The Perseverance rover, pictured on Mars in a NASA illustration, is due to arrive there in February aboard a rocket launched last July.


David W. Brown’s “Mars or Bust” (Review, Dec. 19) is spot on: Mars is the next true destination for humans in space exploration. Over the past 20 years NASA’s Mars Exploration Program has changed our understanding of the planet’s extensive rivers and oceans, ability to support past or present life, and ability to support human explorers. Human-scale entry and landing systems are the only real remaining technology hurdle, yet Mars Science Laboratory”s Curiosity and Perseverance landing systems have significantly moved us forward, and with pinpoint landing they can become the explorer’s resupply lines. The first round-trip mission to another planet, to collect and return soil samples from Mars, is under way.

Past agency and administration commitment to sending humans to Mars has been fickle, ranging from extensive study teams producing viable roadmaps, to posters and slogans with little substance. Lunar programs to enable Mars are largely a distraction. No technologies for Mars require demonstration at the moon; landing on an airless moon has no bearing on systems needed for planetary atmospheres. The moon may be an exciting commercial destination, but not for the next generation of explorers. Mars is the next major step in human exploration, exciting the public, spurring new global partnerships, creating unimaginable technological spin-offs, and uniting us by pushing ever closer to answering “Are we alone?” in this vast universe of planets. NASA needs to make the financial and leadership commitments to land humans by 2040, and avoid distractions. The Mercury, Gemini and Apollo programs prove we can do this, so let’s get on with it!

J. Douglas McCuistion

Lothian, Md.

Mr. McCuistion was director, NASA Mars Exploration Program, 2004-12.

Mr. Brown portrays NASA’s Artemis lunar program as a misguided attempt to reboot Apollo and argues that NASA should cancel it and send astronauts directly to Mars. While the president has made it clear that Mars is our destination, and that we will get there via the moon, Mr. Brown’s “plan” is another expensive mission to nowhere.

The 2016 transition team at NASA, which I participated in, was composed of scientists, academics, businesspeople and an astronaut. Our perspectives varied, but we came to agree that America must return to the moon immediately and permanently. Doing that is technically, fiscally and politically possible. Over the last four years the vice president’s National Space Council has engaged all of government in building a practical program that maximizes NASA’s existing investments in deep-space exploration systems and empowers America’s space entrepreneurs. It engages international partners from Japan to Italy in constructive competition with China’s aggressive lunar aspirations. It establishes legal precedents for commercial space activities. It develops the infrastructure, capabilities and experience required for us to really get to Mars. Artemis has broad support in the space community and bipartisan backing in Congress.

Since Gene Cernan left the moon 48 years ago, billions of dollars have been spent on cancelled NASA exploration programs. Mars and the moon are uninhabited today, not because we couldn’t get there, but only because we have not maintained our focus. Let’s finish this job for America and for the future of all humankind.

Greg Autry

Vice president of Space Development, National Space Society

Yorba Linda, Calif.