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The End of Astronauts: Why Robots Are the Future of Exploration
A History Today Book of the Year
A world-renowned astronomer and an esteemed science writer make the provocative argument for space exploration without astronauts.
Human journeys into space fill us with wonder. But the thrill of space travel for astronauts comes at enormous expense and is fraught with peril. As our robot explorers grow more competent, governments and corporations must ask, does our desire to send astronauts to the Moon and Mars justify the cost and danger? Donald Goldsmith and Martin Rees believe that beyond low-Earth orbit, space exploration should proceed without humans.
In The End of Astronauts , Goldsmith and Rees weigh the benefits and risks of human exploration across the solar system. In space humans require air, food, and water, along with protection from potentially deadly radiation and high-energy particles, at a cost of more than ten times that of robotic exploration. Meanwhile, automated explorers have demonstrated the ability to investigate planetary surfaces efficiently and effectively, operating autonomously or under direction from Earth. Although Goldsmith and Rees are alert to the limits of artificial intelligence, they know that our robots steadily improve, while our bodies do not. Today a robot cannot equal a geologist’s expertise, but by the time we land a geologist on Mars, this advantage will diminish significantly.
Decades of research and experience, together with interviews with scientific authorities and former astronauts, offer convincing arguments that robots represent the future of space exploration. The End of Astronauts also examines how spacefaring AI might be regulated as corporations race to privatize the stars. We may eventually decide that humans belong in space despite the dangers and expense, but their paths will follow routes set by robots.
A world-renowned astronomer and an esteemed science writer make the provocative argument for space exploration without astronauts.
Human journeys into space fill us with wonder. But the thrill of space travel for astronauts comes at enormous expense and is fraught with peril. As our robot explorers grow more competent, governments and corporations must ask, does our desire to send astronauts to the Moon and Mars justify the cost and danger? Donald Goldsmith and Martin Rees believe that beyond low-Earth orbit, space exploration should proceed without humans.
In The End of Astronauts , Goldsmith and Rees weigh the benefits and risks of human exploration across the solar system. In space humans require air, food, and water, along with protection from potentially deadly radiation and high-energy particles, at a cost of more than ten times that of robotic exploration. Meanwhile, automated explorers have demonstrated the ability to investigate planetary surfaces efficiently and effectively, operating autonomously or under direction from Earth. Although Goldsmith and Rees are alert to the limits of artificial intelligence, they know that our robots steadily improve, while our bodies do not. Today a robot cannot equal a geologist’s expertise, but by the time we land a geologist on Mars, this advantage will diminish significantly.
Decades of research and experience, together with interviews with scientific authorities and former astronauts, offer convincing arguments that robots represent the future of space exploration. The End of Astronauts also examines how spacefaring AI might be regulated as corporations race to privatize the stars. We may eventually decide that humans belong in space despite the dangers and expense, but their paths will follow routes set by robots.
- GenresScience
192 pages, Hardcover
Published April 19, 2022
7 people are currently reading
164 people want to read
About the author
Donald Goldsmith
54 books28 followersDonald Goldsmith is an astrophysicist, popular science author and screenwriter. He is the president of Interstellar Media. He is also the winner of the 1995 American Astronomical Society's Annenberg Foundation Award for Education and the Klumpke-Roberts Prize for his contributions to the public understanding of astronomy.
He received his Ph.D. in astronomy from the University of California, Berkeley in 1969.He taught at Stony Brook University before becoming a full-time popularizer, and has written, co-written, or edited a number of popular science books.
His book "Origins," co-written with Neil Tyson, was the companion volume to the four-hour PBS series with the same title. Dr. Goldsmith worked on Carl Sagan's "COSMOS" series, and on Neil Tyson's series of the same name, and was the science editor and co-writer of the six-part PBS series "THE ASTRONOMERS." He has written many popular articles for journals such as Scientific American, Natural History, Discover, and Astronomy.
He received his Ph.D. in astronomy from the University of California, Berkeley in 1969.He taught at Stony Brook University before becoming a full-time popularizer, and has written, co-written, or edited a number of popular science books.
His book "Origins," co-written with Neil Tyson, was the companion volume to the four-hour PBS series with the same title. Dr. Goldsmith worked on Carl Sagan's "COSMOS" series, and on Neil Tyson's series of the same name, and was the science editor and co-writer of the six-part PBS series "THE ASTRONOMERS." He has written many popular articles for journals such as Scientific American, Natural History, Discover, and Astronomy.
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Displaying 1 - 12 of 12 reviews
May 17, 2022
I was hoping this book was going to be written more informally. That said, Goldsmith and Rees have compelling arguments about why robots should not only lead space exploration but replace astronauts. I found myself questioning why I want to see astronauts in space while reading and the answer is because science fiction has been so ingrained into me that the idea of one day living in outer space is appealing.
Overall, I'd say that if you like slightly dry research-driven persuasion essays about space, this is the book for you. I'll even go further and say that if you are curious about what is happening in space and like to read research papers, this is for you.
Honestly, if the book were just written for a broader audience I would have rated this higher. As it is, I feel that it isn't as accessible to readers as it should be if the aim was to convince the vast majority of people interested in space exploration.
Overall, I'd say that if you like slightly dry research-driven persuasion essays about space, this is the book for you. I'll even go further and say that if you are curious about what is happening in space and like to read research papers, this is for you.
Honestly, if the book were just written for a broader audience I would have rated this higher. As it is, I feel that it isn't as accessible to readers as it should be if the aim was to convince the vast majority of people interested in space exploration.
September 18, 2022
Some interesting information, but unfortunately quite dry and dull in places.
October 30, 2022
Not enough robot
May 23, 2022
In the past decade, many high-profile individuals in science and technology have suggested that humans must colonize other planets like Mars and build space settlements. Climate change activism has added fuel to it by creating fear among the public in the past decades. All this has made the ultra-rich to want to leave the Earth if they can afford it. The narrative is that we have ruined our planet through pollution, and so you have to make a fresh start in a pristine world elsewhere. Elon Musk and Stephen Hawking expressed fears that there will be an extinction event on Earth and so we must prepare for being a spacefaring civilization. Hawking expected this to happen within a century. However, all this sounds like science-fiction and fantasy to the rest of us on Earth. Ninety-five percent of the world’s population lives in just ten percent of the Earth’s land surface. However, only ten percent of land on Earth is ‘remote’–over 48 hours from a large city. This sounds nothing like an over-populated planet, as some environmentalists would like us to believe. The authors, Martin Rees and Donald Goldsmith, are both well-known figures on astronomy. They analyze the future of space-faring and show with great clarity that the future of distant space travel must belong to robots rather than humans. They believe humans should confine themselves to near-earth orbit with public funded research, leaving inter-planetary exploration to the private enterprise, with all its attendant risks.
It may come as a dampener to many that the authors are not enthusiastic about human exploration of distant planets like Mars and even further. They believe human space travel brings with it high costs and risks that are unacceptable to the public on tax-payer funded programs. It is up to the private sector like Space X and Blue Origin to take the risks and open up new frontiers in space. However, the authors would like the public to be better aware of the diverse dangers in space, the longer humans spend time there. I have recounted some of their key arguments in the next paragraphs.
The International Space Station (ISS) is the single most expensive experiment humans have built to stay in space for prolonged lengths of time. It showed that humans can assemble sizable habitats in space and survive months of weightless conditions. In 2019, astronauts manufactured a material called ZBLAN in space under weightless conditions. It highlighted the advantages and limitations of humans in space. But the space station is not inexpensive. The ISS cost $150 billion and each mission of the space shuttle to it cost $1,5 billion. The shuttle flew 135 missions costing $195 billion. But its payoff has been far less than robotic missions. We have seen public support for manned space missions decrease over time since the heady days of Apollo 11. ISS attracts attention now only when its toilet malfunctions or when the Canadian astronaut Chris Hadfield plays a David Bowie song on his guitar there! However, some would say that it demonstrates how successful the ISS program is.
Prolonged human space travel creates psychological and physiological problems. The Soviet cosmonaut Valery Ryumin summed up his two six-month orbits in space by quoting the writer O. Henry. The American writer had said, “if you want to instigate the art of manslaughter, just shut two men up in an eighteen-by-twenty-foot cabin for a month. Human nature won’t stand it”. Some astronauts have experienced anxiety, depression, alcohol abuse and marital difficulties upon returning to Earth. The authors suggest they may stem from the void left after an intense wave of fame had washed over them. For example, in the 1960s, the nation saw astronauts as heroes and intrepid explorers. Buzz Aldrin detailed his problems on this adulation in his memoir. Physiological problems are more severe. Prolonged weightlessness leads to loss of bone and muscle mass (which the astronauts can avoid somewhat through exercise), and changes in cardiovascular function. It also impacts eyesight and red-blood cell production. Changes in the brain's position within the cranium are another fallout of weightlessness. Sleep difficulties arise because of changes to the circadian rhythm. Serious blood flow complications and blood clotting have affected astronauts in the ISS. Skeletal deterioration occurs, and it does not recover easily.
Astronauts in space face a steady barrage of solar wind, cosmic ray particles, x-rays, gamma rays and the possibility of danger from coronal mass ejections (CMEs). This is because there is no atmosphere in space to protect them. NASA aims for not over three percent of all astronauts to die from cancer because of these exposures. Scientists conducted a study of 418 Russian, European and American astronauts. They found that after an average interval of twenty-four years following their time in orbit, almost 30 percent of deaths arose from cancer.
Elon Musk has said that he would like to die on Mars. Leaving aside contaminating Mars with a human dead body, a trip to Mars and back might kill humans, going by the dangers of radiation. One day in space is equal to the radiation received on Earth for a whole year. On a trip to Mars, the astronaut would receive at least 60 percent of the total radiation dose recommended for a full career. Time on Mars offers no atmospheric protection from solar and cosmic radiation. When we add this to the return trip, it would push this over the recommended limit even with no increase in solar storms or flares. Contrary to the rosy pictures painted by billionaires like Bezos and Musk, risking the survival of the astronauts would be the central discussion before sending humans to Mars.
Apart from the dangers of prolonged human space travel, there are arguments in favor of sending robots on distant planetary exploration. The authors use an analysis by Ian Crawford, a planetary scientist and astrobiologist at the University of London, to compare humans and robots for space travel. Crawford identified eighteen different skills on a scale ranging from “total advantage to humans” to “total advantage to robots” for the comparison. We could make objective measurements on some of these skills and others only subjectively. The skills are: strength, endurance, precision, cognition, perception, detection, sensory acuity, speed, response time, decision-making, reliability, adaptability, agility, versatility, dexterity, fragility, expendability and maintainability. Crawford did the comparative analysis in 2012. Of the first seventeen items, robots won in four. They are precision, sensory acuity, reliability and expendability. Humans won the other thirteen. The last item, maintainability, was a tie. This might look as though humans are more suited to space exploration. However, the authors look ahead to the 2030 - 2040 decade. If we extrapolate current trends in artificial intelligence, communication and computer technology, they say humans would win only in two categories out of the thirteen they won in 2012. They would be cognition and decision-making. However, the authors may be guilty of putting too much faith in AI. Artificial Intelligence has always promised a lot, but delivered much less in the past seven decades. It may take decades longer than 2040 for AI to win in sixteen of the eighteen categories, as the authors suggest. Even if AI fulfils this promise, we still have to reckon with the dangers humans face in space.
In conclusion, Rees and Goldsmith say companies like Space X and Blue Origin can cut costs and tolerate higher risks than a western government on publicly funded civilian astronauts. Therefore, private funds and sponsorship should front manned missions. Rees cautions them against using terminology like ‘space tourism’ because it trivializes the dangers in space and makes people think space travel is routine and low risk. They should sell these exploits as dangerous sports or intrepid exploration.
I am in full agreement with the authors that robots should be the future of deep space exploration. On Earth, we have essential problems of eradicating poverty, disease and promoting education around the world and so, public funds must go to them. The Earth is still the most beautiful planet in the solar system and we can preserve it. It is also a mistake to think that only a spirit of adventure and exploration motivates space travel. Countries send astronauts into space not just to do scientific research. There is always the geo-political one-upmanship and prestige involved, not to mention military reasons. Martin Rees says it is a delusion to think that space offers an escape from Earth’s problems. It does not and we must solve our problems here and now. There is no Planet B.
I found it a courageous and honest book by the high-profile authors to oppose the current trends and pitch for robotic space travel.
It may come as a dampener to many that the authors are not enthusiastic about human exploration of distant planets like Mars and even further. They believe human space travel brings with it high costs and risks that are unacceptable to the public on tax-payer funded programs. It is up to the private sector like Space X and Blue Origin to take the risks and open up new frontiers in space. However, the authors would like the public to be better aware of the diverse dangers in space, the longer humans spend time there. I have recounted some of their key arguments in the next paragraphs.
The International Space Station (ISS) is the single most expensive experiment humans have built to stay in space for prolonged lengths of time. It showed that humans can assemble sizable habitats in space and survive months of weightless conditions. In 2019, astronauts manufactured a material called ZBLAN in space under weightless conditions. It highlighted the advantages and limitations of humans in space. But the space station is not inexpensive. The ISS cost $150 billion and each mission of the space shuttle to it cost $1,5 billion. The shuttle flew 135 missions costing $195 billion. But its payoff has been far less than robotic missions. We have seen public support for manned space missions decrease over time since the heady days of Apollo 11. ISS attracts attention now only when its toilet malfunctions or when the Canadian astronaut Chris Hadfield plays a David Bowie song on his guitar there! However, some would say that it demonstrates how successful the ISS program is.
Prolonged human space travel creates psychological and physiological problems. The Soviet cosmonaut Valery Ryumin summed up his two six-month orbits in space by quoting the writer O. Henry. The American writer had said, “if you want to instigate the art of manslaughter, just shut two men up in an eighteen-by-twenty-foot cabin for a month. Human nature won’t stand it”. Some astronauts have experienced anxiety, depression, alcohol abuse and marital difficulties upon returning to Earth. The authors suggest they may stem from the void left after an intense wave of fame had washed over them. For example, in the 1960s, the nation saw astronauts as heroes and intrepid explorers. Buzz Aldrin detailed his problems on this adulation in his memoir. Physiological problems are more severe. Prolonged weightlessness leads to loss of bone and muscle mass (which the astronauts can avoid somewhat through exercise), and changes in cardiovascular function. It also impacts eyesight and red-blood cell production. Changes in the brain's position within the cranium are another fallout of weightlessness. Sleep difficulties arise because of changes to the circadian rhythm. Serious blood flow complications and blood clotting have affected astronauts in the ISS. Skeletal deterioration occurs, and it does not recover easily.
Astronauts in space face a steady barrage of solar wind, cosmic ray particles, x-rays, gamma rays and the possibility of danger from coronal mass ejections (CMEs). This is because there is no atmosphere in space to protect them. NASA aims for not over three percent of all astronauts to die from cancer because of these exposures. Scientists conducted a study of 418 Russian, European and American astronauts. They found that after an average interval of twenty-four years following their time in orbit, almost 30 percent of deaths arose from cancer.
Elon Musk has said that he would like to die on Mars. Leaving aside contaminating Mars with a human dead body, a trip to Mars and back might kill humans, going by the dangers of radiation. One day in space is equal to the radiation received on Earth for a whole year. On a trip to Mars, the astronaut would receive at least 60 percent of the total radiation dose recommended for a full career. Time on Mars offers no atmospheric protection from solar and cosmic radiation. When we add this to the return trip, it would push this over the recommended limit even with no increase in solar storms or flares. Contrary to the rosy pictures painted by billionaires like Bezos and Musk, risking the survival of the astronauts would be the central discussion before sending humans to Mars.
Apart from the dangers of prolonged human space travel, there are arguments in favor of sending robots on distant planetary exploration. The authors use an analysis by Ian Crawford, a planetary scientist and astrobiologist at the University of London, to compare humans and robots for space travel. Crawford identified eighteen different skills on a scale ranging from “total advantage to humans” to “total advantage to robots” for the comparison. We could make objective measurements on some of these skills and others only subjectively. The skills are: strength, endurance, precision, cognition, perception, detection, sensory acuity, speed, response time, decision-making, reliability, adaptability, agility, versatility, dexterity, fragility, expendability and maintainability. Crawford did the comparative analysis in 2012. Of the first seventeen items, robots won in four. They are precision, sensory acuity, reliability and expendability. Humans won the other thirteen. The last item, maintainability, was a tie. This might look as though humans are more suited to space exploration. However, the authors look ahead to the 2030 - 2040 decade. If we extrapolate current trends in artificial intelligence, communication and computer technology, they say humans would win only in two categories out of the thirteen they won in 2012. They would be cognition and decision-making. However, the authors may be guilty of putting too much faith in AI. Artificial Intelligence has always promised a lot, but delivered much less in the past seven decades. It may take decades longer than 2040 for AI to win in sixteen of the eighteen categories, as the authors suggest. Even if AI fulfils this promise, we still have to reckon with the dangers humans face in space.
In conclusion, Rees and Goldsmith say companies like Space X and Blue Origin can cut costs and tolerate higher risks than a western government on publicly funded civilian astronauts. Therefore, private funds and sponsorship should front manned missions. Rees cautions them against using terminology like ‘space tourism’ because it trivializes the dangers in space and makes people think space travel is routine and low risk. They should sell these exploits as dangerous sports or intrepid exploration.
I am in full agreement with the authors that robots should be the future of deep space exploration. On Earth, we have essential problems of eradicating poverty, disease and promoting education around the world and so, public funds must go to them. The Earth is still the most beautiful planet in the solar system and we can preserve it. It is also a mistake to think that only a spirit of adventure and exploration motivates space travel. Countries send astronauts into space not just to do scientific research. There is always the geo-political one-upmanship and prestige involved, not to mention military reasons. Martin Rees says it is a delusion to think that space offers an escape from Earth’s problems. It does not and we must solve our problems here and now. There is no Planet B.
I found it a courageous and honest book by the high-profile authors to oppose the current trends and pitch for robotic space travel.
April 7, 2025
Martin Rees is a highly accomplished cosmologist and astrophysicist, is professor emeritus at Cambridge where he directed the Institute of Astronomy, has authored over 500 academic papers and several books. In The End of Astronauts he raises the question of what is the best way to explore the universe. I suspect his is a minority opinion but like former director of JPL William Pickering and astrophysicist James Van Allan he concludes that robotic missions are the most efficient and practical means. Rees musters a good deal of solid evidence to back his position, and this book offers a fine review of humanity’s many accomplishments in space. He addresses the many imponderables affecting the issue as well as hard facts and budget, things like human destiny and inspirational values.
This is not the most well-argued book. It drifts off into speculation about the future, despite its citing the Yogi Berra aphorism “making predictions is hard, especially about the future”. In the chapter on space colonization Rees speculates about a possible distant future of huge self sufficient free floating human settlements in cylindrical spaceships built from materials mined from asteroids. I mean, really? Rees also speculates about future human-cyborg hybrids, in what seems a fever-dream of Futurism. Yes, and one day our dogs may learn to talk.
There is also a chapter on space law and the lack thereof. And speculation about mining huge asteroids, including predictions about the personality of space miners. Really! It seems to me Rees would have made a better cause by sticking to what we know, which is the past 70 years of spaceflight. Fact is, the Buck Rogers dreams have not come true, and our robotic missions have reached Pluto and beyond while the far better funded astronaut program is still stuck in near earth orbit, circling a mere 250 miles up. The current ambition, if it can be called that, is a return to the moon, a repetition of the triumph of 1969. For the past 50 years the crewed space program has gone nowhere fast while robotic missions are exploring Mars, orbiting Jupiter, have sampled asteroids, and are in interstellar space (Voyager). I can’t help but think Martin Rees has left out the most obvious and compelling arguments.
This is not the most well-argued book. It drifts off into speculation about the future, despite its citing the Yogi Berra aphorism “making predictions is hard, especially about the future”. In the chapter on space colonization Rees speculates about a possible distant future of huge self sufficient free floating human settlements in cylindrical spaceships built from materials mined from asteroids. I mean, really? Rees also speculates about future human-cyborg hybrids, in what seems a fever-dream of Futurism. Yes, and one day our dogs may learn to talk.
There is also a chapter on space law and the lack thereof. And speculation about mining huge asteroids, including predictions about the personality of space miners. Really! It seems to me Rees would have made a better cause by sticking to what we know, which is the past 70 years of spaceflight. Fact is, the Buck Rogers dreams have not come true, and our robotic missions have reached Pluto and beyond while the far better funded astronaut program is still stuck in near earth orbit, circling a mere 250 miles up. The current ambition, if it can be called that, is a return to the moon, a repetition of the triumph of 1969. For the past 50 years the crewed space program has gone nowhere fast while robotic missions are exploring Mars, orbiting Jupiter, have sampled asteroids, and are in interstellar space (Voyager). I can’t help but think Martin Rees has left out the most obvious and compelling arguments.
October 27, 2022
Whatever straw men might exist to counter the obvious title, they are only posited by aerospace salesmen to make money. Mankind is not 'destined' to explore; it is not 'in our DNA'. Humans do not do things better in space than robots/AI, a gap that grows greater every generation. This is not a book for Star Wars/Star Trek fans; save the space romanticism for the sci-fi section of the library, and our exploration and knowledge of the cosmos will be the better for it.
A small caveat, at the end of the book, has to do with the nature of reality and the idea that man may someday 'think' they are out in the universe, exploring and discovering, without actually being there. Take that for good or ill.
A small caveat, at the end of the book, has to do with the nature of reality and the idea that man may someday 'think' they are out in the universe, exploring and discovering, without actually being there. Take that for good or ill.
February 2, 2023
This is a rambling book, full of opinions, but lacking crisp arguments, and evidence. The title makes the book sound like a polemic FOR robotic exploration, and AGAINST astronauts doing exploration.
Actually, the book is not a polemic. The book presents opinions of the value of both humans and robots in space exploration, with the weighting in favor of robots. Generally, comparisons aren't drawn; contrasts are not explained; conclusions are hedged. The result is a muddle.
The authors evidently felt they had something important to say, but I didn't get it.
Actually, the book is not a polemic. The book presents opinions of the value of both humans and robots in space exploration, with the weighting in favor of robots. Generally, comparisons aren't drawn; contrasts are not explained; conclusions are hedged. The result is a muddle.
The authors evidently felt they had something important to say, but I didn't get it.
September 10, 2024
This short book was more like a collection of (admittedly interesting) topics related to space exploration. Unfortunately, I was hoping for a coherent and focused discussion of human vs. robotic exploration.
Most chapters, it felt as if the authors forgot what the book was supposed to be about and hurriedly added a few sentences at the end about robotic exploration. In any case, the discussion of human vs. robotic exploration was largely superficial and lacked any real technical discussion.
Most chapters, it felt as if the authors forgot what the book was supposed to be about and hurriedly added a few sentences at the end about robotic exploration. In any case, the discussion of human vs. robotic exploration was largely superficial and lacked any real technical discussion.
November 25, 2022
Stays solidly and insightfully on the purported topic (unmanned vs manned exploration) in the first half; strays into related, but less relevant stuff towards the end.
February 2, 2023
Reads like a college research paper… which is cool but not when I expected/wanted it to be less formal.
April 12, 2023
Dull and dry with typos literally everywhere
October 7, 2024
very interesting topic !! non fiction is usually not for me it felt like i was reading a textbook . also took me over a month to finish
Displaying 1 - 12 of 12 reviews