During the mid-1980s, Gene Roddenberry, the creator of Star Trek, delivered a talk at my campus. After his presentation, Roddenberry fielded questions from the audience. One of the students asked him about the future of manned space travel. Roddenberry replied that the idea just did not make sense to him. Space exploration, he explained, is a job for machines, not humans. You could have heard the boos from the sold-out auditorium on Ceti Alpha V.1 Coming from the creator of Captain Kirk, Mr. Spock, Lieutenant Uhura, and Mr. Sulu, this response felt like a betrayal. After all, few people in recent decades have made the notion of space exploration seem quite so appealing. Yet his candid assessment of the prospects for manned spaceflight has proven to be entirely accurate. Roddenberry was right. It simply does not make sense.

Surveys have shown that, generally speaking, the American public has always been favorably disposed towards the US space program.2 Since the middle of the twentieth century, American presidents have often spoken about the goal of manned spaceflight and most have announced some scheme or another with this goal in mind. In the mid-1950s, Dwight Eisenhower, with the support of his vice president Richard Nixon, was the first president to propose sending Americans into space.3 During his 1962 address at Rice University, John F. Kennedy committed the US to a moon landing by the end of the decade.4 Announced at the beginning of 2004, George W. Bush’s “Vision for Space Exploration” set a goal of returning to the moon by 2020.5 His successor, Barack Obama, discarded the idea of a return to the moon in favor of a manned expedition to Mars by the 2030s.6 Donald Trump, on the other hand, has issued a directive to send astronauts back to the moon as the necessary first step before a mission to Mars.7

Support for the US space program among the American public has often been accompanied by varying levels of concern about the attendant costs.8 And, in fairness, human space travel has always been anything but cheap.

• Project Mercury (1959–1963), the first US manned spaceflight program, cost US$292 million (US$2.3 billion adjusted for inflation).9
• Project Gemini (1962–1967), the successor to Mercury, cost US$1.3 billion (US$9.7 billion with inflation).10
• Under the Apollo program (1961–1972) eleven moon-landing missions were launched, of which ten were completed successfully. The total cost was US$25 billion (US$148 billion with inflation).11
• Apollo was followed by the Space Shuttle program (1972–2011), which proved costly in both human and financial terms. By 2010, the program had cost about US$199 billion (US$225 billion with inflation).12

In his 1972 announcement of the US Space Shuttle program, President Nixon proposed an “entirely new type of space transportation system designed to help transform the space frontier of the 1970s into familiar territory, easily accessible for human endeavor in the 1980s and ’90s.”13 Safe, reliable, and affordable access to space was always a primary objective.

In January 1986, the shuttle Challenger exploded just 73 seconds after takeoff, claiming the lives of all seven astronauts onboard. A presidential commission was formed to study the causes of the disaster.14 Richard Feynman, a member of the Rogers Commission, was told by NASA’s management that they had estimated the probability of a fatal accident as 1 in 100,000—equivalent to daily shuttle flights with an average of 300 years between accidents.15 An independent engineer consulting for NASA, on the other hand, told Feynman that the probability was more likely to be 1 or 2 in 100.16 The actual failure rate of the shuttle flights was 2 in 135.

The Rogers Commission identified the impact of cold weather on an O-ring seal in one of Challenger’s solid rocket boosters to be the proximate cause of the explosion.17 In his 1986 autobiography, Feynman described a broader problem with the Shuttle program:

You don’t want to fire people and send them out in the street when you’re done with a big project, so the problem is, what to do? You have to convince Congress that there exists a project that only NASA can do. In order to do so, it is necessary—at least it was apparently necessary in this case—to exaggerate: to exaggerate how economical the shuttle would be, to exaggerate how often it could fly, to exaggerate how safe it would be, to exaggerate the big scientific facts that would be discovered [emphasis original].18

Almost two decades later, NASA claimed in its 2005 budget request that the Shuttle program “plays a vital role in NASA’s enabling goal to extend the duration and boundaries of human use and development of space by providing safe, routine access to space [emphasis added].”19 This was just two years after a second shuttle, Columbia, had exploded, also killing all seven crew members onboard.

Writing in 2013, Lawrence Krauss described the shuttle program as a “largely useless international make-work project that was criticized by every major science organization in the US.”20 The best justification for the shuttle program was the thirty-six trips back and forth to build and supply the International Space Station (ISS), another project with limited value. Work on the ISS began in 1985, but it was not until 2000 that the first crew arrived.21 In 2015, the ISS had already cost about US$150 billion.22 The cost of the shuttle flights alone amounted to US$50 billion. The ISS is likely the most expensive man-made object ever constructed and NASA has funded two-thirds of its overall cost.23

In a 2012 article entitled “Moondoggle: The Forgotten Opposition to the Moon Launches,” The Atlantic reported that

[p]olls both by USA Today and Gallup have shown support for the moon landing has increased the farther we’ve gotten away from it. 77 percent of people in 1989 thought the moon landing was worth it; only 47 percent felt that way in 1979.24

Was it really worth it? If assessed as voyages of discovery, the expeditions to the moon could hardly be compared to those of Christopher Columbus, for example, each of whose expeditions was to a different destination, bringing back fantastic items, plants, animals, and humans that enriched the mother country. The astronauts walked. Later they rode. They hit a golf ball.25 They brought back 842 pounds of rocks and soil. Adjusted for inflation, the total cost of the Apollo program was US$148 billion. The meager pile of rocks and soil collected during these missions cost a staggering US$175 million per pound. According to a 2008 New York Times article, “Each year an independent peer review panel evaluates new research proposals, and curators mail out about 400 lunar samples to 40 to 50 scientists worldwide.”26 While recipients may be fascinated by these, few of us who footed the bill share their enthusiasm.

Technology developed for the space program, despite frequent protestations to the contrary from those involved, has delivered scarcely any tangible benefits for life on earth. In an op-ed published in early 2018, former astronaut Mark Kelly urged US lawmakers to continue funding the ISS. “Solar technology,” Kelly claimed, “miniaturized computer chips, CT scans, and MRIs are just a few examples of the technologies that were developed and delivered to the American consumer as a result of NASA’s innovation.”27

The discoveries that led to the development of the solar cell began almost two centuries ago and silicon solar cells were being produced prior to the launch of Sputnik in 1957.28 NASA’s own website notes that “NASA did not invent MRI technology”;29 Felix Bloch and Edward Purcell were awarded the Nobel Prize in 1952 for the foundational work that led to the development of MRI.30 Microchip technology was first patented in 1957.31 NASA utilized CT scans but were not involved in their development.

The space missions were not responsible for Tang, Velcro, Styrofoam, or even Space Food Sticks, as widely believed.32 Other innovations attributed to the space program would likely have appeared anyway, such as cordless vacuum cleaners. Martin Cooper’s ideas for the first handheld mobile phone originated in science fiction, namely Star Trek.33

An article on NASA’s website identifies 15 benefits for life on earth that can be attributed to research undertaken on the ISS.34 Some of the benefits listed are vacuous, such as the ISS “[p]roviding students opportunities to conduct their own science in space.” Others, such as “[m]onitoring natural disasters from space,” are performed by an automated system and could done just as well from unmanned satellites. “Making inoperable tumors operable with a robotic arm” resulted from technology developed for lifting objects and performing maintenance on the ISS—technology whose purpose is to replace humans in space.35

Steven Weinberg has described the ISS as an “orbital turkey”:

The only real technology that the space station has produced concerns the technology of keeping humans alive in space—which is a senseless and circular process if you realize there is no point in having humans in space.36

Each manned space program, it seems, whatever the reasons given at the time, becomes in effect the justification for the following manned space program.

One of the reasons often given for persisting with human space exploration is that we may someday need a means of escape from our home planet. According to the astronomer Seth Shostak,

we are living on a world with limited real estate and finite resources. Both are expected to become critically stretched within a century. Frankly, homo sapiens will be a flash in the pan if we don’t get some members of our species off the planet. So whether we construct colonies in orbit around Earth or build underground condos on the moon or Mars, our future demands learning how to send people to space.37

A recent Deutsche Bank study, on the other hand, concluded that

world population will peak around 2055 at 8.7bn and will then decline to 8.0bn by 2100. In other words, our forecasts suggest that world population will peak at least half a century sooner than the UN expects and that by 2100, and that level will be 2.8bn below the UN’s prediction.38

The notion that the earth cannot sustain indefinite population growth is nothing new and can be traced back to the work of Thomas Malthus at the end of the eighteenth century.39 Two hundred years later, it seems that humankind just keeps coming up with new ways to avoid running out of resources.40

At any rate, it seems unlikely that we will be able to relocate large numbers of people away from the earth prior to 2055. The challenges involved in any manned expedition to Mars are formidable. Traveling in either direction, the voyage alone would take nine months.41 Everything needed for human survival—food, water, the air we breathe—would need to be transported along with the astronauts.42

Some of these obstacles would be diminished if we could travel to Mars much more quickly. We still use propulsion technology similar to that patented by Robert Goddard over a century ago, including combustion chambers, exhaust nozzles, propellant feed systems, and multistage rockets.43 Launched in 1999, NASA’s Deep Space 1 spacecraft was the first to utilize an ion propulsion system.44 Ion engines, which have been in development since the 1950s, have also been used to keep geosynchronous communications satellites in position.45 The X3 ion thruster, designed by researchers at the University of Michigan in cooperation with NASA and the US Air Force, is performing well during initial tests. Such a propulsion system could accelerate a spacecraft to speeds of forty kilometers per second, roughly eight times faster than chemical rockets.46 But journeys beyond Mars seem impossible with current technology. The nearest potentially habitable exoplanet, Proxima b, is 4.25 light-years away.47 Current spacecraft would take about 50,000 years to travel there. Even ion propulsion would be insufficient to make traveling distances on this scale a practical possibility.48

Even if the logistical challenges could be overcome, sending humans to Mars would still remain a prohibitively expensive undertaking. NASA has estimated that the total cost for all of their current projects to put humans on Mars will exceed US$210 billion by 2033.49 Per-person estimates for the journey vary widely. According to the advocacy group Mars One, a one-way trip for the first four Martian colonizers could cost US$6 billion.50 Elon Musk, the founder of SpaceX, has estimated that ticket prices could be brought down to less than a mere $200,000 per person.51 Yet no one has ever been able to provide a good explanation as to why anyone would actually want to live on Mars. Colonies should be desirable locations like Virginia or the Ivory Coast, or be capable of providing resources to the mother country with enough left over for the colony to sustain itself. Mars has no drinking water, no breathable atmosphere, and nothing to sustain human life. And for now, at least, there is nothing to monetize there. Finding a million people who would want to live on Mars in the next 40 to 100 years, as Musk has proposed, seems like a tough sell unless the motivation is to escape an earth that has become unlivable.52 Without the costly life support and safety measures necessary for sending humans into space, machine-only space exploration is a vastly more efficient approach. NASA’s lower-bound estimate for the cost of a manned Mars mission is the same as that for one hundred Mars 2020 rovers. Consider NASA’s Kepler Space Telescope. Launched in 2009 and deactivated earlier this year, Kepler traveled through deep space searching for exoplanets that might be capable of supporting human life. For a budget of US$600 million, Kepler discovered more than 2,600 such exoplanets.53

In 2013, NASA’s Voyager 1 probe passed beyond the heliopause and entered interstellar space.54 A second robotic probe also launched in 1977, Voyager 2, is traveling across the solar system on a different trajectory. Voyager 2 sailed into interstellar space in December, 2018.55 During the course of their missions, the probes have been the first spacecraft to pass close by planets, moons, and asteroids. The total cost for the Voyager program is US$865 million.56 Launched in 2006, the New Horizons probe made the first fly-by of Pluto and became the first spacecraft to explore the Kuiper Belt.57 Earlier this year, New Horizons took the farthest-ever images from Earth.58 To date it has cost about US$700 million.59

“The real science done by NASA has not involved humans,” writes Krauss.

We have sent robots to places humans could never have survived and peered into the far depths of the cosmos, back to the early moments of the big bang, with instruments far more capable than our human senses, all for a fraction of what it costs to send a living, breathing person into Earth’s orbit.60

Until recently, a pair of robotically operated motor vehicles, or rovers, Opportunity and Curiosity, were surveying the surface of Mars. For the past 14 years and 7 years, respectively, they have been gathering data and transmitting it back to scientists on Earth.61 While Curiosity remains in operation, Opportunity’s mission was declared complete in February, 2019. Curiosity’s array of instruments includes:

• a drill attached to a robotic arm to collect samples for onboard analysis;
• a sample analyzer to test for the presence of carbon, hydrogen, oxygen, and nitrogen;
• a chemistry and mineralogy instrument that uses an X-ray diffraction to identify minerals;
• a Dynamic Albedo of Neutrons, whose function is to search for water;
• a weather station62; and
• a ChemCam comprised of a laser that can vaporize rocks up to seven meters away and a spectrograph that analyzes the resulting plasma to determine the rock’s composition.63

When machines are able to gather, analyze, and transmit data for such long periods, just what is it that we are hoping humans will discover in a few days, or even weeks? What can manned missions offer that we cannot currently obtain from machines? We can truly explore space and its resources through the use of robots and remote guidance. When we abandon manned missions, all that we will be leaving behind are fragile bodies that cannot survive in the absence of costly, complicated, and cumbersome life-support systems.

1. For the uninitiated, Ceti Alpha V was the planet on which Khan Singh and his crewmembers lived in Star Trek II: The Wrath of Khan
2. Roper Center for Public Opinion Research, Fly Me to the Moon: The Public and NASA Blog, Cornell University.
3. John Logsdon, “Ten Presidents and NASA,” NASA.gov
4. NASA, John F. Kennedy Moon Speech, Rice Stadium, September 12, 1962
5. Clive Neal, “If We Want to Send Astronauts to Mars, We Must Go Back to the Moon First,” Scientific American, July 1, 2016.
6. Barack Obama, “America Will Take the Giant Leap to Mars,” CNN, October 12, 2016.
7. Dan Merica, “Trump to Send Astronauts Back To The Moon—And Eventually Mars,” CNN, December 11, 2017; “Astronauts Are Baffled by Trump’s Space Travel Plans,” PRI’s The World, April 27, 2017.
8. Roper Center for Public Opinion Research, Fly Me to the Moon: The Public and NASA blog, Cornell University.
9. Linda Neuman Ezell, NASA Historical Data Book, II: Programs and Projects, 1958–1968 (Washington, DC: NASA Scientific and Technical Information Division, 1988), 121. Conversions to today’s currency have been made through this website
10. Jane Van Nimmen, Leonard Bruno, and Robert Rosholt, NASA Historical Data Book, 1958–1968, I: NASA Resources (Washington, DC: NASA Scientific and Technical Information Division, 1976), 134, 141.
11. Linda Neuman Ezell, NASA Historical Data Book, II: Programs and Projects, 1958–1968 (Washington, DC: NASA Scientific and Technical Information Division, 1988), 121. Ezell clarifies, “Totals for any one program are hard to determine, but … [t]hese totals include facilities, salaries, research and development, operations, and hardware (spacecraft and launch vehicles) expenditures.”
12. Claude Lafleur, “Costs of US Piloted Programs,” The Space Review, March 8, 2010.
13. NASA, “President Nixon’s 1972 Announcement on the Space Shuttle,” January 5, 1972.
14. NASA, Report of the Presidential Commission on the Space Shuttle Challenger Accident, June 6, 1986
15. Richard Feynman, “Appendix F – Personal Observations on the Reliability of the Shuttle,” in Report of the Presidential Commission on the Space Shuttle Challenger Accident, Vol. 2.
16. Richard Feynman, “Appendix F – Personal Observations on the Reliability of the Shuttle,” in Report of the Presidential Commission on the Space Shuttle Challenger Accident, Vol. 2.
17. Union Calendar No. 600, 99th Congress, 2d Session, HR 99-1016, Investigation of the Challenger Accident: Report of the Committee on Science and Technology House of Representatives, 98.
18. Richard Feynman, What Do You Care What Other People Think? Further Adventures of a Curious Character, ed. Ralph Leighton (New York: W.W. Norton & Co., 1988), 214.
19. NASA, “Major Events in 2004,” Theme: Space Shuttle, SFC 3-1.
20. Lawrence Krauss, “The Space Shuttle Programme Has Been a Multi-Billion-Dollar Failure,” The Guardian, July 21, 2013.
21. NASA, What Is the International Space Station? February 7, 2018.
22. In February, 2018, the Trump administration released a budget request that would eliminate US funding for the ISS beyond 2024, saving at least USD$3 billion per year. There were also suggestions that the ISS could be privatized or leased to commercial enterprises. Christian Davenport, “Donald Trump Planning to Turn International Space Station into Commercially-Run Property Venture,” Independent.co.uk, February 12, 2018; NASA Office of Inspector General, Office of Audits, “Extending the Operational Life of the International Space Station until 2024,” Audit Report, September 18, 2014; Emily Stewart, “Trump Wants to Privatize the International Space Station,” Vox, February 11, 2018. 23. Richard Hollingham, “How the Most Expensive Structure in the World Was Built,” BBC, December 21, 2015; Dave Mosher, “Congress and Trump Are Running out of Time to Fix a$100-Billion Investment in the Sky, NASA Auditor Says,” Business Insider, May 18, 2018.
24. Alexis Madrigal, “Moondoggle: The Forgotten Opposition to the Apollo Program,” The Atlantic, September 12, 2012.
25. Apollo 14 – Golf on the Moon,” YouTube video, uploaded February 26, 2008.
26. Guy Gugliotta, “The Keepers of the Moon,” The New York Times, July 8, 2008.
27. Mark Kelly, “Don’t Give Up on the International Space Station,” The New York Times, February 7, 2018.
28. Alyssa Baker, “A History of Solar Cells: How Technology Has Evolved,” SolarPowerAuthority.com, July 13, 2016.
29. NASA, “Did NASA Invent Magnetic Resonance Imaging (MRI)?”
30. MRI’s Inside Story,” The Economist, December 4, 2003.
31. Mary Bellis, “Who Invented the Microchip?ThoughtCo.com, October 16, 2017.
32. Shelby Spires, “The Teflon Myth and Other ‘Inventions’ from NASA,” Chicago Tribune, March 5, 2000; “Space Food Sticks,” Space Food Preservation Society. It is also an urban legend that NASA spent $12 billion to develop “space pens” for writing in zero gravity! David Mikkelson, “NASA’s ‘Astronaut Pen,’” Snopes.com, April 19, 2014. 33. Paul Sloane, “Martin Cooper,” in Think Like an Innovator: 76 Inspiring Business Lessons from the World’s Greatest Thinkers and Innovators (Harlow, England: Pearson, 2016), 136–39. 34. NASA, “15 Ways the International Space Station Is Benefiting Earth,” October 30, 2015. 35. The robotic arm built from this technology can perform surgeries inside an MRI machine and with more precision than a human hand. NASA, “neuroArm: Robotic Arm Lends a Healing Touch,” February 29, 2002. 36. Robin McKie, “Astronauts Lift Our Spirits. But Can We Afford to Send Humans into Space?The Guardian, December 7, 2014. Now the Trump Administration has announced a budget that would eliminate US funding for the ISS beyond 2024, saving US taxpayers$3–$4 billion per year. Christian Davenport, “Donald Trump Planning to Turn International Space Station into Commercially-Run Property Venture,” Independent.co.uk, February 12, 2018; NASA Office of Inspector General, Office of Audits, “Extending the Operational Life of the International Space Station until 2024,” Audit Report, September 18, 2014. 37. Seth Shostak, “Why Hominids and Space Go Together,” in “Is Manned Space Flight Obsolete?Room For Debate: A New York Times Blog, February 9, 2010. 38. Steven Perlberg, “Deutsche Bank: World Population Will Peak in 2055 Unless We Discover the ‘Elixir of Immortality,’” Business Insider Australia, September 9, 2013. 39. Thomas Malthus, An Essay on the Principle of Population (London: J. Johnson, 1798). 40. Matt Ridley, “The World’s Resources Aren’t Running Out,” The Wall Street Journal, April 25, 2014. 41. NASA, “How Long Would a Trip to Mars Take?” 42. Efficiency solutions can be extreme: urine is recyclable, and there is even a possibility of turning astronauts’ feces into edible food using microbes. Liam Jackson, “Microbes May Help Astronauts Transform Human Waste into Food,” Penn State News, January 25, 2018. 43. Cliff Lethbridge, “Robert Hutchings Goddard,” Spaceline.org, 2001; NASA, “Dr. Robert H. Goddard, American Rocketry Pioneer,” August 4, 2017. 44. Jet Propulsion Laboratory, “Deep Space 1.” 45. NASA, “NASA – Ion Propulsion,” January 11, 2016, last updated August 7, 2017. 46. Tereza Pultarova, “Ion Thruster Prototype Breaks Records in Tests, Could Send Humans to Mars,” Space.com, October 13, 2017. 47. Emily Calandrelli, “Astronomers Have Found the Closest Exoplanet to Earth,” TechCrunch.com, 2016. 48. Lest you think of that darling of sci-fi movies, human hibernation, don’t. Animals still age while hibernating, though they may age more slowly. Hibernation cannot allow humans to travel longer than their current lifespans; it can only make the voyage less boring. Anna Salleh, “Hibernation May Slow Aging,” ABC Science, February 6, 2013; Fraser Cain, “Is Human Hibernation Possible? Going to Sleep for Long Duration Spaceflight,” Phys.org, June 22, 2017. 49. NASA Office of Inspector General, Office of Audits, NASA’s Plans for Human Exploration beyond Low Earth Orbit, Report No. IG-17-017, April 13, 2017. 50. What Is Mars One’s Mission Budget?Mars-One.com 51. Tim Fernholz, “Elon Musk Detailed His Ambitious Plan to Put Humans on Mars for under$200,000 per Ticket,” Quartz, September 27, 2016.
52. Tim Fernholz, “Elon Musk Detailed His Ambitious Plan to Put Humans on Mars for under \$200,000 per Ticket,” Quartz, September 27, 2016.
53. NASA, “NASA Retires Kepler Space Telescope, Passes Planet-Hunting Torch,” October 30, 2018; Elizabeth Howell, “Kepler Space Telescope: Exoplanet Hunter,” Space.com, December 7, 2018.
54. NASA, “Voyager 1 Fires up Thrusters after 37 Years,” December 1, 2017.
55. Alexandra Witze, “Voyager 2 Enters Interstellar Space after 41 Years,” Nature News, December 10, 2018.
56. Jet Propulsion Laboratory, “Fact Sheet: The Voyager Planetary Mission.”
57. NASA, “Kuiper Belt.”
58. Zoë Schlanger, “NASA Just Published the Farthest-Ever Images Taken in Space,” Quartz, February 10, 2018.
59. Alex Knapp, “How Do New Horizons Costs Compare to Other Space Missions?Forbes, July 14, 2015.
60. Lawrence Krauss, “The Space Shuttle Program Has Been a Multi-Billion-Dollar Failure,” The Guardian, July 21, 2011.
61. Jet Propulsion Laboratory, “Mars Exploration Rover – Opportunity”; Mike Wall, “Touchdown! Huge NASA Rover Lands on Mars,” Space.com, August 6, 2012.
62. Mike Wall, “11 Amazing Things NASA’s Huge Mars Rover Can Do,” Space.com, November 20, 2011.
63. Jet Propulsion Laboratory, “Chemistry & Camera (ChemCam).”

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