This morning (October 21, 2011), at 10:30 Greenwich Mean Time (5:30am Central Daylight Time), a Soyuz rocket lifted off from a brand new launch pad in the South American jungle with two European navigation satellites, making history on its first mission from Guiana Space Center. Russia and Europe opened the new Soyuz launch site to allow the Russian rocket to better compete for commercial and European space missions. By launching close to the equator in French Guiana, the Soyuz rocket gets a boost in performance.
In 1998, the European Space Agency (ESA) first began studying the possibility of Soyuz launches from the Guiana Space Center. ESA officially started this program in 2004, with construction work in French Guiana beginning in 2005 and the first Russian components arriving three years later, in 2008.
This launch, designated VS01 in Arianespace’s launcher family numbering scheme, will deploy two Galileo satellites. Galileo is Europe’s program for a global navigation satellite system to provide highly accurate, global positioning services, and will be interoperable with the U.S. Global Positioning System and Russia’s Glonass network.
The newspaper El Mundo has an informative animation on the launch vehicle and Galileo satellite (in Spanish).
We often hear about gravity being different on other planets--the Moon is an oft-cited example of how weaker gravity makes you weigh less. But did you know that gravity actually varies on our own planet?
There's this thing called a geoid. It sounds like something out of a sci-fi story, but it's quite real. The geoid is a map of the Earth's gravitational field. And since gravity impacts things like sea level and currents, it's important to understand how it varies.
Luckily, those crafty Europeans came up with the GOCE (Gravity field and steady-state Ocean Circulation Explorer) satellite, which has painted the clearest picture yet of the geoid. With its variations exaggerated, it makes the Earth look like a giant potato. The variations come from unevenness in earth's mass and shape. Its wobbly surface represents what shape the oceans would take without current, wind, or tide to move them. The satellite also studies ocean circulation and the movement of ice.
This information is particularly important to understanding sea level rise. Scientists predict that, on average, sea level will rise 3 feet overall by 2100. But those three feet will be distributed differently throughout the world, and studying that distribution is pretty complicated. There's the impact of the geoid and of gravity from large ice sheets, but winds and water circulation, water temperature, salinity, meltwater from ice sheets, rainwater runoff, and land changes all leave their marks.
Some of these changes redistribute water (ex. geoid), others add to the volume of seawater (ex. temperature increases), and still others modify the land's height relative to the water (ex. land changes, such as sedimentation and oil extraction). Some changes leave a lasting impact (ex. meltwater from glaciers), while others can vary by the hour or the season (winds).
By developing this most-accurate-to-date geoid and ocean circulation model, researchers have created a picture of sea level at its natural state and modeled some of the processes that alter that state, so that we have a reference point for understanding many of the less-defined factors in sea level rise. And that, my friends, will help us better anticipate and plan for the changes ahead.
Plus it's just kinda cool to see how the Earth is really shaped, huh?