We Fried Ma­jor Tom!

Sci­en­tists hope vests and vitamins can pro­tect as­tro­nauts from deadly space ra­di­a­tion

Newsweek - - NEWS - BY SWAPNA KR­ISHNA @skr­ishna

RA­DI­A­TION. It’s ev­ery­where, from the fall­out of nu­clear weapons to med­i­cal X-rays. It’s a cause of cancer, but it’s also one of the pre­ferred forms of cancer treat­ment. There’s also a lot of it in space, and if we want to send as­tro­nauts to Mars safely, that’s a prob­lem.

The charged par­ti­cles com­monly called ra­di­a­tion are a se­ri­ous threat to any­one trav­el­ing in space, whether it’s a stay on the In­ter­na­tional Space Sta­tion or be­yond. The Earth’s mag­netic field pro­tects peo­ple on the planet from ra­di­a­tion by trap­ping the par­ti­cles in ra­di­a­tion belts that

sur­round the globe. These dough­nut-shaped ar­eas in space, called Van Allen belts, lie up to 36,000 miles from Earth’s sur­face. Within Earth’s or­bit, as­tro­nauts are pro­tected, but you can’t get to the moon, Mars or be­yond with­out ven­tur­ing past them. Once as­tro­nauts travel through and be­yond the Van Allen belts—haz­ards in and of them­selves be­cause they trap these harm­ful par­ti­cles—their bod­ies be­come vul­ner­a­ble.

Deep space as­tro­nauts have to con­tend with two types of ra­di­a­tion. The first is com­posed of galac­tic cos­mic rays, high-en­ergy par­ti­cles that travel at close to the speed of light. These cos­mic rays, which are mostly pro­tons but can also con­sist of heav­ier el­e­ments, can dam­age hu­man DNA, trig­ger mu­ta­tions and change gene tran­scrip­tion. When gene tran­scrip­tion oc­curs, DNA pro­duces RNA, which car­ries the in­struc­tions from DNA to the cells in the body. When that process is changed, RNA car­ries im­per­fect in­struc­tions to the cells. Over the medium and long term, these er­rors can be­come per­ma­nent mu­ta­tions.

It seems inevitable that hu­mans are go­ing to Mars, so both pub­lic and private com­pa­nies are test­ing and retest­ing every as­pect of that jour­ney. But un­less they fig­ure out the ra­di­a­tion prob­lem, all that prepa­ra­tion will be moot.

Sci­en­tists at the Wake For­est In­sti­tute for Re­gen­er­a­tive Medicine just wrapped up a NASA­funded study that ex­am­ines the ef­fects ra­di­a­tion from a Mars mis­sion might have on as­tro­nauts. The team fo­cused on the hematopoi­etic sys­tem, which is pri­mar­ily com­posed of the spleen, thy­mus, lymph nodes and bone mar­row. “We know from stud­ies on the atomic bomb sur­vivors that the hematopoi­etic sys­tem is one of the more sen­si­tive tis­sues in the body to the ef­fects of ra­di­a­tion,” says Christo­pher Po­rada of Wake For­est Univer­sity, a se­nior re­searcher on the project. Leukemia, un­like many other types of cancer, can de­velop quickly. “It would ac­tu­ally com­pro­mise both the mis­sion and the as­tro­nauts’ health dur­ing that two-year pe­riod of time,” Po­rada says.

Galac­tic cos­mic rays have a low ra­di­a­tion dose rate; dur­ing shorter trips, it’s not as se­ri­ous an is­sue. “Go­ing to the moon, as­tro­nauts re­ceived very min­i­mal ra­di­a­tion,” Po­rada says. But its cu­mu­la­tive ef­fect means that dur­ing a longer Mars mis­sion (a min­i­mum of two years, round trip), ra­di­a­tion is a much larger and more present threat.

But the news isn’t all bleak: The same team posits that a daily oral vi­ta­min might be able to pro­tect as­tro­nauts from space ra­di­a­tion’s harm­ful ef­fects. “We’ve found a di­etary sup­ple­ment that ap­pears to res­tore about 75 per­cent of the po­ten­tial of the cells, if we put them on the cells be­fore we ex­pose them to the ra­di­a­tion,” says Po­rada. The pill isn’t ab­sorbed well orally, so the team is work­ing on a way to im­prove its sol­u­bil­ity.

If we can’t pro­tect from within, how about from with­out? Stem­rad, an Is­raeli com­pany based in Tel Aviv, spe­cial­izes in ra­di­a­tion pro­tec­tion for nu­clear work­ers and first re­spon­ders. Now, it has de­signed a vest that will pro­tect as­tro­nauts from space ra­di­a­tion. Or­gans, tis­sues and stem cells are par­tic­u­larly vul­ner­a­ble to ra­di­a­tion, and the vest was de­signed to specif­i­cally shield those del­i­cate ar­eas. The vests come with a pretty big caveat: As­tro­nauts would have to wear them around the clock. Stem­rad’s aim is to tailor each vest to each as­tro­naut for max­i­mum com­fort and flex­i­bil­ity.

The com­pany an­nounced on March 3 that the vest will be on Ex­plo­ration Mis­sion-1, the un­manned test of NASA’S new space vehi- cle Orion, cur­rently sched­uled for a late 2018 launch. Two dum­mies will fly aboard the cap­sule on its cir­cum­lu­nar flight. Only one dummy will wear Stem­rad’s vest. Upon their re­cov­ery, NASA will per­form tests on both dum­mies to de­ter­mine the ef­fec­tive­ness of the vests’ ra­di­a­tion pro­tec­tion. (It’s also pos­si­ble NASA will de­cide to put a hu­man crew on EM-1; it is con­duct­ing a fea­si­bil­ity study. No word on whether a hu­man would don the vest.)

Un­for­tu­nately, there’s a sec­ond type of ra­di­a­tion NASA needs to worry about: so­lar. “So­lar proton events, or so­lar par­ti­cle events, are en­er­getic


par­ti­cles that are emit­ted by the sun,” says El­sayed Talaat, a dis­ci­pline sci­en­tist in NASA’S he­lio­physics di­vi­sion. Par­ti­cles dis­charged by space weather events, such as so­lar flares, can af­fect as­tro­nauts acutely in the short term, dam­ag­ing the cen­tral ner­vous sys­tem and re­sult­ing in im­paired mo­tor func­tion and cog­ni­tive func­tion. In the long term, these par­ti­cles in­crease their cancer risk.

NASA is test­ing var­i­ous meth­ods to pro­tect Mars as­tro­nauts from so­lar ra­di­a­tion. The Orion space­craft will be equipped with ra­di­a­tion sen­sors, the crew will be no­ti­fied if a so­lar flare or other ra­di­a­tion event oc­curs, and the crew will have time— be­tween 30 min­utes and a few hours—to take shel­ter in the space­craft’s cargo area, pro­tect­ing them­selves from the bulk of the ra­di­a­tion.

But what if sci­en­tists could pre­dict these ex­plo­sions and whether one would trig­ger a ra­di­a­tion event? “Our ul­ti­mate goal is pre­dictabil­ity of these space weather ef­fects,” says Talaat. “That is hope­fully the endgame of phys­i­cal un­der­stand­ing, if you’re able to pre­dict the phe­nom­ena.”

It’s clear that the an­swer to pro­tect­ing as­tro­nauts from space ra­di­a­tion lies in a bal­anc­ing act: outer ver­sus in­ner, pre­dic­tion ver­sus pro­tec­tion. Re­gard­less of how NASA does it, the ra­di­a­tion prob­lem is one we need to solve. Oth­er­wise, we’re look­ing at a long fu­ture of go­ing nowhere at all.

VEST PRAC­TICES: Re­searchers say an as­tro­naut’s bone mar­row, spleen thy­mus and lymph nodes are par­tic­u­larly vul­ner­a­ble to space ra­di­a­tion.

DRA­MATIC FLARE: Mon­i­tors will warn Mars as­tro­nauts when a ra­di­a­tion event, such as a so­lar flare, oc­curs, and they will have at least 30 min­utes to take shel­ter.

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