Cancer Ribbon Pictures

steve sandford: welcome backfor the fifth installment, the fifth lecture in our series,for those of you who have been here the whole time of course westarted off with an overview of the future of the american spaceprogram and where we are going, then we followed that upwith our two lectures about our transportation system which iswhat we are working on right now, we have money to that andfunding to do that and that is happening todayacross the country. and then last week we talked toyou about one of the two really

tough problems, i sometimes saymiracles that have to happen for us to pull this off, and thatwas landing human scale payloads on the surface of mars throughthe really poor atmosphere that mars has. and today we are going tohear from dave moore and martha clowdsley about how we are goingto attack the problem of the effects ofradiation on astronauts. so, it is a long trip to mars,and mars doesn't have the same protections that we enjoyhere on earth

from our magnetic field. and so we have to come up withways to protect the astronauts on the way and while theylive on the surface of mars. and you have got two of the bestexperts here this morning and i am going to turnit over to them. [applause] dave moore: thank you. can you all hear me?okay, good. as steve mentioned we are goingto give you all a briefing on

the radiation protectionefforts that we are ongoing now over at nasa. as most of you are aware theeffects of radiation here on earth, how it canaffect our power grids, our water system, ourcell phone service, the airline industry, but aswe move further away from the earth's protective magneticfield there are issues with protecting theastronauts and their safety. as steve mentioned we arelooking at missions that could

go anywhere fromtwo to three years. so we are working onprocesses to protect the astronauts going forward. steve also hit on,i guess this is, we are the fifth in theinstallment and you guys have probably already seen kind ofour flow chart how we propose to get to mars and what i wantyou to take away here on the far right, you see ourmissions two to three years, so we have a big effort ongoingin the agency to address the top

problem with space radiation. to give you kind of perspectiveof what prior astronauts have seen with exposure in space,you can see on the graph here, all the human missions, themercurys and the geminis and what i want you to focus on isover in the right you see the mars, little box for mars, weare looking at this exposure that we are expecting theastronauts to see is a factor of 10 greater than whatanybody has ever received currently and flown.

so this is a big problem forus and we are spending a lot of effort trying to address it. to give you another perspectiveand put it in context of what we see here on earth, youstart near the line, you see over herein the far left, if you go for an officevisit to get a chest x-ray or a mammogram, the kindof exposure you get, and as we movefurther to the right, you see commercialairline pilot,

maybe a factor of 10or greater exposure, and then if we move one stepfurther over into the iss realm, the astronauts there are seeinglike a 1000 times greater than what we see here on earth. then if you move away, we areproposition to go to mars on a three-year mission we areseeing something like 10,000 times greater than whatwe currently see on earth. we are very blessed to have theearth's shielding protected with these magnetic fields.

i am going to turn it over nowto martha and she is going to give you a briefing on theenvironments that the astronauts are subject to and some of therisks that they have to endure and then she will turn it backover to me and i will give you a briefing on some of themitigation efforts that we are doing here at langley. martha clowdsley: so, i am goingto try in a very few minutes to explain why we areworried about space radiation. there are really three typesof environments we are worried

about, there is galactic cosmicrays which are heavy ions that are out there all the time,there are solar particle events which are isolated events butcan provide a very large dose and then there isradiation that's trapped in the earth'sgeomagnetic fields. we are going to talk a littlebit more about each of those. galactic cosmic rays are highlycharged energetic nuclei that enter our solar system fromoutside the solar system. it is modulatedby the solar wind.

so, we have 11-year solar cycleand it will go from more intense to less intense, butit is always there. it is about a factor of 2it varies from solar max to solar min. the galactic cosmic rays, itranges from protons all the way up to much heavierions like carbon, aluminum, gold, iron, andthere is a huge range of energy, from just a few evto tens of gevs. so the heavier the faster onesare moving at speed of light and

just very, very penetrating.so, that's our problem. so, you don't get enough dosefrom galactic cosmic rays to worry about itfor short missions. so, it was never a problemfor the apollo missions. you know they werethere for a few days, didn't get enough exposure. but for these longer durationmissions you are getting enough dose so we are worryingabout increased risk of cancer especially.

so, it becomes a shieldingproblem for the three-year mars mission is something we justcan't actually close on it, we can't provide enoughprotection right now. question? audience: do the rays affect thehuman dna and if so what can you do to protect them? martha: yes, yeah, and we aregoing to talk a little bit more about that in a few slides, butthe question was do the rays can they affect the human dnawhere they break the dna strand,

and the answer is yes. so solar particle eventsunlike the galactic cosmic ray environment whichis always there, solar particle eventsare isolated events. they correspond to coronalmass ejections from the sun, though the way they relateis not always intuitive. so you can have a big coronalmass ejection and not have a big solar particleevent or vice versa. so it is really hard to predictand dave is going to talk a

little more about that in a bit. really large events that wouldprovide significant risks to astronauts are pretty rare. we see one or twofor 11-year cycle, but a large event thatcaught astronauts on eva without protection on spacewalkswould be a challenge, it could be a real health risk. so, the one thing that's goodabout solar particle events is that it is mostly protons andthey range in energy again from

a few ev, thistime about 1000 mev. so, they don't goquite as high as the gcr. shielding is muchmore effective for them. so the point is that we haveto get astronauts in a place where they are shielded. it is a solvable problembut we have to make sure that we address it. entrapped radiation -- we arenot going to talk a whole lot about that because we are mostlyfocusing on exploration

missions that go beyond theearth's magnetic field, mostly worried aboutthat mission to mars. but i did want to mention itbecause it is another source of space radiation and one thatastronauts have been exposed to. what happens is that protons andelectrons especially and a few other particles but mostlyprotons and electrons get trapped in the earth'smagnetic field lines, and basically they swirl aroundthe field lines and they just follow the field lines backfrom pole to pole

and they are always there. the space station is at a prettylow orbit so it doesn't go through the worst of the vanallen's belt which is why the astronauts are relatively safe. it does sort of pass throughthem on each rotation and you get a proton doseas that happens. so they do getsome dose from this. the magnetic fields also provideprotection to us on earth and to the astronauts on iss.

the lower energy galactic cosmicray particles are actually, their path gets deterredso they provide a lot of protection to earth. just backing up, what are thesecharged ions are talking about, for those of you who rememberyour high school chemistry class this picturemight look familiar. so, just rememberwhat an atom is, an atom is basically anucleus surrounded by electrons. now this picture isnot at all to scale.

the entire atom is about 10,000times bigger than the nucleus. so, most of the volume of theatom is the electrons rotating and the nucleus is verysmall and very tightly packed. now the electrons are negativelycharged and you have an equal number of positivelycharged protons in the nucleus, and those are bound togetherwith neutrally charged neutrons. so the nucleus is made up ofneutrons and protons packed tightly together and then youhave got orbiting electrons. so, when we talk abouthow shielding works,

picture your aluminum wallwhich is between the astronauts, and yeah this is areally old graphic i know, but the astronauts areon inside of the vehicle, the space radiationenvironment starts out on the outside of the environment. you get tightly packed nucleusof protons and neutrons which impact the wall. now the wall, again most of thevolume is those electrons and then every so often ona very miniature scale

you have a nucleus. mostly what happens is theseparticles moving through the wall they are positively chargedbecause they have been stripped of all their electrons, so theyare trying to grab an electron from the atoms makingup the shielding wall, and it slows downas they do that. so the particles coming in areslowing down and then every so often they bump into anucleus of the shielding wall, aluminum or whatever itis, and they will break up,

and secondary particleswill be produced. it is possible that theenvironment behind the shielding will be worse thanthe environment outside the shielding. if you picture some heavy ionshere and they come through the shielding and now you havegot protons and neutrons being produced and more and moreparticles being produced so we have to be really careful in howwe work shielding that we don't actually make it worse.

permissible exposure limits-- how much radiation are the astronauts allowed to get? we have several kinds oflimits, we have 30-day limits. 30-day limits arebasically a threshold value. you don't want to get morethan this amount of radiation to avoid things like radiationsickness and it is basically what you are worried about isthe astronaut being on a space walk when a solarparticle event happens. as long as they get theprotection before the solar

particle event happensthe 30-day limits don't come into play. we also have career limitsfor some specific effects, circulatory system,central nervous system, we're not going to talk alot about those. the big challenge for us isthis requirement that risk of exposure induced death will beless than 3% and that we ensure that at a 95% confidence level. we are going to talk more aboutwhy that 95% confidence level

statement is there, but whatthis means is we all have a risk of dying of cancer. the astronaut's risk of dying ofcancer due to the exposure they are getting should be nomore than 3% more than average geo-americans. the other thing is radiationexposure should be kept as low as reasonably achievable andthis is the alara principle and it sounds likereally squishy words, you guys go and dothe best you can,

but it is actually areally important requirement, because what this requiresis that every time we send an astronaut in space we need todo all of the trade studies to ensure we have done everythingwe can to keep them safe. so you need to look at yourvehicle and is there a way you can redesign it andevaluate each possible way you can redefine it. you need to look at your missionops plan for when they are going to be doing space walks andbasically test each one and

figure out what's the best wayto keep the radiation exposure as low as reasonably achievable. it is a very importantrequirement for us. so, again, why are we so worriedabout this space radiation environment and why do we haveat 95% confidence requirement. so the spaceradiation as we said, it is protons but it is alsoheavier ions and it is basically different than anythinghumans have been exposed to. we have a very limited numberof astronauts that have had some

extensive time on iss thathave been exposed to a somewhat similar environment, but the lowenergy particles are pretty much cut off at iss because themagnetic field protects them. so we don't have any populationof humans that have been exposed to a lot of heavy ions. there is no way forthat to happen on earth. so, most of our risk estimatesare based on atomic bomb survivor data. so we are extrapolating froma totally different type of

radiation and a totallydifferent population with a totally different diet thanpeople were eating back then. so, there is a lot ofextrapolating going on. if you look at this pictureon the right which might be a little bit confusing, what thisis this is the path of different types of particlesthrough a material. hydrogen protonsare on the left. helium are just a little bitheavier and then as you move to the right it gets heavierand heavier

all the over to iron ions. this is sort of the path theycarve through the material. so the ion is bigger. it is basically justclearing a bigger path, so would be causing more damageto dna and shooting off more delta rays, sort of the scatterlook are delta rays coming off the particle whichalso can cause damage. so, again, the problem is thatwe haven't had humans exposed to this so how do weestimate the risk?

even if we can calculateperfectly how much radiation they are seeing how dowe estimate the risk? and the way we are working thisis by doing more and more animal testing in heavy ionbeams, but it takes time. so, your question aboutdna, these are just diagrams, here is an intact dnastrand and up here you see, if an x-ray would come throughit might be able to do damage to one very, very smallpart of that dna strand. however, heavy ion has theability to break both strands of

the dna and it is shootingoff delta particles which are doing more damage. so heavy ion has the ability toaffect this dna strand so that it can't repair itself, whichactually wouldn't be the worse thing, if you kill a few cells,we have got lots of cells, it is when they repairthemselves in a bad way that we end up with cancer. so, there are threethings that can happen, you can have a single strandbreak where a particle goes

through one strand of thedna and those sometimes repair themselves correctly. you can have a double strandbreak and this is a problem because they can come backtogether the wrong way and now you have got a mutated cell andthat mutated cell propagates at some point you have gotcancer, or you can have chemical changes to the dna. all of these are big worries butthe double strand breaks that you see with heavy ions isreally our greatest concern.

so, how do we calculateastronaut risk? there is a bunch of differentparts that go into that. we have to be able to evaluatethe space radiation environment and i showed you plots of whatthe gcr environment looks like. we actually have apretty good fix on this. it is not perfect on any givenday but we have a pretty good fix on what types ofparticles are there and what energies are there. we need a radiation transportcode to calculate how that

environment changes as it goesthrough aluminum shielding or whatever kind of shielding andas it goes through human tissue, i mean your body isproviding shielding to your internal organs. we need models of the shielding,we need models of the vehicle, we need models ofthe human body. all of those things have someerror associated with them in the way we do it now. it is small, but wedon't have it perfect.

once you have done that thoughand you actually know the exact radiation that is being absorbedby your liver and by all of your internal organs we need tobe able to figure out what biological risk that poses. so we need radiation qualityfactors that take into account the fact that one type ofparticle is much more damaging to humans than another. we need tissue weighting factorswhich take into the account the fact that one type oftissue is much more sensitive to

radiation, you are muchmore likely to get one kind of cancer than another. and we need radiationcoefficient factors to convert to risk and we need dose anddose rate reduction factors. when we test things in the labwe give it a lot of dose really quickly whereasthe gcr environment, you know as i said, you have tobe out there for quite a while before it becomes a problem, itis a much more slow dose that you are getting.

all of these we have significantuncertainty with those. so there is our problem, youknow if we don't know really reliably what that qualityfactor is how do we tell the astronauts what their riskis, and that's where that requirement that we ensure thatastronauts gets no more than a 3% risk of exposureinduced death is ensured at 95% confidence. this probability distributionfunction may or may not be confusing looking but the redline could represent our best

guess at the astronaut's risk. so, you take the bestenvironment model we can come up with, you use thebest transport codes, you use the bestmodels for the vehicle, you calculate the organ doses,you convert that to risk using the best qualityfactors you have, however, if the quality factorsare little higher this is another estimate, the qualityfactors are little lower this another, if the dose ratefactors are little higher,

so all of these black linesrepresent possible answers for the same exact mission, howmuch risk is the astronaut is really seeing. so if we want to ensure that theastronaut has no more than a 3% risk of exposure induceddeath at a 95% confidence, we have to provide shieldingthat gets us way over here on this plot, and that's wherewe end up with a mission that doesn't close. we don't know how to providethat much protection for a

three-year mission to mars andit is something we are still all actively working onas fast as we can. so, let's talk aboutshielding materials. most vehicles are made out ofsome sort of aluminum alloy, though there are a lot ofplastics involved in current vehicles in the internalstructure and of course the things you bring food, water,but anyway aluminum is not a great shielding material. these plots are effective doseto the astronaut versus shield

thickness, so you can seeyou are getting a much greater reduction in materialsthat have a hydrogen content, polyethylene, water, purehydrogen would be even better it is really hard to build avehicle out of pure hydrogen. so, anyway, one thing to noteis that materials with hydrogen provide better shieldingfor the same amount of mass. so when we can we want touse those types of materials. the other thing to note fromthis plot is you know on the left you have got one forgalactic cosmic rays and on the

right you have got onefor solar particle events. the plot on the right,this is a log scale, so as we said before, shieldingsolar particle events is much more effective, you are gettinga significant reduction in dose here by adding alittle bit of shielding. over here you are gettingmuch less reduction in dose by adding shielding. so we can prettymuch shield spes, we just need tomake sure it happens.

galactic cosmic rays isa whole another issue. the other things you see aboutthese two plots is that the plots are leveling off. add a little bit of shieldingyou are getting a good amount of reduction, then you keep addingmore and more shielding and you are getting a lotless bang for your buck. and i know you have heard theprevious speakers talk about how every pound, launchingevery pound is a problem. the goal is absolutely tominimize mass and here we are

adding more and moremass and getting very little reduction in dose. so that's our problemthat's our challenge. here are some calculationsfor how many safe days in space astronauts have before theyreach that 3% risk of exposure induced death,calculated in 95% confidence. there are some assumptionsthat went with this calculation. if you had different assumptionsyou get slightly different numbers but it givesyou a real feel for it,

in this case the astronauts werein a 20 g per centimeter squared aluminum vehicle,so think mork's egg, it was just a sphericalvehicle for these calculations. two things to note, well thebig one is that no matter what assumptions you make andwhich astronauts you send we are looking at less than a yearbefore they reach that 3% risk of exposure induced deathwith the 95% confidence. the other thing to note is thatmales can stay longer before they reach it, andthe younger people,

females or males, can staylonger than older people--the other way around,older people can stay, younger peoplehave greater risk, excuse me. right now this isthe nasa model, the 2012 model. so these are thenumbers you would use. the right hand column is a newmodel that people are looking at, basically our astronautpopulation is a very healthy

group of people. if we assume that none of themhave ever smoked which is a pretty close to real assumptionthey have a lower risk of cancer, so they couldmaybe stay a few more days, but none of these models areshowing that you can stay for three years, so againthis is our problem. so what are we going todo about the problem? well, basically we are going toattack it from every angle we can and what's not shown on herebut was mentioned at last week's

meeting for those who were here,so i want to bring it up the absolute best thing wecan do is get there faster. astronauts stay ashorter amount of time, they get lessradiation exposure, they have less risk. so if there is a propulsionbreakthrough that allows us to go to the mars and backfaster that is the best answer. and i don't have that on thesecharts because those of us in the radiation communityaren't really working on

that part of the problem. so, there are four waysthat we can attack it. the first is radiobiology andbiological counter measures. reducing that uncertaintywould definitely help. you saw how muchan affect that has. and if we can find some way togive astronaut medications or find some way to help withthat radiation that will be great too. forecasting and detection --we got to make sure those

astronauts get into shelters theminute the spes are happening. shielding materials andconfiguring vehicles better is a big part of it and there isa possibility that active shielding will bepart of our solution. so we are just working them allat the same time in trying to together come up witha solution that works. i am going to talk about theradiobiology and biological counter measures briefly andthen hand back off to dave. so, as we showed on ourprobability distribution

function we have got about450% uncertainty associated with astronaut cancer risk. so if we can reduce thatpossibly they can get more dose and still stay under that 3%risk of exposure induced death. so that is really abig, big part of our goal. we have current modelscompletely rely on atomic bomb survivor data andthat's a problem, we need more datarelated to heavy ions. we have some evidence thatheavy ions have a

different effect on humans. we are seeing earlier tumorgrowth and more aggressive tumor growth in animals that havebeen exposed to heavy ions. so this is something we arereally worried about and nasa does support an extensivebiological experiment program. as far as radio protectorsand mitigators this work is really in its infancy. and if we had this allpinned down we would have solved the cancer problem.

the nih would come to us and wecould tell them how to solve it. it is a really challengingproblem but it is being worked. couple of focuses, they arelooking at biomarkers that would predict radiation diseasesearlier so then we could get people to treatment earlierwhich might reduce the chance of dying of cancer. hopefully this will allow us toget earlier treatment and it may in the future allow usto actually do personal risk assessments.

so instead of talking aboutfemale astronauts that are 35 years old as compared to femaleastronauts that are 45 years old, we can talk about astronautdave moore and have a complete model of dave moore's body and acomplete model of dave moore's risks that includes all of hisrisk factors from his previous life experience,that's a long way off, but that is the goal. just one picture, we are reallyproud of our space radiation laboratory up at nsrl, it isa laboratory at brookhaven

national lab, so webasically partner with them, we use their beam lines butwe have our own facility on their center. brookhaven is adepartment of energy facility. so this is the beam line, youbasically accelerate particles faster and faster and then itcomes shooting down the line into our facility and we canput cell cultures in the line, we can put smallanimals in the line. problem is it is a slow process.

you saw the galactic cosmicray environment is all kinds of different particles atall different energies, you got to do one particleand one energy at a time here. so it is a bigchallenging problem, but we are working it. and i am going to pass off todave who is going to talk about engineering approaches. questions? audience: don't we havechernobyl and japanese meltdown

and 3 mile island, oris this different ions? martha: its different ions. you have the same typeof problem where you are extrapolating from a different,the question was what about data from chernobyl and the japanesemeltdown and 3 mile island, don't we have some moredata other than just atomic bomb survivor data? the answer is you have gotthe same problem with chernobyl where it is adifferent type of radiation.

you also have muchsmaller populations, especially with thejapanese situation. so we don't have a whole lotof data to build models on. you had a question...audience: active shielding, is that being and electronic,impulsive type of thing? martha: it means creating amagnetic field and dave will talk a little bitmore about that. the question was, whatis active shielding? and the answer is dave isgoing to talk about it.

audience: do we know that thereis significant bone loss during extended space travel? will the astronauts even beable to walk by the time they get to mars? martha: i don't knowthe answer to that. we do know that there issignificant bone density loss for missions and i don't knowwhere we are currently with studies about three-yearmissions and so i can't answer that one. question?

audience: would the astronauts'medical history give us a tendency towards cancer,en route to a place? martha: question is with theastronauts' medical history, with his or her tendency toget cancer enter to it at all? right now we keep track ofall of their previous exposures because we have many astronautswho go up more than once and that does enter into it. they use that to decidewhether they can fly again. we do not have, we donot use specific,

you know, your type ofgroup is more likely to get cancer than someother group, we don't, we had some evidence that womenwere more susceptible than men, we don't use that in decidingwho gets to go at this point. there is research looking atthat but we don't use that as a qualifying or adisqualifying factor. and as far asspecifically whose risk, how much risk individuals have,we are really not there with the science to be able topredict, my risk being

more or less thandave's. question? audience: you mentionedthis a couple of times; what is delta-radiation? martha: delta radiation--i amnot sure i am going to do a good job explaining it. as the particle goes through,it is basically other particles, delta rays are emitting energy,so you are passing near nucleus and it is having interactionthat's causing that particle that is coming throughto shoot off a delta ray.

audience: a differenttype radiation? martha: yes, yeah, sorry,i am not doing a great job explaining that. dave: will see they willclap when i am finished! all right, another area we areworking on integrated approach is forecasting and detection. if you can forecast the oncurrents of the events you know that gives your astronautsthat much more warning, that much more time to go seekshelter especially when an spe

is occurring, and then also weare working on capabilities to improve our detectionpossibilities, i will show you here. in the area of space weatherforecasting there is a lot of research and models being donethat we work on addressing the issue of forecasting andarrival time, when the event will actually hityou and what that dose will be and how long thatevent will occur. but that has all been upto last few years

been kind of researching. we have got an effort ongoingnow at langley to integrate that work into an operationalplatform where we can have the console operators on ground orthe astronauts that are actually in space have all thosecapability and knowledge right in front of the screen for them. it is a suite of softwarethat we put together, as you can see on thegraphic on the left, it kind of givesthem a stoplight chart,

red, green, red isbad, green is good, it can give them other featureswhere they can go in and check on the duration of the event,when it is going to arrive, how it compares to otherhistorical events that we have recorded data on. so this is some work thatwe are doing in the area of space weather. just to dig a little deeperin the clear forecasting area, we are hoping to increaseour warning time capability.

current state of theart is an hour or so. we are hoping to expand thatfrom 4- to 24-hour window and we are doing that inpartnership with noaa. the idea here, likei mentioned prior, was to give the astronauts moretime to seek shelter but also this helps in theoperations planning, say you need to go outside yourhabitat to do some maintenance or whatever, if you know thatthat day is going to be a good day to go out and do aneva this is ideal for you.

operators on ground can plana mission for the astronauts. what you see on thegraphic on the right is an image of the sun. we have numerous assetscircling the sun recording data, measuring activity and workingwith our partners at noaa we can identify the active regions andthen we take this data and run it through out analysiscodes and make these forecast predictions. an area of arrival times, we areagain working with noaa in this

area we are making use ofthe terrestrial weather, what we currently do, everybodyhere is familiar with the hurricane forecasting, we haveseen it all in the news and tv. we are following the sametype of logic in process. with modern computers youcan now do massive amounts of simulations in a short periodof time and you play with many variables and it will help youidealize when that event will hit you and occur. and you can see in the graphon the left there it is sort of

like tracking the hurricane, asthe event gets closer to land our prediction capabilities arebetter but as we extend further out our uncertainties grow, butwe are working to minimize that and i think you get the there,i mean if we can increase that arrival time estimate thatgives that astronaut just more time to seek shelter. all right, in an area ofenvironmental monitoring we have got a quite a bit of workgoing on there too now. what you see here is rem,radiation environmental monitor.

this is actually flying on iss. we have in a prior, i guess,this too is new technology within the last few years,we have been able to miniaturize it. before it wasmore breadbox size, mailbox, now we have been withimprovements in computer power been able to bring itdown to a thumb drive size. so what you see in graphics isthe thumb drive inserting into portable laptop and you see theastronaut inside one of the us

labs up in the iss. this capabilityas it progresses, we were forecasting, it willhave these embedded inside the structure of the habitat itself. so it will berealtime monitoring. it is just another way to givethe astronaut an indication of what the exposure is he iscurrently seeing and maybe some warnings, hey thingsaren't going well, so you go seek shelter.

in the area of particlespectrometer it is another detector, we just recently, ithink you are probably aware we flew the curiosity rover,it is currently up on mars. well this piece of detectiveequipment was embedded inside the rover. so this gives us realtimeestimates of what the radiation environment is on mars. but also this provided usdata on transit to mars, a flight, you are leaving earth,taking the six to nine months it

takes to get to mars, this gaveus a good understanding of what we would see, howmany spes would occur, what your daily radiationat gcr environment was. it is very low mass andlow power and it is doing a great job. we are still receiving datadaily on this that the modelers on earth can use tohelp improve their models. next, we are going to talkabout shielding materials. use of passive shielding.

martha showed a few charts aboutthe different materials and which ones are better to use. so we are trying to take thatknowledge and integrate into our future habitats and how todo a better job of providing shielding on the capsules. you can see here in thisgraphic everything is in play. if we can do a better ofthe shell structure material, instead of aluminum maybe somecomposite would be structure, maybe the secondary structurethe same way and also the

equipment that'sinside the habitat. anything to give them morehydrogen based shielding materials will improve the stayof the astronauts and give them that much better protection. another area that we are lookingat you know when we get to mars maybe we can make use of theregolith which is another fancy word for mars dirt. maybe we can make use ofthe dirt that's there, the top soil andtake our habitat,

you see on the right, weencapsulate ourselves with, put large amount of this aroundour habitat or seek a cave or a lava tube and embed your habitatin there and just take use of the surface protectionthat's available. next, we talked aboutthe passive materials, now another area and that areais configuration optimization. maybe doing a better job oflaying out your equipment, your subsystemsaround your habitat. this is an effort that has gota lot of work that is done now,

before--let meback up here a bit, you can see on theleft the habitat focus, if we just let the designerswithout radiation perspective design it you would envisionthat they would put it ergonomically like you wouldlike to setup in your office or your home, but if you have aneccentric radiation focus you are going to see like a littlein-comb fort like you would build in your parent's livingroom when you were little. so there is this dynamic thatis always going on amongst the

designers and the analyst folks. so, we have got a collaborativeeffort going now in the agency to work together. so they bring in martha into thehabitat design and try to see if we can do a better wayof placing what we have as we go up. along those lines there is aneffort i oversee at langley for designing protection systemsfor spes and we call this reconfigurable logistics.

when you are in transit to marsthere is no phone home or supply ship coming right behindyou, so you have to make use of everything you have onthat capsule at that time, that includes yourwater, your food, even your trash, i meaneverything is in play, everything has to have asecondary purpose if you are going to make use ofthe total mass to give you that protection. so you see over on yourleft slide there just

a typical cargo bag. so we worked with the peopledown at johnson in operations and said, hey how about if weadd a few zippers here and this unfolds and turnsinto a drape a curtain, so we could mount thison one of the racks, typical rack, and hang massstructure on there to provide shielding for the astronauts. just something simple, buteverything you got to think outside the box.

so what you see onyour right here, in our labs we did abunch of humans in the loop, human factor type analysis. it does us no good to come upwith shielding ideas and the astronauts say this won'twork, this is not practical. we do a lot of humans, we bringpeople in into lab there and we them a set ofinstructions, we time them, we ask them aboutthe difficulty, we do a lot of, trying tofigure if it is practical to do.

i was going to say,i am still saying, this prior to me andmartha starting the task, this is what weused to look like. much younger. another area we are lookingat is making use of water. water is a great shield. hydrogen content is high so wehave a lot of contingency water on our missions. so the idea is here, maybe wecan take that water and if we

can move it from point a overto point b in a relative bit of time we can providethat much extra protection to the astronauts. so, our team we looked atmaybe we could retrofit a crew quarters, the astronauts spenda lot of time, you now they sleep in here, thisis where they go to interact with their family, solike a little private space. so we looked at maybeadding some water bladders, what would be entailed forplumbing actuators and valves to

move water over and to providethat temporary shielding but the idea of this will be temporary,it gives them the shielding until the event passes. the event can last maybe a dayto a day and half and then we will move that water back towhere it was originally supposed to be. on the area of personalprotection we really don't have a habitat concept in place yet. everything is going that waybut we don't have a design yet.

so we were looking at whatcan we do in the meantime. so this is an area where we lookat maybe this can be portable and go to any habitat design youcome up with but also just be a personal wearable. so you could see over on theleft the astronaut candidates wearing this little vest. the idea here is you pack thisfull of polyurethane or maybe water or you can insert food,anything to give you that mass, to give you thatextra protection.

sorry, was there a question?yes sir? audience: well, there seemsthere to be no protection for many importantthings like the brain? dave: yeah, well we, thisone is designed to protect the vital organs. martha: you would probablywant a helmet to go with it in protection through the lenses,but this covers where the bone marrow is most prevalent. dave: we have done some work inthat area of giving them a cover

and all, and we have somepictures in our labs and it is very popular on the tour,everybody wants to get their picture made nextto this mannequin, but yeah, we have looked at thatand it is a difficult problem. sleeping, the astronauts whenthey sleep in space they are sleeping in what acalled a sleep restraint. it is actually mounted, velcromounted to their sleep area just so they won't floataround while they are asleep. so, we looked at areas where wecould retrofit a sleeping bag

contraption that would wraparound them and entomb them the same logic as thevest, pack it full of food, water, whatever to givethem that extra protection. all right, okay i got a moviehere that i am going to show you, this kind of bringeverything into perspective what in the prior slides iwas just showing you, but i think this willhelp explain a lot better. it is a, i willtell you a few things, i will highlight a few items.

[video presentation] dave: here is anartist rendition of warning, you seesomething occurs on sun, it gives theastronaut a realtime, got to go seek shelter, theevent is arriving and we are transitioning here, weare looking at retrofitting crew quarters. this one is thewater wall design. it is as simple asturning a valve.

in our lab actually we havelike ipads and we do it all automated, we can move it,through a suite of software we can move the water into an app. this is on lines ofreconfigurable logistics, moving mass stationed in adifferent part of the capsule or your habit over into whereyou need it to provide that temporary shelter. here is kind of an idea what'sinvolved to do that because you wouldn't want this protectionmass just sitting around,

you want it to beportable and put away. here is a visualizationof the bags, the zipper unfolding. what you see here in these whitetiles is an effort we have going on to repurpose the trash. currently as you each awaythrough the mission you have all these byproducts, the trash, sothere was an effort at johnson and ames to compact the trash,burn it and reprocess it and turn it into shielding tiles, soif you get enough of these tiles

you can get added protection,so that's the idea, you know you consume it, youreprocess it and turn it into shielding materials. we have the astronauts here,you can see they are in close quarters, we try to doublebunk them because you have limited amount of mass, so youtry to get him as tight as you can so you can get as muchshielding between them and the exposure as possible. so they will sit in this tombhere for a day and day and half,

they can go out as they needto, to check vital systems, but they will spend majorityof their bunkered-down in these little mini forts. yeah, there is no gravity. people always ask about that,do you want to be the one in the bottom or one on the top. is that a cue forme to speed up? here is the drape idea, we takeout those folding bags that can move these drapes, mounton to where they need to,

to mount for structureand shielding. everything has a dual purpose,that's the takeaway here. we try to get them todo like 30 minutes, that's one of therules, 30 minutes. the question was how quickcan they build these shelters? and we target 30 minutes. audience: what about croutons,like when you go to the store and its in something protectiveand then you eat it and then you put it back?

dave: well we take that--haveyou all ever seen space food, how it is packaged? we take thatpackage, we burn it, compact it and turn itinto those protection tiles. so everything is reused. all right, the last item i amgoing to hit on very briefly active shielding, the questionwas raised by the audience. this work is inits very infancy. there is a lot of bang for yourbuck if we could perfect it,

but there are lots ofengineering issues we have to overcome to make it work. some of the itemsare, the amount of, the size of themagnet, what's required, the power, the structure,how much they are, the mass, how do we mounton to our capsule structure, there are a lot of engineeringissues they have to overcome but the idea is surround yourselfand create an artificial magnetic field like earth hasand the idea is if the radiation

comes in it is repulsed, butthere is still a lot of work that needs to bedone on this right now. this is more research realm. all right, i thinkthat is the... audience: thesewould be electro-magnets orpermanent magnets? dave: they would be permanent.are there any questions? yes sir... audience: you discussed tinysized radiation particles.

what about moremassive particles? dave: i will have toturn that over to martha. martha: micromediatype protection, actual pieces of, that'sa whole different area. it is very important and thereis a lot of research that goes on especially at nasa langleyabout designing shields and spacing different materials sothat they slow down those types of projectiles, butthat's not our area, i guess.

audience: does mars have aprotective belt similar to our own here on earth? i think there isanother belt also on mars. dave: does mars have its ownprotective belt like earth, and the answer is no. yes sir... audience: this is sortof a basic and i think it is a two part question; my experiencewith the medical imaging community as in x-raysand so on years ago, those badges, those...

dave: the decimators? audience: yeahdecimators, its called radiants. that's changed now. again, i don't knowwhat the terminology is... and then dave, youmentioned something else. you mentioned space. that's not analogous, you saidwe had these energy ions which are different fromx-rays and gamma rays. what's the unit of measurement?

i saw the scales there, whatis the unit of measurement? martha: we still talkabout astronaut dose in terms of sievert. is that what youmean by the unit? audience: yes, sievert.do you still use that? martha: so, dose is measuredin gray which is just energy deposited per unit mass. however, there is another unit called dose equivalentwhich is

measured in sievert whichactually has a quality factor folded into it that accounts forthe risk that these particles provide to humans. so, two different types ofparticles can basically deposit the same dose but providevery different risk to humans. so we use sievert to be ameasure of how much risk the humans have. audience: so eventhough it's different, it's not analogous to thegamma ray and the x-ray,

it's still sievert, just adifferent component in it? martha: sievert is how muchdose equivalent astronauts are getting from anytype of particle. so basically you have got x-raysand gamma rays that you talk about here on earth, inspace we have charged protons, charged helium ions andthose which are primary concern. we measure astronaut riskfor many of them in terms of sievert. question? audience: how ever do youburn something in the capsule;

talking about burning the trash? dave: yes, that is one of theissues that we are trying to overcome, thebyproducts, the gases, the out gassing, yes, we havedone this on earth but it is like, before we could ever flythis on a vehicle going to mars we have to demo it inlike an iss environment, there is no way thatthey would let us do that. audience: is there any problemfrom this radiation over an extended period of timedegrading electronic

equipment and stuff? dave: yes, that's, i canbriefly talk about that. there is a big cost associatedof rad hardening electronics and equipment and that would be allconsidered in anything you fly that far away from earthand for that amount of time. yes ma'am... audience: ittakes three years to get there? dave: no, ma'am, it takes sixto nine months to get there, but we just don't want togo there and get there, we want to stay there.

audience: three years?dave: yeah, three years, yeah. audience: so, how long intotal; nine months to get there, nine months to get back? dave: and mainly a year onthe surface or around it. yes... audience: you talked interms of using water bladders and so on. and i guess i maybeanticipate something; i don't, i think you talkedabout the space vehicle itself. in some of the earlierpresentations there indicated

there is water on mars. would there be any engineeringprojections to extract some of that water? use it in a bladder system?that would be helpful. dave: the question was can wemake use of the water on the surface of mars if there isappreciable amount of it? and the answer is yes, we woulddefinitely want to use that. you saw this sketchahead with regolith, that could be some supplement,you could use water plus that.

audience: i was wondering ifsomebody was doing preliminary work on that now? martha: yeah, you also wantwater for the astronauts for any number of reasons that don'thave to do with radiation. so there have been someengineering efforts for how would you get that water. one thing is thatwater is not everywhere, so you need to either plan yourmission to be where the water is or you can't rely on it.

but there is work going on toutilize the water on the surface of mars. dave: yes sir... audience:in the bladder system, in what way is that waterchanged by the radiation? martha: almost not at all. so you asked about damageto materials from radiation, that is a very slow process. the reason humans have so muchmore of a risk is because if the particle comes in and damagesthe dna and then you get a

mutated cell and thatmutated cell propagates you can have cancer. if a particle comes through anddamages one hydrogen atom within the water you have adamaged hydrogen atom, but it doesn't have a wayto propagate that damage through it. so you would need waymore radiation than we are seeing in space. dave: and i will answer thenext question before it comes.

the same answer for food.i get asked that a lot. yes ma'am... audience:three years is a long time. what provisions are youmaking in case of a failure during that time? dave: that's not an option.failure is not an option. i don't know theanswer to that one. audience: you just burn it? dave: yeah, yeah,reuse them as shielding. you get the point.

yes sir, in the back...audience: two part question. one, are there any unusualradiation events that you have detected from thesensors that are on mars now? they repeat thatinformation back to earth. and the second question; whatabout this medical attention i am seeing on this chart? what type of attentionare we talking about? dave: i can answer the firstquestion and i will turn the second one over.

the first question was when weflew the mission to mars with the rover what did we see? i think we saw eitherthree or four spes, the events that we candesign and shield against. so that was great knowledge. i mean we did not, that was thebest we have had to date what an actual transit tomars would look like. so that was great knowledgeand about the medical question, martha: i don't reallyhave an answer either.

so the question was what can wedo in terms of providing medical attention to help astronauts whohave been exposed to radiation, and we have an ongoing researchproject looking at those. again, you are sort ofbordering on can we cure cancer, if we figure this out we willhave solved lots of problems, they are researchingantioxidants which you probably have read in anynumber of magazines, might improve your risk ofgetting cancer on earth. but they are also looking atways to basically tell the cell

it is being damaged. so basically tell the cellto go ahead and kill itself, rather than propagating. but all of thatreally is at its infancy. we are working it, but rightnow we don't have good counter measures for space radiation. dave: yes ma'am... audience: to go back toyour question about dying in space, i yesterdaymorning discovered a youtube

channel called ask a mortician,and that was the first question that was asked onask a mortician. dave: can i giveyou the microphone! martha: okay,regarding dying in space, yesterday morning i went onlineand logged into a website on youtube called ask a mortician. it is real, it is conductedby licensed morticians. and that was the first questionthat i encountered on there. and in essence the body could beejected into space and would be

frozen and there is a wholeexplanation as to orbiting and entering differentgravitational fields, but should you comeback to the planet earth, the mortician said thebody will enter at 17,000 plus miles per hour andbecause it doesn't have a heat shield will be super-crematedwhen it hits our atmosphere. but i would adviceyou to check into that, ask a mortician. dave: thank you.

audience: i'm sorry. dave: yes, next nasa employee. yes sir... audience: is thereenough known about the water on mars to know what theisotonic composition is? dave: i don't thinkthat we know that yet. that question was do weknow the composition of the water on mars. martha: i don't think weknow the answer to that. i think we believe that itis similar to here on earth.

they actually have twokinds of ice on mars, they have co2 iceand they have water, h2o ice, and the h2o iceshould be similar to what we have here we think. audience: seems like wecould check the compound counts. martha: yeah, i don't know. audience: i believe one of theother presenters said the mars water, not the co2, wassimilar to earth water. martha: i think that'swhat last week's

presenter said, but yeah. dave: any other? yes ma'am... audience: um,one i had heard that another space craft,nathan, is... dave: maven? audience: yes, it hadrecently reached mars? sounded like itwas working on mars. um, i assume that was beinghelpful for you as far as how the atmosphere?

dave: help me out steve, youknow what's on maven? steve: maven is designedto help us understand why marslost its atmosphere. so it is going to study thecomposition of the atmosphere that is being torn away frommars all the time at this point. audience: we're all exhausted! dave: is that it? those were somevery good questions. thank you all very much.

steve: yeah, those weregreat questions. i am thinking about how to getyour guys on our design team so that we can, i know a lot ofyou actually worked at nasa, so of course wewant you guys back. i hope that the last five weekshave given you a sense of the excitement of the space programthat we could have and given you sort of brought you upto data in where we are. i also hope that it gave you agood sense of how hard it is to do what we are trying to do.

i think that, i just wantto reiterate the importance of that fact. kennedy actually said thiswhen he kicked off the apollo program, he said, "we do thisbecause it is hard." and it kind of sounds like asimple statement, but because of the difficulty ofwhat we are trying to do we are going to reap tremendousbenefits across many different aspects of the societyfrom geopolitical, to economic, to social benefitsand that's the payoff of what we

do in the space program. and as we talked about lastspring that payoff is well over 100% and very low risk. we know from history that we getthat payoff when we invest in the space program. i hope that you have enjoyed itand we really appreciated your interest and the questions andinteracting with you over the past five weeks.thank you. [applause]

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