Space

May 15, 2013

NASA probe counts space rock impacts on Mars

nasa-mars
Scientists using images from NASA’s Mars Reconnaissance Orbiter 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 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.

 




All of this week's top headlines to your email every Friday.


 
 

 

Headlines February 25, 2015

News: Army to send headquarters group to Kandahar in first sign of revision to Afghan withdrawal plan - In the first official sign that the Pentagon plans to keep a U.S. military presence in southern Afghanistan after this year, the Army is sending the 7th Infantry Division headquarters from Joint Base Lewis-McChord on a year-long deployment...
 
 

News Briefs February 25, 2015

Lithuania restores compulsory military service Lithuania will restore compulsory military service for young men as tensions in Ukraine continue to worry the small Baltic nation, the government said Feb. 24. After a meeting of military leaders and top government officials, President Dalia Grybauskaite said the measure was necessary because of growing aggression in Ukraine. Military...
 
 
Sensor Concepts Inc. photograph

Air Force Research Labís handheld imaging tool expands aircraft inspection capability

Sensor Concepts Inc. photograph An operator demonstrates the portability of the handheld imaging tool. The technology provides maintainers the ability to evaluate aircraft in the field to ensure mission-readiness. When pilots c...
 

 

Boeing, Royal Australian Air Force test extended range weapon

The Boeing Joint Direct Attack Munition Extended Range demonstrated significant range increase while maintaining its expected accuracy during flight testing conducted by Boeing and the Royal Australian Air Force. The testing centered on a new wing kit that, when used in conjunction with the weaponís guidance kit, increases the bomb’s range from approximately 15 miles...
 
 

DRS Technologies to provide comm systems for Royal New Zealand Navy frigates

DRS Technologies Inc., a Finmeccanica Company, announced Feb. 25 that its Canadian subsidiary will be providing tactical integrated communications systems to the New Zealand Ministry of Defense for the Royal New Zealand Navy’s ANZAC-class frigates. This subcontract was awarded to DRS Technologies Canada Ltd. in support of a communications modernization contract from Lockheed Martin Canada...
 
 

Northrop Grumman LITENING achieves two million operating hour milestone

In the life cycle of every military system, some milestones stand out as signature achievements. One million operating hours is one of them – and Northrop Grumman’s fielded AN/AAQ-28(V) LITENING pods have hit that number for the second time. “This is a significant milestone for the LITENING program and our team is proud to be...
 




0 Comments


Be the first to comment!


Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>