Insight | Humans to Mars soon, robots first, or floating cities instead?
Martin Rees weighs robots against human pioneers on Mars, Jim Gates doubts a Mars landing by 2030, Ariel Ekblaw argues floating cities may beat Mars, Adam Frank discusses Mars and space habitats, and Brian Greene talks about the engineering of exploration. Comparing them separates the timelines and the reasons for sending people from the enthusiasm.
How sure is S. James Gates Jr. that no human will reach Mars by 2030? Show answer
He says he is extraordinarily convinced it will not happen, and he guesses a landing somewhere around 2090 to 2120.
What yardstick does Gates use to judge Mars timelines? Show answer
Apollo, which used about 5% of the country's economic output for ten years to go 250,000 miles, while Mars is about 100 times farther and spending is about a tenth of that.
Why does Gates see radiation as the hardest problem? Show answer
A traveller with current technology would spend about two years outside Earth's magnetosphere, and he says that radiation probably means cancer.
Why does Martin Rees think robots should do the work on the Moon and Mars? Show answer
Robots need neither food for the roughly 200-day journey nor a trip home, and future AI will be able to do geology, so useful work can be done far more cheaply by machines.
What role does Rees give human spaceflight? Show answer
Adventure only; he says public agencies like NASA should not fund it, and private adventurers who accept high risks should be cheered on.
Why does Rees reject Mars as a refuge from Earth's problems? Show answer
He says it is far easier to deal with climate change on Earth than to terraform Mars, so for ordinary people there is no planet B.
What does Rees expect Mars pioneers to do to themselves? Show answer
Use genetic and cyborg modification, which will likely be regulated on Earth, because they are poorly adapted to Mars and may become a new, post-human species.
When does Ariel Ekblaw think small Mars outposts are feasible? Show answer
In the 2030s, as supplied outposts similar to McMurdo station in Antarctica.
What are Ekblaw's two central challenges for long missions? Show answer
Radiation, which raises cancer risk and needs heavy shielding, and mental health, keeping crews happy, balanced and cooperating.
Where does Ekblaw expect larger populations in space to live? Show answer
In floating microgravity cities built piece by piece from self-assembling tiles, growing near resources such as the Moon, asteroids and Lagrange points.
What habitat did Adam Frank's group propose instead of a hollowed-out spinning asteroid? Show answer
A small asteroid wrapped in a giant nanofiber bag and spun, so the bag inflates and could hold about a Manhattan's worth of material.
Why does Frank say Mars is not a backup plan now? Show answer
A self-sufficient colony needs a material economy two to three centuries away, while climate change and nuclear war are threats pressing now.
