Author: Inara Pey

In 1990, engineer-scientists David Baker and Robert Zubrin published Mars Direct, a paper outlining a relatively cost-effective means to initiate the human exploration of Mars. The paper was primarily written in response to NASA’s own 90-Day Study on Human Exploration of the Moon and Mars, a sprawling document rolling out of George H.W. Bush’s Space Exploration Initiative (SEI), a plan which NASA estimated would cost some US $500 billion in 1989 terms, and require NASA’s budget at the time be increased by 50% (from US $11 billion to $16.6 billion annually), and then adjusted for inflation every year from then on for some 30 years – and that was without accounting for the funds NASA would need to carry out all its other programmes.

While the 90-Day Study (as it was abbreviated to) outlined the means by which the United States could achieve a permanent presence in low-Earth orbit, then on the Moon before going onwards to Mars, it contained much within it that was nonsensical or at least highly questionable in terms of reaching Mars with crewed missions. However, it was the price tag that very quickly killed it – no surprises there.

Mars Direct, by contrast – whilst also controversial in several areas – was written to provide NASA with a means to go, as the name implied, directly to Mars in a manner that could be achieved in a finite time frame (10 years from project initiation through to the first crew setting foot on Mars) and at a cost that would not break NASA’s budget (and additional US $1 billion a year). A key idea of the outline – and one greatly expended upon by Zubrin in his 1996 book The Case for Mars: The Plan to Settle the Red Planet and Why We Must – was that of ISRU (in-situ resource utilisation), the use of resources available on Mars that could be leveraged to both reduce the complexities of the mission and also provide the means for an outpost on Mars to have a degree of self-sufficiency in several key areas.

This recognised that Mars has a lot of natural resources that could help support human missions to Mars – notably, but not limited to – the planet’s carbon dioxide atmosphere, which Zubrin demonstrated could be leveraged to produce vehicle propellants, water and oxygen using processes based on the Sabatier Reaction. Zubrin demonstrated this capability at his own facility in Colorado, and NASA has more recently tested it for oxygen production using their Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE) on the Mars 2020 rover, Perseverance.

Zubrin also pointed out that parts of the Martian surface are potentially mineralogically rich, and these minerals could be put to a wide range of uses in support of human operations on Mars, including producing fertilisers for growing food, producing plastics, ceramics and construction materials, generating oxygen and hydrogen, etc. Like many of the ideas Zubrin developed from 1996 through the early 2000s, his views on ISRU were met with a mix of conservatism and an attitude of “not invented here” on the part of NASA, leading to the agency largely downplaying or ignoring the potential for over a decade.

Since the success of MOXIE, NASA has encouraged research into ISRU. Now a new study led by the Planetary Sciences and Remote Sensing Group at the Institute of Geological Sciences, Freie Universität Berlin, not only outlines the wider potential for ISRU using hydrated minerals, it highlights regions on Mars which are not only rich in said minerals but offer potentially “safe” landing zones for crewed missions, they are in and of themselves interesting areas for scientific study.

The research paper – due to be published in the October 2024 issue of Acta Astronautica – initially focused on the extraction of hydrates for the production of water (and by extension, hydrogen and oxygen), a-la Zubrin’s ideas with Mars Direct (allowing for the latter focusing on doing so using the Martian atmosphere). However, as the study progressed, the research team – which included representatives from Germany, France and NASA – realised the extraction and use of hydrated minerals could yield additional benefits.

The hydrated minerals on Mars are the largest water reservoir on Mars known to date (mainly sulphates and phyllosilicates). Water can relatively easily extracted from sulphates and as described in the paper [it] is the most important resource, especially propellant production. However, the [resultant] minerals [obtained through the extraction process] can also be used as fertiliser for food production [while] the phyllosilicates could be used as building material or, for example, making ceramics.

Christoph Goss, Freie Universität Berlin, research lead

The team further noted that the extraction of these hydrates, which are located within the surface regolith rather than within the permafrost layer below it or deeper within the Martian crust, can be achieved through known techniques that are relatively fast and lightweight and do not require complex drilling and other deep-level extraction mechanisms. Thus, they could be achieved relatively easily via robotic means ahead of any human presence, in much the same way as Mars Direct proposes propellant production on Mars in advance of the arrival of any exploratory crew.

Robotic precursor missions could start mining and refining the resources, especially for propellant production. Also, for example, the robotic construction of habitats or the pre-production of oxygen are conceivable projects.  

Christoph Goss, Freie Universität Berlin, research lead

In analysing data gathered from a range of Mars observation satellites, including data gathered by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) instrument aboard NASA’s Mars Reconnaissance Orbiter (MRO) and mineralogical maps produced by ESA’s Mars Express mission orbiter, the researchers identified several locations on Mars where crewed exploration could be undertaken whilst leveraging mineral ISRU. Two of these locations in particular are especially well suited for this purpose. These are Mawrth Vallis, an ancient flood channel that opens into the Chryse Planitia plains in Mars’ northern hemisphere, and Juventae Chasma, a 5 km deep basin located north of Valles Marineris. Both present excellent opportunities for landing multiple vehicle on Mars and for carrying out a range of geological and scientific research.

In this, Mawrth Vallis is particularly interesting as it was one of the regions considered for exploration by both NASA’s Perseverance rover prior to Jezero Crater being selected for that mission, and also as a possible landing zone for ESA’s (hopefully) upcoming ExoMars rover, Rosalind Franklin – although the nearby Oxia Planum was eventually selected as the landing zone for that mission.

The study further points out that NASA and commercial organisations have looked at various technologies of ISRU utilising materials gathered from the surface of Mars. Whilst none are specifically referenced, one of the latter worth mentioning here was the MARCO POLO/Mars Pathfinder study conducted by engineers at Kennedy Space Centre in 2016.

MARCO POLO comprised an integrated system of a mock-up lander vehicle containing a “pressure cooker” designed to extract water, hydrogen and oxygen from an analogue of Martian regolith, and a robotic excavator, the Regolith Advanced Surface Systems Operations Robot (RASSOR). Operating on an automated basis, RASSOR demonstrated how a robot vehicle could harvest the analogue material from a test sandbox, and then deliver it to the mock-up lander for processing – with a robot “hopper” vehicle acting as a transfer vehicle between RASSOR and “lander” when the former was operating at greater distances from the that, so that RASSOR didn’t have to spend time making the transfer itself.

Ultimately, MARCO POLO went no further than the demonstration phase – the work was later re-targeted for use on the Moon in order to further develop concepts for use in the proposal Resource Prospector mission. However, the mission was cancelled in 2018 whilst still in its formulation stage.

This report might yet encourage the ideas developed by MARCO POLO (which also included the testing of a robot “hopper” tractor which could be used as an intermediary for transferring material from RASSOR to the “lander” thus allowing RASSOR to focus on gathering surface materials without having to constantly trundling back and forth to the lander to make the transfers itself) to once again be considered for future use on Mars.

Has JWST Found an Actual Water World?

LHR 1140 is a nominally unremarkable class M dwarf star located some 48 light-years away, and is now known to have two planets orbiting it. The first, discovered in 2017 and called simply LHS 1140 b, was initially thought to be an gaseous “mini Neptune” some 1.7 times the size of Earth and orbits its parent star every 25 terrestrial days. However, studies using the James Webb Space Telescope (JWST) during a series of observations of the planet as it transited its parent star have shown the planet is actually a rocky “super Earth”, with around 5.6 times the mass of our planet; what’s more, these studies have turned up a curiosity with the planet: calculations of its density suggest it has an abnormally – by Earth standards, at least – high level of water, with between 10-20% of the planet being water by mass (for comparison, only 0.02% of Earth is water by mass).

This potentially means that LHS 1140 b is the first confirmed “water world” discovered outside of the solar system. However, whether than water exists as a liquid or as ice (in full or in part) is open to question. Obviously, for LHS 1140 b to have liquid water present on its surface, this requires a dense enough atmosphere – and it’s going to take another year of observations at least to determine whether it does have an atmosphere, its composition and its density. In some ways, the odds of this being the case are weighted against LHS 1140 b.

Planets orbiting their parent star as close as LHS 1140 b does to its star face two challenges. The first is that class M stars like LHS 1140 are generally very violent, prone to excessive outbursts of flares and mass ejections. This can, given enough time, rip away any atmosphere of a nearby planet – and at just 9.6% the average distance between the Earth and the Sun, LHS 1140 b is very close to its parent star. The second is that such proximity to its star means that LHS 1140 b is tidally locked with its parent, always keeping the same hemisphere facing the star and in perpetual light and the other in perpetual, freezing darkness.

The first might be mitigated by the fact that LHS 1140, by red / brown dwarf standards, exceptionally calm. Therefore, it is possible that LHS 1140 b may have had a dense enough atmosphere to survive the star’s more violent phases and even now remains dense enough to support liquid water on its surface – at least within one hemisphere; the other will undoubtedly be frozen, and the regions separating the two subject to storms.

But even if the planet does not have an atmosphere, this also doesn’t necessarily all of the water it may contain is frozen; it may actually mean the planet is a gigantic “exo-Europa”, a planet covered in a shell of ice tens of kilometres thick and with a liquid water ocean beneath it, thanks to a mix of natural heating from the planet’s core, a degree of gravitational flexing as it is influenced by the gravities of both its parent star and the other known planet in the system, LHS 1140 c, and as a result of direct heating from the star itself.

This in turn raises a further point of intrigue and speculation. If LHS 1140 b does have an atmosphere, it could mean that whilst the majority of the planet is covered in ice, a single ocean – a “bull’s eye”, if you will – might exists at the point where the planet consistently receives the greatest amount of heat and light from its parent star. Estimates made by the astronomers studying the planet suggest that such an ocean could be up to 4,000 km in diameter – roughly half the size of our Atlantic Ocean – and with water temperatures reaching around 20oC, which is very approximately the average temperature of the Atlantic Ocean between the tropics.

Obviously, if this were to be the case, then LHS 1140 b would be a truly unique world; the problem being that unless we manage to send to probe to it, we’ll never be able to look down on such a strange sight. And even putting aside the idea of such an exotic ocean existing on a faraway world, it’s going to take as much as a year’s worth of careful observations of the planet in order to be able to detect whether or not it has an atmosphere.

There is still a lot to be learned about LHS 1140 b, including whether or not it has an atmosphere, as noted above. But right now, all the evidence points to the fact that whether fully or partially ice, the fact that LHS 1140 b appear to have so much water in terms of its mass has important connotations for the potential of water being present on other worlds beyond our solar system.

Ariane 6 Launch Update

On Tuesday, July 9th, as as previewed in my previous Space Sunday article, the European Space Agency (ESA) successfully completed the maiden launch of its new Ariane 6 heavy lift launch vehicle (HLLV).

The rocket departed the pad at the Kourou launch site in French Guiana at 1901 UTC, making a flawless ascent, its two solid rocket boosters separating just over two minutes into the flight at an altitude of 62 km. The core stage, powered by its single Vulcain motor, continued to burn for another 6 minutes, carrying the upper stage to orbital velocity prior to shutting down and the core stage separating. The upper stage Vinci motor then fired to raise the vehicle onto its designated orbital track so that deployment of the rideshare payloads could commence from a 577-km altitude circular orbit.

Deployment of the core payloads proceeded smoothly and was completed within two hours of launch. However, problems were encountered during the demonstration of the Vinci engine’s ability to restart itself. Two engine burns were schedule for the flight, the second of which failed when the auxiliary power unit (APU) controlling the engine’s restart suffered an anomaly. This curtailed the planned de-orbit burn of the upper stage, leaving it in orbit. This caused the planned deployment of two re-entry test capsules to be cancelled. The upper stage is now expected to undergo a natural orbital decay and re-enter the atmosphere on its own in the future.

Despite this issue, the launch is seen as a success, and ArianeGroup and ESA are now focused on the next Ariane 6 launch, which is due to place France’s CSO-3 spy satellite into orbit later this year.