Putting life on Mars

The atmosphere on Mars is mostly carbon dioxide, the planetary surface is too cold to sustain human life, and the gravity there is just 38 percent of Earth’s. And yet, life on Mars has fascinated and inspired people around the world seemingly since it first occurred to us we could leave Earth behind.

The Red Planet holds many secrets, some of which have been elucidated by plucky robots like the Mars Rover Opportunity and, in the wake of its death, attention is turning to how humans could survive a similar journey.

A human mission to Mars has been the subject of science fiction, aerospace engineering, and scientific proposals since the 19th century, and now we’re getting serious. But despite all plans of terraforming or colonising, getting there in the first place is the main concern.

NASA is still the only agency that has been capable of landing a spacecraft on Mars—all attempts by the European Space Agency have dramatically failed, with the recent crash of the Schiaparelli probe a fine example. The lessons learnt from this are that entry, descent and a soft landing on Mars are the components of the most critical phase in a spacecraft’s journey, and uncertainty as to atmospheric density and navigation errors make it even more strenuous.

‘Landing on Mars is super hard,’ explains Dr Thomas Zurbuchen, Science Mission Director at NASA. ‘On average, 50 percent of the missions that go to Mars fail. We have the worst of both worlds on Mars: if you come into the Earth from the space station, the atmosphere slows you down. We have a massive atmosphere and we know how to handle this. If you land on the moon, that’s easy because there’s no atmosphere, and we use retro boosters to handle that. If you want to land on Mars, you can’t ignore the atmosphere, but it’s not going to help you. You have to use a shell, a supersonic parachute, and then the retro rockets—all autonomously—to get your spacecraft to the surface. If any of this fails, you’ll make a new crater.’

Presuming a successful landing, the next step for mankind is simply surviving. Space agencies and aerospace companies around the world continue to address the challenges of living in space, such as using existing resources, options for disposing of rubbish, and more. Missions to the moon are about 1,000 times farther from Earth than missions to the International Space Station, requiring systems that can reliably operate far from home, supporting all the needs of human life. Then, there’s the 34 million mile trip to Mars to consider. Mars has a strange orbit compared to Earth’s, meaning there’s an optimal time to leave Earth to make the shortest journey—every 26 months. Miss this launch window and you’re looking at a 300 day commute.

Innovative companies have been designing habitat prototypes that are self-sustaining, sealed against the uninhabitable atmosphere, and capable of supporting life for extended periods without support from Earth. Environmental control and life support systems are nothing new—thanks to the International Space Station—and crew are used to air locks and docking ports. But ISS crew members and astronauts are used to short missions in space.

Spaceflight of any kind presents unique stressors, from high G forces, increased radiation and microgravity, to sleep deprivation and nutritional complications. A mission to Mars and back would take a minimum of 520 days and see the crew journey around 360 million kilometres from home—that’s 520 days experiencing microgravity, confinement, stress from high expectations and risk of equipment failure, and microgravity-induced changes such as alterations in body fluid distribution.

‘Combining advanced machines and bioengineering healthcare solutions in pursuit of one goal—human presence in space—is a fascinating topic,’ says Dr Cesare Stefanini, Associate Professor of Biomedical Engineering at Khalifa University, Abu Dhabi. ‘There are two primary factors conflicting with life in space: microgravity and the presence of radiation. Other aspects, such as circadian rhythm, absence of atmosphere and extreme temperature ranges can be addressed and compensated with engineering solutions in a relatively easy way, but the two main aspects are less easy to tackle, with potentially severe consequences.’

Microgravity

‘Microgravity is the word used to refer to a whole set of physical phenomena that occur in a vehicle in orbit—it is not the lack of gravity,’ explain Dr Elena Fantino, Assistant Professor of Aerospace Engineering at Khalifa University. ‘In low-earth orbit, the gravity (or better, the gravitational acceleration) is still more than 90 percent of the gravity on the surface. And gravity is the only reason a satellite can be in orbit around Earth, around Mars, or in interplanetary space (around the Sun). What causes “microgravity” is the fact that in the frame of reference of the vehicle (spacecraft, or platform, or satellite), people and objects feel the same acceleration towards the Earth and this acceleration is the cause of the orbital motion. Gravity is not felt as force that pulls downwards, but as a force that pulls an object in a circle. An astronaut floats inside the ISS because both the astronaut and the ISS move on the same circle around the Earth—it’s a different experience of gravity. But this enables all sorts of chemical and physical phenomena (such as the fact that particles don’t settle in a solution because they are not pulled downwards) that has paved the way to a new branch of scientific research.’

What effects then does microgravity have on the human body?

‘Microgravity impacts on the properties of bone, making them less dense and strong; cardiovascular physiology (heart atrophy); and vision due to damage to the eye from increased intracranial pressure,’ says Dr Stefanini.

Equally, there’s a risk to immune health as studies have demonstrated a key role for microgravity in microbial physiology: bacteria can proliferate more readily in space, which suggests that this environment is better able to initiate growth that could lead to contamination, colonization and infection. A total of 234 species of bacteria and microscopic fungi were identified in the Mir space station environment between March 1995 and June 1998, and if these bacteria can survive the extreme conditions of spaceflight, they pose a considerable risk of contaminating not just the crew on board, but also wherever they may land. ‘To counteract this,’ said Dr Stefanini, ‘we need to restore gravity, and solutions can be developed by implementing artificially-generated inertial forces, for example via rotating systems.’

Radiation

Since Yuri Gargarin, over 450 people have travelled into space, but only those on Apollo missions have ventured beyond the first 500km of the low-Earth orbit. Low-earth orbit has a protective measure for humans planet-side and in space: the Earth’s magnetic field deflects a significant amount of radiation, but beyond the Van Allen radiation belt, where charged particles are trapped in this magnetic field, astronauts are exposed to solar and cosmic radiation. A 520-day round-trip to Mars would mean an astronomical amount of exposure for the crew on board.

‘Radiation in space is characterised by high energy and carcinogenicity, especially for long missions such as the one for reaching Mars. Shielding is more difficult than in terrestrial applications, but the development of new materials opens the door to potential solutions,’ explains Dr Stefanini.

Exploration of the moon and Mars is intertwined: the moon provides the opportunity to test new tools, instruments and equipment that could be used on Mars to build self-sustaining life-support systems away from Earth. But sending humans far from Earth raises another intriguing problem: the one of space medical treatment and how to intervene on a patient by remote presence. Robots can be of great help here, allowing surgeons on Earth to operate at very long distances via teleoperated surgical systems, but while that distance isn’t unsurmountable, it presents a challenge in communication.

If a robot needs to operate on a human on Mars, there’ll be around a 20 minute delay between the Earth-bound surgeon’s instructions and the robot complying. Likewise, if something goes wrong on Mars, it’ll be 20 minutes before anyone on Earth knows about it and can react. Much of the communication difficulty could be solved if the robots sent to Mars were autonomous but autonomy is very hard, explains Prof Lakmal Seneviratne, Professor of Robotics at Khalifa University. ‘When you have a remote-controlled robot, you’ve got the time delay to contend with. But achieving autonomy is a sensory issue—it’s both software and hardware as they form a continuum. We don’t have the feedback going into the sensors, and we don’t have the processing methods to interpret the feedback.’

The challenges are enormous and need to be overcome as Mars presents a seriously hostile environment for human habitation. With all these hazards, why would we want to go anyway?

Stupid question for the adventurous.

Humans are intrepid. Curious.

Imagine living on another planet, gazing up into the sky and seeing your home among the stars. Imagine stepping onto a spaceship on Earth and embarking on the ultimate adventure. It’s a wonderful feeling stepping off a plane in a new country—imagine your first footprint on the surface of Mars. Imagine being the first human to take that next giant leap.

Not only does space research play an important role in building our future and progressing humanity beyond a one-planet species, it’s the final frontier, and Mars is just the beginning. ■