While Roger D. Launius’ op-ed piece “Rationales for Human Spaceflight after the Shuttle” [Feb. 11, Commentary, page 19] tries to stay above the fray, he repeats some accepted “wisdom” that is highly questionable. He states that, among other rationales, scientific discovery and understanding “have been accomplished with lesser cost and arguably greater efficiency using robotic spacecraft, thank you very much.”

That may be true if you look only at the absolute costs of the missions. However, when measured by scientific productivity — cost per unit of science — that is very unlikely to be true. Despite using 1960s technology, Apollo still provides the only absolute dates for any planetary scale body in the solar system to this date, and unfortunately for the foreseeable future. Every other date for a planetary impact crater, a martian lava flow, a fault on Europa or anything else is relative to the Apollo record — they are little more than educated guesses that may have little relevance in the outer solar system.

Apollo astronauts achieved in hours what it has taken automated robots years to do on Mars, and did it more completely and better. With today’s technology and skills, it is far from clear that a flagship-class automated Mars sample-return mission would cost significantly less than a human mission, but it would certainly accomplish far less science. Once the architecture was paid for, each Apollo flight cost about the same as a flagship planetary mission, but provided far more science. Just as Apollo costs were beginning to come down and scientific productivity was at its peak, we canceled it.

Supporters of automated spaceflight lay claim to the Hubble Space Telescope, but that is part of the human space program. It never could have been as productive an instrument without regular repair and upgrade. NASA’s smartest decision, possibly ever, was to provide passive docking facilities for Orion on Hubble’s replacement, the James Webb Space Telescope (JWST). If Orion ever flies, on the Space Launch System or a Delta 4 Heavy, that inexpensive decision, if sustained, has the potential to convert the JWST into a similarly long-term productive investment.

Automated science has a role for initial reconnaissance, but it is inappropriate for in-depth science, particularly sciences that require fieldwork. Now that the costs of human spaceflight are finally beginning to come down, its advocates should never concede the scientific rational, yet they seem curiously willing to do so.

Donald F. Robertson

San Francisco

Donald F. Robertson is a retired space industry journalist and technical writer based in San Francisco.