Why Should the United States Prioritize Mars

Critical Questions by Clayton Swope

Published January 23, 2025

During his inaugural address on January 20, 2024, President Donald Trump indicated he will prioritize U.S. space endeavors focused on Mars. While NASA has a long history of Martian exploration, including operating ongoing missions to the Red Planet, the president's remarks suggest Mars may play a more central role in NASA's agenda during the coming years. Unless accompanied by a budget increase for NASA, prioritizing Mars missions may impact other NASA activities, such as the Artemis program, NASA's effort to return humans to the Moon and establish a long-term lunar presence. A Martian pivot may signal recognition of the far greater scientific and strategic value, not to mention the national prestige at stake vis-à-vis China, of Mars than the Moon. Beyond national interests, Mars might ultimately be the linchpin for the long-term survival of humanity, as it's the most obvious place other than Earth where, with the right technology, humans may be able to survive somewhat independently of our home planet.

Q1: What is special about Mars?

A1: There is no other planet quite like Earth in the Solar System, though Mars is by far the most Earth-like of the seven other planets. The fourth planet from the Sun, Mars is often called the Red Planet because its solid surface is covered with orange-red iron oxide, a material with a similar composition to rust. Mars is significantly smaller than Earth, with a diameter about half that of Earth and a mass one-tenth in size. A day on Mars is about the same amount of time as on Earth, lasting 24.6 hours. Mars has an atmosphere, albeit a weak one compared to Earth, containing carbon dioxide, argon, and nitrogen, and water ice at its poles. Gravity on Mars is only about 38 percent of Earth's gravity. In the past, Mars may have had water oceans.

No conclusive signs have been found that indicate life originated or currently exists on Mars, though due to its similarities with Earth, scientists believe that it may have once been habitable for some type of life, probably microorganisms. But to date, no scientist has been able to thoroughly examine material from Mars, as no one has yet brought back a sample of the Martian surface for analysis on Earth. So far, all scientific analysis of Mars has been conducted remotely, such as by instruments attached to landers and rovers operating on its surface.

Q2: What is the history of Mars exploration?

A2: Mars is one of the night sky's brightest natural objects, clearly visible from Earth by the naked eye. Some of the earliest surviving records of Martian observations date to ancient Egypt. In 1610, Galileo Galilei, an Italian astronomer, made observations of Mars using a telescope. Soon, astronomers had spotted the Martian ice caps and, by the end of the nineteenth century, noticed yellow clouds on Mars. By the 1960s, the United States and the Soviet Union were in a race to send uncrewed spacecraft to Mars, with the United States becoming the first country to successfully reach Mars in 1964 when Mariner 4 conducted a flyby of the planet. The Soviet Union made the first soft landing on Mars in 1971. That same year, the United States successfully placed Mariner 9 in Martian orbit, becoming the first nation to send a spacecraft into orbit around another planet. The United States landed Viking 1 on Mars in 1975, becoming the first successful lander to reach Mars.

NASA landed its first Martian rover mission, Pathfinder, on July 4, 1997. Since Pathfinder, the United States has launched a number of Mars rovers, including one that deployed a small helicopter, and orbiters. Over the last 25 years, the European Space Agency (ESA), India, China, and the United Arab Emirates have also executed successful missions to Mars, in most cases placing spacecraft into orbit. China's Tianwen-1 mission to Mars, launched in 2021, was notable because it involved an orbiter, lander, and rover. Its success marked the first time a country had been able to conduct a soft landing and deploy a rover on its maiden mission to Mars. In total, there are currently about seven active spacecraft in orbit around Mars and two operational rovers on the Martian surface, NASA's Perseverance and Curiosity rovers. As part of its mission, Perseverance has been collecting and caching samples of the Martian surface for pickup and retrieval by NASA's future Mars Sample Return (MSR) mission.

Q3: What future missions are planned for Mars?

A3: For over two decades, NASA has been investigating the possibility of returning samples from Mars to Earth. In 2009, aiming to bring back samples to Earth in the 2020s, NASA began working with ESA on what would eventually become the MSR mission, signing an agreement to work together in 2018. In 2022, the National Academies recommended that "the highest scientific priority of NASA's robotic exploration efforts this decade should be completion of Mars Sample Return as soon as is practicably possible," echoing similar recommendations from 2011 and 2003. In November 2023, NASA paused work on MSR after a review board estimated that the mission's price tag would well exceed what NASA had been expecting.

In April 2024, NASA sought ideas from industry to cut costs and accelerate the mission timeline, targeting a return of the samples collected by Perseverance to Earth in the mid-2030s. After narrowing down the revised options to two in early January 2024, NASA said it would take the next 18 months to conduct further assessments and decide on a new plan. Meanwhile, China is accelerating its own Mars plans. In September 2024, China said that it intended to move up the launch for a Mars sample return mission, called Tianwen-3, to 2028. As Chinese space officials have noted, the mission would last about three years, and China would probably be able to return its samples to Earth around 2031, several years before NASA.

Additionally, SpaceX is pursuing its own plans to reach Mars, announcing in October 2024 that it will begin launching uncrewed Starship rockets to Mars in 2026, which is the next time on a 26-month cycle when Mars and Earth are closest together in orbit. The goal of the tests is to demonstrate that Starship can successfully reach and land on Mars, paving the way for future crewed missions to the Red Planet, possibly as early as 2028 or 2029. In December 2024, NASA released its updated plans for its Moon to Mars architecture, which incorporates the Moon and Artemis program as key testing opportunities for capabilities intended to land humans on Mars. NASA has not revised its goal set during the Obama administration for sending astronauts to Mars by 2033. In 2021, China set its own goal for landing humans on Mars, aiming also for 2033.

Q4: What happens next?

A4: Though the United States and several other countries, including China, have demonstrated they can successfully reach Mars and land missions on the Martian surface, the next phases of Martian exploration will prove exceptionally challenging-and expensive. Successfully executing the MSR mission and developing plans to send humans to Mars will take more resources than NASA has heretofore allocated to these initiatives, confronting NASA leaders with difficult budgetary choices. Though NASA links its Moon-focused initiatives to its future plans for Mars, as operating on the Moon is a good Martian test environment, the emphasis on returning humans to the Moon has come at a cost to other initiatives, such as MSR.

For fiscal year 2025, NASA had planned to spend nearly a third of its budget on the Artemis program, its plans to return humans to the Moon. Without a significant overall agency-level budget increase, NASA may have to reassess the scope of the Artemis program to free up more resources for Mars. Realigning Artemis primarily as a test bed for technologies and procedures for operating on Mars, and less about establishing a long-term lunar presence, might create the right balance. This could allow NASA to return astronauts to the Moon before China gets humans there for the first time and use the Moon as a proving ground for crewed technologies and systems intended for Mars.

In addition to spending more on Mars initiatives, NASA will also have to decide and commit to a Mars plan of action. In the short term, NASA will need to decide what to do with MSR. Right now, it plans to wait 18 more months to decide on a way forward, at a time when China will be hard at work designing and building its own sample return mission hardware. That SpaceX is independently working to send Starships to Mars next year strongly suggests there is an opportunity both to refocus MSR plans around an accelerated timeline and find further cost savings. Ultimately, a successful and accelerated MSR supports efforts to land humans on Mars, as data gleaned from Martian samples will help scientists and engineers better understand and use the Martian environment for future crewed missions.

Q5: What is at stake?

A5: Simply put, the future of humanity is likely tied to Mars. Though a human could not survive unaided on the Martian surface today-surviving on Mars would take a similar level of equipment as would living on the Moon-critical building blocks are present for creating a more habitable environment. These include chemical compounds, frozen water, sources of energy, such as solar and geochemical, and Earth-like physical characteristics, enumerated earlier, that could be used by as-yet-not-invented technologies to shape Mars into something more conducive to human life. The scale of such an activity would be enormous, but there is no better place than Mars should humans wish to carve out another place to live that is not Earth.

Additionally, there is science and national prestige on the line, maybe to a greater extent than during Moon Race 1.0 between the United States and the Soviet Union because the possibilities of Mars are so great. The success of MSR would provide U.S. scientists the chance to look for signs that life once existed on Mars. Conclusive evidence that life originated there might be one of the most important discoveries in human history. The willingness of the new administration and Congress to prioritize funding and resources, as well as NASA's willingness to reexamine Artemis, will likely determine whether the United States can accomplish a Martian sample return and, probably, whether it can land astronauts on Mars before China. Should China achieve either of these humankind firsts, future generations of Americans would wonder why the United States let up on the accelerator and lost the Mars race.

Clayton Swope is the deputy director of the Aerospace Security Project and a senior fellow in the Defense and Security Department at the Center for Strategic and International Studies in Washington, D.C.

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