Study proposes new radiation standards in space
A new report issued today from the National Academies of Science is recommending that NASA adopt a new health standard for limiting the exposure of astronauts to radiation during long space missions. The new standard, based on a maximum accumulative dosage of 600, is indicated by the figure to the right, taken from the report [pdf] and annotated to show both the new recommendation as well as the standards used by other space-faring nations.
The key result of this change is expressed in the report in this one sentence:
Compared with the existing standard, this proposed standard will increase the allowable exposure for a 35-year-old female by a factor of ~3 and for a 55-year-old male by a factor of ~1.5.
The new recommendations however remain below the 1,000 dose standard used by Russia, Canada, and Europe, as shown by the figure.
Based on the present technology planned for any year+ Mars mission, all these standards would still be exceeded and will thus require a waiver of the standard in order for NASA or the other space agencies to send their astronauts.
The report also recommends that NASA develop detailed procedures for issuing that waiver:
NASA should develop a protocol for waiver of the proposed space radiation standard that is judicious, transparent, and informed by ethics. To avoid the perception that an exception to the standard is built into the space radiation standard itself, NASA should follow the ethics decision framework in developing a waiver protocol and it should provide supporting analysis and explanation justifying any waiver to the standard.
The new recommendations are being suggested partly because the present health limits, first established in 1989, make it difficult if not impossible for any young woman to participate in a Mars mission. Their health risk is greater than a comparable male partly because of the risk to any future children the woman may have, and partly because past radiation research has suggested that women are more vulnerable to high doses of radiation. The new standard eases these restrictions for female American astronauts, and puts it more in line, though still more stringent, with the standards being used by other nations.
These health standards are meant as a guide to NASA and its astronauts in planning future manned interplanetary missions. While they are not law, and do not restrict the decisions of non-NASA space tourists, do not assume the government will not try to impose these rules on private manned launches also. We live in a time that ignores the clear constitutional limits on the federal government, so I fully expect the federal government will eventually try to make these rules apply to everyone. Though these radiation limits appear somewhat reasonable if limiting, what if a private citizen decides they want to go, even if it means the radiation exposures will be higher than these limits?
In a free society they should have that right. Sadly I doubt we live in such a free society.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
A new report issued today from the National Academies of Science is recommending that NASA adopt a new health standard for limiting the exposure of astronauts to radiation during long space missions. The new standard, based on a maximum accumulative dosage of 600, is indicated by the figure to the right, taken from the report [pdf] and annotated to show both the new recommendation as well as the standards used by other space-faring nations.
The key result of this change is expressed in the report in this one sentence:
Compared with the existing standard, this proposed standard will increase the allowable exposure for a 35-year-old female by a factor of ~3 and for a 55-year-old male by a factor of ~1.5.
The new recommendations however remain below the 1,000 dose standard used by Russia, Canada, and Europe, as shown by the figure.
Based on the present technology planned for any year+ Mars mission, all these standards would still be exceeded and will thus require a waiver of the standard in order for NASA or the other space agencies to send their astronauts.
The report also recommends that NASA develop detailed procedures for issuing that waiver:
NASA should develop a protocol for waiver of the proposed space radiation standard that is judicious, transparent, and informed by ethics. To avoid the perception that an exception to the standard is built into the space radiation standard itself, NASA should follow the ethics decision framework in developing a waiver protocol and it should provide supporting analysis and explanation justifying any waiver to the standard.
The new recommendations are being suggested partly because the present health limits, first established in 1989, make it difficult if not impossible for any young woman to participate in a Mars mission. Their health risk is greater than a comparable male partly because of the risk to any future children the woman may have, and partly because past radiation research has suggested that women are more vulnerable to high doses of radiation. The new standard eases these restrictions for female American astronauts, and puts it more in line, though still more stringent, with the standards being used by other nations.
These health standards are meant as a guide to NASA and its astronauts in planning future manned interplanetary missions. While they are not law, and do not restrict the decisions of non-NASA space tourists, do not assume the government will not try to impose these rules on private manned launches also. We live in a time that ignores the clear constitutional limits on the federal government, so I fully expect the federal government will eventually try to make these rules apply to everyone. Though these radiation limits appear somewhat reasonable if limiting, what if a private citizen decides they want to go, even if it means the radiation exposures will be higher than these limits?
In a free society they should have that right. Sadly I doubt we live in such a free society.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
While I hope they would not impose these standards on a private citizen spending their own money to go to space, the government will take the opportunity to regulate it if informed consent shows that these dangers are ignored by the service companies. Fortunately, private space firms seem very eager to not hurt their customers so I doubt this will be a problem. Yet.
If the destination of the astronauts is closer to the sun, there would be a problem, particularly during an active sun phase.
Moving away from the sun decreases the radiation exposure, other methods of shielding can protect against cosmic radiation. Water blanket and magnetic field is particularly effective.
Nothing can shield neutron radiation, that’s why neutron detectors are deep underground for accurate readings away from decaying granite.
Any spacecraft hit by a coronal mass ejection during an active sun phase would most likely be fatal, as well as solar panels degradation and electrical systems malfunction shutting down life support.
Here is a short YouTube education on radiation exposure. A man travels to all the hotspots taking direct measurements. Who receives more radiation than astronauts? Fast forward to the end for the surprise conclusion.
https://www.youtube.com/watch?v=TRL7o2kPqw0
Note that radiation on humans is one thing, but at least we have an immune system. But consider the problem with the biota humans will be carrying that have 1) fast reproduction times, 2) can be mutated by radiation. These are within humans. How to deal with this? Quarantine? What level of risk is this? Not only can mutated microbes foul the environmental support, but humans can get sick by things we have trouble curing given a year of country-level resources.
The biggest danger of a Mars mission is not radiation damage…it is simply getting back alive, which is not a good bet at this point.
Max,
I once worked with a radiation expert who would talk to us in terms of “banana equivalent dose.” He truly hoped that he wasn’t putting us off bananas, as they are good for us despite the very tiny amount of radioactive potassium. Everybody needs potassium, and like carbon, a certain amount is radioactive.
And, yes, sleeping next to your spouse gives you around one banana equivalent dose. Separate bedrooms, anyone?
The smaller the creature the less chance it has of being hit by a radiation.
One reason why bugs will live through an atomic bomb better than we will.