On December 7, 2001, a Delta II rocket launched from Vandenberg Air Force Base carrying a spacecraft designed to observe a little known area of the atmosphere that experiences some of the most dramatic energy fluctuations in the near-Earth environment.The area stretches from about 40 to 110 miles above the surface of the Earth, encompassing the lower thermosphere and the mesosphere. This is where incoming energy from the sun transforms into the lights of the aurora, where glowing night-time noctilucent clouds appear, and where a dynamic electromagnetic system experiences space weather effects that can interrupt man-made satellites and human communications. For 10 years, the mission called TIMED (Thermosphere Ionosphere Mesosphere Energetics and Dynamics) has gathered more data on this region than has ever been seen before and has created a whole new picture of Earth's environment, as well as how it responds to changes in the sun."One of the most exciting things, is that we have collected data over almost an entire solar cycle, which lasts about 11 years," says Richard Goldberg, a space scientist at NASA's Goddard Space Flight Center in Greenbelt, Md. and NASA's project scientist for TIMED. "We've been able to watch how the atmosphere responds to the sun moving from solar max to solar minimum and back again."The instruments on TIMED were designed to provide a comprehensive overview of the composition of this mesosphere and lower thermosphere/ionosphere (MLTI) region of Earth's atmosphere, and to watch how it changes over time. A wide variety of sources can add energy to the MLTI region, some from above such as the solar wind and solar flares, and others from below, including human-induced effects.