"We're setting expectations for something that is decades away. The public has a short attention span," said Lori Garver, the former deputy administrator of Nasa under President Barack Obama.
Doug Cooke, a former Nasa associate administrator for exploration, thinks Nasa needs to spell out intermediate steps to Mars. There's one obvious stopping point between the third and fourth rocks from the sun: The moon. Cooke says it could be a proving ground for off-world living.
"There needs to be more of a plan for actually getting there," Cooke said. "You can't have a flat-line budget indefinitely and think you're going to put all of this together by 2030."
John Grunsfeld, Nasa's top official for science and an astronaut himself, doesn't see a problem with the Mars-centric media relations.
"Sure, 'JourneytoMars' is a slogan. There's no question about that. But it does capture the excitement of the various activities that we're doing. Each individual piece does have traceability to future missions to Mars," Grunsfeld said. "One of the reasons I wanted to be an astronaut was to go to Mars. So I'm very impatient."
Mars is far away, inhospitable, and due to the orbital dynamics of Earth and Mars, any mission to the red planet's surface would take at least two years round-trip (a fly-by, without landing, theoretically could be done in about 500 days).
The technical challenges are significant, but Nasa's engineering prowess is legendary, and this may be a case where the impossible simply takes longer. The most serious challenge may be budgetary.
When President George H. W. Bush proposed a human mission to Mars in 1989 as part of a massive new push in outer space, shock at the cost sank the plan. Estimates put it in the range of US$400 billion. The consensus among space policy analysts is that a Nasa mission to Mars with astronauts would require a political mandate that currently does not exist.
Going to Mars raises a suite of technical challenges. Nasa engineers need to figure out how to land heavy payloads on Mars. They also have to devise systems to protect astronauts from radiation in outer space. Nasa can point to progress in understanding how to keep astronauts alive on Mars by letting them live off the land. Jim Green, Nasa's director of planetary science, said the next Mars rover, scheduled for launch in 2020, will have instruments that can extract oxygen from the Martian atmosphere.
And then there's the water: Mars, Green said, has more moisture in the soil than previously believed, and more humidity in the air. It's possible the ephemeral, salty water suggested by a much-hyped study last week comes from fresh-water ice or aquifers below the surface, he said.
Green, a consultant on the movie The Martian, said Damon's character could have taken advantage of that water.
It's not clear that the US Government will ever decide that a human mission to Mars is worth the cost, and Mars may wind up visited first by private-sector dreamers.
Reasons you're not going to Mars
1 Nasa's budget won't pay for a Mars mission
2 Mars is far away, inhospitable, and any mission there and back would take at least two years
3 A Nasa space capsule won't be ready until 2023 and it's for 21-day missions, not for trips to Mars
4 Nasa is looking at a Mars mission in the 2030s at the very earliest
5 Nasa has to work out how to land heavy payloads on Mars and protect astronauts from radiation in outer space.
- Washington Post-Bloomberg