NASA Spacecraft Ready for Science-Rich Encounter With Venus

Jun 04, 2007
Messenger Spacecraft
This artist's impression shows NASA´s Mercury-bound MESSENGER from the sunshade side. The sunshade shields the spacecraft's instruments from heat and solar radiation. Image Credit: Johns Hopkins University Applied Physics Laboratory

NASA's MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft will make its closest pass to Venus on Tuesday, June 5. This will place the spacecraft on target for a flyby of Mercury in January 2008. MESSENGER will be the first probe to visit the innermost planet in more than 30 years.

Threading its path through an aim point 209 miles above the surface of Venus, MESSENGER will use the pull of the planet's gravity to guide it closer to Mercury. During this flyby, Venus's gravity will change the spacecraft's direction around the sun and decelerate it from 22.7 to 17.3 miles per second.

"Typically, spacecraft have used planetary flybys to speed toward the outer solar system," said Andy Calloway, MESSENGER mission operations manager, Johns Hopkins University Applied Physics Laboratory (APL), Laurel, Md. "MESSENGER, headed in the opposite direction, needs to slow down enough to slip into orbit around Mercury."

This will be MESSENGER's second pass by Venus. During its first flyby of the planet, in October 2006, no scientific observations were made. Venus was at superior conjunction, placing it on the opposite side of the sun from Earth, leading to a two-week radio contact blackout between the spacecraft and its operators. This upcoming encounter offers opportunities for new observations of Venus's atmosphere, cloud structure, space environment and perhaps even its surface. The spacecraft will train most of its instruments on Venus during the upcoming encounter.

"During the flyby we'll ensure that the spacecraft and payload remain healthy, calibrate several of the science instruments, and practice many of the observations planned for the Mercury flybys," said Sean Solomon, MESSENGER principal investigator and planetary scientist at the Carnegie Institution of Washington.

The team plans to image the upper cloud layers at visible and near-infrared wavelengths for comparison with earlier spacecraft observations. Magnetic field and charged particle observations will be made to characterize the solar wind interaction with Venus and search for solar wind pick-up ions. Ultraviolet-visible and X-ray spectrometry will permit detailed observations of the composition of the upper atmosphere, and MESSENGER will search for lightning on the Venus night side.

MESSENGER will join the European Venus Express spacecraft, currently orbiting Venus, to make new observations of the Venus environment. To understand fully how 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 characteristics at Venus. The combined MESSENGER and Venus Express observations will be the first opportunity to conduct such two-spacecraft measurements.

"By coordinating and comparing these observations, we will be able to maximize the science from both missions and potentially learn things that would not be revealed by one set of observations alone," said APL's Ralph McNutt, MESSENGER project scientist.

MESSENGER is only the second spacecraft to set sights on Mercury. NASA's Mariner 10 sailed past the planet three times in 1974 and 1975 and took detailed images of about 45 percent of the surface. Carrying seven scientific instruments on its compact and durable composite frame, MESSENGER will provide the first images of the entire planet. The mission also will collect detailed information on the composition and structure of Mercury's crust, its geologic history, the nature of its thin atmosphere and active magnetosphere, as well as the makeup of its core and polar materials.

Launched in August 2004, MESSENGER has completed more than 40 percent of its 4.9-billion mile journey to Mercury, which includes 15 loops around the sun. An Earth flyby one year after launch and a large propulsive maneuver in December 2005 set the spacecraft on course for the first Venus flyby in October 2006.

Next up for MESSENGER is a trio of swings past Mercury, in January and October 2008 and September 2009. During these flybys, the probe will map most of the planet and determine surface and atmospheric composition. These data will be used to help plan priorities for the yearlong orbital mission, which begins in March 2011.

The MESSENGER project is the seventh in NASA's Discovery Program of lower-cost, scientifically focused space missions. The Applied Physics Laboratory built and operates the MESSENGER spacecraft and manages the mission for NASA's Science Mission Directorate, Washington.

Source: NASA

Explore further: SpaceX will try again Fri. to launch station cargo (Update)

add to favorites email to friend print save as pdf

Related Stories

40th anniversary of Mariner 10 Venus mission

Feb 06, 2014

Exactly 40 Years ago today on Feb. 5, 1974, Mariner 10, accomplished a history making and groundbreaking feat when the NASA science probe became the first spacecraft ever to test out and execute the technique ...

Mercurial magnetosphere shaped by solar winds

Aug 05, 2013

Just before NASA's MESSENGER spacecraft began sending back stunning pictures of the Earth and the moon from its orbit around Mercury earlier this summer, two University of Alberta scientists were using NASA ...

Coronal mass ejection headed toward Mercury and Venus

Jul 02, 2013

On July 1, 2013, at 6:09 p.m. EDT, the sun erupted with a coronal mass ejection, or CME, a solar phenomenon that can send billions of tons of solar particles into space that can affect electronic systems ...

Investigating exoplanet surfaces

May 27, 2013

In order to better understand the composition of rocky exoplanets, researchers have proposed a method to identify chemical signatures from surface materials. A better understanding of exoplanet surface compositions ...

Recommended for you

Let's put a sailboat on Titan

3 hours ago

The large moons orbiting the gas giants in our solar system have been getting increasing attention in recent years. Titan, Saturn's largest moon, is the only natural satellite known to house a thick atmosphere. ...

Image: Rosetta's Philae lander snaps a selfie

3 hours ago

Philae is awake… and taking pictures! This image, acquired last night with the lander's CIVA (Comet nucleus Infrared and Visible Analyzer) instrument, shows the left and right solar panels of ESA's well-traveled ...

User comments : 0

More news stories

Let's put a sailboat on Titan

The large moons orbiting the gas giants in our solar system have been getting increasing attention in recent years. Titan, Saturn's largest moon, is the only natural satellite known to house a thick atmosphere. ...

ESO image: A study in scarlet

This new image from ESO's La Silla Observatory in Chile reveals a cloud of hydrogen called Gum 41. In the middle of this little-known nebula, brilliant hot young stars are giving off energetic radiation that ...