Space Exploration

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!

First Earth-Sized Planet in Habitable Zone

Posted on by Chris McMahon

The last few decades have been an exciting time for the exploration of other solar systems. So many exoplanets have been found, with the total going from literally zero to thousands. First with Kepler, then Spitzer, and now TESS — the Transiting Exoplanet Survey Satellite — which can detect minute fluctuations in the light emitted by target stars as their planets transit in front of their suns. This has been described as analogous to analysing the light from a lit-up skyscraper at night and being able to detect someone shifting down their office blind by one centimetre! More on TESS here.

All the planets of interest identified by the TESS will be classified with the TOI prefix ( Transiting Exoplanet Survey Satellite Object of Interest).

TESS has already had its first find. An Earth-sized planet in the habitable zone of the star designated TOI 700, which is 100 lightyears away. Cosmic spitting distance! For the astronomically minded, this star is in the constellation of Dorado. It’s so exciting  to imagine these stars as fostering a solar system favourable to life. TOI 700 is a cool M dwarf star, also known as a red dwarf star, the coolest in the cosmic stellar sequence, the most common, and the longest-lived stars. This red dwarf has 50% of our Sun’s surface temperature, and 40% of its radius — like a cool little sister.

TOI700 d First Earth-Sized Planet in a Habitable Zone

The planet that all the excitement is about is TOI 700 d, which is the outermost of three identified planets in that system. It is estimated to be around 20% larger than Earth, with an orbital period of 37 days, receiving perhaps 86% of the energy that our Sun provides to Earth. All three planets in this system are thought to be tidally locked to their star. This means they rotate once per orbit, with one face always toward its sun and the other permanently facing away — day and night sides — much like how the Moon is tidally locked to Earth.

Based on our solar system, we are used to the idea of rocky planets existing closer to the sun, with gas giants appearing further out. In TOI 700 the closest planet to the sun (TOI 700 b) is Earth-sized and rocky, the second (TOI 700 c) is likely have a composition similar to Neptune, while the goldilocks third planet (TOI 700 d) is Earth-sized and rocky!

What makes TOI 700 d unique is that it’s the first Earth-sized exoplanet located in the habitable zone. Astronomers have found thousands of Jupiter-sized planets, many of them “hot Jupiters” that orbit very close to their star, and other rocky planets, some of which are Earth-sized, but all of which lay outside the zone where liquid water might exist on their surface.

The only hitch for TOI 700 d is that despite receiving less solar energy, it is thought to be receiving up to 35 times more extreme UV radiation, which is not so great news for developing life. Regardless, TOI 700 d is a solid candidate for a habitable world, and one in our close stellar neighbourhood.

Future work will be targeted at characterisation of the planets’ atmospheres, and if possible, their actual compositions. Given the fact that they are likely to be tidally locked, the 3D climate modellers are going to have their work cut out for them!

The likelihood that the three planets in this system might be tidally locked has really tickled my SF brain, since one of the major premises of my SF book The Tau Ceti Diversion, was that the target planet (where all the action takes place) is tidally locked to its sun.

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 finally reach a habitable planet. The last thing they expected was to find it already occupied . . .

Get The Tau Ceti Diversion here!

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!

Atmosphere on a Fictional Planet

Posted on by Chris McMahon

So you’ve got your story working, but how do you sketch out the atmosphere on a fictional planet? Maybe you have some idea of the mass, radius and gravity and you’ve got the orbit in the ‘sweet spot’ goldilocks zone where liquid water can be present on the surface, but what will conditions on the surface actually be like?

What sort of factors go into whether that planet, presumably an Earth-like rocky world, will have an atmosphere that can support terrestrial life?

Planets above a blue planet

The gravity of the planet is one key variable, along with surface temperature, and the strength of the planet’s magnetosphere, which can protect against atmospheric stripping due to solar wind.

The surface temperature of a planet will determine how much kinetic energy, and so velocity, the gas particles will have. If that temperature, and velocity, is high enough it will exceed the planet’s escape velocity and the molecules will fly off into space like tiny spaceship explorers. Earth has lost most of its very light gases like hydrogen and helium in this way, whereas the gas giants have enough gravity to retain them. We kept our water, and we’ve got a lot of it! If Earth was sitting where Venus is things would be different, the additional temperature would give those lighter gases like water vapour enough energy to escape, and also prevent any being trapped on the planet’s surface itself (whereas some is ‘sequestered’ on Earth as water and ice at our lower surface temperature). But beyond the early, settling down period where the lighter gases are lost, any world larger than Earth, orbiting in that goldilocks zone, will not continue to lose a significant proportion of its atmosphere through thermal processes.

Here’s a cool pictorial on thermal escape (source: Wikipedia).

Solar_system_escape_velocity_vs_surface_temperature.svg

Beyond that thermal stripping process, is where the magnetosphere comes into its own, deflecting the solar wind – one of the main non-thermal processes leading to atmospheric loss. The very thickness of a planet’s atmosphere (retained due to its gravity, and as a function of surface temperature), will also protect a planet from the solar wind, even in the absence of a magnetosphere. It’s thought that Venus’ thick atmosphere, ionized by solar radiation and the solar wind, produces magnetic moments that act out to 1.2-1.5 planetary radii away from the planet to deflect the solar wind, much like a magnetosphere (but an order of magnitude closer to the planet). In fact, it’s thought the dominant non-thermal atmospheric loss process on Venus is actually from a type of naturally induced electrical acceleration. On Venus, the stripping of the lighter electrons from the atmosphere causes an excess of positive charges, accelerating ions like H+ out of its atmosphere.

Our explorers need a breathable atmosphere, but they also need an atmospheric pressure like our own Earth’s.

My fictional planet of Cru, in the Tau Ceti Diversion, has comparable surface temperatures to Earth, but a higher surface gravity. The higher surface gravity, and its lower density, allowed me to assume a lighter atmospheric composition, and allow an atmospheric pressure, or weight of atmosphere, close to surface much like Earth’s. That atmospheric composition is crucial to having a reasonable atmospheric pressure – its not just the gravity of the planet. Venus, even though it has slighter lower gravity than Earth, has a crushing atmospheric pressure of 90 times Earth’s due to its heavier  atmosphere of CO2.

Check out what my my intrepid explorers found in my novel The Tau Ceti Diversion when they touched down on the planet!

Read it now on Amazon!

Tau-Ceti-Diversion-severed-ebook-cover (Medium)

SpaceX Claims the Title of World’s Most Powerful Rocket

Posted on by Chris McMahon

This week’s launch of the Falcon Heavy Booster on Tuesday (February 6) means that Elon Musk’s SpaceX claims the title of world’s most powerful rocket. The Falcon Heavy can carry twice the payload as its nearest competitor, the United Launch Alliances Delta IV Heavy – and at a lower cost.

Every time I see footage of the SpaceX boosters touching down on reentry I get a shiver down my spine. This is really some revolutionary technology, driven by revolutionary thinking. All based on the simple premise that the most expensive thing about spaceflight is the hardware – not the fuel. If you can reuse the booster that gets you to orbit, then the whole ball game changes.

Watch the Falcon Heavy launch footage here.

 

The two smaller side-boosters completed their vertical reentry landing without a hitch, but the much larger central booster missed its drone-ship landing and crashed into the ocean. Still, the test is considered a success.

Falcon Heavy can lift an impressive 64 metric tons, certainly more than adequate for the astronaut-come-space-dummy and Tesla Roadster that Musk send into orbit around the sun, which is expected to orbit for hundred’s of millions of years! That’s a hell of a time capsule!

Falcon Heavy launches come at an estimated cost of $90 million, with the Delta IV launching 29 metric tons for between $300 and $500 million per flight. It’s easy to see how SpaceX’s paradigm is changing the future of space travel.

 

There are two more Falcon Heavy launches scheduled for this year. The first is a communications satellite, and the second a Space Test Program for the US Air Force that will also launch a solar sail for the Planetary Society. As well as the possible launch of two passengers in a trip around the moon. To apply for a ticket, click here – no, just kidding! – but wouldn’t that be awesome?

And this isn’t the end for the development of SpaceX’s reusable launch systems. SpaceX’s BFR (Big F- Rocket), a megarocket capable of a single-stage to orbit fully fuelled, will potentially launch a spaceship carrying up to 100 passengers, taking us further on a development path that might lead to the establishment of a city on Mars – one of Musk’s ultimate goals.

Space exploration is at the heart of my novel The Tau Ceti Diversion! But they got a little further than the asteroid belt!

Read it now on Amazon!

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