May 15 2013

From The Space Library

RELEASE: 13-142 - NASA PROBE COUNTS SPACE ROCK IMPACTS ON MARS --WASHINGTON -- Scientists using images from NASA's Mars Reconnaissance Orbiter (MRO) have estimated that the planet is bombarded by more than 200 small asteroids or bits of comets per year forming craters at least 12.8 feet (3.9 meters) across. Researchers have identified 248 new impact sites on parts of the Martian surface in the past decade, using images from the spacecraft to determine when the craters appeared. The 200-per-year planetwide estimate is a calculation based on the number found in a systematic survey of a portion of the planet. MRO's High Resolution Imaging Science Experiment (HiRISE) camera took pictures of the fresh craters at sites where before-and-after images by other cameras bracketed when the impacts occurred. This combination provided a new way to make direct measurements of the impact rate on Mars. This will lead to better age estimates of recent features on Mars, some of which may have been the result of climate change. It's exciting to find these new craters right after they form, said Ingrid Daubar of the University of Arizona, Tucson, lead author of the paper published online this month by the journal Icarus. "It reminds you Mars is an active planet, and we can study processes that are happening today." These asteroids or comet fragments typically are no more than 3 to 6 feet (1 to 2 meters) in diameter. Space rocks too small to reach the ground on Earth cause craters on Mars because the Red Planet has a much thinner atmosphere. HiRISE targeted places where dark spots had appeared during the time between images taken by the spacecraft's Context Camera (CTX) or cameras on other orbiters. The new estimate of cratering rate is based on a portion of the 248 new craters detected. If comes from a systematic check of a dusty fraction of the planet with CTX since late 2006. The impacts disturb the dust, creating noticeable blast zones. In this part of the research, 44 fresh impact sites were identified. The meteor over Chelyabinsk, Russia, in February was about 10 times bigger than the objects that dug the fresh Martian craters. Estimates of the rate at which new craters appear serve as scientists' best yardstick for estimating the ages of exposed landscape surfaces on Mars and other worlds. Daubar and co-authors calculated a rate for how frequently new craters at least 12.8 feet (3.9 meters) in diameter are excavated. The rate is equivalent to an average of one each year on each area of the Martian surface roughly the size of the U.S. state of Texas. Earlier estimates pegged the cratering rate at three to 10 times more craters per year. They were based on studies of craters on the moon and the ages of lunar rocks collected during NASA's Apollo missions in the late 1960s and early 1970s. Mars now has the best-known current rate of cratering in the solar system, said HiRISE Principal Investigator Alfred McEwen of the University of Arizona, a co-author on the paper. MRO has been examining Mars with six instruments since 2006. The longevity of this mission is providing wonderful opportunities for investigating changes on Mars, said MRO Deputy Project Scientist Leslie Tamppari of NASA's Jet Propulsion Laboratory, Pasadena, Calif. The University of Arizona Lunar and Planetary Laboratory operates the HiRISE camera, which was built by Ball Aerospace & Technologies Corp. of Boulder, Colo. Malin Space Science Systems of San Diego built and operates the Context Camera. JPL manages the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate in Washington. Lockheed Martin Space Systems of Denver, built the orbiter.

RELEASE: 13-143 - SIERRA NEVADA CORPORATION DREAM CHASER TESTING BEGINS AT NASA DRYDEN, LANGLEY --EDWARDS, Calif. -- Sierra Nevada Corporation's (SNC) Space Systems Dream Chaser flight vehicle arrived at NASA's Dryden Flight Research Center in Edwards, Calif., Wednesday to begin tests of its flight and runway landing systems. The tests are part of pre-negotiated, paid-for-performance milestones with NASA's Commercial Crew Program (CCP), which is facilitating U.S.-led companies' development of spacecraft and rockets that can launch from American soil. The overall goal of CCP is to achieve safe, reliable and cost-effective U.S. human access to and from the International Space Station and low-Earth orbit. Tests at Dryden will include tow, captive-carry and free-flight tests of the Dream Chaser. A truck will tow the craft down a runway to validate performance of the nose strut, brakes and tires. The captive-carry flights will further examine the loads it will encounter during flight as it is carried by an Erickson Skycrane helicopter. The free flight later this year will test Dream Chaser's aerodynamics through landing. Meanwhile, on the east coast, several NASA astronauts will be at the agency's Langley Research Center in Hampton, Va., this week to fly simulations of a Dream Chaser approach and landing to help evaluate the spacecraft's subsonic handling. The test will measure how well the spacecraft would handle in a number of different atmospheric conditions and assess its guidance and navigation performance. Unique public-private partnerships like the one between NASA and Sierra Nevada Corporation are creating an industry capable of building the next generation of rockets and spacecraft that will carry U.S. astronauts to the scientific proving ground of low-Earth orbit, said William Gerstenmaier, NASA's associate administrator for human exploration and operations in Washington. "NASA centers around the country paved the way for 50 years of American human spaceflight, and they're actively working with our partners to test innovative commercial space systems that will continue to ensure American leadership in exploration and discovery." The Dream Chaser Space System is based on Langley's Horizontal Lander HL-20 lifting body design concept. The design builds on years of analysis and wind tunnel testing by Langley engineers during the 1980s and 1990s. Langley and SNC joined forces six years ago to update the HL-20 design in the Dream Chaser orbital crew vehicle. In those years SNC has worked with the center to refine the spacecraft design. SNC will continue to test models in Langley wind tunnels. Langley researchers also helped develop a cockpit simulator at SNC's facility in Louisville, Colo., and the flight simulations being assessed at the center. NASA is partnered with SNC, Space Exploration Technologies (SpaceX) and The Boeing Company to meet CCP milestones for integrated crew transportation systems under the Commercial Crew Integrated Capability (CCiCap) initiative. Advances made by these companies under their funded Space Act Agreements ultimately are intended to lead to the availability of commercial human spaceflight services for government and commercial companies. While NASA works with U.S. industry partners to develop commercial spaceflight capabilities, the agency also is developing the Orion spacecraft and the Space Launch System (SLS), a crew capsule and heavy-lift rocket to provide an entirely new capability for human exploration. Designed to be flexible for launching spacecraft for crew and cargo missions, SLS and Orion will expand human presence beyond low-Earth orbit and enable new missions of exploration in the solar system.

MEDIA ADVISORY: M13-077 - DEPUTY ADMINISTRATOR TOURS NASA'S NORTHEAST OHIO FACILITIES, MEETS MEDIA THURSDAY --CLEVELAND -- Media representatives are invited to join NASA Deputy Administrator Lori Garver as she visits the agency's Glenn Research Center in Cleveland on Thursday, May 16 and tours facilities advancing future spaceflight missions. The locations include Lewis Field and the Plum Brook Station in Sandusky, Ohio. Garver will tour several facilities at Lewis Field beginning at 12:15 p.m. EDT. She will get updates on the work being done in additive manufacturing and cryogenic propellant systems for future extended missions in space and to advance solar electric propulsion technologies for asteroid exploration. At 3:15 p.m., Garver tours the Spacecraft Propulsion Research Facility, the Space Power Facility at Plum Brook Station and the newly-built Reverberant Acoustic Test Facility.

MEDIA ADVISORY: M13-078 - NASA HOSTS KEPLER SPACECRAFT STATUS TELECONFERENCE TODAY --WASHINGTON -- NASA will host a news teleconference at 4 p.m. EDT, today, May 15, to discuss the status of the agency's Kepler Space Telescope. Kepler is the first NASA mission capable of finding Earth-size planets in or near the habitable zone, which is the range of distance from a star where the surface temperature of an orbiting planet might be suitable for liquid water. Launched in 2009, Kepler has been detecting planets and planet candidates with a wide range of sizes and orbital distances to help scientists better understand our place in the galaxy. The briefing participants are: -- John Grunsfeld, associate administrator, Science Mission Directorate, NASA Headquarters, Washington -- Paul Hertz, astrophysics director, NASA Headquarters, Washington -- William Borucki, Kepler science principal investigator, Ames Research Center, Calif. -- Charles Sobeck, deputy project manager, Ames Research Center, Calif.