Space Exploration, Positive Stewardship, and Christian Identity

In the following sections I use a short story to explore these subjects. There are three parts, with commentary as the storyline progresses.

In the first part we meet Sasha and her father. It’s not immediately apparent where they are...

Sasha’s Story. Part 1: Awesome

"It's awesome, Dad!", Sasha gushed, a little overwhelmed and momentarily frozen in place.

"I knew you'd like it," he replied, "don't forget to look around you."

She slowly panned left to right, hardly noticing the bulk of the oversized space helmet. As she looked down, her spacesuit and gloved hand shimmered reddish pink, reflecting back the otherworldly objects that dominated the scene. To her left, an astronaut was securing a flag on the alien surface. As he tapped the pole, streaks of pink-grey soil flew out in graceful arcs for many meters, some striking Sasha's spacesuit and bouncing off. The ground around them was awash with footprints. She squinted, and could see a tiny tear of pride in the corner of the astronaut’s eye as he stood next to the flag. Carefully, she turned around in place scanning the sky, and there it was. Barely larger than a star, and the only blue object anywhere in sight. The Earth.

She couldn't contain herself; "It's exactly like the IMAX movie we just saw!"

"That's right, Sash. But remember, what you're seeing is not a movie, it's a recording. This actually happened six months ago on Phobos, one of Mars' moons."

"I know that Dad! We’ve been following the mission in school for a couple of years now. And Mars has another moon called Deimos... I can't believe how close Mars looks from here. It's just huge! I guess it should look big since it's the same size as all the land on Earth, huh?" While only fifteen years old, she was confident she knew much more about astronomy than most of the people in line behind her.

"And you made all this happen, right Dad!"

"Not by myself!" he chuckled. "I just worked on the software for the virtual reality helmets, like the one you have on. The astronauts you're looking at now used the same technology to remotely control the robots down on Mars – that's how they found the fossils."

Sasha's father was a little envious of his daughter and the thousands of others gathered at the Science Center's Mars Exhibit. They were enjoying for the first time – with clarity very close to that experienced by the astronauts – the scene that now defined this generation. He had been in mission control during the actual landing, but was far too busy monitoring engineering data to really appreciate the history-making moment. But Sasha was right; the landing on Phobos made for an awesome picture, immediately surpassing the iconic space images from the previous century. For his daughter's generation, the 'Earthrise' image taken from Apollo 8 in 1968 was now merely an ancient weekend holiday snap, and the pictures of the first astronauts on the surface of the moon were by comparison grey, dull, and uninspiring.

A voice in Sasha's earpiece announced she had just 30 seconds left before she'd have to relinquish the virtual reality helmet to the next person in line, so she took one last look around. Above the undulating and cratered surface of Phobos hung the rusty visage of Mars, with its spectacular canyons, record-breaking mountains, and snowy frozen ice caps. From here it took up a full third of her view – 6000 times larger than the Moon when seen from Earth. At the horizon, barely perceptible, was the shimmer of the tenuous Martian atmosphere.

Sasha didn't appreciate it yet, but this amazing view of an international crew of humans visiting alien worlds so far from home had done more for international relations than a decade of UN diplomacy. Just as the entire world had claimed the 1969 Apollo 11 lunar landing as a success for all Earth-people, this landing had united the planet and fostered a sense of optimism for the global future that many had thought impossible.

"I want to go!" Sasha declared, as she handed the helmet to the attendant. "I want to be the first person to walk on Mars!"

Notes on Part 1: Science Fiction vs. Real Life

The tone in this short story is reminiscent of a great deal of popular science fiction, i.e. euphoric utopianism. Unlike most science fiction, however, this story connects directly to policy decisions being made right now. The Obama White House has just received the “Review of US Human Spaceflight” report produced by the Augustine Commission. In it, they evaluate several options for NASA, including a trip to the moons of Mars. It remains to be seen if the report will lead to any bold plans. Given the current economic climate this seems highly unlikely without increased public support.

Who might possibly advocate for history-making space missions and an inspiring science-centered future like the one described in the story? I will make a prediction: it won’t be religious folk. As the saying goes, it’s always a mistake to generalize, but if religious people have something to say about science, technology and the future, it is more likely to be predicting doom and gloom at the hands of amoral scientists than pondering the wondrous discoveries they may soon unearth.

Should Christians be concerned that they are often perceived to be technophobic and lacking in enthusiasm for bold scientific research?

More specifically, should Christians support the space program, and missions to explore Mars looking for life? These are big questions, and I can only scratch the surface here, but some of the related issues are:

Two theological resources that would inform such a debate are the concept of stewardship, and the parable of the talents.

A great deal of good has come from connecting the mandate in Genesis 1:26 – to be stewards of this world – to climate-change and other environmental concerns. But stewardship in this context has thus far been applied only in negative terms: rescuing endangered species, reducing energy usage and emissions, slowing the loss of coastal lands and averting cataclysmic climate change. And that’s completely appropriate. To be good stewards of the Earth we need to stop the harm that uncontrolled technological-industrial advancement and rabid consumption will surely bring.

But I propose that good stewardship should lead to positive action as well as negative; being stewards of resources does not simply mean hording and coddling them. Meanwhile, the parable of the talents reminds us of the value of investing our resources wisely to build a more bountiful future, and that simply preserving the status quo is the less virtuous path.

Would anyone say the excitement Sasha felt seeing the sky filled with an alien world, and her hunger for new knowledge is at odds with Christian values? Surely not. But we won’t arrive at this kind of future by simply stopping, slowing, and reducing. We need to boldly go, expecting to succeed.

In short, the role that stewardship should play within any discussion is as a forward-looking and moderating force, not merely a backwards-looking, negating one.

Numerous topics would benefit from a moderating, forward-looking influence, perhaps most obviously biomedical ethical controversies, but the debate over space exploration is in particular need of this. Typically, two extreme positions dominate the conversation. Some argue any space programs are less than worthless because they siphon funds from more worthy causes here on Earth, while others are convinced our destiny lies in space, and the sooner we leave Earth behind the better. On to the stars!

Interestingly, the most passionate advocates of human spaceflight do so in almost eschatological terms. British physicist Stephen Hawking has famously said that he fears the future of humankind is at risk until we establish a permanent presence in space.[1]

Certainly some space enthusiasts are simply caught up with the romance of the technology, but others see more practical economic, and societal justifications. The billions ploughed into the Apollo program undoubtedly led to new technologies, industries, and associated employment. It also placed the United States, in a positive light, at the center of the world stage. Determining the ultimate value of these effects is difficult, but it’s not inconsequential.

Meanwhile, the cost of a mission to establish a Mars base is truly staggering, and the technological hurdles are just as formidable.

Can we find a middle way? Can we build a space program that sets exciting but achievable goals within a constrained budget? In other words, a space program that draws resources from the public coffers to a degree that we can justify within the larger context of being good stewards of finite resources?

While the story so far smacks of utopian science fiction, as we return to Sasha and her father, we learn that NASA has followed what I believe to be one possible middle way, a moderately conservative, moderately bold approach to exploring the red planet...

Sasha’s Story. Part 2: Disappointment

"I want to go!" Sasha declared, as she handed the helmet to the attendant. "I want to be the first person to walk on Mars!"

"Whoa! I think you need to finish school first," her Dad replied, "Besides, no-one really thinks we're going to get the funding approved for a landing mission, not in the middle of a recession." He immediately knew he'd made a mistake.

The look on Sasha's face was a mixture of anger, surprise, and sadness. Her hands were on her hips, which was always a bad sign.

"I'm sorry, Sasha. I didn't mean to sound so harsh, but it's really complicated, and involves reasons I'm sure you'd consider boring. The main problem is it would be really, really expensive, and many people think we could use the money for better things here on Earth."

"But if we can land on Phobos, why not Mars?" Sasha asked, hands still on hips, not wanting to believe there could be any good reason at all.

"Well, to be honest it's only 2025 and we don't yet live in the science-fiction future you see in TV programs. Landing humans on Mars is very hard to do – much harder than on Phobos – there are many engineering problems we really haven't solved yet, so it would be very dangerous. And since I'm a big fan of robotics, I'd much rather see them do the dirty work on Mars than put my favorite daughter in jeopardy."

Sasha's arms fell to her sides, but she wasn't defeated yet. "I don't understand. Why is it more difficult to land on Mars? And why don't people want to spend the money? I mean, how could we come this far if people don't think it's worth it? My friends in Space Club at school say we're basically living out Star Trek. After all, we did 'boldly go on a five year mission to explore strange new worlds.' We even found fossils of ancient microbes on Mars! What if there's life still there now, maybe underground..."

"Those are all good questions", her dad replied. "and I'll try and answer them as best I can..."

Sasha’s Story. Part 3: History

“Let's see." Sasha's father said, "How did we come this far so quickly? To some extent it’s simply down to good luck, but I guess it all started back in 2010 when some people at NASA made some very smart decisions. That's only fifteen years ago, just before you were born. There wasn't much public enthusiasm for human spaceflight or space research back then. NASA hadn't done anything really exciting for nearly 40 years. They had built the International Space Station of course, and repaired the Hubble Space Telescope, but nothing that sparked the public imagination the way the moon landings had.

“The Space Shuttle was being retired, and the new White House administration had invited suggestions on how the space program might evolve, and what goals it could realistically set for NASA.

“Scientists were generally agreed that Mars was a very interesting place in the Solar System, mainly because we thought we might find evidence of life there, but also because Mars is a world that’s undergone catastrophic climate change. We knew there would be valuable lessons for us here on Earth. The idea of a manned mission to Mars had been discussed since the Apollo days, but no plans had ever made it off the drawing board.”

“What’s a drawing board?” asked Sasha.

“Um, it’s like a tablet computer without the computer... It doesn’t really matter. As you know we had sent several simple robot Rovers to Mars by 2010, which were a scientific success, but quite limited in range and capability, especially when you consider we were exploring an entire planet. The fact is there are big challenges with operating rovers remotely, and the biggest one is due to Einstein."

Sasha's eyes brightened, "you mean the speed of light problem?"

"That's exactly right. Mars is very far away, so it can take up to 40 minutes for a radio command to travel from Earth to a Mars rover and for a response to come back. It’s a tedious process. The rovers NASA launched in 2003 worked this way, and ended up covering only about two miles every year. As you know I love robots, but today most people agree that if we'd continued with just robots it would have been decades before we discovered those Martian fossils.

“People who wanted a manned mission to Mars said a human geologist could accomplish everything the NASA rovers achieved in just a week or two! But plans for manned missions to Mars always assumed we'd land and stay on the surface. They were immensely expensive, complicated and dangerous, and since they were making plans when money was tight – just like now – most people had given up hope of ever getting scientists onto the surface. My robotics friends would also point out that manned lander missions would always be less capable than theirs because robots didn’t need to take food, water – or toilets – so you’d always be able to send more rovers to more sites for the same cost.

“There was also a third idea that people looked at: a ‘sample return mission.’ While we were sending ever more capable rovers, such as the Mars Science Laboratory, nicknamed Curiosity, they were always going to be limited in the kind of analysis they could do. So, instead of sending robot geologists to Mars, the idea with ‘sample return’ was to bring Mars back to the geologists here on Earth. The trouble is this type of mission required a very large, complex, and therefore expensive rover. It needed to be able to find an interesting sample, load it into an on-board rocket that could launch from the surface, enter Mars orbit, head back to Earth, and then a year or so later re-enter our atmosphere where the geologists would be patiently waiting. That’s a lot of hardware to carry to the Mars surface, and a lot that can go wrong. Plus it’s only one sample. What if you picked a boring rock by mistake?

“That’s when they hit on the idea that we now know worked so well, a way to get most of the advantages of all three approaches, while avoiding their biggest problems. Public enthusiasm for the plan snowballed, the money was found, and here we are today.

“The original plan for the Mars Orbital Laboratory was a simple rover control room, where geologists would operate multiple rovers on the surface in real-time from the safety and comfort of Mars orbit. That’s how my company got involved. The astronauts used our helmets – like the one you tried in the exhibit – to see through the Rover’s camera eyes. For them it was like actually being on the surface, but of course since they were actually in the orbiting lab they didn’t have to deal with the freezing temperatures, or worry about dust. Plus they could work at a rover site in the northern hemisphere in the morning and switch to the south in the afternoon! I should also say the Mars Sample Geochemistry Module was added pretty quickly after planning started, and it’s these guys we have to thank for finding life on Mars.

“Until they came up with the MOL plan there were two competing camps within NASA that could never agree. On the one hand you had the remote science and robotics fans, which the astronauts criticized for being ineffective and boring, and on the other side was the astronaut corps, which the science and robotics teams dismissed as simply grandstanding Buck Rogers wannabe’s who sapped funds from their serious work.

“With the MOL proposal, the Mars remote rover drivers could see the value of being an astronaut geologist ‘on-site.’ They were now all on one side.

“Plus there was an economics argument that persuaded many. Come to think of it, I bet you’ll approve of it too.

“We had planned to continue sending orbiters and rovers to Mars every twenty-six months – just as we’d done since the late 1990s – with some missions scheduled decades out. With the MOL plan, we could vastly accelerate how quickly the research was done. The idea was to spend all the money in one go. Rather than spend 200 million a year for 16 years, put the whole 3.2 billion into the MOL pot. It was a gamble, of course, but the idea of an intensive research program that brought in the data decades earlier was very compelling.

“NASA also decided to hand over nearly all Moon missions to the private sector. That freed up money for MOL, and led to the startup of many of today's commercial space companies. They make a nice profit doing sample return projects for NASA and other space agencies. This also marked the real beginning of the space tourism industry.

“The value of knowledge gained from MOL is really hard to judge in financial terms. If we’d not found the fossils, I’m sure you’d find more people who’d say it was a waste of money. But we were lucky enough to have a series of governments who saw the value of the program, and the money kept flowing. But I guess my point is the MOL mission was approved because of the science return it promised, and because it explicitly didn’t need the expense of a human base on Mars.”

Sasha was unconvinced. “OK. I can see the advantages of operating rovers from orbit, and the virtual reality stuff was cool, but surely it would be better to be there in person. You haven’t explained why it’s so hard to do that. What’s so easy about landing on Phobos and hard about landing on Mars?”

“Well, with Phobos you have no atmosphere and essentially no gravity, so ‘landing’ there is a matter of moving your spacecraft close enough to touch it.

“As for Mars... I already mentioned that Einstein makes life difficult for us. It turns out that Newton and Maxwell cause us headaches too. The basic problem is the atmosphere on Mars is very thin, less than 1% as thick as it is here on Earth. When we send spacecraft on their way to Mars they are going very fast since they’ve got such a long way to go. The trouble is when you get there you need to slow down.”

“Sure,” said Sasha. “So you have a heat-shield and a parachute. Just like Apollo, and just like the Mars Rovers.”

“That works for smaller spacecraft that have a fairly small amount of momentum to shed. But if you do the math for a spacecraft the size of a manned ship and habitat, the atmosphere isn’t thick enough to slow you down to a speed where you can safely open the parachutes. There are ways around the problem of course, like using an enormous heat-shield, or firing the engines to slow you down ahead of time, but both of these require a ship much larger than the MOL. Plus a manned ship that lands in just one place can’t do anywhere near as much science as we can today with multiple rovers. But it’s the guys who figured out we could fit small rock-sample rockets on the rovers that really made this option a winner. Once we had the orbiting lab in place, the rockets only had to launch the samples into low orbit where a tug could capture them and bring them back to the geologists in the MOL. There they ran tests, and directed the other rovers to promising sites, and ultimately found the fossil."

Sasha wrinkled her nose. “So how many samples did they look at in the Mars Lab before finding the fossil?”

“Seven. From six different sites. And the Geochemistry Module onboard is far more sophisticated – and by that I mean larger and heavier – than anything we could reasonably fit into a manned lander.

"So basically, we got this far so quickly by arguing we didn't need the expense of a manned Mars landing, so it's hard to convince the people who control the money we want to do one now.”

He had overdone it. Sasha was looking at her feet.

“Of course, there are plenty of people who think a manned landing is the next logical step, and if we don’t do it first someone else will. I don’t want sound too discouraging! It’s just that it might not happen for a few years yet, while we wait for those rocket scientists to work their magic. I just don’t want you to be disappointed!”

“It’s OK, Dad,” she said. “I can be patient. But in the meantime I’m going to walk on Deimos instead.”

“That’s my girl.”

Notes on Parts 2 and 3: A New (Moderately) Bold Space Program?

So, the Mars Orbital Laboratory in the story is a compromise mission, falling somewhere between forgoing the challenge, and a no-holds-barred manned research station on Mars.

And remember, while this story reads like science fiction, very little of the science is made up. It really could happen. Granted, I assume that there are fossils of ancient life on Mars waiting to be found. That makes the story more exciting, and that part might be fiction, but we’ll never know if we don’t look...

In the appendix I take a closer look at the technological hurdles facing Mars missions, but assuming I’m correct and the events in the story could happen by 2025, isn’t this an exciting project that’s worth investigating further?

In order for the date to be realistic I assume that a full-tilt fully funded program begins in 2010. This would be along the lines of the Apollo program that got into high-gear right after John F Kennedy’s famous “we choose to go the moon” speech in 1962.

I also assume that the project proceeds with no major setbacks and redesigns, which is perhaps wishful thinking, but is not science fiction. If there are major technical difficulties, or if this administration decides human space-exploration is not a worthwhile investment, then 2025 becomes a dream. But the mission-concept doesn’t recede into fantasy, it will just be delayed until the technology is ready and the public wants to go.

For most people the thrill of the ‘Space Age’ is now either a distant memory, or a story told by prior generations that sounds suspiciously like a fairy tale.

We all know how the fairy tale ended: Shortly after Neil Armstrong and Buzz Aldrin walked on the moon in July of 1969, the cost of continuing the Apollo program was deemed too high. Assembly of Saturn rockets was halted, flights were cancelled, and forty-two months later we concluded this spectacular era in human history. We had left home for the first time, and returned safely to Earth.

But a question hung in the 80% nitrogen air: When would we next leave the protective atmosphere of our birth and travel to other worlds? And after that question came others: should we travel to other worlds, and if so, why?

Thirty-seven years have now passed since we left the moon, and the White House is on the cusp of making far-reaching decisions on the future of human spaceflight. I have tried to argue that sometime soon we will be able to plan missions beyond Earth that could yield phenomenal scientific knowledge. Furthermore, if we are clever, we will find ways to execute these missions in a manner that is consistent with stewardship of constrained resources.

But this won’t happen without increased support from the public and from within the scientific community. In recent times Christians have not been known for championing daring scientific research projects like the one in the story. I wonder if that will have changed by 2025.

Appendix: The Science Behind the Story

The mission described in the story tried to convey a quirk of spaceflight that isn’t widely appreciated: some things are catastrophically hard to do, but others are surprisingly easy. The story hopes to show that if we defer what’s very hard, we can still realistically plan some amazing missions.

First let’s talk about what’s easy. Space is a unique environment, and building spacecraft entails meeting design challenges that occur in no other industry. But there are also commonalities, most notably with aircraft and submarine design. One striking similarity with commercial aircraft design is as follows: both kinds of vehicle spend much of their service life in a surprisingly benign environment. For commercial aircraft it’s high-altitude cruise, and for spacecraft it’s orbital cruise. The reason airliners can stay in the air for so much of their lifetime is cruising at high altitude induces very few loads on the airframe. The engine thrust exactly matches the drag produced by the oncoming air stream, and the net stresses on the vehicle are not significantly different from those acting on an aircraft supported by its undercarriage in a hangar on the ground. The same is true for spacecraft. Once in orbit, regardless of the speed it travels, the stresses on the craft are not that significant.

When closest to Earth, Mars is 140 times further away than the moon. That’s a long way. But it doesn’t follow that it’s 140 times technically harder to get there. It certainly would take 140 times longer to get there (assuming you didn’t upgrade your moon rocket engines). If there were humans on board you’d need 140 times as many sandwiches as the moon missions, but you don’t need 140 times as much fuel because once at speed, there’s no friction slowing you down.

The point is that the difference between a journey to Mars and the Moon is principally one of duration. It’s no co-incidence that NASA and Russia have spent the last several decades learning about long duration spaceflight, most recently aboard the International Space Station alongside European, Canadian, and Japanese colleagues. Several humans have spent the equivalent of a Mars mission journey aboard space stations, so the technical challenges here are well understood.

So, building a Mars Orbital Laboratory and sending it all the way to Mars, as described in the story is not that big a challenge. Today, a typical mission to the Space Station lasts for six months, which just happens to be how long it takes current rocket technology to get to Mars. It would make no difference to an astronaut if that time were spent endlessly circling the Earth, or on a journey that concluded in orbit around Mars.

But landing a human outpost on Mars is very probably 140 times technically harder than landing on the Moon for reasons I explore briefly in the story. If you ignore the problems with landing large masses, then a mission with a surface research outpost would require the development of Mars-capable spacesuits, tools, and vehicles, etc. Importantly, such an outpost would need to land with a fueled vehicle that can take the crew back to Mars orbit where it would dock with an Earth-bound sister vehicle, so that’s two additional spacecraft. Advocates of this plan suggest the Mars research equipment would be first tested and refined on the Moon, so that’s an additional mission (or missions).

In the story, Sasha’s dad is aware that in 2025 none of the infrastructure for a landing has been developed. The MOL plan was approved in 2011 because it was achievable without the high risk and cost of developing the Mars lander, Mars ascent stage, Lunar test missions, and the surface operations hardware. This is why he doesn’t want Sasha’s to get her hopes up about a Mars landing...

But the number one challenge for a Mars surface outpost is one that also plagues the orbital mission concept in the story, and in fact plagues every other space project: Energy.

With unlimited energy you could land large masses on Mars, and could build robust extra-safe hardware with countless backup systems. You could also get to and from Mars more quickly.

But to date, every space mission has been starved for energy because the cost of getting hardware and fuel into orbit is so high. Once in orbit, the energy available for a mission is limited by either the mass of rocket fuel brought along, or the size of solar panels, or the capacity of RTGs (radioisotope thermoelectric generators). But in every case it’s a limiting factor.

While landing an outpost on Mars requires phenomenal energy (which translates into numerous launches, and cost), the energy needed to orbit Mars is LESS than that needed to land an equivalent mass for a Moon mission. My goal for the story was to keep the realism high, so while Sci-Fi writers can assume plentiful energy, I did not. I’m confident we’ll land on Mars some time in the distant future, but in 2025 a surface outpost is not realistic, but an orbital mission is.

There are two other key technical considerations, and both are related to astronaut health.

The first is the muscle and bone loss that occurs in weightlessness. This can only be partially alleviated when astronauts follow a vigorous exercise program while in space. Understanding and mitigating this problem drives much of the research onboard the International Space Station today. Critics of missions to Mars have suggested that after six months (or more) of weightless flight-time astronauts would arrive incapable of standing, or would at least have trouble completing the mission. The gravity on Mars is roughly one third as strong as here on Earth, so it’s not clear that such a sudden increase in gravity would be debilitating. On the other hand, since astronauts could spend up to two years on the surface, it’s also unclear if that’s sufficient gravity to prevent further deterioration. If not, explorers will find they need to spend much of their time on Mars at the gym.

While the International Space Station was designed for zero-G research, a Mars Orbital Laboratory would not have that requirement. As far back as Gemini XI in 1966 NASA experimented with inducing artificial gravity by spinning two craft around a central point, one acting as a counter-weight. Without going into details, we might reasonably expect this technique could be used to fly the MOL astronauts in a 1 G environment – just like here on Earth – for the majority of their mission. (Sadly, if the spin were maintained while at Mars, the view out of the window could make the astronauts pretty dizzy. But in 2025 it’s a good guess that the display technology, including virtual reality, will give them a spectacular view of their surroundings.)

The second consideration is potentially more grave. Here on Earth there are several mechanisms that shield us from Solar and cosmic radiation. Astronauts that head for the Moon or Mars will fly beyond that protection. There are several technologies that could mitigate this problem which are on the cusp of becoming science-fact rather than science-fiction, but for now the health of the crew is best served by simply making the mission as short as possible. Shielding the crew behind water, or polyethylene provides some protection, but because this is unknown medical territory, the first Mars explorers will once again be chosen from volunteers with the ‘right stuff.’

And we’re back to energy again. If we have energy to spare we can reduce the journey time by accelerating and then braking as we near Mars. Similarly, if we have the energy we can build a spacecraft with lots of (heavy) radiation shielding.

Most of the design studies for Mars missions assume traditional chemical rocket technology will be used. And sending the required mass to Mars needs plenty of rockets and lots of fuel. The most recent credible plan requires launching about 12 times as much payload as the Apollo lunar missions. To loft this much mass with current launchers like the Space Shuttle would take 57 separate flights. These numbers are for a surface mission, so an orbital mission will need far fewer, but the scale is still huge.

There is no doubt that at some point in the future space exploration will switch to nuclear propulsion and nuclear power; the options opened up by the availability of energy are just too enticing to ignore. The difference will be similar to the shift that occurred in commercial air transportation from propeller driven craft to jets. We could have stuck with propeller aircraft and learned to live with their limitations, but the considerable cost of developing efficient jet engines has proven to be a winning investment. So nuclear propulsion will happen, it’s just a question of when, who will do it first, and precisely what technology will be used.

One of the key findings of the Augustine Commission is NASA has been unable to drive technology development forward while busy operating the Shuttle and building the Space Station. As a result, new plans for exploration are to a large extent picking up from where we left off in the 1970s. I wholeheartedly agree with the commission; developing new technology is the right role for NASA.

The story doesn’t require it, but in one possible variant we can imagine that an aggressive nuclear space propulsion technology program begins in 2010. The technology has not been worked on much since the 1970s, but if it were funded in parallel to the other elements of the mission in the story, it might be ready by the 2020 timeframe, and the story timeline would still add up. It would be a gamble, but the payoff would be significant.

One related technology that looks promising is a plasma rocket called VASIMR. It’s far enough along that a test version will be used on the Space Station in 2012. (This is actually happening; it’s not part of my story!) It’s a small rocket, but the designers claim that if it were scaled up and driven by a 200 megawatt nuclear powerplant it could send a 60 metric tonne spacecraft to Mars in just 39 days. Progressively smaller powerplants give more modest transit times, but still beat chemical rockets by a wide margin.

The current NASA Mars Design Reference Architecture requires a 540 day stay on the surface of Mars and a 30 month mission duration. This is driven by energy limitations; once you have set up the outpost you need to wait for Mars and Earth to become aligned properly in order to get home.

With a nuclear propulsion system driving a Mars Orbital Lab, we can conceive of a 120 day shakedown mission (one month stay), returning to Earth for a refit, and then longer duration missions.

If I were Sasha’s dad, I know which one I’d choose.

Suggested Links

[1] Highfield, Roger. "Colonies in space may be only hope, says Hawking." 21 Oct, 2001.