GPIS Epilog

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Chapter 10: I Was Just Wondering GPIS Contents Appendices


This material was originally contributed by Bruce Irving from the 2nd edition of Go Play In Space. Refer to the page's View History tab to see subsequent changes.

Your Future In Space[edit]

This final chapter is different from the others, because it is concerned with real space flight, and with some of my own ideas and opinions about the future of space flight, and the future in general. The rest of this manual has been about simulated “playing in space,” using Orbiter for fun and as a framework to encourage you to explore certain aspects of space flight in a fairly realistic way. If you find this sort of thing to be interesting, and depending on where you are in your schooling or career plans, you might consider doing something that’s connected with real space flight. It could lead to involvement with some of the most interesting and important developments of the next 50 years or so. You could get involved now by joining a space advocacy group.

Opinions expressed here about the importance of space for the future of humanity, and on the feasibility of human flights to Mars in the near future, are my own take on various things I have read and thought about. But some aspects of this epilogue were inspired by several writers in particular. The nonfiction writings of Dr. Robert Zubrin and Dr. Raymond Kurzweil, and the writings of science fiction authors Kim Stanley Robinson, John Barnes, Stephen Baxter, and Gregory Benford have been particularly helpful. I will provide references and more detailed credits at the end of this chapter.

Mars for less
Mars for Less is a reference mission designed by Grant Bonin for MarsDrive Consortium, a group that is trying to organize other groups and individuals in support of human missions to Mars within the next twenty years. Mars for Less is a variation of Robert Zubrin’s Mars Direct that proposes to make use of existing medium-lift launch vehicles (MLLV) to place modular crew, utility, and propulsion units in low Earth orbit for assembly into complete vehicles for Mars injection. The MarsDrive ships (ERV, top, MTSV, bottom, graphic used with permission) are not (yet) an Orbiter add-on. There is more on MarsDrive and Mars for Less later in this epilogue, and even more at

Space Is Real[edit]

While it’s true that Orbiter is only a space flight simulation and in some respects a game, space is real, and you may have a real future in space. In fact, space may be more important than you may think. What is so important about space? For one thing, space truly is “the final frontier,” and frontiers have been very important in human history. Think about the role of Columbus and other early explorers in discovering the Americas. The discovery of a “new world” previously unknown to the European trading nations of the 1500’s stimulated technology to develop better sailing ships and navigation methods. It created new opportunities for trade and eventually for new places to live, allowing European colonists to escape religious and social oppression, or simply to start a new life. Of course this opportunity came at a cost – it was expensive and risky to cross the Atlantic Ocean in those early days. Those who made it faced many hardships (and the hardships for the native people they encountered were often worse – the treatment of native people by early explorers and settlers was terrible and sad even if we consider that at the time, there was nothing like our modern appreciation of the value of different cultures). The existence of the New World (today’s North and South America) provided new sources and markets for goods and new places to live, but even more importantly, it opened the doors to new ways of thinking about everything.

Later (mainly in the 1800’s) the American West became a New Frontier, and the challenges of expanding the United States from coast to coast became another major economic and social driver that created opportunities for many as well as new markets for goods, services, and ideas. Much has been written about the importance of frontiers in the development of the modern nations of Europe and North America. Dr. Robert Zubrin explores these and many other ideas in his books The Case for Mars and Entering Space. These are just a few examples, and while this is not a history book, I believe that one thing that is missing in today’s world is a significant frontier. This is not to say that we lack challenges and problems to solve. We certainly have plenty of those. But some of history’s most productive periods have occurred when there was a frontier to stimulate exploration and new ideas – and to provide focus or direction. This is related to a fundamental human trait – willingness to step out into unfamiliar territory in search of new ideas and opportunities and in spite of the uncertainties of such ventures.

Uncertain Future – The future IS uncertain, of course. Thirty years ago, some people believed that there was a “population bomb,” that runaway human population growth would soon outpace our ability to grow food, leading to mass starvation. While there are still tragically bad conditions and even starvation in some regions of the world, it seems that when technology and social efforts lead to better living conditions, populations stabilize over time – people in more developed countries live longer lives, but under better conditions and with fewer children. Population is still a serious issue, but no bomb yet.

Of course we still face many risks – global warming and other environmental threats to the Earth’s atmosphere and water; war and terrorism; various diseases, old and new; and a variety of natural disasters ranging from earthquakes and tsunamis to a possible giant asteroid strike. Technology and other human efforts can be used to reduce some of the risks and to help people when they are hurt by these things. Humans are very resourceful and there is reason for optimism in spite of the many challenges we face. But there are still many uncertainties.

OK, but what does this have to do with space? I’m getting to that, I promise! But first a case of good news and bad news. Consider the idea of living longer, healthier lives, which seems to be the result of improved nutrition, health care, education, and economic conditions in many parts of the world. Of course this is a good thing. There are some people who believe that molecular biology and medicine may be close to solving even the basic problems of aging, so that people could eventually have the chance to live much longer but still healthy lives, perhaps 120 years or more as a typical healthy and active lifespan. No one knows for sure yet if this is possible or how far it could go, but many people think it is plausible (some think we could reach this stage in the next 15-25 years, while others think it could happen but may take a hundred years or more to solve the many sub-problems of aging). But think about this – it means that if you were born in 1985, you might still be alive, healthy, and active in 2105. Is this a good thing?

Yes and no (yes for you personally, maybe no for society as a whole). While it’s not quite the same as a “population bomb,” consider a population of many millions of healthy 70-to-120-year-old people who in the past would have mostly been retired from their jobs (or in many cases, have died). What will we do with these people?

Send them into space? Not quite! My point is that the “good news” of greatly extending the lives of so many people could have unplanned consequences or “bad news” side effects. It could change the nature of our societies, of our working lives, and the nature of the opportunities that young people have. Not only is there no “new frontier” on Earth, but even the idea of a career that progresses over time from entry level to more complex, responsible, and better-paid positions could break down if the senior people remain on the job for many more years because they are still healthy and active and either need to or want to continue working. And this is not even considering the likelihood that we will develop computers and robots with something more similar to human intelligence which (who?) will also compete for some of the jobs that can only be done by humans today (robots already do much of the repetitive factory work that used to be done by people, and the Internet and advanced telecommunications are already changing the nature and distribution of work, entertainment, government, and more, changing every day).

Change will continue and accelerate, leading to a very different world in the future – maybe a better world, with chances for multiple careers, continuing education, creative pursuits, and more leisure time. Maybe the problems of a society where long, healthy lifetimes are the norm will take several generations to solve. No one really knows. Of course there are other scenarios too – what if a disease worse in its effects and harder to fight than AIDS becomes an epidemic? What if terrorism becomes more widespread and destructive? These are terrible prospects to consider – people will do everything they can to prevent such things from happening, and they probably will succeed – but maybe not.

I’m personally optimistic about the future, and I’m not trying to frighten anyone here. But I’m certainly not the first one to think about the unpredictable mix of good and bad changes that could come about in the next 10-50 years. This is making a pretty big leap on the basis of a lot of “what ifs,” but some might even imagine the Earth becoming a boring place (in the “people live very long healthy lives without any special challenges” case), or a place that is quite terrible for many more people. Most likely it will be a mix, with some regions doing better than others, as is the case now. Science fiction (SF) and some nonfiction writers have explored many of these “what if” situations in books, and I will provide references for a couple of interesting examples later.

We need space – Finally we get back to space. What are some of the reasons space could become more important in the future? Here are a few that I have thought about based on my reading.

  • A new frontier – Providing new challenges for people willing to leave the familiar world of Earth, as well as for the many who will stay here to develop and support the technology, the missions, and the eventual colonies. Mars would be the likely first step (we could revisit the Moon as well, but Mars offers many more useful resources), and I have a few notes about Mars exploration and colonization plans at the end of this chapter.
  • New places to live – Colonies on Mars and perhaps other places in the Solar System (e.g., space colonies built from Moon materials or asteroids) could provide new and largely independent places to live, though for relatively few people within the first few years. Barring some unimaginable catastrophe, the vast majority of humans will probably continue to live on Earth for many years to come, even if space colonies are developed. Space is not likely to be a near future solution to excessive population growth on Earth.
  • New sources of materials and energy – The Moon has a lot of material that could eventually be used for the construction of space colonies and satellites, possibly including solar power satellites that could collect solar energy and beam it to Earth as microwaves (there are some problems with the economics of such a system, but things could change). When nuclear fusion power plants are eventually developed, Helium-3 is an attractive fuel, and the Moon could be a good source of this substance. Materials on Mars will probably be used mainly there (at least at first), but Mars could also be a base for eventual asteroid mining (asteroids contain huge quantities of many valuable materials).
  • More options in case unexpected things happen – This connects with the two points above. We certainly hope that we can preserve and even improve the Earth’s environment, live in peace, solve any major medical problems that emerge, and wisely use, conserve, and share the resources we all need. We hope that if a large near-Earth asteroid (NEA) heads our way in the next hundred years or so that we will have the technology to detect and safely deflect it in time. We certainly will not give up the Earth easily to such disasters, but there is some benefit to having part of humankind’s population living “off planet” as a sort of backup or insurance plan.
  • Science and Technology Spin-offs – Science is often cited as the main reason for going into space, and it is important. The search for knowledge has long been one of humankind’s fundamental drives as well as the source of basic knowledge that drives technology. We have also derived many side benefits from technology that was originally developed specifically for space flight, in addition to the direct benefits of satellites for communications, weather forecasting, navigation, etc.

Many people say that science in space is best done by robotic spacecraft. For many missions, this is true, and robotic spacecraft certainly are essential for knowing what to expect and for planning piloted missions. But humans are still the best observers, opportunity-takers, and improvisers, and when we have humans on Mars and other planets, they will learn more, learn faster, and get more done than if we use only robots.

These are just a few reasons to consider space as the logical next step for mankind. Although there are some who say, “we should learn to limit what we want and to conserve, share, and use more wisely the resources of our only planet, the Earth, ”that is not the way it works in practice! Of course we should try to conserve and make the best use of limited resources, but as people become more prosperous, they soon want more options and more comfort, in the forms of cars, appliances, better heating and cooling, better health care, better education for their children, better entertainment, vacation travel, and just more of everything.

These are things that many people in the world take for granted (e.g., in North America, Europe, parts of Asia, and a few other areas), and it’s only natural that other people should want these things too. But all of this takes more energy – which is one of the reasons we are using up the remaining supplies of oil and other fossil fuels so quickly now. More people on Earth want them. When people look back on today from 100 years in the future, the era of cheap and rapidly expended energy from fossil fuels will probably be seen as a strange, unique, and rather brief time. We will learn to make better use of solar and other alternative energy sources, and we will develop safer and more powerful nuclear power systems based on nuclear fusion in addition to more advanced uses of nuclear fission. These developments will help us in space as well as with the energy needs of Earth. Space will give us more options, and will give us a new frontier that will inspire our future generations.

But Aren’t We Already in Space?[edit]

It’s true that we have been sending men and women into space for over forty years, including the small number of Moon flights in the Apollo program that were the first in which humans visited a world other than Earth (1968-1972). A few countries (mainly the U.S. and Russia) have since continued to send people into low Earth orbit for research and a few other purposes. Space stations have been built and occupied for thousands of days, and the first reusable “space transportation system” (the U.S. Space Shuttle) has been flown with much success since 1981, despite the tragic loss of Challenger and Columbia and their crews. The experience gained and the technology derived from these flights are certainly valuable, and people from around the world have now experienced space flight. While I wish we had continued our piloted exploration of the Solar System right after Apollo, I’m glad that we have not given up on space completely, and I honor and appreciate the important efforts and sacrifices of all the people who have made space a place and not just an abstract idea.

But these pioneering, largely exploratory, research oriented flights are not the real future of space. I believe the future of space will involve people going to and eventually living on other planets and moons in the Solar System and perhaps beyond. The technology to go to Mars already exists. I think we are moving in that direction, and I think this will be one of the most important developments of the next fifty years. As the late Carl Sagan said in his 1980 book Cosmos (Chapter VII, final paragraph),

“Exploration is in our nature. We began as wanderers, and we are wanderers still. We have lingered long enough on the shores of the cosmic ocean. We are ready at last to set sail for the stars.”

...or at least to start with Mars!

What about you, the reader?[edit]

If you have stuck with me this far in this epilogue, you may be wondering if there’s something specifically for your future, or just some more discussions about trends and problems in general. I don’t know what will really happen in the future or what jobs or careers will be needed most in ten years, let alone twenty or fifty, though I do have a few thoughts about what I would do if I were starting out now.

But first let me quote a passage from a favorite science fiction novel, John Barnes’ The Sky So Big and Black. The story takes place on Mars in the late twenty-first century when colonies have been established there in the wake of multiple disastrous events that take place on Earth in the early years of the century. The main characters are a father and his teenage daughter Teri who work as an “ecospecting” team, searching for underground deposits of water, methane, and other materials that are needed by the colonists who are terraforming Mars (modifying its climate to eventually be more directly suitable to humans). They are discussing the next step in Teri’s education, and how pre-disaster Earth educational systems tended to teach students to be paper-pushers and consumers. Teri had attended a Mars “CSL” school which taught students to be independent, self-sufficient, technically savvy, and resourceful. Teri replies to a comment by her father on the old “high school” system:

“And that’s what we’re going back to?” For the first time in my life I was glad I to have gone to CSL school. “Naw, it was just an example of the way every society always makes the kids it needs. Up until about 2000, they just didn’t need anybody very smart or capable – what they needed was people to buy stuff and follow rules.” [Barnes, The Sky So Big and Black, page 121]

Teri’s father later adds that after the Earth-wide disasters of the early 2000’s,

“...just to keep the species going, you needed people who would learn anything, and use everything they knew, all the time. You not only couldn’t afford to be stupid, you couldn’t let your neighbor be stupid.” [Ibid, page 122]

Current educational systems in most places are not as bad as Barnes’ characters portray here, and teachers certainly work hard to prepare their students for the challenges and changes ahead. But the point is that in a relatively stable and prosperous society that lacks a frontier, the standard educational system does not necessarily prepare you for the future in all the ways you may need if things start to change dramatically or catastrophically. (Video and PC games supplement the educational system for many students, and there are some indications that these actually do a better job at developing certain problem solving skills than mainstream education does.)

I wouldn’t presume to tell anyone what to do, but I’ve thought about what I might do if I were younger and starting out now in my education and career and wanted to be involved in space. I would want to go on space missions myself if I could, but even if I were to have some other role in space flight, I think the preparation would be much the same.

  • Education – I would pursue a technical education of some sort and make sure it was at a school and in a program that emphasized fundamentals and problem solving, including math, physics, computers, and some aspects of current practical technology, while recognizing that any technology learned today will be mostly obsolete within 10-15 years. Strategies for continued learning and re-learning (as well as acceptance of the need for this) are vital parts of any modern education. I don’t know if I would focus on space science and technology or not – a lot depends on the program. People of many specialties will be needed in space related jobs.
  • Other preparation – I would try to pursue other skills, physical and mental, that might be useful in space exploration. Flying might be one of those skills, even though not every astronaut needs to be a pilot. Flying encourages 3D thinking, a methodical approach to complex tasks, and the ability to quickly evaluate, prioritize, and solve problems (I wish I had learned to fly earlier than I actually did – if you have an interest, I suggest you start saving the money and taking lessons as soon as you can). I would also pursue more varied physical activities – space flight is not all that strenuous, but many tasks require good coordination, strength, and dexterity. Some classes and field experience in geology and biology would also be valuable – learning to observe your surroundings in detail. Experience with caves and rock climbing could be useful too.
  • Versatility – In The Case for Mars, Dr. Zubrin suggests that early piloted Mars exploration missions will likely have a crew of four, and that the needs of a long flight (~6 months each way) and long surface stay on Mars (~500 days) are so diverse, that you could hardly afford to have a dedicated pilot-astronaut in this small group. Of course even with automated systems, you need one or two skilled pilots, if only for backup, but more important skills will be engineering (mechanical, electrical, chemical, aeronautical, maybe others, with hands-on skills for maintaining, repairing, and improvising) and science (geology, biology, material science, etc.). Piloting and even medicine will be “cross trained” (along with horticulture, small group psychology, and a variety of other things) over a good mix of other skills. Versatility will help if you ever go to space, but it will also help if you happen to live 120 years or so and need to have three or four careers!

So that’s what I would do if I were starting out today – if any of those ideas work for you, that’s great. I think that even without the disasters imagined in The Sky So Big and Black, the next century will be a period of rapid and probably surprising changes, and we will need a lot of people (to paraphrase Barnes) “who will learn anything, and use everything they know, all the time.”

Mars Direct, Mars for Less, VSE, Other Options?[edit]

Although there are other “design reference missions” (DRMs) by NASA, ESA, and others, certain aspects of Robert Zubrin’s well-known Mars Direct proposal have been adopted in almost every humans-to-Mars study since it was published in the early 1990’s, especially the ideas of sending an unmanned Earth return craft to Mars ahead of the astronauts, and of using local resources to make propellants for the return (known in the Mars trade by the acronym ISRU, in situ resource utilization).

Live Off the Land – Mars Direct suggests using extensions and variations of existing launch vehicle and spacecraft technology, along with some clever but relatively simple and even demonstrated innovations. The plan started as a reaction to overly complex and expensive Mars mission plans developed in the 1980’s. Perhaps its hallmark is the ISRU idea, using local resources to “live off the land.”

What does this mean? In the case of Mars, it mostly means that instead of carrying all the fuel you need with you to Mars (requiring an immense launch vehicle), you make most of it on Mars. Zubrin recognized that the mostly carbon dioxide (CO2) Mars atmosphere can be used to make rocket fuel right on Mars. With the addition of hydrogen (H2, possibly available from water on Mars, but light and fairly easy to transport to Mars if necessary), a simple chemical process can turn CO2 and H2 into methane (CH4) for rocket fuel, and oxygen (O2) for the oxidizer (since there is no oxygen in space, space vehicles must carry their own oxygen or alternate “oxidizer,” or the fuel will not burn).

So “live off the land” means “make your return rocket fuel from mostly local materials.” A huge proportion of spacecraft mass on any long-range mission is propellant, so the ability to make most of your return-trip propellant on Mars rather than carrying it from Earth saves a lot of weight. It makes it possible to perform the mission with a reasonable payload using current-technology rocket engines. The chemical engineering needed to do this is well known and easily automated. Power to run the chemical plant (and later the Mars base itself) is the big problem, but a small nuclear reactor solves this. A bigger problem will likely be the political and environmental concerns over launching nuclear reactors into space, but the safety issues are manageable, and there is no other practical way to supply the needed power at the distance of Mars (solar panel arrays would have to be huge and would only generate power on the surface of Mars in daylight hours – Mars rotates at about the same rate as Earth and has a similar day/night cycle with a 24.6 hour day).

Shuttle-derived HLLV booster
Shuttle-Derived HLLV Booster could build upon Space Shuttle launch technology to create a powerful new heavy-lift launch vehicle (HLLV), shown here with the Mars Direct HAB and upper stage. Note the side-mounted cluster of engines derived from the Shuttle Main Engines, the rust-colored external-tank- like main body (solid rocket boosters and payload faring already jettisoned). Two HLLV launches would be needed for the original heavy-lift Mars Direct mission. NASA’s ESAS describes plans to eventually develop and deploy a similar CaLV (cargo launch vehicle) as well as a smaller CLV (crew launch vehicle).

The Technology – Another key point of Mars Direct and most other recent DRMs is the use of multiple spacecraft and launches, though the number of launches, the payload capability of the launchers, and how and when the craft are deployed vary considerably among the various Mars plan. In Mars Direct itself, the first craft to launch direct for Mars would be the ERV (Earth return vehicle), which would land under autopilot/remote control, deploy a small nuclear reactor for power, deploy a small automated chemical plant for methane/oxygen production, and start making propellants for the astronauts’ return voyage (hence the name ERV). Robots and computers would operate this setup, and video cameras and other sensors would allow Earth based engineers to control and monitor these processes.

Pseudo Gravity can be generated by rotation. For Mars Direct and similar missions, a 330 m long tether (very strong cable) could be used to attach the top of the HAB to the empty final stage of the launch vehicle, which serves as a non-critical counterweight (it isn’t needed for anything else). The HAB’s thrusters can start the pair spinning to generate 0.38G (Mars normal) of pseudo gravity directed toward the floors oftheHAB. Thiswillavoidtheharmfullong-term effects of zero G during the six month flight to Mars. Original image courtesy Orbiter Mars Direct Project, from web site Gallery page at, used with permission.

With their fully fueled ERV sitting on the surface of Mars, the piloted “habitation vehicle” (HAB) would launch two years later. For safety reasons, the crew would most likely be launched in a separate “CEV” (Crew Exploration Vehicle), a smaller craft that will be developed specifically for transporting astronauts, to dock with the HAB in low Earth orbit (LEO rendezvous and docking is a routine maneuver). A clever but simple “tether” (cable) method could be used to slowly spin the HAB in a circle for most of the six- month flight, using the empty final stage of the rocket booster as a counterweight. The spin would generate Mars-equivalent artificial gravity, protecting the astronauts from the harmful effects of a long timeinzero-G. After a six month voyage to Mars, the HAB would be landed very near the ERV, and using several methane/oxygen fueled “rover” vehicles, the astronauts would begin their exploration of Mars. After some 500 days on the surface, the low-energy “launch window” for return to Earth would open up, and the astronauts would launch in the ERV for the long trip home.

There is more to Mars Direct than this, but that’s the gist of it. It doesn’t require breakthrough science, Moon bases, or huge space stations, though it does require development of a new heavy-lift launch vehicle (125 metric tonne [mT] class HLLV) in addition to several new spacecraft, a new upper stage, and a number of advanced automated systems.

These things involve a lot of careful engineering and modifications of existing technology, but they are generally extensions of things we know how to do. They also involve a lot of money, of course. Although the U.S. has announced plans to return to the Moon and eventually go on to Mars, the timing and long-term funding are uncertain, and there are many difficult milestones to achieve. Mars is an ambitious project for any one nation, even the U.S.

Other Mars Possibilities – The U.S. Vision for Space Exploration (VSE) was announced in 2004, and NASA’s ESAS (Exploration Systems Architecture Study, search for ESAS) was released in 2005 to describe specific system-level plans for human space exploration over the next twenty years. It starts with the development of new spacecraft (CEV by 2012-2014) and launch vehicles (CLV, CaLV) that will take U.S. astronauts back to the Moon by 2018, and will be the basis of further developments needed for human Mars missions some years later. Although ESA (European Space Agency) has also studied human Mars missions, the U.S. is likely the only nation capable of near future development of a HLLV in the required 125 mT range. Since this sort of launch vehicle is needed for Mars Direct and for most other design reference missions (DRMs), its development is a prerequisite for any of these proposed missions. The web site of Dr. Donald Rapp is an extensive, well-researched, and readable source for information on the ideas and tradeoffs for various Mars mission designs (

Mars for Less – One bottleneck for both Mars Direct and for NASA’s various Mars plans is the need for a HLLV with a payload in the 125 mT range. While such a vehicle certainly can be developed, it is an expensive project with no critical application other than human Moon and Mars missions. Its development over a number of years, presidential administrations, and budgets is certainly in question, and if the mission depends on this one vehicle, failure to develop it would be a complete “show stopper.” It is also difficult for other nations or private groups to participate in a significant and secure way when theprimarylaunchvehicleisunderexclusiveU.S.control. ThecompletionoftheInternationalSpace Station (ISS) is dependent on the still troubled Space Shuttle (and thus is in doubt) because large ISS modules developed by partner nations can only be carried by the Shuttle. A similar “critical path” would be formed for Mars missions based on a U.S.-controlled HLLV.

Grant Bonin of MarsDrive Consortium (MDC) has developed an alternative reference mission that is similar to Mars Direct, but designed around modular components that can be launched using medium-lift launch vehicles (MLLV, 20-30 mT class). The modules would be designed for ease of assembly in low Earth orbit. Although there are risks associated with multiple launches (a total of perhaps 12 MLLV launches, vs. 2 or 3 HLLV launches for Mars Direct and various NASA DRMs), there is less critical functionality in any one launch, and there are multiple LV types that could handle the required payloads, allowing partner nations to share launch duties. Eight of the nominal twelve MLLV launches would be carrying identical propulsion modules which would be relatively easy to replace if lost (backups could be available). Loss of an unmanned crew module (MTSV: Mars Transfer and Surface Vehicle, ERV: Earth Return Vehicle) or utility modules would be more expensive but might not kill the project. The crew itself would require a later launch in a CEV-type vehicle to board the assembled MTSV for injection for Mars.

Visit for more on MDC’s Mars for Less reference mission and other plans.

Mars Missions and Orbiter – As you perhaps have experienced in chapter 6, Orbiter can help you to start thinking about Mars and to start planning how to get there. The Delta Glider won’t really be around for a few years, but there are other rides you can take in the meantime. In addition to giving you a basic familiarity with the concepts and tools of space flight, and helping you to know your way around the Solar System, Orbiter familiarizes you with orbital maneuvering, especially rendezvous and docking. This is sure to be an important part of any future human Mars missions, especially a Mars for Less mission, which I hope will become an Orbiter add-on in the near future.

There is an Orbiter add-on available with the basic components of Mars Direct (by “jgrillo2002” – search for Mars Direct at As shown in some pictures in this book, there is a also a current multi-person add-on development project which aims to model Mars Direct in more detail. Progress has been made (e.g., the HLLV model on E-8 and the beta HAB below), but work remains to be done. See


I hope you have found the main part of this book to be a fun and informative introduction to space flight. I really think Orbiter is the ideal way to get a feel for some of the things that are involved in flying in space, and while it took a lot of words and pictures, if you actually followed chapters 2-6, you got to experience a lot in a pretty short time – and you even flew to the Moon, to the ISS, and to Mars! I also hope that this epilogue has given you a few things to think about regarding the future in general, and yours in particular, and whether you might actually have a future in space. If this book gets even a few people thinking about and working toward this, it will have been well worth the time to write it (not to mention it was actually fun to write, especially with Andy McSorley’s help on this second edition).

I have recently gotten involved with educational outreach for the MarsDrive Consortium (MDC, I believe we humans can and should get to Mars sooner rather than later and I want to help if I can. If you have an interest in this, I hope you will join MDC or another space advocacy group. Thanks again to Dr. Martin Schweiger for creating Orbiter so that you and I and I hope a lot more people can virtually play in space. Maybe some of you reading this will truly go play in space someday.

Mars Direct mashup
Mars Direct Mashup – Several add-ons were combined to create this Mars scene in Orbiter. The 3D terrain is Vallis Dao by “jtiberius” and the ERV (left background) is from jgrillo2002’s Mars Direct add- on (both available at The rovers are actually Andy McSorley’s “Jason” Moon rover from his Prometheus CEV add-on (also available at The beautifully modeled HAB in the foreground is a beta version from an ambitious Mars Direct Project for Orbiter that is still in development. For more information, check the link below, especially the Mars Direct Forum link found there. March-April 2006 posts indicate some recent progress on this big add-on project. marsdirectproject/marsdirectproject.htm

References for This Chapter[edit]

These are just a few of many excellent books that relate to the topics in this epilogue.

Barnes, John, Orbital Resonance (novel), Tor Books 1991

Part of a series that also includes The Kaleidoscope Century, this book takes place in a space colony built from an asteroid as part of an off-Earth “lifeboat” plan following a series of planet-wide disasters on Earth.

Barnes, John, The Sky So Big and Black (novel), Tor Books 2002

Takes place on Mars in the late 21st century some years after Orbital Resonance. Interesting ideas about the future and about human life on Mars.

Baxter, Stephen, Voyage (novel), Harper Prism 1996

This is a huge, detailed, and fascinating “alternate history” SF novel that assumes that instead of deciding in 1972 to build the Space Shuttle after the Apollo program, that President Nixon decided to pursue a Mars project based on Apollo technology. Excellent in many ways, including the descriptions of what space flight is like. Richard Wall developed an extensive add-on for an earlier version of Orbiter based on Baxter’s descriptions in Voyage, but I have not tried this add-on and don’t know if it will work in Orbiter 2006 (search for richard wall on, at least three files starting with

Benford, Gregory, The Martian Race (novel), Warner Books 1999

This book features a privately-funded Mars mission based on the Mars Direct approach, but it is also an excellent SF novel in its own right, apart from any connection with Mars Direct. Believable characters, credible situations, many surprises. A really good read.

Bonin, Grant, Reaching Mars for Less: The Reference Mission Design of the MarsDrive Consortium Technical paper presented at International Space Development Conference (ISDC), May 2006

This paper describes the Mars for Less reference mission in more detail, including discussions of trajectories; propulsion and propellant storage issues; spacecraft design; orbital assembly issues; lunar mission variations; artificial gravity; multiple launch issues; and the effects of propulsion stage failures and launch delays. Bonin points out that by breaking the mission into approximately 25 metric tonne modules, existing MLLVs (Ariane V, Delta IV-H) and in-development or planned MLLVs (NASA CLV, SpaceX Falcon 9-29, Chinese Long March 5) could be used to launch the mission components for orbital assembly.

Crossman, Frank and Zubrin, Robert (editors), On To Mars 2 , Apogee Books 2005

A collection of papers from the Mars Society’s 2002-2004 annual conferences, this book provides an interesting cross-section of the Mars-exploration-related thinking and research that is going on today. The papers cover plans for proposed Mars missions, research on various aspects of Mars missions (including reports from the Mars Society’s arctic and desert Mars analog research sites), propulsion issues, tools, social issues of settling Mars, and much more. The book includes a bonus CD-ROM with a large number of additional papers.

Edwards, Bradley & Westling, Eric, The Space Elevator , BC Edwards (avail., 2003

Subtitled “A Revolutionary Earth-to-Space Transportation System” and based on a study done for NIAC (NASA Institute for Advanced Concepts,, this book describes what is needed to build a space elevator in amazing but readable detail. Carbon nanotubes will make it possible, and it could possibly be built within the next 20 years. A 43 page PDF summary:

Kurzweil, Raymond, The Age of Spiritual Machines , Penguin Books, 1999

Subtitled “when computers exceed human intelligence,” this book concerns the future and the implications of rapidly growing technology and especially of the arrival of machines (something beyond computers and robots as we know them) with intelligence beyond that of humans. Whether or not this is a good thing, and whether or not you accept Kurzweil’s ideas of the possible timing (his premise is that the rate of change will soon move from rapid to explosive), this fascinating book is well reasoned and thought provoking.

Kurzweil, Raymond and Terry Grossman, M.D., Fantastic Voyage: Live Long Enough to Live Forever , Rodale Books 2004

One of Kurzweil’s other interests is life extension (he clearly believes the future will be pretty interesting and would like to be around for more of it). The book outlines a detailed (if somewhat controversial) approach to radical life extension.

Robinson, Kim Stanley, Mars Trilogy: Red Mars, Green Mars, Blue Mars , Spectra, 1993-1997

The most comprehensive and realistic treatment of the human settlement of Mars, this trilogy is a modern SF classic. There are many impressive things about these books, from the detailed geology and other science descriptions, to the amazing yet believable technology that develops over 100+ years. But perhaps most impressive are the characters, who seem like they could be real people, with all the diversity and conflicts this entails. The Martian society that evolves is also believable – not that it will happen just this way, but when Mars is eventually settled, it will be like this in many ways – messy, confusing, conflicted, non-linear, and surprising, just like any truly human endeavor. Someday there will be Martians, and they will be different for sure, but definitely human. These books also explore the benefits and problems of extreme life extension.

Sagan, Carl, Cosmos , Random House, 1980.

Carl Sagan was a planetary scientist and one of the most successful and influential populizers of science. Several of his books were best sellers, and the Public Television series Cosmos remains one of the most successful science series ever broadcast. Although it dates from 1980 (when outer planet data from the Voyagers had just become available), it remains worth reading for the quality of its insights and writing. His 1994 book Pale Blue Dot is also highly recommended for anyone with an interest in space.

Stiennon, Patrick and Hoerr, David, The Rocket Company , AIAA (avail., 2005

This book is the subject of a cool Orbiter add-on and is briefly discussed on page 8-12 of this book. Although it is fiction, the book is a detailed and highly readable portrayal of the creation and growth of a private space venture, and the “history” of its development of an innovative, fully reusable, two-stage launch vehicle. This book demonstrates that while “rocket science” may get the glory in the well-worn cliché for something that is intellectually difficult, it is rocket engineering that’s really tough to get right. Illustrated by Doug Birkholz.

Zubrin, Robert, The Case for Mars , Touchstone Books, 1996

Subtitled “The Plan to Settle the Red Planet and Why We Must,” I’ve talked a bit about the subject of this book in the section above on Mars Direct, which Zubrin defines in detailed but very readable form here. Highly recommended.

Zubrin, Robert, Entering Space: Creating a Spacefaring Civilization , Tarcher/Putnam Books, 1999

Zubrin’s follow-up to The Case for Mars extends the discussion of the various reasons why and of the practicality of becoming a “spacefaring civilization.” Very good.

Web References for This Chapter[edit]

This is certainly not a complete list of web sites related to the subjects discussed in this epilogue, but it’s a start. Note that the various space interest groups (Mars Society, Planetary Society, National Space Society, MarsDrive Consortium, and others) welcome people with interests in space issues, so please consider joining one or more. The web sites below are listed in no particular order.

The Mars Society – Founded by Dr. Robert Zubrin.

MarsDrive Consortium – An organization dedicated to sending humans to Mars and establishing permanent bases there in the next two decades – working to unite individuals and other organizations who support these basic goals. Information on Mars for Less can be found here.

The Planetary Society – Co-founded by the late Dr. Carl Sagan.

National Space Society – Since 1974, “dedicated to the creation of a spacefaring civilization.”

NASA’s Vision for Space Exploration and ESAS Final Report

Mars Direct Project for Orbiter

Red Colony – Red Colony is “...devoted to developing methods for colonizing and terraforming Mars.” – An excellent space information, discussion, and educational site. – An eclectic future-oriented site from Dr. Raymond Kurzweil. SENS – Strategies for Engineered Negligible Senescence, life extension web site of Aubrey de Grey.

4 Frontiers Corporation – Space commerce company formed in 2005 to pursue mining of space resources and Mars settlements by 2025. The four frontiers are Earth, Moon, Mars, and the asteroids.

Mars Foundation – “Working toward the first permanent settlement on Mars.”

SpaceX – Another private space venture, this company is developing a family of launch vehicles “intended to reduce the cost and increase the reliability of access to space ultimately by a factor of ten.”

LiftPort Group – “The space elevator companies,” working to make it happen by 2018.

Chapter 10: I Was Just Wondering GPIS Contents Appendices


This article has a precis and appears in the Random addon or Random article section on the Main Page. The precis can be found at GPIS Epilog/precis and is displayed below.


Go Play In Space, Epilog. Go Play In Space is the classic introduction to Orbiter for new orbinauts and those looking to expand their horizons. Admit it: You’ve wondered if you can find a space-related career. This Epilog can help you focus your ambition. (More...)