Universe Today
NASA's MESSENGER and ESA's Venus Express spacecraft are going to be at Venus together on June 6, giving scientists an opportunity to see our "evil" twin planet from two vantage points.
Of course, Venus Express has been orbiting its namesake planet since April 11, 2006, but Messenger is passing through, enroute to Mercury. And that's not all. Several ground-based observatories will be joining in on the party as well, taking images and gathering data during the MESSENGER flyby.
During its closest approach, MESSENGER will pass just 337 kilometres (210 miles) above the surface of Venus. And during this time, Venus Express will be behind Venus, but will be able to view many of the same regions imaged by MESSENGER. Scientists will then be able to compare the data gathered by the two spacecraft.
After 30 hours of observations, MESSENGER will be finished with Venus, and focused again on its final target. It'll finally reach Mercury in March, 2011.
ESA News Release