To Mars or Bust - Colonizing the Hard Way
(Originally posted November 22, 2016 on Blogger)
Mars. Perhaps the most popular planet on Earth. Wait... Did I say that right? It certainly has been popular over the decades. Over 50 movies have been made about the red planet since the '50s, with the most recent being the very successful "The Martian" which came out last year, based off a book of the same title. It seems every month a major publication is printing articles about Mars; Popular Mechanics, National Geographic... in fact NatGeo has a new series titled, "Mars" making its debut as I write this! Mars has been popular for millenia; the ancient Hebrews called it Ma'adim (One who blushes), to the Babylonians it was 'Nergal' (Star of Death), the Egyptians called it Har dècher (The Red One), the ancient Chinese called it 火星 (Fire Star). The infamous radio Halloween episode of 1938 that sent a nation into hysteria was all about Martians! Want a chocolate bar? Grab a Mars bar! There's even a 'Google Mars'!
Mars is rightfully a popular planet. The little guy hosts the biggest mountain in the solar system in Olympus Mons, has as much land mass as Earth, shows signs of having liquid water, and this could mean it supported life in its distance past. There's even a small chance that Mars currently hosts subterranean microbial life! That would be, in a word, awesome! In fact, it'd be a paradigm shift in the way we approach an understanding of the beginnings of life. But even if no life is found, nor evidence suggesting life had ever existed there. fact remains... Mars has a population already! Mars is the only planet in the solar system with a planetary population made up entirely of robots!
Mars is no slouch. It's working on a new look currently only donned by the gas giants; in 30-50 million years tidal forces acting upon Phobos will tear that tiny moon apart. Part of that debris will create a ring around Mars which could last anywhere from a million to a hundred million years! Mars is taking its fame seriously!
Mars is a fascinating planet, and deserves attention and further exploration over the coming decades; but I have to ask; should colonizing it be our primary objective?
Mars One founders, Bas Lansdrop & Arno Wielders think it should be, and now Elon Musk has joined the ranks, having outlined a plan to colonize the red planet. And let's not forget Robert Zubrin, president of the Mars Society, whose passion to travel to and colonize Mars is arguably unparalleled. All of them have plans to travel to, and establish colonies on Mars.
Zubrin's plan involves two heavy-lift boosters; one sent to Mars with an Earth-return vehicle (fully fueled) along with a supply of hydrogen, a chemical plant, and small nuclear reactor... the second booster would be used to send a crew of four along with their living habitat. Once on Mars, the crew sets up the habitat then returns to Earth in the waiting Earth-return vehicle, leaving behind the nuclear reactor, chemical plant, supplies, and of course the habitat. Future missions to Mars would, in theory, become easier as supplies on Mars grow with each mission. According to Zubrin, the tech we need to do this already exists, and in his words, all we really need is some focus and a little moxie to get it done.
The founders of Mars One have a plan of their own. It involves a series of relatively closely-timed missions to Mars. The first in 2020. This would be a proof-of-concept mission establishing the feasibility of current technology to support a manned mission to Mars. Along with this ground-based proof-of-concept tech, a communication satellite (COMSAT) would be put into Martian orbit. This would be used along with a COMSAT that would later be put into a trailing orbit 60 degrees behind Earth (L5 Lagrangian point of Sun-Earth system) to allow 24/7 communication with Earth. In 2022 a rover would be sent to Mars. Once on the Martian surface, the rover would locate and clear a good landing site. The landing site would be chosen for its access to sunlight (near enough to the equator), yet where soil moisture might be highest (near enough to the poles). This happy compromise would be where the rover also clears an area for solar panel deployment. In 2024 a cargo mission would deliver a second rover to the red planet along with supplies, two life-support systems, two living units, and a supply unit. The rover would set up the habitat so it would be fully functional when the first humans arrive. That arrival would be 2026, a journey that would start with the crew docking in low-Earth orbit with a waiting transit habitat.
Elon Musk's idea is far more ambitious. He wants to see a million people living in a self-sustaining city on Mars (over time of course). He already has an unmanned mission to Mars set for 2018 in The Red Dragon. I can't think of cooler name than that! He wants to start manned missions in 2024 using powerful, reuseable rockets that can be refueled in space. (I'll have to write a separate blog entry on refueling a rocket loaded with people another time.) When I say powerful, I mean POWERFUL. Elon wants to be able to send 100 tons of cargo (people and/or equipment) at a time, which would require nearly 29 million pounds of thrust at lift off! This would require about 40 Raptor engines to achieve that kind of thrust. Once in orbit, refueling of the Interplanetary Transport System (ITS) would take place from a second rocket send up carrying fuel as its cargo. Meanwhile, two solar arrays would be deployed generating some 200 kW of power, and its off to Mars. According to Elon, the ITS would be a 'fun' place to be for the 8-month journey to Mars. Once on Mars, people can produce the methane-based propellant to send the reusable ITS back to Earth for the next crew/cargo mission. This would continue, with rockets heading to Mars in this manner like 'trains out of a station' according to its inventor.
It's impressive how far we've come. Sputnik was less than 60 years ago, and now there is very serious talk of colonizing another planet! This sort of foresight and enthusiasm is just what we, as a species, need. It drives technologies that will invariably have other uses (medical preferably over militaristic), and would, in theory, generate cross-cultural cooperation. Something we need a lot more of in my humble opinion.
Ahh, but colonizing Mars? This is where my little blog entry takes a turn. I love Mars, and want more missions sent there. I have high hopes life is found there, or at least evidence thereof. However, I just don't love the idea of sending people. It's suicide, if not immoral given current technologies. Particularly when there is a better target (as I will argue for shortly). Some might say, 'why not practice by establishing a moon base?' I think that is a good idea. It's close and has Helium-3. ;) It would advance our learning curve with relatively minimal risk to human life (as compared to sending people to Mars straight away). At any rate, if we're going to put focus and moxie to good use with current tech, and must reach that milestone of sending people to another planet, then we ought to turn our eyes towards our sister planet; Venus.
TRAVEL TIME & DISTANCE
Let's look at travel time for starters; It will take just over 8 months to reach Mars when the planet is at its closest to Earth. Though Google says this is 33.9 million miles, that figure would only happen when Mars is at Perihelion and Earth is at Aphelion at the same time. This hasn't happened in recorded history. The last time Mars was close to being 33.9 million miles was in 2003, when it was 34.8 million miles from Earth. That was the closest it has been in 60,000 years! So 8 months seems a fair assessment for travel time (not to be confused with time travel), and it seems to be agreed upon by Mars One folks, Elon Musk, and Robert Zubrin. Venus, on the other hand, is the closest planet to Earth. Travel time to Venus would be less than half that of Mars (about 3 months). It's closest pass to Earth is, on average, about 25 million miles and can be as close as 24 million miles.
There are some obvious reasons why being closer is better. The first being that resupply missions would be much quicker. Sending missions to Venus would also be much, much less expensive. But perhaps most importantly from a standpoint of morality, exposure to radiation in-flight would be cut in half or more due to the shorter travel time.
The Mars Science Laboratory Spacecraft sent to Mars years ago delivered the rover, Curiosity. We all remember that impressive mission! It was the mission that lowered Curiosity to Mars' surface using a sky crane maneuver the likes of which would put most sci-fi books and movies to shame! Go JPL! But that mission had a second objective; to measure radiation inside the spacecraft as it made its journey to Mars.
From December 6, 2011 to July 14, 2012 (253 days), a Radiation Assessment Detector (RAD) measured radiation inside the spacecraft; radiation which comes from the Sun and interstellar space. Before I tell you what it measured, let me preface it by saying that NASA has established a 3% increased risk of fatal cancer as a CAREER-limit threshold for astronauts. An accumulation of 1 sievert (Sv) over time by an astronaut would equate to a 5% risk of fatal cancer. The RAD recorded 0.66 Sv with an error of +/- 0.12 Sv. That's up to 0.78 Sv for the shortest possible trip to Mars.
0.78 Sv is like getting 6,600 (7,800 if you assume 0.78 Sv) chest x-rays over an 8-month period, meaning you'd have to go to the doctor for an x-ray every 55 minutes for 253 days. According to the Environmental Protection Agency (EPA), the average annual dose per person in the United States is 0.0062 Sv. A round trip visit to Mars (excluding time on the planet), would result in over 100 times the average dosage experienced by Joe Schmo here on Earth. So it stands to reason that the less time a crew spends in interplanetary travel, the better... no matter how 'fun' their ITS may be.
Zubrin has argued that exposure to radiation during flight can be minimized by simply stacking a bunch of stuff from within the spacecraft between the crew and the Sun (back of the spacecraft). This could help mitigate some of the less-energetic particles, but will be useless against HZE ions from interstellar sources. Not even a thick hull would stop such heavy ionized nuclei as Iron-26. HZE ions are devastating to DNA; breaking them apart and killing cells, and ultimately, the host. Interstellar source HZE ions aren't the only threat unhindered by hulls and stuff stacked against a wall in a spacecraft... Solar storms, or worse, shock waves associated with coronal mass ejections (CMEs)can be proportionally devastating to genes. Such events can easily spike radiation exposures far beyond 1 Sv for a single flight.
Once on Mars, consider the fact that a crew cannot just return at will. That fueled-and-waiting Earth return vehicle won't be of any use until Earth and Mars are close enough for a return journey... and that takes between 18-20 months. That's 18-20 months on a planet that lacks a structured global magnetic field. NASA's Mars Odyssey measured 0.22 mSv per day on Mars' surface. A solar storm, or CME can spike these levels to 0.2 Sv in a single day. Mark Watney may have been spending more time in a hospital back on Earth than in a classroom discussing how to grow potatoes (that was a reference to The Martian).
Exposure to radiation on Mars' surface is a serious concern (at least for NASA), and they've awarded money ($7,000) to people who came up with ideas to shield against radiation. There were 5 winners out of 136 submissions, and not one of them were able to reduce galactic cosmic ray exposure by the required factor of four. So NASA has raised the prize money limit from $7,000 to $30,000! And I think it is still going, so if interested, go for it!
Ok, so on the point of radiation, travel time alone makes Venus the safer option by a large margin. Though Venus has no magnetic field of its own, it does have an induced magnetosphere which would protect a crew from radiation. I'll get to Venus' extreme surface pressure, heat, and pesky sulfuric acid clouds soon... but on the point of radiation, Venus beats Mars hands down.
Another extremely important factor to consider is gravity (or the lack thereof)... since the 60s, the American and Russian space programs have collected a lot of data on the effects zero and low-gravity environments have on the human body, and they're not good... Spaceflight Osteopenia. It's an unavoidable condition from prolonged exposure to a zero-g environment. 1-2% bone mass loss per month, plus increases in serum calcium ion levels that lead to irreversible skeletal damage. According to a paper in the Journal "Gravitational and Space Biology", even exercise to prevent bone mass loss at zero g has not been effective. Though diets high in calcium and vitamin D help, they do not stave off this bone mass loss.
Makes 8 months (16 months round trip) look less, and less enticing. A zero g environment can lead to a bone mass loss 10 times that of someone with advanced osteoporosis. Muscle atrophy is another concern. If you Google "effect of spaceflight on the human body" you'll find a host of maladies affecting the cardiovascular system, fluid redistribution within the mostly-water human body, vision, taste... there's asthenization syndrome, and don't even think about getting sick out there. Even a generally harmless hay fever can be an epic adventure even Odysseus wouldn't want to embark upon... tears from your watery eyes that just stick over your eyeballs blurring your vision indefinitely because they cannot shed. Mucus.. ok, I'm not even going to go there. You get the point. Also, you better hope you have respectable crew members. Odors permeate very quickly in zero g... no joke.
At least with a trip to Venus, your zero g experience would be cut by more than half. A huge benefit if ever there was one.
Ahh, but then you get to Mars, finally able to feel some gravity only to discover it has 0.376 g. Darn it to heck! There aren't even any studies (that I'm aware of) that have figured the effects of low-g environments such as Mars' surface. But it doesn't take a genius to infer that if your species evolved on a planet with 1 g and your species goes and moves to a planet with 0.376 g, and knowing what we know about 0 g effects on the body, that life on Mars wouldn't be so grand. Low g environments have also been linked to brain issues... issues which can negatively affect decision making and response skills.
But if you go to Venus... the gravity there is an Earth-like 0.904 g. Suffice it to say that your body would fair much better under such wonderful strain than it would on Mars... because there's few things more annoying than having the fluids in your body migrate into your upper body all the time.
ATMOSPHERE & TEMPERATURE
Moving on to temperature. Yes, Venus is a hot, hellish planet with surface temperatures of at least 462 degrees Celsius (C), making it hotter than even Mercury. Whereas on Mars, the average temperature is -55 degrees C, with lows to -153 degrees C, and if you are on the equator (in non winter "months") at noon, you might experience a balmy 20 degrees C. Although, these aren't really feels like temperatures since the atmosphere is so thin. About 1% that of Earth's.
I'll get back to Venus' temperatures in a moment, but want to mention a few things about Mars extremely thin atmosphere. On Earth we experience 1 atmosphere (atm) at sea level, generally speaking. On Mars, surface pressure is 0.00628 atm. pffft. I'm pretty sure with air that thin that Mark Watney would have never experienced a wind strong enough to knock him 20 yards off his feet (movie science at it again). Kind of a let down when the entire movie's plot is hinged on that scene.
Movies aside, fact remains that a super thin atmosphere (and lack of a structured planetary magnetic field) leaves folks on the surface exposed to some serious radiation. Radiation isn't the only threat. That thin atmosphere won't even protect against 2,700 to 59,000 tons of micrometeorites that pelt Mars each year. These micrometeorites (in the 60 to 1200 micrometer diameter range) can travel at 150,000 mph, and easily survive to the surface since the air is too thin to melt them by friction. Walking around on the surface, and living in habitats on the surface is a risky venture considering both can be shot to hell by micro bullets from space. If the space forecast calls for a meteor shower while you're on Mars, I highly suggest you not grab a lawn chair and warm drink to go watch.
Enter Venus... here the atmosphere is plenty thick enough to handle those pesky micrometeorites. Even 50+ km up, the atmosphere is as thick as Earth's at its surface. And this leads me back to temperature again. Mars isn't the closest thing to an Earth-like environment in our solar system. Venus is.... at about 50 km up from its surface. The temperature between 52.5 and 54 km is between 20 and 37 degrees C. That sounds like California temperatures to me. At 50 km, the air pressure is nearly identical to Earth's at just over 1 atm. At 52.5 to 54 km it's about 0.65 atm.
There is the issue of sulfuric acid clouds over Venus, but consider this... you can get away with wearing a suit like this on Venus:
The stylish acid-resistant Venus suit... Obviously you'd also have gloves, breathing apparatus, and helmet.
Being 50km up in Venus' atmosphere isn't as terribly hard as one might think, and NASA already has a plan on how they'd approach the issue (Google HAVOC... High Altitude Venus Operational Concept)... I'd go into it, but my write up here is already getting way too long! :/ Because the atmosphere below 50km becomes dense rapidly towards the surface, a habitat could float using regular, breathable, Earth air. In fact, the air we breath would be as buoyant in Venus' atmosphere at 50km as helium is here on Earth.
Rotation... it is true, the rotation of Mars is similar to Earth's; about 24 hours, 39 minutes. So as far as circadian rhythm goes, a Martian day looks a lot better than a Venusian day (243 Earth days to one Venusian day). Venus' slow, retrograde rotation would do your circadian rhythm no good. Of course, this can be remedied with artificial lighting systems. Or... consider that unlike geostrophic winds on Earth, Venusian winds are cyclostrophic and this results in their super-rotation... super-rotation meaning the winds circle the planet faster than the planet rotates. Wind speeds below 50-degree latitudes may howl at 100 meters per second, but these winds decrease towards the poles and a happy place can be found somewhere in between where a day could, theoretically, equal an Earth day.
Another bonus with the Venusian atmosphere is that there is a lot more carbon dioxide, from which you could theoretically extract oxygen. And I'm certain there are plenty of studies that can be done from cloud cities over Venus that would have implications for Earth; particularly regarding the runaway 'greenhouse' effect that has made 50km above Venus so enticing. ;)
I should also add that missions to Mars' surface have not all fared well, with about half ending in failure, with some of those that did make it, make it but to varying degrees of success. Landing on Mars is NOT easy, and requires some serious engineering. Whether it's a legged landing system, a sky crane, or air bag system, engineers have to tackle very complicated obstacles. There are also touchdown sensing systems that need to work. Landing on Mars, with its thin atmosphere, will not likely ever be a safe venture. Entering the upper atmosphere of Venus on the other hand, far less complicated and therefore, on those grounds, arguably safer.
So way up there I wrote out one of the planned missions to Mars was to set out solar panels. This is nice. Yes, as Mark Watney demonstrated, you can blow the dust off the panels to ensure they keep working well... but know that the amount of solar power available on Mars is less than half that of Earth's. Solar irradiance on Earth is about 1361.0 w/m2, whereas on Mars it's about 586.2 w/m2. For every one solar panel on Earth, you'd need two on Mars, in theory. This available solar energy only lessens with increasing latitude. And it's in the higher latitudes where water ice is.
A paper published today by scientists at JPL (http://onlinelibrary.wiley.com/doi/10.1002/2016GL070138/abstract;jsessionid=AD475154942A8CCAFD752931F2C7FF91.f02t04) in the journal Geophysical Research Letters explains that beneath the cracked and pitted surface of Mars' Utopia Planitia may contain as much water as Lake Superior (frozen). This is incredible if true, but Utopia Planitia is at nearly 50 degrees north latitude where available solar energy lower as compared to the equator.
Venus.. well... there you'll have double the power availability... 2601.3 w/m2. Some research has shown as much as 4 times the solar energy available on Venus as compared to Earth! This is important... nuclear reactors next to your bunk aside, energy to run a habitat is as important as being able to communicate with mission control back home.
And speaking of communication, data sent back to Earth would take a lot longer than they would between Venus and Earth, and this time would only increase once a crew lands as Earth and Mars diverge ever further in their respective orbits. In an emergency, quick, efficient communication would be imperative... making Venus a better option with this regard where communication time could be cut in a little less than half.
Communication as close to real-time as possible may be of some importance for psychological reasons as well. In addition to there being a lot of studies on the effects of zero g on the human body, there have been an equal or greater number of studies looking at the effects of space travel on the mind. No studies, obviously, exist for interplanetary travel, but consider that on-orbit near-Earth experiences (ISS for example) with astronauts and cosmonauts that have shown irritability increases, fatigue, emotional liability, attention/concentration difficulties, as well as appetite and sleep issues may be worsened in interplanetary travel.
Think humans get along in closed environments? Try working in an air traffic control tower, or work in an office, or Google "Biosphere 2" and see how squabbling, management issues, oxygen depletion, low food, and injuries can end a 2-year habitat experiment in 2 weeks! The Health Hazards Report issued by the NASA Office of Inspector General describes how crew members in space have decreased scope and content in their communications with mission control. They tend to filter what they say to outside personnel, something that is so prevalent that it actually has a term now, "Psychological Closing". Crew member ego goes up over mission control, and as a result, listening skills start to go out the window... so to speak. Sub groups and outliers negatively affect group cohesion, and you begin to have crews in space that start to view us humans on Earth as potential threats! It's true. This is with ISS crew members, and past space shuttle flight crews! Imagine a crew on Mars. Lord of the Flies much?
Interpersonal problems during the second half of mission increase, resulting in transient anxiety and depression... two things I doubt anyone wants to experience first or second hand while stuck in a tiny "habitat" on a planet that is NOT the closest planet to Earth.... ever. And these are things that have been observed rather consistently in astronauts (and cosmonauts) that made it through EXTREMELY rigorous psychological testing and training long before they were ever sent into space.
There are also psychosomatic reactions; physical manifestations of this stress and anxiety. All this makes the notion of longer-than-necessary space flight going to Mars less, and less attractive. At least for me. Though some folks enjoy drama.. ie. Maury Povich.
That 8 months travel time to (and don't forget the 8 months back)... and the 18-20 months on Mars, will require a lot more food and water than a trip to and from Venus. Just saying.
It's unfortunate, but Venus just can't compete with Mars' incredible public relations team of celebrities, billionaires, and Hollywood blockbusters. I think there have been maybe a dozen movies about Venus and all of them are from the 1950s and 60s. There was one in the early 70s, but it was actually about Earth being destroyed while a couple were fleeing to Venus.
Venus does indeed have a PR problem. Even the set of manned mission concepts NASA came up with to go to Venus has a less-than-inviting-or-inspiring name... HAVOC? Really? NASA has tons of missions going on right now with less intimidating, more inspiring names... GRACE, DAWN, Mars Odyssey... Elon Musk wants to name his first manned spacecraft to Mars the "Heart of Gold"... what will a spacecraft to Venus be named? The "Dearly Departed"?
Aside from public relations issues, Venus has surface issues... or I should say, WE have surface issues.. or more aptly, surface bias. NSF Astronomy & Astrophysics postdoctoral fellow, Gabe Perez-Giz made a great point when he said most people suffer from "surfacism". It's a term he coined, and it refers to humankind's experiences and need to "plant a flag on something"... to be able to anchor and set foot on dry land is something ingrained in the human psyche. Venus has too often been judged by its surface; a place only a very small handful of probes have seen (and not for very long). We are a species that has spent our entire history living on Earth's rocky surface. So it's difficult to accept that the most Earth-like environment in the solar system (other than Earth obviously) is not on the surface of any planet, but in its atmosphere.
It is only just recently that scientists are discovering life doesn't necessarily need the ingredients we once thought it did in order to survive. Extremophiles for example, have really challenged our understanding of what it takes to create life in the universe. Where once we were looking for life on rocky planets with liquid water, now we're looking at moons with sub-surface oceans.
Speaking of extermophiles, science has discovered acidophiles, which not only survive in environments such as sulfuric acid, but thrive in them. So don't knock those sulfuric acid clouds over Venus just yet. If there's one thing in science that has moved it forward in leaps and bounds, it has been thinking outside the box. Plate tectonics, evolution, quantum mechanics... such paradigm shifts are what have set us further ahead than we otherwise would have ever achieved... and all thanks to outside the box thinking. Ask Schrodinger's cat about thinking outside the box.. or ask a Boltzmann brain.
Venus is the smarter, safer, cheaper, most logical choice as a first planet target for manned missions. Why it isn't has more to do with psychology of Perez-Giz's "surfacism" than it does with anything else. I prefaced this entire write up with how great Mars is... I want to reiterate that. I want to reiterate that I want to see more missions to the red planet. That I believe there is a chance it hosts life, or once did. But to send humans there to live? That isn't just stupid, it's suicidal. Mars One doesn't even have a plan to return anyone. At least with closer Venus, people can be brought home when they realize the nostalgia of living on (or above) another planet has worn off and they just want to go home.
I think there's a certain ethic that should be considered when drawing up grandiose plans to send people to live on a planet that will eventually kill them. We do have technologies to get us to other planets, but safely? Well, I suppose that's a relative question. But at the very least, NASA's 3% risk assessment should be met before any people are sent anywhere. One 'giant leap' to that goal would be a shorter trip. All eyes ought to turn to Venus for manned missions... in my strong opinion. But as always, what do I know?
Lando likes it!