Story 2014-10-23 2TMA Future manned Mars exploration at risk due to lowered solar activity

Future manned Mars exploration at risk due to lowered solar activity

by
in space on (#2TMA)
Does the worsening galactic cosmic radiation environment observed by CRaTER preclude future manned deep-space exploration? That is the conclusion of of a recently published paper that posits the recent decrease in solar activity has led to increased incidence of cosmic rays, which are dangerously radioactive. That may just put a damper on anyone interested in organizing manned exploration of the Red Planet.
The Sun and its solar wind are currently exhibiting extremely low densities and magnetic field strengths, representing states that have never been observed during the space age. The highly abnormal solar activity between cycles 23 and 24 has caused the longest solar minimum in over 80 years and continues into the unusually small solar maximum of cycle 24. As a result of the remarkably weak solar activity, we have also observed the highest fluxes of galactic cosmic rays in the space age, and relatively small solar energetic particle events. We use observations from the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) on the Lunar Reconnaissance Orbiter (LRO) to examine the implications of these highly unusual solar conditions for human space exploration. We show that while these conditions are not a show-stopper for long duration missions (e.g., to the Moon, an asteroid, or Mars), galactic cosmic ray radiation remains a significant and worsening factor that limits mission durations.
Very interesting and at least for me counter intuitive. I would have thought: Less solar activity means less radiation. But it seems that the solar wind normally has the effect of reducing the amount of dangerous cosmic radiation that can reach the inner solar system. But to that, point, the article points out: While particles and radiation from the Sun are dangerous to astronauts, cosmic rays are even worse, so the effect of a solar calm is to make space even more radioactive than it already is.
Reply 12 comments

Aye aye captiain (Score: 0)

by Anonymous Coward on 2014-10-23 13:40 (#2TMD)

We'll just reverse the polarity, plugin in a spare lithium reactor, don't you worry about it

Should be fine... (Score: 2, Insightful)

by evilviper@pipedot.org on 2014-10-23 15:04 (#2TMF)

Nobody is lined-up and waiting to blast-off to Mars right now, so I think we're good. In a few years, when people are ready to go, solar weather will be swinging the other way. It's an extreme case right now, but still part of a cycle that has been observed going for several centuries, so it's only a matter of a bit more time before things get back to normal:

https://upload.wikimedia.org/wikipedia/commons/2/28/Sunspot_Numbers.png

Re: Should be fine... (Score: 1)

by tanuki64@pipedot.org on 2014-10-23 18:49 (#2TMX)

Nobody is lined-up and waiting to blast-off to Mars right now
This might be true. But it still is sad. More and more hurdles against human space flights are discovered. Faster than light... good chances that it will never happen. Manned interstellar flights?
At speeds above 0.3c, which is for all its worth far too slow to get anywhere, the space dust turns into deadly and hard to shield radiation:

http://arxiv.org/pdf/physics/0610030
When a ship accelerates to a relativistic velocity above 0.3c, interstellar gas becomes a flow of relativistic nucleons, which, in itself, is nothing less than hard radiation bombarding the starship, its travelers, and all of the electronic equipment aboard.
And now even flying around within the solar system is no really reliable possible.

Re: Should be fine... (Score: 1)

by evilviper@pipedot.org on 2014-10-23 19:45 (#2TN4)

Manned interstellar flights? At speeds above 0.3c, which is for all its worth far too slow to get anywhere, the space dust turns into deadly and hard to shield radiation
I'd sign-up for a flight to Alpha Centauri AB at 0.3c...

14 years in a capsule won't be fun, but still doable, and with amazing new worlds all to myself, at the other end of the trip.

Re: Should be fine... (Score: 2, Funny)

by tanuki64@pipedot.org on 2014-10-23 19:47 (#2TN5)

28 years. Don't forget the way back... when you don't find anything usable there. ;-)

Great summary! (Score: 1)

by kwerle@pipedot.org on 2014-10-23 16:02 (#2TMK)

Fascinating stuff - I had no idea. Thanks for the great article.

Re: Great summary! (Score: 1)

by zafiro17@pipedot.org on 2014-10-23 16:38 (#2TMM)

Yes, agree - this was very interesting, and I didn't know about any of it. I wonder if this doesn't strengthen the case for increased/additional/future robotic exploration of the type already happening and with some considerable success.

I fear politicians choose projects of this type more for their "splash" and "cool" factor than for their scientific merit, whereas the technical folk might argue for different projects or types of projects. In fact, there might be no obvious need to do manned exploration of Mars at the moment, since our little wheeled machines are exploring them so admirably. This keeps the politicians on their leashes, where they belong, and might help encourage funding of missions like the ones already under way.

You keep using that word... (Score: 1)

by czert@pipedot.org on 2014-10-24 23:01 (#2TPH)

...I do not think it means what you think it means.

http://en.wikipedia.org/wiki/Radioactive_(disambiguation)

Re: You keep using that word... (Score: 1)

by tanuki64@pipedot.org on 2014-10-25 06:47 (#2TPS)

When you are showered by gamma/cosmic rays, or high energy particles, does it matter where they come from?

Re: You keep using that word... (Score: 1)

by czert@pipedot.org on 2014-10-25 09:00 (#2TPW)

My point is, cosmic rays or space itself cannot be "radioactive". Radioactivity is a property of ordinary matter.

But yeah, I'm being needlessly pedantic. Thanks for the submission, I did enjoy the "article". And thanks for linking directly to the source, by the way -- that's something that rarely happens on /. these days.

Re: You keep using that word... (Score: 1)

by zafiro17@pipedot.org on 2014-10-26 09:43 (#2TQC)

Curiosity but also a chance for me to learn: what would be a better word? Is there one? Or are we stuck with "showered with gamma particles" etc.?

Re: You keep using that word... (Score: 2, Informative)

by evilviper@pipedot.org on 2014-10-26 16:56 (#2TQG)

what would be a better word? Is there one? Or are we stuck with "showered with gamma particles" etc.?
Hmm, let's try a few...

Original: cosmic rays, which are dangerously radioactive.

Option1: cosmic rays, which are dangerously high-energy radiation.

Option2: cosmic rays, which are dangerous high-energy particles.

Option3: cosmic rays, which are dangerous high-energy atomic nuclei.

Option4: cosmic rays, which are dangerous ionizing radiation.

Option5: Cosmic Ray's, which is the most dangerous pub in the universe.