Manned Mars Missions 2

By Duncan Lunan

In some circles, only unmanned exploration of Mars would be considered acceptable:  the ‘Case for Mars’ conferences at the University of Colorado in Boulder, in the 1980s, were organised by the local chapter of the Planetary Society as a challenge to that society’s exclusive emphasis on unmanned exploration, and although they succeeded in putting manned exploration back on the agenda, it was on the insistence that it was purely for scientific purposes and had no practical object.  At the first ‘Case for Mars’ conference, which I attended, Dr. Brian O’Leary advanced a new version of Dr. Fred Singer’s ‘PH.D.’ scenario, in which Phobos and Deimos were to be strip-mined to supply materials which would lower the cost of space development in the Earth-Moon system.  In response, Dr. Ivan Almaar of Budapest immediately proposed that they be declared a scientific reservation, off-limits for any practical uses.  But after a hiatus of nearly 20 years, the unmanned exploration of Mars was suddenly back on:  since 2004 we have had a succession of orbiters, landers, rovers, and now a helicopter!  

NASA plan for Marsbase, Johnson Space Center, 1985

If Russia’s Phobos-GRUNT mission had succeeded, there would have been sample return from Phobos well before now.  That was the main aim of the 2010 mission, which also carried two biological packages.  The Planetary Society was sending ten different species including tardigrades (‘water bears’), seeds and bacteria, mostly in dormant states, to test the possibility of panspermia, in which life may travel from planet to planet, hitching a ride on fragments of planetary material.  Tests would be carried out when Phobos-Grunt returned to Earth to see if the bacteria survived.  The Russian package included crustaceans, mosquito larvae, bacteria and fungi, to study how cosmic radiation can effect these different types of life during an interplanetary trip.   (Ian O’Neill, ‘Russia Will Send Life to Phobos’, Universe Today,  March 1st, 2009.)   Sadly however the flight sequencer failed in Low Earth Orbit and the Phobos-Grunt probe fell back to Earth – but there is a second attempt in the works.  Meanwhile, the Perseverance rover now in Jezero crater is stockpiling samples to be picked up and returned by a future mission, for which the European Space Agency is building the carrier vehicle.

Phobos Mars Moon HIRISE MRO PIA10368

The Space Exploration Initiative devised by NASA under President Geoge Bush Snr proposed nuclear-powered spacecraft, refuelling from Phobos, and building a massive Mars base.  Described by its opponents as ‘Battlestar Galactica’, it completely failed to win the backing of Congress and Senate.  Under George Bush Jnr a new plan was formulated for a programme called Constellation, which would use a solid-fuel rocket called Ares 1 to put astronauts into orbit, and a liquid-fuelled one with solid clip-on boosters, Ares 5, for a return to the Moon and for manned Mars missions.  The first stage of Ares 1 had a test launch after President Obama took office, but after that Constellation was cancelled except for continuing work on the Orion crew capsule, which eventually had a test launch on a Titan IV Heavy rocket to 6000 miles’ altitude, in 2014.  Meanwhile, protests from Republican supporters of the space programme led to the start of work on the Space Launch System, as a replacement for Ares V.  Solid-fuel boosters for it have been under test since 2015, and in the same year firings began of the main engines, which are being reused from the Space Shuttle programme  (wastefully, since those engines are reusable but will be used only once each on SLS).  Due to budget limitations the SLS programme is years behind schedule, but the vehicle for the first unmanned launch is now under assembly at Kennedy Space Centre.  President Trump’s demand for a manned lunar landing by 2024 seems certain to be postponed, but the programme is advancing and the eventual target is Mars.

The world’s longest-running SF graphics series was Jeff Hawke, created for the Daily Expressby Sydney Jordan from Dundee.  Just before the Moon landing in July 1969, I pointed out that ten years earlier he had predicted the date of the first landing as August 4th, 1969, only two weeks out. 

In the later version of Jeff Hawke, published in the Daily Record as Lance Mclane, he predicted in 1984 that the first manned mission to Mars would be a Phobos landing in 2033, and that too may prove prophetic.  NASA has looked at manned Mars missions in the early 2030s, in the Constellation and SLS programmes.   Mars is at opposition on June 27th 2033, and at its closest to Earth on July 5th.  In 2007 NASA announced 2037 as a possible mission date, but in 2012 it was revised to 2031, and at the moment 2033 is the proposed date, to be followed by a Mars landing in 2039.

As of 2013, the newest player in the ‘manned Mars’ game was Elon Musk, already leading the field in the new private US space initiatives with his Falcon 9 launcher and Dragon capsule, which had twice taken cargo to the International Space Station.  Musk is now flying crews to the Space Station and has achieved three successful flights of his Falcon Heavy rocket, which could be used for Mars missions.  In 2012 he declared that he could put astronauts on Mars for $2.5 billion, against NASA estimates of $500 billion.  When asked if his figure wasn’t ridiculous, he replied, “Yes, but we’re so used to overspending on space that I had to put an extra zero on the end to get people to listen to me.”   Whatever the budget, Musk is now conducting prototype launches of his Starship vehicle, capable of taking 100 people to Mars to found a settlement, and has unveiled and test-fired the Super Heavy booster which is to launch it.  We’re still a long way from a crewed mission to Mars, let alone a permanent settlement, but we shall see.

In the ‘strategic approach to the Solar System’ proposed by the late Prof. Krafft Ehricke, harnessing its resources for the future well-being of mankind, he regarded Mars as a distraction, or a detour.  With half the mass of Earth, one-third of its surface gravity, and a surface atmospheric pressure equivalent to Earth’s twenty miles up, Mars is ‘strategically’ the worst of all possible worlds:  big enough to be hard to leave, uneconomic to export from, but not big enough to hold free oxygen, so exposed at the surface to almost the full force of solar ultra-violet radiation.  The atmosphere is dense enough to sustain violent dust storms but not dense enough to hold what heat there is in at night;  the planet has no proper core and no magnetic field, leaving it fully exposed to solar flare storms.  And worst of all, the atmosphere is too thin to provide protection from high-energy cosmic rays, meaning that anyone who has travelled, unshielded, from Earth to Mars, will have to spend most of the rest of their life underground.  Three years’ exposure to primary cosmic rays is enough to produce measurable damage to the central nervous system, and to block them off you need protection equivalent to five metres of rock.

For the strategic approach, the first targets are the Moon and the Earth-grazing asteroids.   Unfortunately, neither is sufficiently glamorous is to command the commitment we need from governments to get there and get things done.  Given that Venus is so similar to Earth in size, perhaps it’s just as well that its atmosphere puts it off-limits to human exploration meantime.   In that respect, Mars is more of a problem, unless a glamorous programme to explore it lets us achieve more worthwhile things on the side.  NASA’s 1985 proposal to get to Mars using lunar liquid oxygen needs serious attention.

In the longer term, the practical possibilities for Mars become a lot more interesting.  The evidence of the river channels suggests that Mars had a dense atmosphere in the past, and it’s possible that the northern hemisphere was once covered with ocean – and could be again.   We could even give Mars a breathable atmosphere:  at that distance from the Sun, and with the gravity it does have, the loss rate for atmospheric oxygen would be quite low and it could be replenished.  As I said in Man and the Planets, some latter-day John Carter may yet have to make his dash to save the great atmosphere factory of Barsoom.  But as an alternative, bear in mind that the low gravity could allow the whole of Mars to be glassed over, turning it into a greenhouse with a land area larger than the Earth’s.  No, that’s not a mistake:  three-quarters of Earth’s surface is under water and unless we bring back the Boreal Ocean, terraformed Mars would have more land area than the Earth.

These color-enhanced views of Deimos, the smaller of the two moons of Mars, result from imaging on Feb. 21, 2009, by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA’s Mars Reconnaissance Orbiter.

The shallow gravity gradient has other advantages.  Mars’s day is only 35 minutes longer than Earth’s, so space elevators are possible, and over Mars, they could be built with known materials such as Kevlar.  And if we do that, nature has handed us an incredible gift in Deimos, which is nearly in areo-synchronous orbit.  From the Martian surface, when Deimos rises in the east it takes three days to reach the western horizon.  The more massive the counterweight, the larger the traffic a space elevator can handle, and if we used Deimos that way then, with all that iron ore lying about on the surface, Mars could fulfil James Blish’s prediction in Earthman Come Home, becoming “the Pittsburg of the Solar System”.  It would of course be necessary to move Phobos out of the equatorial plane, and keep its new inclined orbit in the right phase to stop it taking out the elevator in a big way.

The volcano Pavonis Mons, on the Martian equator and standing high on the Tharsis Ridge, might be the ideal anchor point for the elevator.  That would at least keep it above all but the worst of the Martian dust storms, though it has to be noted that in the 1971 global storm Mariner 9 tracked dust moving at 400 miles per hour, half the local speed of sound, over the still higher summit of Olympus Mons.  Nothing so extreme has happened during the Viking and Curiosity sojourns on the Martian surface, nothing like that happened even when a global obscuration was in progress, so not all storms are equally violent  (though the one in 2018 was thick enough to kill the solar-powered Opportunity rover).  But if they ever happen, like the one at the beginning of The Martian, presumably our settlements will have to be protected from them – rebuilding a devastated colony on Mars would be a little harder than reconstructing beach property in Florida.

One of the curiosities in 2001, a Space Odyssey is in the lunar shuttle touchdown sequence  (in which the Earth and the descending globular spacecraft are, impossibly, in completely different phases).  The segments of a dome open like petals below it, and the spacecraft touches down on a pad which turns out to be an elevator, lowering it into a huge underground hangar which is red-lit and therefore in vacuum – in any case, you can still see black space overhead all the way to the end of the sequence, because the hatch is still sliding shut.  So what is the dome for – what function does it serve?  On Mars it would make sense, protecting the launch and landing pad from dust storms, preventing it from being damaged or buried.

Because of the near-irrelevance of Mars to the strategic approach meantime, I titled its chapter in Man and the Planets after Von Braun, Bonestell and Ley, calling it The Exploration of Mars, not the settlement, colonisation, development or industrialisation.  And however much we change Mars in the middle term, for the long term we should recall the final cautionary remark:  “… it’s worth remembering that Mars can’t be permanently terraformed.  Someday, unless our persistence in renewing the air and water quite literally outlasts the Sun’s, the great storms will come again.”

Related article: Manned Mars Missions – 1

Leave a Reply