NASA's "MAVEN" Mars orbiter launched without a hitch

NASA's Mars orbiter MAVEN launched successfully today from Cape Canaveral, Florida at 1:28PM EST. Once it arrives in orbit around the Red Planet, the Mars Atmosphere and Volatile EvolutioN orbiter will gather data about Mars' upper atmosphere to try and discover how exactly the planet got to be so dry and atmosphere-poor. Earlier probes suggest the planet used to be much more like Earth in terms of moisture and atmosphere thickness.

MAVEN was launched aboard a United Launch Alliance Atlas 5 rocket. The orbiter itself, which was assembled by Lockheed Martin, arrived at Cape Canaveral earlier this year after passing a battery of tests in February in Denver, Colorado proving its ability to withstand the launch as well as the conditions over Mars. Not wasting any time, NASA launched MAVEN at the very first moment of today's two-hour window. Had MAVEN missed the window, it could have taken advantage of other launch windows between now and Dec.7, but if it missed those, it couldn't have departed for another two years.

Along the way, MAVEN may also catch sight of the comet ISON–now visible with the naked eye here on Earth–using ultraviolet sensors around Dec. 10, when the comet is at its brightest. If and when MAVEN successfully reaches Mars, it will join NASA's Mars Reconnaissance Orbiter, Mars Odyssey and the European Space Agency's Mars Express in orbit. Add those to NASA's Mars rovers Curiosity and Opportunity–as well as Indian's Mangalyaan, launched Nov. 5 and scheduled to arrive two days after MAVEN's Sept. 22, 2014 arrival–and the robot population of the planet will have risen to seven. NASA officials say they might be able to coordinate with Mangalyaan to share data.

Some scientists believe Mars may once have had lakes and atmosphere capable of producing fluffy clouds. That belief is predicated on data sent back to Earth from the existing orbiters and rovers, which have been collectively exploring the surface and the atmosphere for years. MAVEN will directly observe the solar wind environment and other climate-affecting factors over Mars, as well as act as a relay station for data from Curiosity and Opportunity.

Also scheduled to launch later this week is Swarm, the ESA's three-satellite Earth orbiter mission created to chart our planet's changing magnetic field.