J Radiat Res. 2004 Mar;45(1):1-9.De Angelis G1, Anderson BM, Atwell W, Nealy JE, Qualls GD, Wilson JW.Author information1Old Dominion University, Norfolk, VA 23508-0369, USA. g.deangelis@larc.nasa.gov2NASA LaRCAbstractOngoing assembly and maintenance activities at the International Space Station (ISS) require much more extravehicular activity (EVA) than did the earlier U.S. Space Shuttle missions. It is thus desirable to determine and analyze, and possibly foresee, as accurately as possible what radiation exposures crew members involved in EVAs will experience in order to minimize risks and to establish exposure limits that must not to be exceeded. A detailed CAD model of the U.S. Space Shuttle EVA Spacesuit, developed at NASA Langley Research Center (LaRC), is used to represent the directional shielding of an astronaut; it has detailed helmet and backpack structures, hard upper torso, and multilayer space suit fabric material. The NASA Computerized Anatomical Male and Female (CAM and CAF) models are used in conjunction with the space suit CAD model for dose evaluation within the human body.

The particle environments are taken from the orbit-averaged NASA AP8 and AE8 models at solar cycle maxima and minima. The transport of energetic particles through space suit materials and body tissue is calculated by using the NASA LaRC HZETRN code for hadrons and a recently developed deterministic transport code, ELTRN, for electrons. The doses within the CAM and CAF models are determined from energy deposition at given target points along 968 directional rays convergent on the points and are evaluated for several points on the skin and within the body. Dosimetric quantities include contributions from primary protons, light ions, and electrons, as well as from secondary brehmsstrahlung and target fragments. Directional dose patterns are displayed as rays and on spherical surfaces by the use of a color relative intensity representation.PMID: 15133283 [PubMed - indexed for MEDLINE] MeSH TermsAstronautsComputer SimulationComputer-Aided DesignCosmic RadiationEquipment Failure Analysis/methods*Extravehicular Activity*FemaleHumansLinear Energy TransferMaleModels, Biological*Occupational Exposure/analysis*Radiation DosageRadiation Protection/instrumentationRadiation Protection/methodsRadiometry/methods*Space Suits*Full Text SourcesJ-STAGE, Japan Science and Technology Information Aggregator, ElectronicMedical Online, Meteo Inc - PDFMedicalOccupational Health - MedlinePlus Health InformationMiscellaneousNCI CPTAC Assay PortalNCI CPTAC Assay Portal

I wish hitchhiking – and picking up hitchhikers – wasn’t so taboo. I quite like giving fellow travelers a lift. Over my past seven years living on the road, I’ve picked up all manner of hitchhikers – men and women, young and old – and I’ve met a lot of great people and never once had a problem. When you do somebody a kindness by giving them a lift and a snack (one of my hitchhiker hostessing tips), I’ve found they’re kind, polite and grateful in return. On Sunday, when I returned to the trailhead after my 8-mile hike to Joeffre Lakes, a guy was thumbing a ride from the side of the road above the parking lot. He was young, reasonably well-kempt, heading my direction and not having any luck. So I waved him over and offered him a sandwich and a lift. Over PB&J’s, Nate told me he was on break from University, where he studies Mandarin and Korean, on his way home to Ontario after thumbing all the way across Canada to take a swim in the Pacific. I put Nate in charge of the ipod – he played Garth Brooks and then the Dirty Dancing soundtrack, making him one of my all-time favorite road trip DJ’s – and we spent the next three hours singing along (Nate made it to the second round of Canadian Idol last year), talking about the lure of travel, the meaning of life and marveling in comfortable silence at the endless natural wonders of British Columbia.

Nate soon confessed that before this trip, he had never once left his home province. After a week on the road, the travel bug had bitten him hard and he was overwhelmed by the sheer scale and beauty of the world and enamored by the kindness of strangers, who had driven him along every spectacular mile. “I don’t know how I’m supposed to stay home after this,” he said, grinning. When I stopped in Lillooet to get a few groceries, Nate got out of the car, but didn’t follow me inside. laptop bags chadstoneDon’t you need anything? costco dslr backpackHe shook his head and I asked if he wanted to wait in the car and he shrugged and said, “I can wait out here. backpack zakmesSee what I mean? boysenberry laptop backpack

Hitchhikers have excellent manners. Nate and I parted ways near 100 Mile House – he was heading east, I was heading north – and we shook hands and wished each other the best of luck. Shouldering his enormous bright yellow backpack, Nate placed his hand over his heart, where I had signed his souvenir travel t-shirt, and said “Mary, thank you, for everything. I’ve had the time of my life.” I’m glad I had my delightful Canadian hitchhiker adventure when I did, because not long after I dropped Nate off at the intersection of highways 97 and 24, I started seeing missing person posters that hit me hard.backpack zuid oost azie Last summer, when I first started talking about a trip to Alaska, a worried friend sent me a link to a scary story about a girl who had disappeared near Vanderhoof, British Columbia. backpacker derawan island

On May 27th, 2011 20 year old Madison Scott was celebrating high school graduation with a bunch of friends at Hogsback Lake. The next morning, after everybody packed up, her tent was still standing in the campground, apparently unused. Maddie has not been seen since, despite exhaustive searches, ubiquitous missing person posters and a $100,000 reward. Maddy’s disappearance is made even more chilling by a long standing pattern of missing women along the Yellowhead Highway, which runs through Vanderhoof between Prince George and Prince Rupert. ems 5500 backpackOver the past 30 years, between 18 and 43 women, depending on whom you ask, have vanished or been found murdered along this stretch of highway 16. Many of the missing women were last seen hitchhiking and there are enough similarities between the cases that authorities suspect they’re dealing with at least one serial killer and possibly several copycats.

Last summer, reading that story gave me pause about driving solo through British Columbia. I have great faith in my fellow man and have always had tremendous fortune when traveling, but I am not immune to scary stories, especially when they are true. Of course, in all my excitement about road tripping through unexplored territory to my 50th state, I completely forgot about the Highway of Tears, until I started seeing Maddy’s face on billboards, gas pumps and bumper stickers. I didn’t pick up any hitchhikers along the Yellowhead Highway. If I had seen a woman thumbing a ride, I might have given her a lift. But it seems all the ominous billboards are working. In 500 miles, the only person I saw thumbing a ride was a middle aged Native man, going the other direction. Giving and getting rides should not be so dangerous. In most cases and places, I would argue that it’s not. When I told Nate I was an American he asked, “Is it true that hitchhiking in America will get you killed?”