September Solar System Mission Roundup

NASA's MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) Mission to Mercury is due to arrive in March 2011 with two flybys of Venus - the first is next month on the 24th and the second in June 2007. MESSENGER passed the 1 billion mile mark, about 1/5th the voyage to Mercury on March 23, 2006. Mercury is not five billion miles from Earth but the flight path it has to take to reach the planet closest to the Sun is a long and complicated one.

MESSENGER already flew by Earth in 2005 to get a "gravity assist" to increase its velocity and change its trajectory. This will happen each time it flys by Venus as well. This technique saves on the overall weight of the spacecraft (and thereby cost) because gravity replaces onboard fuel to make these maneuvers. MESSENGER will also perform three flybys of Mercury before it finally settles into orbit around the planet. For the October flyby, MESSENGER mission managers will exchange trajectory information with the European Space Agency (ESA) Venus Express team.

MESSENGER will provide us a lot of information about this intriguing planet as the mission it is the first mission to Mercury since Mariner 10 in 1974 and 1975.

Read About MESSENGER

The European Space Agency (ESA) Venus Express spacecraft successfully inserted itself into Venus orbit on April 11th. The objective of the mission is to study the enigmatic atmosphere of Venus with a sophisticated suite of instruments.

The spacecraft has reached its final orbit and in June started its science operations phase. The spacecraft is returning valuable data and photographs of the Venusian atmosphere. One of the big finds to date is the discovery of a double vortex in the atmosphere at the south pole.

Read About Venus Express

On Mars the two intrepid Rovers - Spirit and Opportunity - are still exploring the Red Planet. Spirit has been doing so for over two and a half years while Opportunity has also passed the two year mark. Not bad for machines who were scheduled for a 90 day mission lifetime.

Spirit had been placed so that its solar cells can receive the maximum amount of sunlight in order to help the rover survive the brutal cold of the Martian winter. The Sun is now climbing higher in the Martian sky and is providing more sunlight to the solar cell arrays and therefore more electrical power. Spirit is operating on five instead of six - and operators have made adjustments to how they operate the rover.

Opportunity is closing in on half-mile wide Victoria Crater which has been its objective since late 2004. The rover is less than 160 feet away from the crater. According to NASA, "The great lure of Victoria is the expectation that a thick stack of geological layers will be exposed in the crater walls, potentially several times the thickness that was previously studied at Endurance and, therefore, potentially preserving several times the historical record."

Read About Spirit and Opportunity

On September 11th, Mars Reconnaissance Orbiter (MRO) completed its six-months of aero braking maneuvers - flying through the thin upper Martian atmosphere to reduce its orbital velocity and thereby bring it lower - reaching the orbit mission planners wanted. With this major milestone completed MRO started full scale science operations and deployed its ground penetrating radar antenna to start exploring the Martian sub-surface.

Read About MRO

Three other missions - Mars Odyssey, Mars Global Surveyor and ESA's Mars Express - are also still actively exploring Mars from orbit.

Read About These Other Missions

The Cassini-Huygens mission is still going strong exploring Saturn, its rings and moons. As I write this Cassini is preparing for a 600 mile flyby of Titan, Saturn's largest and most intriguing moon. The closest point of approach will be at 4:21 p.m. our time. NASA states, "Scientists will use the observations to study the composition at the very highest levels of Titan's atmosphere."

Cassini has also discovered a new ring and other features at Saturn and caught our very own planet in an image - see the Astrophoto.

Read About Cassini

Want to know where in the solar system the New Horizons Mission to Pluto is? Use the link to check on the whereabouts of this speedster of a spacecraft.

Read About New Horizons

Got a Topic That Interests You? I literally have a whole universe of topics to select from for my column. But I'm interested in hearing from WTOP readers about what interests them. Feel free to contact me at gredfern@earthlink.net with your suggestions and comments.