Artist's rendering of the twin spacecraft of the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission, scheduled to launch in May, 2018. GRACE-FO will track the evolution of Earth's water cycle by monitoring changes in the distribution of mass on Earth. https://photojournal.jpl.nasa.gov/catalog/PIA22431

This artist's rendering shows the twin spacecraft of the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission, a partnership between NASA and the German Research Centre for Geosciences (GFZ). GRACE-FO is a successor to the original GRACE mission, which began orbiting Earth on March 17, 2002. GRACE-FO will carry on the extremely successful work of its predecessor while testing a new technology designed to dramatically improve the already remarkable precision of its measurement system. The GRACE missions measure variations in gravity over Earth's surface, producing a new map of the gravity field every 30 days. Thus, GRACE shows how the planet's gravity differs not only from one location to another, but also from one period of time to another. https://photojournal.jpl.nasa.gov/catalog/PIA21607

The Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) twin satellites, attached to turntable fixtures, at the Astrotech Space Operations processing facility at Vandenberg Air Force Base, California. GRACE-FO will extend GRACE's legacy of scientific achievements, which range from tracking mass changes of Earth's polar ice sheets and estimating global groundwater changes, to measuring the mass changes of large earthquakes and inferring changes in deep ocean currents, a driving force in climate. To date, GRACE observations have been used in more than 4,300 research publications. Its measurements provide a unique view of the Earth system and have far-reaching benefits to society, such as providing insights into where global groundwater resources may be shrinking or growing and where dry soils are contributing to drought. GRACE-FO is planned to fly at least five years. https://photojournal.jpl.nasa.gov/catalog/PIA22338

The Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) twin satellites, attached to turntable fixtures, at the Astrotech Space Operations processing facility at Vandenberg Air Force Base, California. GRACE-FO will extend GRACE's legacy of scientific achievements, which range from tracking mass changes of Earth's polar ice sheets and estimating global groundwater changes, to measuring the mass changes of large earthquakes and inferring changes in deep ocean currents, a driving force in climate. To date, GRACE observations have been used in more than 4,300 research publications. Its measurements provide a unique view of the Earth system and have far-reaching benefits to society, such as providing insights into where global groundwater resources may be shrinking or growing and where dry soils are contributing to drought. GRACE-FO is planned to fly at least five years. https://photojournal.jpl.nasa.gov/catalog/PIA22340

One of the two Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) satellites and its turntable fixture at the Astrotech Space Operations processing facility at Vandenberg Air Force Base, California. GRACE-FO will extend GRACE's legacy of scientific achievements, which range from tracking mass changes of Earth's polar ice sheets and estimating global groundwater changes, to measuring the mass changes of large earthquakes and inferring changes in deep ocean currents, a driving force in climate. To date, GRACE observations have been used in more than 4,300 research publications. Its measurements provide a unique view of the Earth system and have far-reaching benefits to society, such as providing insights into where global groundwater resources may be shrinking or growing and where dry soils are contributing to drought. GRACE-FO is planned to fly at least five years. https://photojournal.jpl.nasa.gov/catalog/PIA22339

The Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) twin satellites, attached to turntable fixtures, at the Astrotech Space Operations processing facility at Vandenberg Air Force Base, California. GRACE-FO will extend GRACE's legacy of scientific achievements, which range from tracking mass changes of Earth's polar ice sheets and estimating global groundwater changes, to measuring the mass changes of large earthquakes and inferring changes in deep ocean currents, a driving force in climate. To date, GRACE observations have been used in more than 4,300 research publications. Its measurements provide a unique view of the Earth system and have far-reaching benefits to society, such as providing insights into where global groundwater resources may be shrinking or growing and where dry soils are contributing to drought. GRACE-FO is planned to fly at least five years. https://photojournal.jpl.nasa.gov/catalog/PIA22341

Karen Fox, of NASA's Office of Communications, introduces Michael Watkins, GRACE-FO science lead and director of NASA's Jet Propulsion Laboratory and Frank Webb, GRACE-FO project scientist at JPL, during a briefing on the upcoming launch of the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission, Monday, April 30, 2018 at NASA Headquarters in Washington. The twin GRACE-FO spacecraft will measure and monitor monthly changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. Photo Credit: (NASA/Joel Kowsky)

Karen Fox of NASA's Office of Communications, introduces David Jarrett, GRACE-FO program executive in the Earth Science Division at NASA Headquarters and Phil Morton, NASA GRACE-FO project manager at JPL, during a briefing on the upcoming launch of the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission, Monday, April 30, 2018 at NASA Headquarters in Washington. The twin GRACE-FO spacecraft will measure and monitor monthly changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. Photo Credit: (NASA/Joel Kowsky)

Frank Webb, GRACE-FO project scientist at JPL, discusses the upcoming launch of the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission, Monday, April 30, 2018 at NASA Headquarters in Washington. The twin GRACE-FO spacecraft will measure and monitor monthly changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. Photo Credit: (NASA/Joel Kowsky)

Frank Flechtner, GRACE-FO project manager for the German Research Centre for Geosciences (GFZ) in Potsdam, Germany, participates in a briefing on the upcoming launch of the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission via a remote video link, Monday, April 30, 2018 at NASA Headquarters in Washington. The twin GRACE-FO spacecraft will measure and monitor monthly changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. Photo Credit: (NASA/Joel Kowsky)

Frank Webb, GRACE-FO project scientist at JPL, discusses the upcoming launch of the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission, Monday, April 30, 2018 at NASA Headquarters in Washington. The twin GRACE-FO spacecraft will measure and monitor monthly changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. Photo Credit: (NASA/Joel Kowsky)

Michael Watkins, GRACE-FO science lead and director of NASA's Jet Propulsion Laboratory, discusses the upcoming launch of the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission, Monday, April 30, 2018 at NASA Headquarters in Washington. The twin GRACE-FO spacecraft will measure and monitor monthly changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. Photo Credit: (NASA/Joel Kowsky)

David Jarrett, GRACE-FO program executive in the Earth Science Division at NASA Headquarters, discusses the upcoming launch of the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission, Monday, April 30, 2018 at NASA Headquarters in Washington. The twin GRACE-FO spacecraft will measure and monitor monthly changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. Photo Credit: (NASA/Joel Kowsky)

Michael Watkins, GRACE-FO science lead and director of NASA's Jet Propulsion Laboratory, discusses the upcoming launch of the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission, Monday, April 30, 2018 at NASA Headquarters in Washington. The twin GRACE-FO spacecraft will measure and monitor monthly changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. Photo Credit: (NASA/Joel Kowsky)

Phil Morton, NASA GRACE-FO project manager at JPL, discusses the upcoming launch of the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission, Monday, April 30, 2018 at NASA Headquarters in Washington. The twin GRACE-FO spacecraft will measure and monitor monthly changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. Photo Credit: (NASA/Joel Kowsky)

The Gravity Recovery and Climate Experiment Follow-on (GRACE-FO) mission is a partnership between NASA and the German Research Centre for Geosciences (GFZ). GRACE-FO is a successor to the original GRACE mission, which began orbiting Earth on March 17, 2002. GRACE-FO will carry on the extremely successful work of its predecessor while testing a new technology designed to dramatically improve the already remarkable precision of its measurement system. The GRACE missions measure variations in gravity over Earth's surface, producing a new map of the gravity field every 30 days. Thus, GRACE shows how the planet's gravity differs not only from one location to another, but also from one period of time to another. Airbus Defence and Space (Friedrichshafen/Germany) is the industrial prime contractor to build the satellites.

Illustration of the twin spacecraft of the NASA/German Research Centre for Geosciences (GFZ) Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission. GRACE-FO will continue tracking the evolution of Earth's water cycle by monitoring changes in the distribution of mass on Earth. https://photojournal.jpl.nasa.gov/catalog/PIA22446

Illustration of the twin spacecraft of the NASA/German Research Centre for Geosciences (GFZ) Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission. GRACE-FO will continue tracking the evolution of Earth's water cycle by monitoring changes in the distribution of mass on Earth. https://photojournal.jpl.nasa.gov/catalog/PIA22441

Illustration of the twin spacecraft of the NASA/German Research Centre for Geosciences (GFZ) Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission. GRACE-FO will continue tracking the evolution of Earth's water cycle by monitoring changes in the distribution of mass on Earth. https://photojournal.jpl.nasa.gov/catalog/PIA22440

Illustration of the twin spacecraft of the NASA/German Research Centre for Geosciences (GFZ) Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission. GRACE-FO will continue tracking the evolution of Earth's water cycle by monitoring changes in the distribution of mass on Earth. https://photojournal.jpl.nasa.gov/catalog/PIA22447

Illustration of the twin spacecraft of the NASA/German Research Centre for Geosciences (GFZ) Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission. GRACE-FO will continue tracking the evolution of Earth's water cycle by monitoring changes in the distribution of mass on Earth. https://photojournal.jpl.nasa.gov/catalog/PIA22445

David Jarrett, GRACE-FO program executive in the Earth Science Division at NASA Headquarters, left, and Phil Morton, NASA GRACE-FO project manager at JPL, discuss the upcoming launch of the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission with Karen Fox of NASA's Office of Communications, Monday, April 30, 2018 at NASA Headquarters in Washington. The twin GRACE-FO spacecraft will measure and monitor monthly changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. Photo Credit: (NASA/Joel Kowsky)

Karen Fox, of NASA's Office of Communications, right, discusses the upcoming launch of the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission with Michael Watkins, GRACE-FO science lead and director of NASA's Jet Propulsion Laboratory, left, and Frank Webb, GRACE-FO project scientist at JPL, Monday, April 30, 2018 at NASA Headquarters in Washington. The twin GRACE-FO spacecraft will measure and monitor monthly changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. Photo Credit: (NASA/Joel Kowsky)

A model of one of the twin Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) spacecraft is seen following a pre-launch briefing on the mission, Monday, April 30, 2018 at NASA Headquarters in Washington. The twin GRACE-FO spacecraft will measure and monitor monthly changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. Photo Credit: (NASA/Joel Kowsky)

NASA Headquarters Public Affairs Officer Steve Cole, left, moderates the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission prelaunch media briefing with David Jarrett, GRACE-FO program executive in the Earth Science Division at NASA Headquarters; Frank Webb, GRACE-FO project scientist at JPL; Frank Flechtner, GRACE-FO project manager for the German Research Centre for Geosciences (GFZ) in Potsdam, Germany; Phil Morton, NASA GRACE-FO project manager at JPL; and Capt. Jennifer Haden, weather officer, 30th Space Wing, Vandenberg Air Force Base, right, Monday, May 21, 2018, at Vandenberg Air Force Base in California. The twin GRACE-FO spacecraft will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. Photo Credit: (NASA/Bill Ingalls)

NASA Headquarters Public Affairs Officer Steve Cole, left, moderates the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission prelaunch media briefing with David Jarrett, GRACE-FO program executive in the Earth Science Division at NASA Headquarters; Frank Webb, GRACE-FO project scientist at JPL; Frank Flechtner, GRACE-FO project manager for the German Research Centre for Geosciences (GFZ) in Potsdam, Germany; Phil Morton, NASA GRACE-FO project manager at JPL; and Capt. Jennifer Haden, weather officer, 30th Space Wing, Vandenberg Air Force Base, right, Monday, May 21, 2018, at Vandenberg Air Force Base in California. The twin GRACE-FO spacecraft will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. Photo Credit: (NASA/Bill Ingalls)

Frank Webb, GRACE-FO project scientist at JPL, left, and \Frank Flechtner, discuss the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission during a prelaunch media briefing, Monday, May 21, 2018, at Vandenberg Air Force Base in California. The twin GRACE-FO spacecraft will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. Photo Credit: (NASA/Bill Ingalls)

David Jarrett, GRACE-FO program executive in the Earth Science Division at NASA Headquarters is seen during a Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission prelaunch media briefing, Monday, May 21, 2018, at Vandenberg Air Force Base in California. The twin GRACE-FO spacecraft will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. Photo Credit: (NASA/Bill Ingalls)

Frank Webb, GRACE-FO project scientist at JPL, discusses the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission during a prelaunch media briefing, Monday, May 21, 2018, at Vandenberg Air Force Base in California. The twin GRACE-FO spacecraft will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. Photo Credit: (NASA/Bill Ingalls)

Phil Morton, NASA GRACE-FO project manager at JPL, discusses the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission during a prelaunch media briefing, Monday, May 21, 2018, at Vandenberg Air Force Base in California. The twin GRACE-FO spacecraft will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. Photo Credit: (NASA/Bill Ingalls)

Phil Morton, NASA GRACE-FO project manager at JPL discusses the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission during a prelaunch media briefing, Monday, May 21, 2018, at Vandenberg Air Force Base in California. The twin GRACE-FO spacecraft will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. Photo Credit: (NASA/Bill Ingalls)

Frank Flechtner, GRACE-FO project manager for the German Research Centre for Geosciences (GFZ) in Potsdam, Germany, discusses the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission during a prelaunch media briefing, Monday, May 21, 2018, at Vandenberg Air Force Base in California. The twin GRACE-FO spacecraft will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. Photo Credit: (NASA/Bill Ingalls)

Phil Morton, NASA GRACE-FO project manager at JPL, second from right, discusses the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission during a prelaunch media briefing, Monday, May 21, 2018, at Vandenberg Air Force Base in California. The twin GRACE-FO spacecraft will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. Photo Credit: (NASA/Bill Ingalls)

Frank Flechtner, GRACE-FO project manager for the German Research Centre for Geosciences (GFZ) in Potsdam, Germany, discusses the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission during a prelaunch media briefing, Monday, May 21, 2018, at Vandenberg Air Force Base in California. The twin GRACE-FO spacecraft will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. Photo Credit: (NASA/Bill Ingalls)

David Jarrett, GRACE-FO program executive in the Earth Science Division at NASA Headquarters, discusses the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission during a prelaunch media briefing, Monday, May 21, 2018, at Vandenberg Air Force Base in California. The twin GRACE-FO spacecraft will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. Photo Credit: (NASA/Bill Ingalls)

Experts discuss the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission during a prelaunch media briefing, Monday, May 21, 2018, at Vandenberg Air Force Base in California. The twin GRACE-FO spacecraft will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. Photo Credit: (NASA/Bill Ingalls)

A graphic is shown as experts discuss the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission during a prelaunch media briefing, Monday, May 21, 2018, at Vandenberg Air Force Base in California. The twin GRACE-FO spacecraft will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. Photo Credit: (NASA/Bill Ingalls)

A graphic is shown as experts discuss the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission during a prelaunch media briefing, Monday, May 21, 2018, at Vandenberg Air Force Base in California. The twin GRACE-FO spacecraft will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. Photo Credit: (NASA/Bill Ingalls)

A photo showing the The twin GRACE-FO spacecraft installed on top of the five Iridium NEXT communications satellites is seen as experts discuss the Gravity Recovery and Climate Experiment Follow-On mission during a prelaunch media briefing, Monday, May 21, 2018, at Vandenberg Air Force Base in California. The twin GRACE-FO spacecraft will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. Photo Credit: (NASA/Bill Ingalls)

Capt. Jennifer Haden, weather officer, 30th Space Wing, Vandenberg Air Force Base, discusses the weather forecast during a Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission prelaunch media briefing, Monday, May 21, 2018, at Vandenberg Air Force Base in California. The twin GRACE-FO spacecraft will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. Photo Credit: (NASA/Bill Ingalls)

NASA Headquarters Public Affairs Officer Steve Cole moderates a Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission prelaunch media briefing, Monday, May 21, 2018, at Vandenberg Air Force Base in California. The twin GRACE-FO spacecraft will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. Photo Credit: (NASA/Bill Ingalls)

At the Harris Spaceport Systems facility at Vandenberg Air Force Base in California, the twin GRACE-FO satellites are integrated with the multi-satellite dispenser structure that will be used to deploy the satellites during launch on the SpaceX Falcon 9 launch vehicle. https://photojournal.jpl.nasa.gov/catalog/PIA22444

GRACE-FO has completed its first mission phase and demonstrated the performance of the precise ranging system that enables its measurements of how mass migrates around Earth. Along the satellites' ground track (top), the inter-spacecraft distance between them changes as the mass distribution underneath (i.e., from mountains, etc.) varies. The small changes measured by the Microwave Ranging Instrument (middle) agree well with topographic features along the orbit (bottom). https://photojournal.jpl.nasa.gov/catalog/PIA22507

The NASA/German Research Centre for Geosciences GRACE Follow-On spacecraft launch onboard a SpaceX Falcon 9 rocket, Tuesday, May 22, 2018, from Space Launch Complex 4E at Vandenberg Air Force Base in California. The mission will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. GRACE-FO is sharing its ride to orbit with five Iridium NEXT communications satellites as part of a commercial rideshare agreement. Photo Credit: (NASA/Bill Ingalls)

The NASA/German Research Centre for Geosciences GRACE Follow-On spacecraft launch onboard a SpaceX Falcon 9 rocket, Tuesday, May 22, 2018, from Space Launch Complex 4E at Vandenberg Air Force Base in California. The mission will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. GRACE-FO is sharing its ride to orbit with five Iridium NEXT communications satellites as part of a commercial rideshare agreement. Photo Credit: (NASA/Bill Ingalls)

The NASA/German Research Centre for Geosciences GRACE Follow-On spacecraft launch onboard a SpaceX Falcon 9 rocket, Tuesday, May 22, 2018, from Space Launch Complex 4E at Vandenberg Air Force Base in California. The mission will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. GRACE-FO is sharing its ride to orbit with five Iridium NEXT communications satellites as part of a commercial rideshare agreement. Photo Credit: (NASA/Bill Ingalls)

The NASA/German Research Centre for Geosciences GRACE Follow-On spacecraft launch onboard a SpaceX Falcon 9 rocket, Tuesday, May 22, 2018, from Space Launch Complex 4E at Vandenberg Air Force Base in California. The mission will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. GRACE-FO is sharing its ride to orbit with five Iridium NEXT communications satellites as part of a commercial rideshare agreement. Photo Credit: (NASA/Bill Ingalls)

The SpaceX Falcon 9 rocket is seen with the NASA/German Research Centre for Geosciences GRACE Follow-On spacecraft onboard, Monday, May 21, 2018, at Space Launch Complex 4E at Vandenberg Air Force Base in California. The mission will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. GRACE-FO is sharing its ride to orbit with five Iridium NEXT communications satellites as part of a commercial rideshare agreement. Photo Credit: (NASA/Bill Ingalls)

The NASA/German Research Centre for Geosciences GRACE Follow-On spacecraft launch onboard a SpaceX Falcon 9 rocket, Tuesday, May 22, 2018, from Space Launch Complex 4E at Vandenberg Air Force Base in California. The mission will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. GRACE-FO is sharing its ride to orbit with five Iridium NEXT communications satellites as part of a commercial rideshare agreement. Photo Credit: (NASA/Bill Ingalls)

The SpaceX Falcon 9 rocket is seen with the NASA/German Research Centre for Geosciences GRACE Follow-On spacecraft onboard, Tuesday, May 22, 2018, at Space Launch Complex 4E at Vandenberg Air Force Base in California. The mission will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. GRACE-FO is sharing its ride to orbit with five Iridium NEXT communications satellites as part of a commercial rideshare agreement. Photo Credit: (NASA/Bill Ingalls)

The NASA/German Research Centre for Geosciences GRACE Follow-On spacecraft launch onboard a SpaceX Falcon 9 rocket, Tuesday, May 22, 2018, from Space Launch Complex 4E at Vandenberg Air Force Base in California. The mission will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. GRACE-FO is sharing its ride to orbit with five Iridium NEXT communications satellites as part of a commercial rideshare agreement. Photo Credit: (NASA/Bill Ingalls)

The NASA/German Research Centre for Geosciences GRACE Follow-On spacecraft launch onboard a SpaceX Falcon 9 rocket, Tuesday, May 22, 2018, from Space Launch Complex 4E at Vandenberg Air Force Base in California. The mission will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. GRACE-FO is sharing its ride to orbit with five Iridium NEXT communications satellites as part of a commercial rideshare agreement. Photo Credit: (NASA/Bill Ingalls)

The NASA/German Research Centre for Geosciences GRACE Follow-On spacecraft launch onboard a SpaceX Falcon 9 rocket, Tuesday, May 22, 2018, from Space Launch Complex 4E at Vandenberg Air Force Base in California. The mission will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. GRACE-FO is sharing its ride to orbit with five Iridium NEXT communications satellites as part of a commercial rideshare agreement. Photo Credit: (NASA/Bill Ingalls)

The SpaceX Falcon 9 rocket is seen with the NASA/German Research Centre for Geosciences GRACE Follow-On spacecraft onboard, Monday, May 21, 2018, at Space Launch Complex 4E at Vandenberg Air Force Base in California. The mission will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. GRACE-FO is sharing its ride to orbit with five Iridium NEXT communications satellites as part of a commercial rideshare agreement. Photo Credit: (NASA/Bill Ingalls)

The NASA/German Research Centre for Geosciences GRACE Follow-On spacecraft launch onboard a SpaceX Falcon 9 rocket, Tuesday, May 22, 2018, from Space Launch Complex 4E at Vandenberg Air Force Base in California. The mission will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. GRACE-FO is sharing its ride to orbit with five Iridium NEXT communications satellites as part of a commercial rideshare agreement. Photo Credit: (NASA/Bill Ingalls)

The NASA/German Research Centre for Geosciences GRACE Follow-On spacecraft launch onboard a SpaceX Falcon 9 rocket, Tuesday, May 22, 2018, from Space Launch Complex 4E at Vandenberg Air Force Base in California. The mission will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. GRACE-FO is sharing its ride to orbit with five Iridium NEXT communications satellites as part of a commercial rideshare agreement. Photo Credit: (NASA/Bill Ingalls)

The NASA/German Research Centre for Geosciences GRACE Follow-On spacecraft launch onboard a SpaceX Falcon 9 rocket, Tuesday, May 22, 2018, from Space Launch Complex 4E at Vandenberg Air Force Base in California. The mission will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. GRACE-FO is sharing its ride to orbit with five Iridium NEXT communications satellites as part of a commercial rideshare agreement. Photo Credit: (NASA/Bill Ingalls)

Long exposure photograph showing the NASA/German Research Centre for Geosciences GRACE Follow-On spacecraft launching onboard a SpaceX Falcon 9 rocket, Tuesday, May 22, 2018, from Space Launch Complex 4E at Vandenberg Air Force Base in California. The mission will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. GRACE-FO is sharing its ride to orbit with five Iridium NEXT communications satellites as part of a commercial rideshare agreement. Photo Credit: (NASA/Bill Ingalls)

The NASA/German Research Centre for Geosciences GRACE Follow-On spacecraft launch onboard a SpaceX Falcon 9 rocket, Tuesday, May 22, 2018, from Space Launch Complex 4E at Vandenberg Air Force Base in California. The mission will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. GRACE-FO is sharing its ride to orbit with five Iridium NEXT communications satellites as part of a commercial rideshare agreement. Photo Credit: (NASA/Bill Ingalls)

The NASA/German Research Centre for Geosciences GRACE Follow-On spacecraft launch onboard a SpaceX Falcon 9 rocket, Tuesday, May 22, 2018, from Space Launch Complex 4E at Vandenberg Air Force Base in California. The mission will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. GRACE-FO is sharing its ride to orbit with five Iridium NEXT communications satellites as part of a commercial rideshare agreement. Photo Credit: (NASA/Bill Ingalls)

The SpaceX Falcon 9 rocket is seen with the NASA/German Research Centre for Geosciences GRACE Follow-On spacecraft onboard, Monday, May 21, 2018, at Space Launch Complex 4E at Vandenberg Air Force Base in California. The mission will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. GRACE-FO is sharing its ride to orbit with five Iridium NEXT communications satellites as part of a commercial rideshare agreement. Photo Credit: (NASA/Bill Ingalls)

The NASA/German Research Centre for Geosciences GRACE Follow-On spacecraft launch onboard a SpaceX Falcon 9 rocket, Tuesday, May 22, 2018, from Space Launch Complex 4E at Vandenberg Air Force Base in California. The mission will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. GRACE-FO is sharing its ride to orbit with five Iridium NEXT communications satellites as part of a commercial rideshare agreement. Photo Credit: (NASA/Bill Ingalls)

The NASA/German Research Centre for Geosciences GRACE Follow-On spacecraft launch onboard a SpaceX Falcon 9 rocket, Tuesday, May 22, 2018, from Space Launch Complex 4E at Vandenberg Air Force Base in California. The mission will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. GRACE-FO is sharing its ride to orbit with five Iridium NEXT communications satellites as part of a commercial rideshare agreement. Photo Credit: (NASA/Bill Ingalls)

The SpaceX Falcon 9 rocket is seen with the NASA/German Research Centre for Geosciences GRACE Follow-On spacecraft onboard, Monday, May 21, 2018, at Space Launch Complex 4E at Vandenberg Air Force Base in California. The mission will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. GRACE-FO is sharing its ride to orbit with five Iridium NEXT communications satellites as part of a commercial rideshare agreement. Photo Credit: (NASA/Bill Ingalls)

The SpaceX Falcon 9 rocket is seen with the NASA/German Research Centre for Geosciences GRACE Follow-On spacecraft onboard, Tuesday, May 22, 2018, at Space Launch Complex 4E at Vandenberg Air Force Base in California. The mission will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. GRACE-FO is sharing its ride to orbit with five Iridium NEXT communications satellites as part of a commercial rideshare agreement. Photo Credit: (NASA/Bill Ingalls)

The NASA/German Research Centre for Geosciences GRACE Follow-On spacecraft launch onboard a SpaceX Falcon 9 rocket, Tuesday, May 22, 2018, from Space Launch Complex 4E at Vandenberg Air Force Base in California. The mission will measure changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. GRACE-FO is sharing its ride to orbit with five Iridium NEXT communications satellites as part of a commercial rideshare agreement. Photo Credit: (NASA/Bill Ingalls)

Almost all of Greenland continued to lose mass in May 2019 as the ice sheet continues to melt. https://photojournal.jpl.nasa.gov/catalog/PIA23340

At the Harris Spaceport Systems facility at Vandenberg Air Force Base in California, the twin GRACE-FO satellites are integrated with the multi-satellite dispenser structure that will be used to deploy the satellites during launch on the SpaceX Falcon 9 launch vehicle. https://photojournal.jpl.nasa.gov/catalog/PIA22442

This drawing illustrates the Hubble Space Telescope's (HST's), Faint Object Spectrograph (FOS). The HST's two spectrographs, the Goddard High-Resolution Spectrograph and the FOS, can detect a broader range of wavelengths than is possible from the Earth because there is no atmosphere to absorb certain wavelengths. Scientists can determine the chemical composition, temperature, pressure, and turbulence of the stellar atmosphere producing the light, all from spectral data. The FOC can detect detail in very faint objects, such as those at great distances, and light ranging from ultraviolet to red spectral bands. Both spectrographs operate in essentially the same way. The incoming light passes through a small entrance aperture, then passes through filters and diffraction gratings, that work like prisms. The filter or grating used determines what range of wavelength will be examined and in what detail. Then the spectrograph detectors record the strength of each wavelength band and sends it back to Earth. The purpose of the HST, the most complex and sensitive optical telescope ever made, is to study the cosmos from a low-Earth orbit. By placing the telescope in space, astronomers are able to collect data that is free of the Earth's atmosphere. The HST views galaxies, stars, planets, comets, possibly other solar systems, and even unusual phenomena such as quasars, with 10 times the clarity of ground-based telescopes. The HST was deployed from the Space Shuttle Discovery (STS-31 mission) into Earth orbit in April 1990. The Marshall Space Flight Center had responsibility for design, development, and construction of the HST. The Perkin-Elmer Corporation, in Danbury, Cornecticut, developed the optical system and guidance sensors.

North America was almost entirely above its long-term average in mass in May 2019, due to Midwestern flooding, with the runoff raising the Great Lakes to record levels. https://photojournal.jpl.nasa.gov/catalog/PIA22840

Executive Director fo the National Council of Negro Women, Janice Mathis, speaks at the MLK Day of Service, Tuesday, January 21, 2020 at NASA Headquarters in Washington. Photo Credit: (NASA/Aubrey Gemignani)

Executive Director fo the National Council of Negro Women, Janice Mathis, speaks at the MLK Day of Service, Tuesday, January 21, 2020 at NASA Headquarters in Washington. Photo Credit: (NASA/Aubrey Gemignani)

S82-E-5317 (14 Feb. 1997) --- Astronaut Steven L. Smith, STS-82 mission specialist, on arm with Faint Object Spectrograph (FOS) after removal from Hubble Space Telescope (HST). This view was taken with an Electronic Still Camera (ESC).

NASA Associate Administrator for STEM Engagement, Mike Kincaid, introduces the heads of agencies that will be participating in an interactive session with students, from left to right, Dr. Johann-Dietrich Worner, director general of the European Space Agency (ESA); NASA Administrator Jim Bridenstine; Sylvain Laporte, president of the Canadian Space Agency (CSA); Dr. Hiroshi Yamakawa, president of the Japan Aerospace Exploration Agency (JAXA); Anthony Murfett, deputy head fo the Australian Space Agency (ASA); Jeong Joo Park, Vice President fo the Korean Aerospace Research Institute (KARI); and H.E. Dr. Ahmad bin Abdulla Humaid Belhoul Al Falasi, Minister of State for Higher Education and Advanced Skills and Chairman of the UAE Space Agency (UAESA), during the 70th International Astronautical Congress, Monday, Oct. 21, 2019 at the Walter E. Washington Convention Center in Washington. Photo credit: (NASA/Aubrey Gemignani)

Technicians inspect the twin GRACE Follow-On satellites and their multi-satellite dispenser at the SpaceX facility at Vandenberg Air Force Base in California. The satellites were subsequently stacked atop another satellite dispenser containing the five Iridium NEXT communications satellites they will share a ride to orbit with. https://photojournal.jpl.nasa.gov/catalog/PIA22452

Author of Rocket Boys Homer Hickam, Jr. (left) and Marshall Space Flight Center Director Art Stephenson during a conference at Morris Auditorium. Homer Hickam worked at MSFC during the Apollo project years. As a young man, Mr. Hickam always dreamed of becoming a rocket scientist and following in the footsteps fo Wernher von Braun. Years later he would see his dream realized and had written Rocket Boys commemorating his life and the people at MSFC.

Robert Gabrys, director of the Office fo STEM Engagement at NASA’s Goddard Space Flight Center, introduces NASA astronaut Ricky Arnold prior to a presentation to employees, Thursday, May 2, 2019 at NASA’s Goddard Space Flight Center in Greenbelt, Md. During Arnold’s 197 days onboard the International Space Station, as part of Expeditions 55 and 56, he ventured outside the space station on three spacewalks in addition to conducting numerous experiments and educational downlink events. Photo Credit: (NASA/Joel Kowsky)

International Space University (ISU) and Singularity University (SU) Emerging Space Nations Panel held at NASA's Ames Research Center 2009 host site. (From let to right) The panel moderator, Ray Williamson, ISU SSP09 distinguished lecturer and exectuive director of the Secure World Foundation and panelsists Sergio Camacho, secretary genreal, Regional Center for Space Science and Tecnology Education fo rLatin America and the Caribbean, and Nicole Jordan, associate liaison for space prizes for the X Prize Foundation, Playa Vista, Calif., prepare before the discussion begins.

KENNEDY SPACE CENTER, FLA. - As the sun begins to rise in the early-morning sky after its departure from Launch Pad 39A, the Space Shuttle Atlantis slowly travels on the crawlerway toward the Vehicle Assembly Building. This marks the second rollback for Atlantis since July because of hurricane threats. Atlantis, which is targeted fo liftoff later this month on the STS-79 Shuttle mission, is returning to the VAB because of the threat from Hurricane Fran. The threat of Hurricane Bertha forced the rollback of Atlantis in July. Atlantis currently is scheduled for launch on the fourth Shuttle-Mir docking mission around mid-September.

NASA astronaut Ricky Arnold presents Robert Gabrys, director of the Office fo STEM Engagement at NASA’s Goddard Space Flight Center, a montage from his mission onboard the International Space Station, Thursday, May 2, 2019 at NASA’s Goddard Space Flight Center in Greenbelt, Md. During Arnold’s 197 days onboard the International Space Station, as part of Expeditions 55 and 56, he ventured outside the space station on three spacewalks in addition to conducting numerous experiments and educational downlink events. Photo Credit: (NASA/Joel Kowsky)

NASA astronaut Ricky Arnold presents Robert Gabrys, director of the Office fo STEM Engagement at NASA’s Goddard Space Flight Center, a montage from his mission onboard the International Space Station, Thursday, May 2, 2019 at NASA’s Goddard Space Flight Center in Greenbelt, Md. During Arnold’s 197 days onboard the International Space Station, as part of Expeditions 55 and 56, he ventured outside the space station on three spacewalks in addition to conducting numerous experiments and educational downlink events. Photo Credit: (NASA/Joel Kowsky)

The mated Pegasus XL rocket - AIM spacecraft is moved onto a transporter in Building 1655 at Vandenberg Air Force Base in California. The launch vehicle will be transferred to a waiting Orbital Sciences Stargazer L-1011 aircraft for launch. AIM, which stands for Aeronomy of Ice in the Mesosphere, is being prepared for integrated testing and a flight simulation. The AIM spacecraft will fly three instruments designed to study polar mesospheric clouds located at the edge of space, 50 miles above the Earth's surface in the coldest part of the planet's atmosphere. The mission's primary goal is to explain why these clouds form and what has caused them to become brighter and more numerous and appear at lower latitudes in recent years. AIM's results will provide the basis for the study of long-term variability in the mesospheric climate and its relationship to global climate change. Launch is scheduled for April 25.

In a clean-room environment containing the AIM spacecraft (background) at North Vandenberg Air Force Base, a technician studies results of illumination testing on the spacecraft's solar array panels. The AIM spacecraft will fly three instruments designed to study those clouds located at the edge of space, 50 miles above the Earth's surface in the coldest part of the planet's atmosphere. The mission's primary goal is to explain why these clouds form and what has caused them to become brighter and more numerous and appear at lower latitudes in recent years. AIM's results will provide the basis for the study of long-term variability in the mesospheric climate and its relationship to global climate change. AIM is scheduled to be mated to the Pegasus XL during the second week of April, after which final inspections will be conducted. Launch is scheduled for April 25.

In Building 1555 at North Vandenberg Air Force Base, workers get ready to attach the overhead crane to the AIM spacecraft. AIM will be moved into an area where a partial deployment of the solar arrays on the spacecraft will take place. The AIM spacecraft will fly three instruments designed to study polar mesospheric clouds located at the edge of space, 50 miles above the Earth's surface in the coldest part of the planet's atmosphere. The mission's primary goal is to explain why these clouds form and what has caused them to become brighter and more numerous and appear at lower latitudes in recent years. AIM's results will provide the basis for the study of long-term variability in the mesospheric climate and its relationship to global climate change. AIM is scheduled to be mated to the Pegasus XL during the second week of April, after which final inspections will be conducted. Launch is scheduled for April 25.

Inside the clean-room "tent" of Building 1555 at North Vandenberg Air Force Base, two of the solar array panels on the AIM spacecraft are deployed for testing. Inside are the instruments that will study polar mesospheric clouds located at the edge of space. The AIM spacecraft will fly three instruments designed to study those clouds located at the edge of space, 50 miles above the Earth's surface in the coldest part of the planet's atmosphere. The mission's primary goal is to explain why these clouds form and what has caused them to become brighter and more numerous and appear at lower latitudes in recent years. AIM's results will provide the basis for the study of long-term variability in the mesospheric climate and its relationship to global climate change. AIM is scheduled to be mated to the Pegasus XL during the second week of April, after which final inspections will be conducted. Launch is scheduled for April 25.

In Building 1555 at North Vandenberg Air Force Base, workers roll the AIM spacecraft into the "tent" where a partial deployment of the solar arrays on the spacecraft will take place. The AIM spacecraft will fly three instruments designed to study polar mesospheric clouds located at the edge of space, 50 miles above the Earth's surface in the coldest part of the planet's atmosphere. The mission's primary goal is to explain why these clouds form and what has caused them to become brighter and more numerous and appear at lower latitudes in recent years. AIM's results will provide the basis for the study of long-term variability in the mesospheric climate and its relationship to global climate change. AIM is scheduled to be mated to the Pegasus XL during the second week of April, after which final inspections will be conducted. Launch is scheduled for April 25.

Inside the clean-room "tent" of Building 1555 at North Vandenberg Air Force Base, a technician places a star tracker cover on the AIM spacecraft during testing of the solar array panel deployment. The AIM spacecraft will fly three instruments designed to study polar mesospheric clouds located at the edge of space, 50 miles above the Earth's surface in the coldest part of the planet's atmosphere. The mission's primary goal is to explain why these clouds form and what has caused them to become brighter and more numerous and appear at lower latitudes in recent years. AIM's results will provide the basis for the study of long-term variability in the mesospheric climate and its relationship to global climate change. AIM is scheduled to be mated to its launch vehicle, Orbital Sciences' Pegasus XL, during the second week of April, after which final inspections will be conducted. Launch is scheduled for April 25.

Inside the clean-room "tent" of Building 1555 at North Vandenberg Air Force Base, technicians place a star tracker cover on the AIM spacecraft during testing of the solar array panel deployment. The AIM spacecraft will fly three instruments designed to study polar mesospheric clouds located at the edge of space, 50 miles above the Earth's surface in the coldest part of the planet's atmosphere. The mission's primary goal is to explain why these clouds form and what has caused them to become brighter and more numerous and appear at lower latitudes in recent years. AIM's results will provide the basis for the study of long-term variability in the mesospheric climate and its relationship to global climate change. AIM is scheduled to be mated to its launch vehicle, Orbital Sciences' Pegasus XL, during the second week of April, after which final inspections will be conducted. Launch is scheduled for April 25.

Inside the clean-room "tent" of Building 1555 at North Vandenberg Air Force Base, technicians in bunny suits prepare for the solar array deployment on the AIM spacecraft. The AIM spacecraft will fly three instruments designed to study polar mesospheric clouds located at the edge of space, 50 miles above the Earth's surface in the coldest part of the planet's atmosphere. The mission's primary goal is to explain why these clouds form and what has caused them to become brighter and more numerous and appear at lower latitudes in recent years. AIM's results will provide the basis for the study of long-term variability in the mesospheric climate and its relationship to global climate change. AIM is scheduled to be mated to the Pegasus XL during the second week of April, after which final inspections will be conducted. Launch is scheduled for April 25.

The mated Pegasus XL rocket - AIM spacecraft is secured onto a transporter at Vandenberg Air Force Base in California. The rocket will be transferred to a waiting Orbital Sciences Stargazer L-1011 aircraft for launch. AIM, which stands for Aeronomy of Ice in the Mesosphere, is being prepared for integrated testing and a flight simulation. The AIM spacecraft will fly three instruments designed to study polar mesospheric clouds located at the edge of space, 50 miles above the Earth's surface in the coldest part of the planet's atmosphere. The mission's primary goal is to explain why these clouds form and what has caused them to become brighter and more numerous and appear at lower latitudes in recent years. AIM's results will provide the basis for the study of long-term variability in the mesospheric climate and its relationship to global climate change. Launch is scheduled for April 25.

In a clean-room environment at North Vandenberg Air Force Base, a technician begins the illumination testing of the AIM spacecraft at left. The AIM spacecraft will fly three instruments designed to study those clouds located at the edge of space, 50 miles above the Earth's surface in the coldest part of the planet's atmosphere. The mission's primary goal is to explain why these clouds form and what has caused them to become brighter and more numerous and appear at lower latitudes in recent years. AIM's results will provide the basis for the study of long-term variability in the mesospheric climate and its relationship to global climate change. AIM is scheduled to be mated to the Pegasus XL during the second week of April, after which final inspections will be conducted. Launch is scheduled for April 25.

Inside the clean-room "tent" of Building 1555 at North Vandenberg Air Force Base, technicians in bunny suits prepare for the solar array deployment on the AIM spacecraft. The AIM spacecraft will fly three instruments designed to study polar mesospheric clouds located at the edge of space, 50 miles above the Earth's surface in the coldest part of the planet's atmosphere. The mission's primary goal is to explain why these clouds form and what has caused them to become brighter and more numerous and appear at lower latitudes in recent years. AIM's results will provide the basis for the study of long-term variability in the mesospheric climate and its relationship to global climate change. AIM is scheduled to be mated to the Pegasus XL during the second week of April, after which final inspections will be conducted. Launch is scheduled for April 25.

The mated Pegasus XL rocket - AIM spacecraft leaves Building 1655 at Vandenberg Air Force Base in California. The rocket will be transferred to a waiting Orbital Sciences Stargazer L-1011 aircraft for launch. AIM, which stands for Aeronomy of Ice in the Mesosphere, is being prepared for integrated testing and a flight simulation. The AIM spacecraft will fly three instruments designed to study polar mesospheric clouds located at the edge of space, 50 miles above the Earth's surface in the coldest part of the planet's atmosphere. The mission's primary goal is to explain why these clouds form and what has caused them to become brighter and more numerous and appear at lower latitudes in recent years. AIM's results will provide the basis for the study of long-term variability in the mesospheric climate and its relationship to global climate change. Launch is scheduled for April 25.

Inside the clean-room "tent" of Building 1555 at North Vandenberg Air Force Base, technicians in bunny suits prepare for the solar array deployment on the AIM spacecraft. The AIM spacecraft will fly three instruments designed to study polar mesospheric clouds located at the edge of space, 50 miles above the Earth's surface in the coldest part of the planet's atmosphere. The mission's primary goal is to explain why these clouds form and what has caused them to become brighter and more numerous and appear at lower latitudes in recent years. AIM's results will provide the basis for the study of long-term variability in the mesospheric climate and its relationship to global climate change. AIM is scheduled to be mated to the Pegasus XL during the second week of April, after which final inspections will be conducted. Launch is scheduled for April 25.

Inside the clean-room "tent" of Building 1555 at North Vandenberg Air Force Base, two of the solar array panels on the AIM spacecraft are deployed for testing. Inside are the instruments that will study polar mesospheric clouds located at the edge of space. The AIM spacecraft will fly three instruments designed to study those clouds located at the edge of space, 50 miles above the Earth's surface in the coldest part of the planet's atmosphere. The mission's primary goal is to explain why these clouds form and what has caused them to become brighter and more numerous and appear at lower latitudes in recent years. AIM's results will provide the basis for the study of long-term variability in the mesospheric climate and its relationship to global climate change. AIM is scheduled to be mated to the Pegasus XL during the second week of April, after which final inspections will be conducted. Launch is scheduled for April 25.

Inside the clean-room "tent" of Building 1555 at North Vandenberg Air Force Base, technicians in bunny suits prepare for the solar array deployment on the AIM spacecraft. The AIM spacecraft will fly three instruments designed to study polar mesospheric clouds located at the edge of space, 50 miles above the Earth's surface in the coldest part of the planet's atmosphere. The mission's primary goal is to explain why these clouds form and what has caused them to become brighter and more numerous and appear at lower latitudes in recent years. AIM's results will provide the basis for the study of long-term variability in the mesospheric climate and its relationship to global climate change. AIM is scheduled to be mated to the Pegasus XL during the second week of April, after which final inspections will be conducted. Launch is scheduled for April 25.

Inside the clean-room "tent" of Building 1555 at North Vandenberg Air Force Base, two of the solar array panels on the AIM spacecraft are deployed for testing. Inside are the instruments that will study polar mesospheric clouds located at the edge of space. The AIM spacecraft will fly three instruments designed to study those clouds located at the edge of space, 50 miles above the Earth's surface in the coldest part of the planet's atmosphere. The mission's primary goal is to explain why these clouds form and what has caused them to become brighter and more numerous and appear at lower latitudes in recent years. AIM's results will provide the basis for the study of long-term variability in the mesospheric climate and its relationship to global climate change. AIM is scheduled to be mated to the Pegasus XL during the second week of April, after which final inspections will be conducted. Launch is scheduled for April 25.

In Building 1555 at North Vandenberg Air Force Base, workers lift the AIM spacecraft from its stand in order to move it into an area where a partial deployment of the solar arrays on the spacecraft will take place. The AIM spacecraft will fly three instruments designed to study polar mesospheric clouds located at the edge of space, 50 miles above the Earth's surface in the coldest part of the planet's atmosphere. The mission's primary goal is to explain why these clouds form and what has caused them to become brighter and more numerous and appear at lower latitudes in recent years. AIM's results will provide the basis for the study of long-term variability in the mesospheric climate and its relationship to global climate change. AIM is scheduled to be mated to the Pegasus XL during the second week of April, after which final inspections will be conducted. Launch is scheduled for April 25.

In a clean-room environment at North Vandenberg Air Force Base, a technician prepares the lights for illumination testing of the AIM spacecraft at left. The AIM spacecraft will fly three instruments designed to study those clouds located at the edge of space, 50 miles above the Earth's surface in the coldest part of the planet's atmosphere. The mission's primary goal is to explain why these clouds form and what has caused them to become brighter and more numerous and appear at lower latitudes in recent years. AIM's results will provide the basis for the study of long-term variability in the mesospheric climate and its relationship to global climate change. AIM is scheduled to be mated to the Pegasus XL during the second week of April, after which final inspections will be conducted. Launch is scheduled for April 25.

Inside the clean-room "tent" of Building 1555 at North Vandenberg Air Force Base, technicians in bunny suits prepare for the solar array deployment on the AIM spacecraft. The AIM spacecraft will fly three instruments designed to study polar mesospheric clouds located at the edge of space, 50 miles above the Earth's surface in the coldest part of the planet's atmosphere. The mission's primary goal is to explain why these clouds form and what has caused them to become brighter and more numerous and appear at lower latitudes in recent years. AIM's results will provide the basis for the study of long-term variability in the mesospheric climate and its relationship to global climate change. AIM is scheduled to be mated to the Pegasus XL during the second week of April, after which final inspections will be conducted. Launch is scheduled for April 25.