Monday, August 3, 2009

Radiation blanket claims utterly fantastic, without hard numbers

Notional habitat on the Moon shielded from radiation by Lunatex, developed under supervision of Dr. Warren Jaspers at North Carolina State University in Raleigh. The fabric-system as described in print purports to protect human life from the wide range of radiation hazards outside Earth's atmosphere and magnetic field. All reports so far, however, fail to mention the certain limitations of the fabric. (Specialty Fabrics Review)

For months, we've taken the quiet, modestly skeptical approach as to Dr. Warren Jaspers LUNAR-TEX, especially matter-of-fact news releases advertising a textile with super powers. Then, on Sunday (and, most peculiarly, just after a private discussion here about mitigating space radiation hazards) the LUNAR-TEX miracle surfaces again, following weeks with little mention anywhere.

Blanket protects lunar outposts
Specialty Fabrics Review

"Textile engineering students at North Carolina State University (NCSU) have the next manned moon landing covered with a blanket that protects lunar outposts from radiation while storing energy for astronauts’ use. The project, one of 10 finalists in the Revolutionary Aerospace Systems Concepts Academic Linkage competition, tackles one of NASA’s key concerns about moon missions that will likely last months at a time—cosmic rays and solar flares that make dangerous radiation hard to stop."

"The “lunar texshield” is made from a lightweight polymer composite with a layer of radiation shielding that deflects or absorbs radiation. The outer shield layer includes solar cells to generate electricity. The design is flexible, lightweight, has a large surface area, and is easy to transport and deploy. “We understand the properties associated with different textile materials,” says Dr. Warren Jasper, NCSU professor of textile engineering and project advisor. “That gives us unique insight on how to troubleshoot some of these issues.”"

To which we replied:

"As much as we admire NC State's engineers and proven science department, this is not the first time we have been casually informed of an astounding claim, without sufficient detail about how well it works.

"According to the National Academies, in "Managing Space Radiation in the New Era of Space Exploration (2008) [] a round-trip manned expedition to Mars, for example, would result in each crew member exceeding NASA's present individually assessed lifetime probable risk of radiation exposure induced death (4%).

"A fabric mitigating this risk on the lunar surface is reasonable, but affording protection from such risk as effectively as does Earth's magnetic field and atmosphere is not reasonable, most especially the risk from cosmic rays at or above 100 MeV. (Ed. Probably more like 500 MeV to 10 GeV, though the "ceiling" and incidence of the highest-energy particles are not yet known, data collected since 1958 show the rate of infall of Galactic Cosmic Rays into the inner Solar System is 50 to 60 percent higher at solar minimum.)

Since reports of this fabric's usefulness have not touched on any detail regarding its certain limitations, we are understandibly skeptical. It begs clarification as to just how this fabric changes hard numbers on well-established risk probabilities. With such numbers, we're prepared to salute a revolutionary development, equal to shielding equal to 11 meters of regolith. But, without such numbers these claims made for Lunatex seem utterly fantastic."

But, that is, as they say, academic. The claims made on behalf of Dr. Jaspers are, indeed, "utterly fantastic." At face value, the reports about LUNAR-TEX might as well claim protection against space debris or meteor bombardment, or hail and lightning. In fact, those claims would be more "probable."

What we have in Dr. Jasper's development is an innovation in systems and materials that are "probably" a real mitigation against the full range of space radiation over spectrum and time. It's probably a real breakthrough, and one that might make round-trips to Mars using present acceleration capability less than life threatening. As such, it may be a real breakthrough.

But enough is enough.

More reports about the development of a panacea cannot go unchallenged. This one is really starting to bug us because space radiation is, as far as we can tell, one of the things that appears to be totally misunderstood or ignored by all parties in the far-flung public space policy debate, currently underway in the United States.

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