Mars

New Perseverance Rover To Land On Mars in 2021

Posted on by Chris McMahon

For a long time the Mars 2020 mission was just that — an unnamed mission to deliver a funky new rover to Mars that had been scheduled for liftoff this year. This is no longer a unnamed mission, with the new perseverance rover to land on Mars in 2021. Its launch is currently scheduled for a window from Jul 17 through to August 5. Its target is Mars’ Jezero Crater, and Perseverance is expected to touch down some time around February 18 2021.

Source: NASA

The new rover’s mission is to look for signs of past microbial life and to study Mars’ climate and geology. Life. The search for something like us outside our own planet. This drives so much of our space exploration.

The new rover is the size of domestic sedan, weighing in around 1 metric tonne. Its design shows the ambitions for NASA’s whole Mars program, with Perseverance, managed by JPL, setup with a sophisticated drill, sampling arm, and sample storage setup that will tuck away soil samples for future return to Earth. Just think about that for a second. That is a game changer. The first planned two-way physical movement between our planetary birthplace and the Red Planet. This is only one part of a wider program, with a Lunar mission in 2024 and plans to maintain a continued human presence on the Moon from around 2028.

When we do eventually get our intrepid explorers to Mars, we will need to know the best place to land and set up a base of operations. One of the keys to this will be knowing where to get water — or in the case of conditions on Mars — water ice.

Recent research has indicated that water ice may be as little as 2.5 cm below the surface. All Martian astronauts should be issued with a portable spade!

There is a good reason water ice is under the surface. In the thin Martian atmosphere, even water ice located directly on the surface would evaporate, sublimating directly from solid to vapour.

One of the key considerations for success of any mission to Mars will be the strategic allocation of a wide range of resources. We will need to know exactly what we need to take with us, and exactly what we should expect to harvest from Mars’ surface and atmosphere. This includes not only water, but chemicals that could be used to make rocket fuels (check out Juggling Molecules on Mars, my prior post on Robert Zubrin’s Mars Direct concept).

One of the ways we can make this assessment of resources from Earth is by using orbiting satellites already in place around Mars. Two of these, which are proving invaluable, are NASA’s Mars Reconnaissance Orbiter (MRO) and the Mars Odyssey orbiter. Both of these have been used to locate Martian water ice potentially accessible to astronauts. Learning how to detect the presence of this water ice has meant piecing together data from multiple sources so that the temperature of the soil could be used as an indicator of the presence and depth of water. The calibration of the temperature-water relationship was achieved by synthesizing data from physical excavation near the poles by the Phoenix lander and data from studies of impact craters by MRO, where the ice has been exposed by asteroid impacts. The Thermal Emission Imaging System (THEMIS) camera on Mars Odyssey, and its Gamma Ray Spectrometer — designed for water detection — have all been crucial.

So where is the accessible water? At the poles and mid-latitudes.

Any landing will likely be in the northern hemisphere though, since the lower elevation means more atmosphere to cushion any landing. Perhaps in sites such as Arcadia Planitia, which shows promising ice deposits close to the surface.

These are preludes to human exploration of one our nearest solar system neighbours. One of our familiar, well-behaved, and unoccupied planets.

What happens when we reach our first exoplanet? What about one that is tidally locked to its star?

Check out what happens in my SF novel The Tau Ceti Diversion when they touch down to explore the first exoplanet.

With the crew dead, and the starship’s fusion drive held back from a lethal explosion, Karic and the surviving officers reach a habitable planet – the last thing they expected was to find it already occupied . . .

Get it now!

The twin Earth almost had

Posted on by Chris McMahon

It’s hard to imagine Mars as a wet place, but that’s exactly what the data and images coming in from the Curiosity rover in Gale Crater are telling us. In fact, Mars is the twin Earth almost had.

Wet Mars.

3.5 billion years ago Gale Crater was filled with ponds of water, with streams cascading down the ancient basin’s walls, down to its wet centre. Eventually these watercourses dried up, but then perhaps the whole cycle repeated numerous times. Of course the water did eventually go for good.

Why?

Unlike Earth, which has a powerful magnetic field protecting its atmosphere, Mars has no such advantage. The solar wind — all those energised particles — just ram straight into it, knocking molecules right out of its atmosphere into space. Which molecules go first? The lightest ones. The hydrogen, the water, the oxygen. What is left is the heavier molecules like carbon dioxide, purely by virtue of the balance between gravitational attraction and the applied force of that solar wind. But that’s planet formation!

How do scientists conclude that there may have been these super wet and dry periods from the geology? By evidence left in the rocks, specifically high concentrations of mineral salts, deposited during periods of evaporation. This is not the first time Curiosity has found evidence of water here. The rover has also unearthed evidence of freshwater lakes.

Gale Crater: Source NASA JPL

The Gale crater itself started life with a bang, and is thought to have been formed by one massive impact. Sediment on the floor of the crater was built in layer upon layer of alluvial deposits, drying into a substantial formation over time. This layered rock was later wind-eroded to form the current Mount Sharp, which Curiosity is busily climbing.

So, we know there was water there, and likely there for long periods of time. The 64 million dollar question is, was this wet environment capable of supporting microbial life at the surface, and if so, for how long? How long were evolution’s engines allowed to turn, working to transform that life? And is that life still present?

If not for the weak magnetic field of Mars, we could have had a celestial twin. A planet in our own solar system with water-based life. Now that is something to think about!

Studies like this are invaluable in understanding our own home. As a SF writer, they provide invaluable insights when it comes to building your own planets! Check out my own world-building in The Tau Ceti Diversion.

With the crew dead, and the starship’s fusion drive held back from a lethal explosion, Karic and the surviving officers reach a habitable planet – the last thing they expected was to find it already occupied . . .

Get it now on Amazon!

When It Rains On Mars

Posted on by Chris McMahon

It’s been raining in Brisbane this week, but does it rain on Mars? Is it raining on Mars right now?

Hardly. 

Things on the Red Planet are a little different. Here’s some background.

mars

Mars has around one third of Earth’s gravity, around one hundredth of Earth’s atmospheric pressure, and its atmosphere is almost entirely composed of carbon dioxide. So far we have not found any trace of water. There is ice at the poles, but it’s dry ice – frozen carbon dioxide.

That hasn’t always been the case. The various Mars probes, orbital surveyors and buggies that are still roaming about the terrain have not found any water, but they have found ample evidence that water existed on Mars in the past. There are plenty of geological features on Mars that are consistent with the movement of large bodies of water, and secondary rocks that have been observed that are almost certain to have formed inside ancient lakes. It seems certain that our smaller solar system neighbour had a Warm Wet past.

So where is all that water now?

Very early in its history, things on Mars may have been very similar to conditions on nascent Earth, but striking differences between the two planets led to major changes.

For a start, Mars lacked the powerful magnetic field that could shunt away the effects of the solar wind. Like our other neighbour Venus, which also lacks a strong magnetic field, that means that lighter molecules are knocked right out of its atmosphere. Carbon dioxide is more than twice as heavy as water. The molecular weight of CO2 is 44, while H2O is 18. That means a lighter grip on the molecule by Mars’ already lower gravity. So Mars’ early water has likely to have been irrevocably lost to space.

So it does not rain on Mars, we can be sure of that, but do we want it to?

I think the answer to that question should be a resounding “Yes!”

We live on a small, single planet in a vast, unwelcoming universe. Our planet-evolved bodies just don’t do too well in space. Even trying to orbit the planet in a tiny capsule a few kilometre above our heads is problematic. We have to take all our food and water. There is exposure to harsh radiation, and the threat of cold as heat radiates away into space. The lack of gravity itself is a major threat to our health. We just weren’t built for space, but that’s fine because we have Earth, right?

Well, there might have been an intelligent dinosaur that thought the same thing as it watched a 100 mile wide asteroid plunge into South America 65 million years ago, sending the Earth into a decades-long winter that saw most life die.

That was not the only mass extinction that Earth has experienced. There have been many. Life survived, sure, but every time it was knocked orders of magnitude back down the ladder of complexity. Sentience requires stability. Shelter.

If humanity wants to protect the precious flame of its civilisation, we need to look outward.

The astronomical programs looking to other solar systems are geared to finding Earth analogues. Other Earth-sized planets with similar gravity, with water, and that are the right distance from their suns for life. But its going to be a long, long time before we have the technology to cross the vast distances of space to these new places. Think about this – at the same velocity as the Voyager 1 probe it would take an astronaut 70,000 years just to get to our closest star, which is only 4 lightyears away.

So what do we do?

We can terraform. We take a planet like Mars and make it habitable for humans. We can thicken the atmosphere, releasing chemicals with high global warming potential that heat the atmosphere. We can add water and oxygen by diverting asteroids with these resources and crashing them into Mars’ surface. Maybe we could even do some genetic tampering to help the new crop of Mars humans cope with the lower gravity.

So when will it rain on Mars?

I hope it wont’ be too long, because when rains on Mars humanity will have taken its next, great step into the future, ensuring its survival.

Need Dry Ice? Try Mars.

Posted on by Chris McMahon

Cropped A3 Poster with Red Button

A new study on the Red Planet suggests that the sharply etched channels that crisscross its surface may have been cut by frozen CO2, rather than water.

The contention is that these gullies are very much active, and continue to form on Mars even now in cold weather. If that’s the case, than it is almost certainly ‘dry ice’ or frozen CO2 that is developing this geological feature.

Recent photographs captured by the HiRISE camera aboard NASA’s Mars Reconnaissance Orbiter, have enable a new look at the phenomenon, allowing researchers such as lead author Colin Dundas to examine the timing of gully formation over the last couple of years.

downhill-end-martian-gully

The conclusion was that the gully formation is occurring in winter, when the Martian atmosphere is condensing out as a solid. Unlike Earth, where the temperature and pressure conditions for the formation of dry ice does not occur in nature, on Mars they occur every winter, most notably in the form of a seasonal polar ice cap.

As many as 38 sites have now been identified as showing active gully formation. All at times when it would be too cold for liquid water to flow.

So if your heading out the Red Planet – don’t forget the Beer Cooler. The dry ice is free :).

 

Juggling Molecules on Mars

Posted on by Chris McMahon

Cropped A3 Poster with Red Button

Here is a little bit of Chemical Engineering in Space.

So much of what we come into contact with is made of four elements – carbon, hydrogen, oxygen and nitrogen – the main elements of living systems. Add phosphorous and sulphur and you have what comprises 98% of all living systems.

The chemistry for juggling these four atoms – C, H, O, N – has been around for a long time.

Engineers and scientists have been confident enough in the chemistry and the various ways of manipulating them to propose various sets of reactions for use in gathering resources out in the vast reaches of space, as part of human exploration. This is part of a wider field of study called In Situ Resource Utilisation (ISRU), which has formed a key part of plans to explore other part of the solar system, particularly Mars, for the better part of two decades.

In the Mars Direct concept Robert Zubrin proposed using the well known Sabatier reaction:

CO2 + 4H2 => CH4 + 2 H2O

To react hydrogen with the Martian atmosphere to produce methane and water – very useful things to have on the red planet. The methane would be stored and kept for use as rocket fuel.

Methane and oxygen are a handy combination. In terms of chemical rocket propellant candidates, the Specific Impulse (Isp) of Methane and Oxygen at 3700 m/s is second only to Hydrogen and Oxygen at 4500 m/s (to convert to seconds of impulse multiply by 0.102).

Meanwhile the water from the Sabatier reaction would be split via very familiar electrolysis reaction:

2 H2O => 2H2 + O2

The idea was that only the hydrogen would need to be transported to the Red Plant. H2 weighs a lot less than CH4, freeing up space and payload for the 6 months transit to Mars.

Various test rigs were constructed on Earth, using analogues of the Martian atmosphere, which has been well characteristed since Viking. Mars has a lot of CO2 – more than 95% of the atmosphere – and a nice analogue of the Martion atmosphere right down to the low pressure could be similated for the rig. The CO2 is initially absorbed onto zeolite (an ever popular sorbent) under conditions simulating the Martian night. During the Martian ‘day’ the CO2 desorbs and passes into the Sabatier reaction vessel with the H2, which is heated to 300C. Reaction then occurs in the presence of the right catalyst (in this case pebbles of ruthenium on alumina). The water from the reaction is condensed out and passed to the electrolysis unit.

Still awake?

OK. Not surprisingly scientists and engineers planning Mars missions were concerned about overly complex systems forming such major part of a critical path.
Current plans for ISRU on Mars revolve around direct dissociation of the Martian atmosphere i.e.

2 CO2 => 2 CO + O2

[BTW if you could pull off this reaction at room temperature on Earth you would be an instant billionaire]

The current Mars Design Reference Mission proposes the production of oxygen on Mars through direct dissociation. Methane will be transported directly from Earth, with the ascent vehicle still using the tasty combination of methane and oxygen in its rocket engines.

So how is the CO2 pulled apart? There are many contenders, all of which uses a lot of energy. On Mars that energy is currently planned to be delivered by a 30 kW fission power system.

The front-runner for CO2 dissociation is thermal decomposition, followed by isolation of the O2 using a zirconia electrolytic membrane at high temperatures.

This system was developed for its first flight demonstration as the Oxygen Generator Subsystem (OGS) on the defunct Mars Surveyor Lander, which would have been launched in 2001 (but was cancelled following a string of Mars mission failures – Mars Climate Orbiter (1999), Mars Polar Lander (1999), Deep Space 2 Probes 2 (1999). That was a bad year. ).

The OGS was to demonstrate the production of oxygen from the Martian atmosphere using the zirconia solid-oxide oxygen generator hardware. This unit was designed to electrolyze CO2 at 750C (1382 F). The Yttria Stabilized zirconia material – once a voltage is applied across it – acts as a oxygen pump allowing the O2 to pass through it and be collected. The plan was to run the unit about ten times on the surface.

As I mentioned there were various contenders for the process. Such as molten carbonate cells, which operate around 550C with platinum electrodes immersed in a bulk reservoir of molten carbonate. Personally, the engineer in me shudders at the thought of trying to manage any sort of molten system that remotely.

The final system for CO2 decomposition used on Mars is probably still a work in progress. It will be interesting to see what develops there.

The fact is the initially proposed Sabatier reactions did not produce enough O2 to react with the methane, so some form of CO2 splitting process was still required.
So there are some things we can do to juggle molecules when we get to Mars.

Is everyone out there looking forward to getting to the Red Planet and grappling with what we find there?