, on the Web at http://ser.sese.asu.edu/MESSENGER_20050802/list_movie_01.html .
Planning is now underway to use the second Venus flyby on June 5 to complete final rehearsals for three Mercury flybys. Those flybys, assisted by four deep space maneuvers, will slow the spacecraft sufficiently for Mercury orbit injection on March 18, 2011.
The upcoming planetary encounter also offers a variety of opportunities for making new observations of Venus' atmosphere and cloud structure, space environment, and, perhaps even the surface. All of the MESSENGER instruments will be trained on Venus during the encounter.
* The MDIS will image the night side in near-infrared bands, and color and higher-resolution monochrome mosaics will be made of both the approaching and departing hemispheres.
* The UltraViolet and Visible Spectrometer, part of the probe's Mercury Atmospheric and Surface Composition Spectrometer (MASCS), will capture profiles of emissions from atmospheric species versus altitude on both the day and night sides as well as observations of the exospheric tail on departure.
* MASCS's Visible and InfraRed Spectrograph will observe the planet near closest approach to assess the chemical composition of clouds. It may also detect near-infrared returns from the surface.
* The MESSENGER Laser Altimeter (MLA) will measure Venus' brightness at 1064-nm by using its pulse return detector as a passive sensor. MLA will also pulse its laser in an attempt to measure the range to one or more cloud decks for several minutes near closest approach.
* The Magnetometer will characterize the magnetic structure of the Venus bow shock and draping of the interplanetary magnetic field over Venus' ionosphere while the Energetic Particle and Plasma Spectrometer will observe charged particle acceleration and plasma flows associated with the bow shock.
The Venus Express mission of the European Space Agency is currently operating in an elliptical polar orbit about Venus, and MESSENGER's June planetary encounter together with the ongoing observations by Venus Express will permit unique observations of the Venus-solar wind interaction. To understand fully how the solar wind plasma affects and controls the Venus ionosphere and nearby plasma dynamics, simultaneous measurements are needed of the interplanetary conditions and the particle-and-field environment at Venus. The combined MESSENGER and Venus Express observations will be the first opportunity to conduct such two-spacecraft measurements.
The Mercury flybys, in January and October 2008 and September 2009, will be used to provide initial maps of the hemisphere of the planet never before seen by spacecraft, as well as the first mineralogical data on Mercury's surface.
Calloway says the remaining sixty percent of the cruise phase will be equally challenging, "But even more rewarding because now we will be collecting information at Mercury that no one has ever seen before."
A Planetary Geologist Keeps Her Eye On The Planets
As the lead instrument scientist for MESSENGER's Mercury Dual Imaging System (MDIS), Louise Prockter is all set to train her keen eye on images of Venus during the spacecraft's second flyby of that planet in June that will send it onward to Mercury. But in her early years, studying the surface of planets was the farthest thing from her mind. Find out how she got her start in geophysics in her profile, online here.
Stat Corner
Now 972 days after launch, MESSENGER is about 53.4 million miles (86.7 million kilometers) from the Sun and 135.3 million miles (217.7 kilometers) from Earth. At that distance, a signal from Earth reaches the spacecraft in 12 minutes and six seconds. The spacecraft is moving around the Sun at 95,841 miles (154,241 kilometers) per hour. MESSENGER's onboard computers have executed 255,719 commands from mission operators since launch on August 3, 2004.
Messenger Gearing Up To Understand Mercury Magnetosphere
Baltimore MD (SPX) Mar 20, 2007
