heat. Volcanic eruptions produce distinctive landforms, rock types, and terrains that provide a window on the chemical composition, thermal state, and history of a planet’s interior.
Magma is a complex, high-temperature mixture of molten silicates, suspended crystals, and dissolved gases. Magma on Mars likely ascends in a similar manner to that on Earth. It rises through the lower crust in diapiric bodies that are less dense than the surrounding material. As the magma rises, it eventually reaches regions of lower density. When the magma density matches that of the host rock, buoyancy is neutralized and the magma body stalls. At this point, it may form a magma chamber and spread out laterally into a network of dikes and sills. Subsequently, the magma may cool and solidify to form intrusive igneous bodies (plutons). Geologists estimate that about 80% of the magma generated on Earth stalls in the crust and never reaches the surface.
As magma rises and cools, it undergoes many complex and dynamic compositional changes. Heavier minerals may crystallize and settle to the bottom of the magma chamber. The magma may also assimilate portions of host rock or mix with other batches of magma. These processes alter the composition of the remaining melt, so that any magma reaching the surface may be chemically quite different from its parent melt. Magmas that have been so altered are said to be “evolved” to distinguish them from “primitive” magmas that more closely resemble the composition of their mantle source. More highly evolved magmas are usually felsic, that is enriched in silica, volatiles, and other light elements compared to iron- and magnesium-rich (mafic) primitive magmas. The degree and extent to which magmas evolve over time is an indication of a planet’s level of internal heat and tectonic activity. The Earth’s continental crust is made up of evolved granitic rocks that developed through many episodes of magmatic reprocessing. Evolved igneous rocks are much less common on cold, dead bodies such as the Moon. Mars, being intermediate in size between the Earth and the Moon, is thought to be intermediate in its level of magmatic activity.
The most common form of volcanism on the Earth is basaltic. Basalts are extrusive igneous rocks derived from the partial melting of the upper mantle. They are rich in iron and magnesium (mafic) minerals and commonly dark gray in color. The principal type of volcanism on Mars is almost certainly basaltic too. On Earth, basaltic magmas commonly erupt as highly fluid flows, which either emerge directly from vents or form by the coalescence of molten clots at the base of fire fountains (Hawaiian eruption). These styles are also common on Mars, but the lower gravity and atmospheric pressure on Mars allow nucleation of gas bubbles (see above) to occur more readily and at greater depths than on Earth. As a consequence, Martian basaltic volcanoes are also capable of erupting large quantities of ash in Plinian-style eruptions. In a Plinian eruption, hot ash is incorporated into the atmosphere, forming a huge convective column (cloud). If insufficient atmosphere is incorporated, the column may collapse to form pyroclastic flows. Plinian eruptions are rare in basaltic volcanoes on Earth where such eruptions are most commonly associated with silica-rich andesitic or rhyolitic magmas (e.g., Mount St. Helens).
Because the lower gravity of Mars generates less buoyancy forces on magma rising through the crust, the magma chambers that feed volcanoes on Mars are thought to be deeper and much larger than those on Earth. If a magma body on Mars is to reach close enough to the surface to erupt before solidifying, it must be big. Consequently, eruptions on Mars are less frequent than on Earth, but are of enormous scale and eruptive rate when they do occur. Somewhat paradoxically, the lower gravity of Mars also allows for longer and more widespread lava flows. Lava eruptions on Mars may be unimaginably huge. A vast lava flow the size of the state of Oregon has recently been described in western Elysium Planitia. The flow is believed to have been emplaced turbulently over the span of several weeks and thought to be one of the youngest lava flows on Mars.”
“A Mars sample return mission (MSR) would be a spaceflight mission to collect rock and dust samples from Mars and to return them to Earth. Sample return would be a very powerful type of exploration, because analysis is freed from the time, budget, and space constraints of spacecraft sensors.
Since it is currently unknown whether life forms exist on Mars, the mission could potentially transfer viable organisms resulting in back contamination—the introduction of extraterrestrial organisms into Earth’s biosphere. The scientific consensus is that the potential for large-scale effects, either through pathogenesis or ecological disruption, is extremely small. Nevertheless, returned samples from Mars will be treated as potentially biohazardous until scientists can determine that the returned samples are safe. The goal is to reduce the probability of release of a Mars particle to less than one in a million. In addition, the proposed NASA Mars Sample Return mission will not be approved by NASA until the National Environmental Policy Act (NEPA) process has been completed. The NEPA process would require a public review of all potential impacts that could result from MSR, including worst case back contamination scenarios. It is likely that a formal Environmental Impact Statement (EIS) would have to be prepared. Furthermore, under the terms of Article VII of the Outer Space Treaty and probably various other legal frameworks, were a release of organisms to occur, the releasing nation or nations would be liable for any resultant damages.
Part of the sample return mission would be to prevent contact between the Martian environment and the exterior of the sample container. In order to eliminate the risk of parachute failure, the current plan is to use the thermal protection system to cushion the capsule upon impact (at terminal velocity). The sample container will be designed to withstand the force of the impact. To receive the returned samples, NASA proposed a specially designed Biosafety Level 4 containment facility, the Mars Sample Return Receiving facility (MSRRF). Not knowing what properties (e.g., size) any Martian organisms might exhibit is a complication in design of such a facility.”
“NASA’s Curiosity rover has found new evidence preserved in rocks on Mars that suggests the planet could have supported ancient life, as well as new evidence in the Martian atmosphere that relates to the search for current life on the Red Planet. While not necessarily evidence of life itself, these findings are a good sign for future missions exploring the planet’s surface and subsurface.
The findings include “tough” organic molecules in three-billion-year-old sedimentary rocks near the surface, as well as seasonal variations in the levels of methane in the atmosphere. Organic molecules contain carbon and hydrogen, and also may include oxygen, nitrogen and other elements. While commonly associated with life, organic molecules also can be created by non-biological processes and are not necessarily indicators of life.
Although the surface of Mars is inhospitable today, there is clear evidence that in the distant past, the Martian climate allowed liquid water – an essential ingredient for life as we know it – to pool at the surface. Data from Curiosity reveal that billions of years ago, a water lake inside Gale Crater held all the ingredients necessary for life, including chemical building blocks and energy sources. “
“The ExoMars rover is a planned robotic Mars rover, part of the international ExoMars programme led by the European Space Agency and the Russian Roscosmos State Corporation.
The rover is an autonomous six-wheeled terrain vehicle once designed to weigh up to 295 kg (650 lb), approximately 60% more than NASA’s 2004 Mars Exploration Rovers Spirit and Opportunity, but about one third that of NASA’s Curiosity rover launched in 2011.
In February 2012, following NASA’s withdrawal, the ESA went back to previous designs for a smaller rover, once calculated to be 207 kg (456 lb). Instrumentation will consist of the exobiology laboratory suite, known as Pasteur analytical laboratory to look for signs of biomolecules or biosignatures from past life. Among other instruments, the rover will also carry a 2-metre (6 ft 7 in) sub-surface drill to pull up samples for its on-board laboratory.
The lead builder of the ExoMars rover, the British division of Airbus Defence and Space, began procuring critical components in March 2014. In December 2014, ESA member states approved the funding for the rover, to be sent on the second launch in 2018, but insufficient funds had already started to threaten a launch delay until 2020. The wheels and suspension system are paid by the Canadian Space Agency and are being manufactured by MDA Corporation in Canada.
By March 2013, the spacecraft was scheduled to launch in 2018 with a Mars landing in early 2019. However, delays in European and Russian industrial activities and deliveries of scientific payloads, forced the launch to be pushed back. In May 2016, ESA announced that the mission had been moved to the next available launch window of July 2020. An ESA ministerial meeting in December 2016 will consider mission issues including €300 million in ExoMars funding and lessons learned from the ExoMars 2016 Schiaparelli mission. One concern is that the Schiaparelli module crashed during its Mars atmospheric entry, and this landing system is being produced in near duplication for the ExoMars lander.”
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