[Crater-team] Link to paper - requires a subscription :-(

Wed Jan 9 15:22:01 EST 2019

I think the point Harlan was making was the assumption in the paper that a transit exposure was ~ the same as a LEO exposure, and of course it’s not. But my point is that it’s probably only about a factor of 2 to 3 different from LEO or the Mars surface.

From: Mark D Looper <mark.d.looper at aero.org>
Date: Wednesday, January 9, 2019 at 12:18 PM
To: "Zeitlin, Cary J (JSC-SD2)[WYLE LABORATORIES, INC.]" <cary.j.zeitlin at nasa.gov>, Harlan Spence <spence at guero.sr.unh.edu>
Cc: "crater-team at lists.sr.unh.edu" <crater-team at lists.sr.unh.edu>
Subject: Re: [Crater-team] Link to paper - requires a subscription :-(

Sorry, I didn’t realize ISS-RAD was inside the ISS, or that the Martian atmosphere was that thick in aggregate… Was the research warning about the riskiness of interplanetary travel based on dose rates like the ones in the figure you just sent, or under less shielding, or over a longer time than LEO astronauts are exposed, or what?  Or was the extra risk due to the different composition of the GCRs, or the likelihood of SEPs (largely shielded out in the ISS orbit)?  I’m trying to understand what the differences are between exposure of astronauts in LEO and that of astronauts on a trans-Mars trip, which is what needs to be pointed out to address this apparent contradiction of the two papers.

Mark D. Looper
Space Sciences Department
The Aerospace Corporation
M/S M2-260
P.O. Box 92957
Los Angeles, CA 90009-2957
Mobile: 310-529-3406
Voicemail: 310-336-6302

From: "Zeitlin, Cary J (JSC-SD2)[WYLE LABORATORIES, INC.]" <cary.j.zeitlin at nasa.gov>
Date: Wednesday, January 9, 2019 at 10:11 AM
To: Mark D Looper <mark.d.looper at aero.org>, Harlan Spence <spence at guero.sr.unh.edu>
Cc: "crater-team at lists.sr.unh.edu" <crater-team at lists.sr.unh.edu>
Subject: Re: [Crater-team] Link to paper - requires a subscription :-(

Yes, absolutely, shielding matters and is especially important for the SAA. ISS-RAD was moved around Station every few months during 2018, which explains part of the variation. And MSL-RAD is under ~ 23 g cm^-2 of CO2, so of course the comparison is not apples to apples. But it’s interesting how it seems to be working out, even if the “agreement” is the product of numerous factors that are sort of conspiring to give such similar results.

From: Mark D Looper <mark.d.looper at aero.org>
Date: Wednesday, January 9, 2019 at 12:03 PM
To: "Zeitlin, Cary J (JSC-SD2)[WYLE LABORATORIES, INC.]" <cary.j.zeitlin at nasa.gov>, Harlan Spence <spence at guero.sr.unh.edu>
Cc: "crater-team at lists.sr.unh.edu" <crater-team at lists.sr.unh.edu>
Subject: Re: [Crater-team] Link to paper - requires a subscription :-(

Is it not also a matter of shielding, in that the LEO SAA spectrum is falling with energy and thus is comparatively easy to shield against, whereas the interplanetary GCR spectrum rises up to very deeply penetrating energies?  What were the assumptions in the paper(s) warning about interplanetary radiation exposure?  The plot you sent is for detectors relatively open to space, right?

Mark D. Looper
Space Sciences Department
The Aerospace Corporation
M/S M2-260
P.O. Box 92957
Los Angeles, CA 90009-2957
Mobile: 310-529-3406
Voicemail: 310-336-6302

From: Crater-team <crater-team-bounces at lists.sr.unh.edu> on behalf of "Zeitlin, Cary J (JSC-SD2)[WYLE LABORATORIES, INC.]" <cary.j.zeitlin at nasa.gov>
Date: Wednesday, January 9, 2019 at 9:51 AM
To: Harlan Spence <spence at guero.sr.unh.edu>
Cc: "crater-team at lists.sr.unh.edu" <crater-team at lists.sr.unh.edu>
Subject: Re: [Crater-team] Link to paper - requires a subscription :-(

Good point! Nuance is completely lost in these things.

OTOH, the exposure isn’t all that different in LEO, as I’ve been learning since we started getting ISS-RAD data. The geomagnetic field is protective, but in terms of dose, the SAA passes more or less undo the protection. So the difference is mostly that the LEO spectrum is more populated at low-LET than deep space, which is an even greater degree of nuance. ☺

From: Harlan Spence <spence at guero.sr.unh.edu>
Date: Wednesday, January 9, 2019 at 11:44 AM
To: "Zeitlin, Cary J (JSC-SD2)[WYLE LABORATORIES, INC.]" <cary.j.zeitlin at nasa.gov>
Cc: "crater-team at lists.sr.unh.edu" <crater-team at lists.sr.unh.edu>
Subject: Re: [Crater-team] Link to paper - requires a subscription :-(

Hi Cary,

   One issue is that the press picked up on this and said that all the prior studies showing that space radiation is a problem is now called into question.  So there’s a bit of damage control for those who didn’t understand the nuances between LEO and deep space exposure.

= Harlan
________________________________

Harlan E. Spence

Director, Institute for the Study of Earth,

   Oceans, & Space and Prof. of Physics
Morse Hall, Room 306
University of New Hampshire

8 College Road

Durham, NH 03824-3525

Phone: 603-862-0322

Fax:   603-862-1915

http://www.eos.unh.edu/Faculty/Spence
________________________________

On Jan 9, 2019, at 2:37 PM, Zeitlin, Cary J (JSC-SD2)[WYLE LABORATORIES, INC.] <cary.j.zeitlin at nasa.gov<mailto:cary.j.zeitlin at nasa.gov>> wrote:

Thanks for the links – I’m glad they did this, even with all the caveats about sample size, etc.

From: Crater-team <crater-team-bounces at lists.sr.unh.edu<mailto:crater-team-bounces at lists.sr.unh.edu>> on behalf of Harlan Spence <spence at guero.sr.unh.edu<mailto:spence at guero.sr.unh.edu>>
Date: Wednesday, January 9, 2019 at 11:32 AM
To: "crater-team at lists.sr.unh.edu<mailto:crater-team at lists.sr.unh.edu>" <crater-team at lists.sr.unh.edu<mailto:crater-team at lists.sr.unh.edu>>
Subject: [Crater-team] Link to paper - requires a subscription :-(

https://oem.bmj.com/content/early/2018/12/04/oemed-2018-105304

________________________________

Harlan E. Spence

Director, Institute for the Study of Earth,

   Oceans, & Space and Prof. of Physics
Morse Hall, Room 306
University of New Hampshire

8 College Road

Durham, NH 03824-3525

Phone: 603-862-0322

Fax:   603-862-1915

http://www.eos.unh.edu/Faculty/Spence
________________________________

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.sr.unh.edu/pipermail/crater-team/attachments/20190109/8f6d6c76/attachment-0001.html>