The High Resolution Imaging Science Experiment (HiRISE) camera aboard NASA’s Mars Reconnaissance Orbiter often takes images of Martian sand dunes to study the mobile soils. These images provide information about erosion and movement of surface material, about wind and weather patterns, even about the soil grains and grain sizes. via NASA http://ift.tt/1Meslre

As NASA missions to Mars progress with science and complex human exploration missions, spacecraft will require larger heat shields to protect against the extreme heat of entering a planet’s atmosphere and decelerating at a safe altitude in the thin Martian atmosphere. via NASA http://ift.tt/1FRPRxG

The Space Shuttle Challenger launches from Florida at dawn. On this mission, Kathryn Sullivan became the first U.S. woman to perform a spacewalk and Marc Garneau became the first Canadian in space. The crew of seven was the largest to fly on a spacecraft at that time, and STS-41G was the first flight to include two female astronauts. via NASA http://ift.tt/1iZTMh2

NASA Astronaut Scott Kelly captured this photo on Oct. 2, 2015, from the International Space Station and wrote on Twitter, “Early morning shot of Hurricane #‎Joaquin‬ from @space_station before reaching ‪#‎Bahamas‬. Hope all is safe. #‎YearInSpace‬.” via NASA http://ift.tt/1VuP879

NASA’s New Horizons spacecraft captured this high-resolution enhanced color view of Charon just before closest approach on July 14, 2015. The image combines blue, red and infrared images taken by the spacecraft’s Ralph/Multispectral Visual Imaging Camera (MVIC); the colors are processed to best highlight the variation of surface properties. via NASA http://ift.tt/1JGKP1O

Galaxy clusters are often described by superlatives. After all, they are huge conglomerations of galaxies, hot gas, and dark matter and represent the largest structures in the Universe held together by gravity. via NASA http://ift.tt/1O1Z0os

Dark narrow streaks, called “recurring slope lineae,” emanate from the walls of Garni Crater on Mars, in this view constructed from observations by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA’s Mars Reconnaissance Orbiter. via NASA http://ift.tt/1jrr9db

A perigee full moon, or supermoon, is seen behind the Washington Monument during a total lunar eclipse on Sunday, September 27, 2015, in Washington, DC. The combination of a supermoon and total lunar eclipse last occurred in 1982 and will not happen again until 2033. via NASA http://ift.tt/1KK3rig

A perigee full moon, or supermoon, is seen next to the Empire State Building at the beginning of a total lunar eclipse, Sunday, Sept. 27, 2015 in New York City. The combination of a supermoon and total lunar eclipse last occurred in 1982 and will not happen again until 2033. via NASA http://ift.tt/1O4Jeup

NASA astronaut Scott Kelly, recently past the halfway mark of his one-year mission to the International Space Station, photographed the Nile River during a nighttime flyover on Sept. 22, 2015. Kelly (@StationCDRKelly) wrote, “Day 179. The #Nile at night is a beautiful sight for these sore eyes. Good night from @space_station! #YearInSpace.” via NASA http://ift.tt/1FlJwu7