Written By Jocelyn Branham
In June of last year, NASA astronauts Butch Wilmore and Suni Williams set out on a highly anticipated mission aboard Boeing’s Starliner spacecraft. Originally intended to last just eight days, the mission took an unexpected turn due to technical issues. The Starliner experienced helium system leaks and thruster malfunctions, ultimately preventing their immediate return. Instead, Wilmore and Williams remained aboard the International Space Station (ISS) far longer than planned, spending a total of 286 days in space before safely returning to Earth on March 18, 2025 (Lee, 2025). While space exploration is inherently expensive and risky, it has the potential to generate groundbreaking scientific knowledge and technological advancements. Wilmore and Williams’ surprising mission extension offers a timely opportunity to reassess the economic value of human spaceflight, particularly in comparison to robotic missions.
Human spaceflight has captured public attention for decades, beginning with milestone achievements like the 1969 Apollo 11 moon landing, where Neil Armstrong and Buzz Aldrin became the first humans to walk on the lunar surface. In the following years, NASA launched the Space Shuttle program, which completed 135 missions before its retirement in 2011 (The Editors of Encyclopedia Britannica, 2025). This program brought major accomplishments but also suffered two tragic disasters: the Challenger explosion in 1986 and Columbia’s disintegration in 2003, whose failures cost NASA a combined total of 14 lives, including those of astronauts, scientists, and engineers (Bell & Esch, 2016), as well as over 10 billion dollars (Associated Press, 2003). Notably, the Discovery flew over 150 million miles in 39 missions and although some shuttles, like the Enterprise, never flew in space, they still contributed to the engineering legacy that enabled future missions (Camusci, 2018).
Alongside human endeavors, robotic missions have played a crucial role in advancing our understanding of the cosmos. The Voyager spacecrafts launched in 1977 and became humanity’s first interstellar emissaries, continuing to send data from the edges of our solar system (Young, 2023). On Mars, the rovers Spirit and Opportunity discovered compelling evidence that the planet once had surface water. They also analyzed Martian meteorites and explored geological formations, enriching our knowledge of planetary evolution (Malik, 2008). Even earlier, in 1965, the Mariner 4 mission captured the first ever close-up image of another planet, paving the path for future exploration (Young, 2023). It is evident that both human-based missions and robot-based missions have contributed greatly to the development of our understanding of space.
Critics claim one major downside to human space missions is the significant price tag as they require extensive investment in astronaut training, life support systems, and safety infrastructure. For instance, NASA’s Apollo program cost the U.S. government an estimated $25 billion at the time, which amounts to roughly $150 billion today (Cangi et al., 2019). And while the program launched eleven piloted missions, only six landed on the Moon, making the cost per landing nearly $24 billion. To put it in perspective, replicating the Apollo effort today would consume close to 4% of the U.S. gross domestic product (GDP), a measure of the monetary value of all final goods and services produced within a country. The Space Shuttle program cost a staggering $224 billion over its lifespan. Each shuttle launch alone cost about $450 million, and due to design complexities and heavier-than-expected materials, maintenance costs skyrocketed (Cangi et al., 2019). A common critique illustrates this point humorously: even if the shuttle were filled entirely with gold, and the value of that gold was added to the gains of the mission, it would still operate at a financial loss (Slakey & Spudis, 2008).
Spaceflight and extraterrestrial exploration present a complex web of ethical issues centered around risks to human health and life. Astronauts face significant physiological challenges in space, including bone density loss, muscle atrophy, and cardiovascular strain, as well as psychological stressors such as isolation and potential trauma (Brettschneider, 2023). Wilmore and Williams’ mission underscores these risks: upon returning to Earth after their trip extension, Wilmore stated, “Gravity makes you tired, very tired” while Williams confessed, “It was very nice to lie down in a bed – we hadn’t done that for many months” (Pawlowski, 2025). This, alongside the potential risk of death, raises questions about the limits of acceptable risk and when it may be more ethical to send a robot into space as opposed to a human. These challenges underscore the need for an ethical framework as humanity pushes further into space.
Despite the heavy costs and ethical considerations, human spaceflight offers unique benefits. Humans are capable of reacting to unforeseen problems, conducting detailed scientific exploration, and making decisions that machines cannot yet replicate. When Skylab launched in 1973, it suffered major damage, losing a heat shield and one solar panel. The crew was able to make critical repairs in space, saving not only the mission but the entire Skylab program (Slakey & Spudis, 2008). This adaptability remains a key argument in favor of maintaining human presence in space. Planetary exploration generally involves two stages: reconnaissance and field study, and while robots can handle reconnaissance by gathering broad data, field study – where detailed observation and hypothesis testing occur – requires humans on the ground. Scientists must be present to adapt to unexpected discoveries, make conceptual models, and carry out real-time decisions (Slakey & Spudis, 2008). A robot can’t redesign itself mid-mission or improvise when faced with surprises. For all their precision, robotic missions cannot yet replace human intuition and adaptability in the field.
Robotic missions offer critical advantages that may be unavailable during manned missions. They can access hazardous environments, such as the surface of Venus or the outer planets, where human survival would be impossible. And without the need for life support, these missions can last for extended periods of time. Programs like NASA’s Discovery initiative encourage compact and efficient probes with the ability to capture precise measurements and transmit high quality images (Slakey & Spudis, 2008). And, in contrast to human spaceflight, robotic missions are often seen as more cost-effective and less risky. These missions require investment in robotic engineering, mission planning, and remote operation systems. The most expensive robotic missions, known as Flagship missions, include projects like the Hubble Space Telescope and the Mars Science Laboratory. These large-scale efforts deliver quality and impactful science, but they are not cheap; Hubble alone cost almost $10 billion over its lifetime (Cangi et al., 2019). Yet, as expensive as that may sound, it makes up a mere 4.5% of the cost of the Space Shuttle program. Similarly, the Mars Pathfinder delivered a wealth of data and images from the surface of Mars for just $265 million (Slakey & Spudis, 2008).
However, robotic exploration is not without its limits. One critical drawback is the communication delay. Even between Earth and the Moon, signals take about 2.6 seconds round-trip, and between Earth and Mars, the delay can reach up to 40 minutes (Slakey & Spudis, 2008). Hence, robots cannot be guided in real time which makes last minute adjustments or gametime decisions nearly impossible, a contrast to the quick decision-making available when humans are present. And, as robotic missions become more ambitious, their costs have not decreased – in fact, they’ve steadily risen (Crawford, 2012). More advanced sensors, extended mission durations, and the complexity of new scientific goals all contribute to this trend. While robotic missions still tend to be cheaper than human ones, the gap in dollar cost may be less significant when measured in terms of scientific productivity. One study indicates that a human in a spacesuit can have an observation rate 25 times faster than that of a 2015-class earth controlled rover (Glass & Briggs, n.d.), and the manned Apollo missions retrieved 382 kg of samples from space, with the rover Luna returning significantly smaller amounts (Crawford, 2012).
Entering space is no small feat, and humanity has made incredible strides in research, exploration, and scientific discovery through both manned and unmanned space missions throughout history. Human spaceflight comes at a hefty cost, yet offers irreplicable intuition and versatility robots cannot match. On the contrary, robot-based missions cost significantly less than humans do and allow for a wealth of knowledge humans may not maintain, while still experiencing drawbacks such as communication delays. Butch Wilmore and Suni Williams’ recent 9-month extended stay on the ISS surfaces complicated ethical dilemmas when considering the health issues humans face with a long-term lack of gravity. Ultimately, humanity’s successes in space cannot be attributed to just one group – it is the combination of human astronauts, engineers, mathematicians (and even the public who help fund extraterrestrial exploration) alongside the rovers, satellites, and other robots that award us the breakthroughs in science and space technology. As NASA and other aerospace organizations continue to push the frontiers of interplanetary endeavors, striking the right balance between human and robotic missions becomes increasingly essential, not only to safeguard astronaut health, but also to maximize scientific progress and discovery.
References
Associated Press. (2003). NASA Puts Cost of Shuttle Inquiry, Cleanup at $400 Million. L.A. Times Archives. https://www.latimes.com/archives/la-xpm-2003-sep-12-na-shuttle12-story.html.
Bell, T. & Esch, K. (2016). The Challenger Disaster: A Case of Subjective Engineering. IEEE Spectrum. https://spectrum.ieee.org/the-space-shuttle-a-case-of-subjective engineering#:~:text=Worst%20failure%3A%20In%20the%20January,%243%20billion%20vehicle%20and%20crew.
Brettschneider, E. (2023). Exploring the Ethics of Human Space Travel: Navigating the Challenges and Implications of Missions Past, Present, and Future. Eastern Kentucky University. https://encompass.eku.edu/cgi/viewcontent.cgi?article=2034&context=honors_theses.
Camusci, T. (2018). When Enterprise Met Discovery. National Air and Space Museum. https://airandspace.si.edu/stories/editorial/when-enterprise-met-discovery.
Cangi, E., Gibson, J., & Luebbers, M. (2019). Mission Costs: Past, Present, Future. LASP Colorado. https://lasp.colorado.edu/mop/files/2019/11/Mission-costs.pdf.
Crawford, I. (2012). Dispelling the myth of robotic efficiency. Royal Astronomical Society. https://lasp.colorado.edu/mop/files/2019/08/RobotMyth.pdf#:~:text=Compare%20the%20382%20kg%20of%20samples%20returned,far%20by%20any%20robotic%20mission20to%20Mars.&text=(2007%20p438)%20concluded%20that%20%E2%80%9Chumans%20could%20be,exploration%20than%20future%20terres%2D%20trially%20controlled%20robots%E2%80%9D.
Crawford, I. (2012). Dispelling the myth of robotic efficiency: why human space exploration will tell us more about the Solar System than will robotic exploration alone. Astronomy and Geophysics. https://arxiv.org/pdf/1203.6250.
Free Stock Photo of Lunar Rover | Download Free Images and Free Illustrations. (n.d.). Freerangestock.com. https://freerangestock.com/photos/24077/lunar-rover.html.
Glass, B. & Briggs, G. (n.d.). Evaluation of Human vs Teleoperated Robotic Performance in Field Geology Tasks at a Mars Analog site. NASA Ames Research Center. https://ntrs.nasa.gov/api/citations/20030032439/downloads/20030032439.pdf.
Lee, G. (2025). After 286 Days in Space, NASA Astronauts Return to Earth with a Splash. Scientific American. https://www.scientificamerican.com/article/after-286-days-in-space-nasa-astronauts-return-to-earth-with-a-splash/#:~:text=5%20min%20read-,After%20286%20Days%20in%20Space%2C%20NASA%20Astronauts,to%20Earth%20with%20a%20Splash&text=Support%20teams%20work%20around%20a,the%20coast%20of%20Tallahassee%2C%20Florida.
Malik, T. (2018). NASA’s Most Memorable Missions. Space.com. https://www.space.com/5853-nasa-memorable-missions.html.
Pawloski, A. (2025). Astronauts may have ‘baby feet,’ get shorter, face strange health problems after return. Today. https://www.today.com/health/news/nasa-astronauts-return-possible-health-problems-rcna196862.
Slakey, F. & Spudis, P. (2008). Robots vs. Humans: Who Should Explore Space?. Scientific American. https://www.scientificamerican.com/article/robots-vs-humans-who-should-explore/.
The Editors of Encyclopedia Britannica. (2025). Space Shuttle. Britannica. https://www.britannica.com/technology/space-shuttle.
Young, C. (2023). 14 of the most important space missions of all time. Interesting Engineering. https://interestingengineering.com/innovation/14-of-the-most-important-space-missions-of-all-time.