The International Space Station. Credit: NASA
Sunday, January 13, 2013
THE IION THRUSTER
FROM: U.S. DEPARTMENT OF DEFENSE
by jtozer
Saturday Space Sight: Ion Thruster Sets World Record
While the Dawn spacecraftis visiting the asteroids Vesta and Ceres, NASA Glenn has been developing the next generation of ion thrusters for future missions. NASA's Evolutionar Xeon Thruster (NEXT) Project has developed a 7-kilowatt ion thruster that can provide the capabilities needed in the future.
An ion thruster produces small levels of thrust relative to chemical thrusters, but does so at higher specific impulse (or higher exhaust velocities), which means that an ion thruster has a fuel efficiency of 10-12 times greater than a chemical thruster.
The higher the rocket’s specific impulse (fuel efficiency), the farther the spacecraft can go with a given amount of fuel.
Given that an ion thruster produces small levels of thrust relative to chemical thrusters, it needs to operate in excess of 10,000 hours to slowly accelerate the spacecraft to speeds necessary to reach the asteroid belt or beyond.
The NEXT ion thruster has been operated for over 43,000 hours, which for rocket scientists means that the thruster has processed over 770 kilograms of xenon propellant and can provide 30 million-newton-seconds of total impulse to the spacecraft. This demonstrated performance permits future science spacecraft to travel to varied destinations, such as extended tours of multi-asteroids, comets, and outer planets and their moons.
Photo Credit: NASA
Saturday, January 12, 2013
THE MARTIAN MOUNTAIN WINDS
FROM: NASAMountain Winds at Gale Crater
This graphic shows the pattern of winds predicted to be swirling around and inside Gale Crater, which is where NASA's Curiosity rover landed on Mars. Modeling the winds gives scientists a context for the data from Curiosity's Rover Environmental Monitoring Station (REMS).
Curiosity's current location is marked with an "X." The rover's setting within a broad depression between the mountain dubbed "Mount Sharp" to the southeast and the rim of Gale Crater to the northwest strongly affects wind measurements collected by REMS.
This snapshot shows midday conditions. In the daytime, winds rise out of the crater, shown by the red arrows, and up the mountain, shown by the yellow arrows. Blue arrows indicate winds that flow along the depression and seem, to Curiosity, to be coming up out of the depression since Curiosity is near the bottom. At its current location, Curiosity may be seeing a mixture of these winds, making it challenging to understand its weather readings.
The patterns reverse in the evening and overnight, when winds flow in the downhill direction.
The background image is an oblique view of Gale Crater, looking toward the southeast. It is an artist's impression using two-fold vertical exaggeration to emphasize the area's topography. The crater's diameter is 96 miles (154 kilometers).
The image combines elevation data from the High Resolution Stereo Camera on the European Space Agency's Mars Express orbiter, image data from the Context Camera on NASA's Mars Reconnaissance Orbiter, and color information from Viking Orbiter imagery.
Image credit: NASA/JPL-Caltech/ESA/DLR/FU Berlin/MSSS
Thursday, January 10, 2013
Wednesday, January 9, 2013
Tuesday, January 8, 2013
Sunday, January 6, 2013
ROVER SELF-PORTRAIT
FROM: NASA
Curiosity Self-Portrait, Wide View
On the 84th and 85th Martian days of the NASA Mars rover Curiosity's mission on Mars (Oct. 31 and Nov. 1, 2012), NASA's Curiosity rover used the Mars Hand Lens Imager (MAHLI) to capture dozens of high-resolution images to be combined into self-portrait images of the rover.
The mosaic shows the rover at "Rocknest," the spot in Gale Crater where the mission's first scoop sampling took place. Four scoop scars can be seen in the regolith in front of the rover. A fifth scoop was collected later.
Self-portraits like this one document the state of the rover and allow mission engineers to track changes over time, such as dust accumulation and wheel wear. Due to its location on the end of the robotic arm, only MAHLI (among the rover's 17 cameras) is able to image some parts of the craft, including the port-side wheels.
Image Credit: NASA/JPL-Caltech/MSSS
Saturday, January 5, 2013
THE DIRT ON MARS
FROM: NASA
A Sampling of Martian Soils
This collage shows the variety of soils found at landing sites on Mars. The elemental composition of the typical, reddish soils were investigated by NASA's Viking, Pathfinder and Mars Exploration Rover missions, and now with the Curiosity rover, using X-ray spectroscopy. The investigations found similar soil at all landing sites. In addition, the soil was usually unchanged over the traverse across the Martian terrain made by both Mars Exploration Rovers.
The Mars Exploration Rover Spirit's landing region in Gusev Crater is seen in both pictures at top; Viking's landing site is shown at lower left; and a close-up of Curiosity's Gale Crater soil target called "Portage" is at lower right.
In Gusev Crater, several white subsurface deposits were excavated with Spirit’s wheels and found to be either silica-rich or hydrated ferric sulfates.
Image credit-NASA-JPL-Caltech
Monday, December 31, 2012
EARTH AT NIGHT
FROM: NASA
This view of Earth at night is a cloud-free view from space as acquired by the Suomi National Polar-orbiting Partnership Satellite. A joint program by NASA and NOAA, Suomi NPP captured this nighttime image by the day-night band of the satellite's Visible Infrared Imaging Radiometer Suite VIIRS. It combines the Earth at night view created by NASA's Earth Observatory with data processed by NOAA's National Geophysical Data Center with the EO Blue Marble: Next Generation.
Credit-NASA Goddard-NASA's Earth Observatory-NOAA-DOD
Sunday, December 30, 2012
NEW ION THRUSTERS MAY TAKE US TO THE EDGE OF THE SOLAR SYSTEM
FROM: NASA
While the Dawn spacecraft is visiting the asteroids Vesta and Ceres, NASA Glenn has been developing the next generation of ion thrusters for future missions. NASA's Evolutionary Xenon Thruster (NEXT) Project has developed a 7-kilowatt ion thruster that can provide the capabilities needed in the future. An ion thruster produces small levels of thrust relative to chemical thrusters, but does so at higher specific impulse (or higher exhaust velocities), which means that an ion thruster has a fuel efficiency of 10-12 times greater than a chemical thruster. The higher the rocket's specific impulse (fuel efficiency), the farther the spacecraft can go with a given amount of fuel. Given that an ion thruster produces small levels of thrust relative to chemical thrusters, it needs to operate in excess of 10,000 hours to slowly accelerate the spacecraft to speeds necessary to reach the asteroid belt or beyond. The NEXT ion thruster has been operated for over 43,000 hours, which for rocket scientists means that the thruster has processed over 770 kilograms of xenon propellant and can provide 30 million-newton-seconds of total impulse to the spacecraft. This demonstrated performance permits future science spacecraft to travel to varied destinations, such as extended tours of multi-asteroids, comets, and outer planets and their moons. Image Credit: NASA
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