Subscribe free to our newsletters via your
. 24/7 Space News .

MESSENGER Adjusts Orbit for a Closer Look at Mercury
by Staff Writers
Laurel MD (SPX) Apr 19, 2012

After Friday's maneuver, the 8-hour orbit will remain highly eccentric, with MESSENGER travelling between 278 kilometers (172 miles) and 10,314 kilometers (6,409 miles) above Mercury's surface.

The MESSENGER mission successfully completed the first of two maneuvers designed to reduce the spacecraft's orbital period about Mercury. This new trajectory will pave the way for more detailed measurements and targeted observations of the Sun's closest neighbor.

The spacecraft was 124 million kilometers (77 million miles) from Earth when the 188-second maneuver began at 3:13 p.m. EDT. Mission controllers at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md., verified the start of the maneuver 6 minutes and 53 seconds later, when the first signals indicating spacecraft thruster activity reached NASA's Deep Space Network tracking station in Goldstone, Calif.

This maneuver - which adjusted the orbital period from 11 hours, 36 minutes to 9 hours, 5 minutes - was designed to deplete the remaining oxidizer of the spacecraft's propulsion system in a final firing of the large bi-propellant thruster.

A second maneuver, scheduled for the evening of April 20, will use the spacecraft's monopropellant system to complete the transition to an 8-hour orbit.

The strategy to complete this transition involves the execution by the MESSENGER flight team of carefully planned command sequences, says MESSENGER Mission Design Lead James McAdams of APL.

"The first orbit-correction maneuver consumed the remaining oxidizer, which is one of two propellants used for the higher-efficiency large thruster," he explains. Although such an "oxidizer depletion" maneuver is not uncommon, new procedures had to be developed and tested to make this MESSENGER critical event possible and safe to perform.

After Friday's maneuver, the 8-hour orbit will remain highly eccentric, with MESSENGER travelling between 278 kilometers (172 miles) and 10,314 kilometers (6,409 miles) above Mercury's surface.

Reducing the orbital period will increase from two to three the number of revolutions the spacecraft will make about the planet each day, increasing the time that the spacecraft will spend closer to the surface, says MESSENGER Mission Systems Engineer Eric Finnegan, of APL.

The additional time at lower altitude, he says, will enhance the science return. It will amplify the effectiveness of the high-energy spectrometers used to determine the composition of the planet's surface and will increase the number of altitude profiles that the laser altimeter will be able to make in the northern hemisphere of the planet, allowing for more detailed topographic maps.

Operations at this lower altitude will also enable higher-resolution imaging of Mercury's southern hemisphere.

"The MESSENGER engineering and operations teams have once again made a critical maneuver look easy," says MESSENGER Principal Investigator Sean C. Solomon, of the Carnegie Institution of Washington.

"The Science Team is now looking forward to being able to address a host of scientific questions on the composition, geological evolution, and environment of Mercury that have been raised by earlier orbital observations. With our new orbit, it feels as though we're embarking on a new mission."


Related Links
News Flash at Mercury
Mars News and Information at
Lunar Dreams and more

Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks DiggDigg RedditReddit GoogleGoogle

Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News

Data from MESSENGER spacecraft reveals new insights on planet Mercury
Santa Barbara CA (SPX) Mar 23, 2012
Thanks to the MESSENGER spacecraft, and a mission that took more than 10 years to complete, scientists now have a good picture of the solar system's innermost planet. On March 17, MESSENGER (MErcury Surface, Space Environment, GEochemistry, and Ranging) completed its one-year primary mission, orbiting Mercury, capturing nearly 100,000 images, and recording data that reveals new information ... read more

Russian Space Agency eyes Moon explorations

Russia postpones Luna-Glob moon mission

Russia Plans to Launch Lunar Rovers to Moon after 2020

Russia to explore moon

Photo Of NASA's Maven Spacecraft and Propellant Tank at Lockheed Martin

Dark regions on Mars may be volcanic glass

Martian impact craters may be hiding life

Russia to Go Back to the Moon Before Reaching for Mars

Tim gets his feet wet

NASA TV Reaches Bigger Audience With Encompass And SES

Designing the interplanetary web

Voyager One Might Have Farther to Go to Exit the Heliosheath

China's Lunar Docking

Shenzhou-9 may take female astronaut to space

China to launch 100 satellites during 2011-15

Three for Tiangong

Commercial Platform Offers Exposure at ISS

Learn to dock ATV the astronaut way

Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES)

Busy first days for ATV Edoardo Amaldi

SpaceX said eyeing Texas launch site

Lockheed Martin Names New Leader for Commercial Launch Services Business

A double arrival for Arianespace's next dual-payload Ariane 5 mission

Another weather satellite payload is readied for launch by Arianespace

ALMA Reveals Workings of Nearby Planetary System

UF-led team uses new observatory to characterize low-mass planets orbiting nearby star

When Stellar Metallicity Sparks Planet Formation

Study On Extrasolar Planet Orbits Suggests That Solar System Structure Is The Norm

Greenpeace says cloud computing 'dirty'

Bristol researchers solve 70-year-old mystery

U.S. Navy Awards Test Devices Contract for High-Cycle Fatigue Research pressed for clean 'cloud'

The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal 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