At left: Steel is seen to corrode into siderite (FeCO3) when immersed in subcritical liquid carbon dioxide (LCO2). At right: Samples of albite (a plagioclase feldspar) and a sandstone core are observed to form red rhodochrosite (MnCO3) when exposed to supercritical CO2 in the presence of a water solution with potassium chloride and manganese chloride, with particularly strong reaction near the interface of the two solutions. In both experiments, water saturation is provided by floating LCO2 on the water. Under the lower pressure conditions characteristic of early Mars, the water would float on the LCO2. Credits:Photos courtesy of Todd Schaef/PNNL (left) and Earl Mattson/Mattson Hydrology (right).
Most people will think of a dry arid landscape when they think of Mars. When seen from orbit, dry river channels and lake-beds can be seen along with mineral deposits thought to be the created in the presence of liquid water. A team of researches now suggest that liquid carbon dioxide could also explain the features seen. On Earth, a process known as carbon sequestration liquefies CO2 which is buried underground. There are a number of mechanisms that could explain the liquid CO2 underground the researchers suggest.
Mars holds a very special place in our hearts. Chiefly because of all the other planets in the Solar System Mars is probably the place we are going to find some tantalising clues or maybe even evidence of prehistoric life. NASA Perseverance Rover has been trundling around the Jezero Crater looking for evidence that it was once hospitable to life. To that end it has not only been collecting rock samples but air samples too and scientists can’t wait to get their hands on them.
Image of the Martian atmosphere and surface obtained by the Viking 1 orbiter in June 1976. (Credit: NASA/Viking 1)
NASA is actively working to return surface samples from Mars in the next few years, which they hope will help us better understand whether ancient life once existed on the Red Planet’s surface billions of years ago. But what about atmospheric samples? Could these provide scientists with better information pertaining to the history of Mars? This is what a recent study presented at the 55th Lunar and Planetary Science Conference hopes to address as a team of international researchers investigated the significance of returning atmospheric samples from Mars and how these could teach us about the formation and evolution of the Red Planet.
Animation showing a series of pre-sunrise images of drifting clouds in the Martian sky taken by NASA's Perseverance rover on March 18, 2023. (Credit: NASA/JPL-Caltech)
NASA’s Perseverance rover mission provided a bluish pre-sunrise gift above Jezero Crater on March 18, 2022, aka Sol 738, or the 738th Martian day of the mission, with “sol” being the official timekeeping method for Mars missions since one Martian day is approximately 40 minutes longer than one Earth day. And, on this particular sol, the car-sized explorer used one of its navigation cameras (Navcam) to snap images of high-altitude clouds drifting in the Martian sky, which it shared on its officially Twitter page on March 23, 2023.
An image from China's Zhurong rover shows spacecraft hardware in the foreground and Martian terrain in the background. (Credit: CNSA)
On May 22nd, 2021, the Zhurong rover – part of Tianwen-1, China’s first mission to Mars – descended from its lander and drove on the Martian surface for the first time. According to the mission’s official social media account, the rover drove down its descent ramp from the Tianwen-1 lander at 10:40 a.m. Beijing time (07:40 p.m. PDT; 10:40 p.m. EDT) and placed its wheels upon the surface of Mars.
Plasma globes are a common enough sight in retails stores across the rich world. If you’ve ever seen one and gotten a chance to touch it, you’ve seen how the plasma will arc toward your touch creating a sense that you’re able to harness electricity like Thor.
That effect does not only take place on Earth – anywhere there is a charge build-up that causes a high enough electrical potential between two points to create an electrical glow or corona. Now a team at NASA think that a large charge build-up might occur when Ingenuity, Perseverance’s helicopter companion, takes to the sky.
On July 19th, 2020, the Emirates Mars Mission (EMM) – aka. Al Amal (“Hope” in Arabic) – launched from the Tanegashima Space Center in Japan on its way to Mars. This mission, the first interplanetary effort to be mounted by an Arab nation, is being carried out by the Mohammed bin Rashid Space Centre (MBRSC) in the United Arab Emirates (UAE) in collaboration with a number of research institutions internationally.
The yellow-white cloud in the bottom-center of this image is a Mars "dust tower" - a concentrated cloud of dust that can be lofted dozens of miles above the surface. The blue-white plumes are water vapor clouds. This image was taken on Nov. 30, 2010, by NASA's Mars Reconnaissance Orbiter. Credit: NASA/JPL-Caltech/MSSS
When a huge dust storm on Mars—like the one in 2018—reaches its full power, it can turn into a globe-bestriding colossus. This happens regularly on Mars, and these storms usually start out as a series of smaller, runaway storms. NASA scientists say that these storms can spawn massive towers of Martian dust that reach 80 km high.
And that phenomenon might help explain how Mars lost its water.
A screenshot of a NASA simulation of Martian water-ice clouds. Image Credit: NASA/Ames Research Center/D. Ellsworth
The Martian atmosphere is a lot different than Earth’s. It’s over 95% carbon dioxide, and contains only trace amounts of oxygen and water vapor. But that trace amount of water vapor still plays a pronounced role in the climate.
CuSat size system and Cargo Bay. Credit: University of Manchester
One of the more challenging aspects of space exploration and spacecraft design is planning for re-entry. Even in the case of thinly-atmosphered planets like Mars, entering a planet’s atmosphere is known to cause a great deal of heat and friction. For this reason, spacecraft have always been equipped with heat shields to absorb this energy and ensure that the spacecraft do not crash or burn up during re-entry.
Unfortunately, current spacecraft must rely on huge inflatable or mechanically deployed shields, which are often heavy and complicated to use. To address this, a PhD student from the University of Manchester has developed a prototype for a heat shield that would rely on centrifugal forces to stiffen flexible, lightweight materials. This prototype, which is the first of its kind, could reduce the cost of space travel and facilitate future missions to Mars.
The CubeSat-sized prototype heat shield designed by the University of Manchester team. Credit: University of Manchester
To put it simply, planets with atmospheres allow spacecraft to utilize aerodynamic drag to slow down in preparation for landing. This process creates a tremendous amount of heat. In the case of Earth’s atmosphere, temperatures of 10,000 °C (18,000 °F) are generated and the air around the spacecraft can turn into plasma. For this reason, spacecraft require a front-end mounted heat shield that can tolerate extreme heat and is aerodynamic in shape.
When deploying to Mars, the circumstances are somewhat different, but the challenge remains the same. While the Martian atmosphere is less than 1% that of Earth’s – with an average surface pressure of 0.636 kPa compared to Earth’s 101.325 kPa – spacecraft still require heat shields to avoid burnup and carry heavy loads. Wu’s design potentially solves both of these issues.
The prototype’s design, which consists of a skirt-shaped shield designed to spin, seeks to create a heat shield that can accommodate the needs of current and future space missions. As Wu explained:
“Spacecraft for future missions must be larger and heavier than ever before, meaning that heat shields will become increasingly too large to manage… Spacecraft for future missions must be larger and heavier than ever before, meaning that heat shields will become increasingly too large to manage.”
Wu and his colleagues described their concept in a recent study that appeared in the journal Arca Astronautica (titled “Flexible heat shields deployed by centrifugal force“). The design consists of an advanced, flexible material that has a high temperature tolerance and allows for easy-folding and storage aboard a spacecraft. The material becomes rigid as the shield applies centrifugal force, which is accomplished by rotating upon entry.
Wu and his team performing the drop test of their heat shield prototype. Credit: University of Manchester
So far, Wu and his team have conducted a drop test with the prototype from an altitude of 100 m (328 ft) using a balloon (the video of which is posted below). They also conducted a structural dynamic analysis that confirmed that the heat shield is capable of automatically engaging in a sufficient spin rate (6 revolutions per second) when deployed from altitudes of higher than 30 km (18.64 mi) – which coincides with the Earth’s stratosphere.
The team also conducted a thermal analysis that indicated that the heat shield could reduce front end temperatures by 100 K (100 °C; 212 °F) on a CubeSat-sized vehicle without the need for thermal insulation around the shield itself (unlike inflatable structures). The design is also self-regulating, meaning that it does not rely on additional machinery, reducing the weight of a spacecraft even further.
And unlike conventional designs, their prototype is scalable for use aboard smaller spacecraft like CubeSats. By being equipped with such a shield, CubeSats could be recovered after they re-enter the Earth’s atmosphere, effectively becoming reusable. This is all in keeping with current efforts to make space exploration and research cost-effective, in part through the development of reusable and retrievable parts. As Wu explained:
“More and more research is being conducted in space, but this is usually very expensive and the equipment has to share a ride with other vehicles. Since this prototype is lightweight and flexible enough for use on smaller satellites, research could be made easier and cheaper. The heat shield would also help save cost in recovery missions, as its high induced drag reduces the amount of fuel burned upon re-entry.”
When it comes time for heavier spacecraft to be deployed to Mars, which will likely involve crewed missions, it is entirely possible that the heat shields that ensure they make it safely to the surface are composed of lightweight, flexible materials that spin to become rigid. In the meantime, this design could enable lightweight and compact entry systems for smaller spacecraft, making CubeSat research that much more affordable.
Such is the nature of modern space exploration, which is all about cutting costs and making space more accessible. And be sure to check out this video from the team’s drop test as well, courtesy of Rui Wui and the MACE team:
