Going To Mercury? Don't Leave Home Without A NIST Calibration

INNER PLANETS

Mercury illustration

Gaithersburg MD (SPX) Aug 20, 2004
The first spacecraft intended to orbit Mercury was launched on Aug. 3, 2004, carrying an instrument for mapping the composition of the planet's crust that was calibrated with a novel procedure at the National Institute of Standards and Technology (NIST).

The procedure, using NIST-produced, high-energy gamma rays, enabled the device to be prepared for the same intense radiation levels typically produced in outer space.

Mercury is a rocky planet like the Earth but smaller, denser and with an older surface. Scientists believe that by studying Mercury they can develop a better understanding of how the Earth formed, evolved and interacts with the Sun.

Scheduled to orbit Mercury in 2011, the National Aeronautics and Space Administration's (NASA) Messenger (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) spacecraft carries seven scientific instruments, including a detector that will measure gamma rays emitted by Mercury's crust as it is bombarded by cosmic rays.

The bombardment releases neutrons, which react with the elements in the crust; analysis of the resulting gamma rays will help identify the elements.

The detector's efficiency (the fraction of incoming gamma rays detected) needed to be calibrated based on the gamma-ray energy for 37 different orientation angles associated with the orbits around the planet.

Typical gamma ray sources, such as those used for medical treatments, emit at lower energy levels than those needed for the calibration.

NIST scientists, in collaboration with the mission's prime contractor, the Johns Hopkins University Applied Physics Laboratory, solved the calibration problem by using a high-intensity neutron beam to irradiate targets made of sodium chloride and chromium.

The targets captured neutrons and emitted gamma rays, which were measured by Messenger's gamma-ray detector. These gamma rays spanned the energy range that will be measured in the planetary assay.

According to Johns Hopkins' Edgar A. Rhodes - lead scientist for the Messenger instrument - the calibration procedure "will likely set a new standard for space-flight gamma-ray spectrometers."

INNER PLANETS

The Long and Winding Road

Kennedy Space Center FL (SPX) Aug 04, 2004
Point your spacecraft in the right direction to pass by the planet as it orbits the Sun, and get whatever information you can during the high-speed rendezvous. That was NASA's strategy during the early days of Solar System exploration, and it provided us with an incredible amount of insight into our universe.

Thanks for being here; We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain. With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords. Our news coverage takes time and effort to publish 365 days a year. If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Contributor $5 Billed Once credit card or paypal		SpaceDaily Monthly Supporter $5 Billed Monthly paypal only

The content herein, unless otherwise known to be public domain, are Copyright 1995-2016 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.