Sometimes scientific measurements provide inconvenient results. Newly reported measurements from the Curiosity Rover mission will force NASA to design better radiation shielding for manned Mars missions and demand the invention of improved propulsion for manned missions to Mars to reduce the time spent in transit. Habitat on the Martian surface will require more robust shielding, too. NASA is spinning the new data as just another bit of information it needs to design systems to protect human explorers from radiation exposure on deep-space expeditions in the future. It is really a much bigger deal than that.
Come out into the tall grass with me to see some of what NASA and some commentators have said, along with a few thoughts for discussion of important issues of government science and space policy.
This has to be a blow to the current NASA policy and NASA and private plans for manned Mars mission development. Some danger of solar and cosmic radiation to humans in interplanetary space is well known. The new data, however, raise serious questions about the adequacy of existing plans and designs. What is new, here, is the precise measurement of such radiation throughout the duration of an entire Earth-Mars transit, measured from within a spacecraft providing shielding similar to that afforded by current designs.
Here is some of what NASA says:
The findings, which are published in the May 31 edition of the journal Science, indicate radiation exposure for human explorers could exceed NASA's career limit for astronauts if current propulsion systems are used.
Two forms of radiation pose potential health risks to astronauts in deep space. One is galactic cosmic rays (GCRs), particles caused by supernova explosions and other high-energy events outside the solar system. The other is solar energetic particles (SEPs) associated with solar flares and coronal mass ejections from the sun.
Here is how the data was obtained:
Curiosity's Radiation Assessment Detector (RAD) is the first instrument to measure the radiation environment during a Mars cruise mission from inside a spacecraft that is similar to potential human exploration spacecraft. The findings reduce uncertainty about the effectiveness of radiation shielding and provide vital information to space mission designers who will need to build in protection for spacecraft occupants in the future.
Courtesy of the New York Times, the proponents of manned Mars missions are heard from:
Advocates for a human mission to Mars say the radiation risk is overblown. “What it shows is that the cosmic ray dose on a Mars mission is not a show-stopper,” Robert Zubrin, founder and president of the Mars Society, said about the new data.
“This is modest proportion of overall risk,” he added. “Therefore, what it means is that we don’t need to delay a humans-to-Mars program until we have a miraculous advanced propulsion system that can get us there faster.”
Mr. Zubrin, of course, is a
lobbyist with ties to Lockheed-Martin Astronautics in Denver. Guess who is the
prime contractor for the Orion crew vehicle for current NASA manned Mars missions. Yep, Lockheed-Martin Astronautics in Denver. Go figure. Somehow the Times description of Zubrin as "founder and president of the Mars Society" doesn't quite convey those seemingly germane details. Paper of record. Sigh. Anyway, any mission based on the technology Lockheed Martin is currently building will practically guarantee fatal cancers for some Mars astronauts.
I have really mixed thoughts about the implications for manned interplanetary missions, particularly to Mars. Robot missions are becoming so robust, it seems like a better use of resources to ramp up those kinds of missions.
Another part of me wonders if necessity really is the mother of invention. Maybe we need to plan for and support manned interplanetary missions, paying way too much money for way too little scientific advantage versus robotic exploration. Maybe that's the only way to push technology forward.
I would welcome full discussion of these and all related issues in the comments.
For all of my Mars diaries and all things Mars on Daily Kos go to Kossacks on Mars.
