During the 2008 presidential campaign, Barack Obama said he would work to launch the Global Precipitation Measurement mission, "an international effort to improve climate, weather, and hydrological predictions through more accurate and more frequent precipitation measurements."

The last time we looked at this promise -- in February 2012 -- we rated it a Compromise, because the pivotal scheduled launch had been pushed back. By now, though, the launch has taken place, and science experts say the system is working well.

As we've previously noted, scientists have a hard time studying rain, snow and ice because the amounts that fall vary widely even within small distances and because weather events can emerge and disappear quickly. That's where the Global Precipitation Measurement system comes in.

NASA has been collaborating with the Japan Aerospace Exploration Agency on the mission, which includes space-borne "core observatory" designed to help unify and advance measurements from a constellation of multinational research and operational satellites carrying microwave sensors. A second, smaller "Low Inclination Orbiter" had been planned, but it was canceled in the fiscal year 2012 budget.

The U.S. and Japanese space agencies launched the GPM Core Observatory satellite on Feb. 27, 2014. It carried advanced instruments to collect precipitation data that is used "to unify precipitation measurements made by an international network of partner satellites to quantify when, where, and how much it rains or snows around the world," according to NASA.

NASA bills the project as something that advances "our understanding of Earth's water and energy cycles, improves the forecasting of extreme events that cause natural disasters, and extends current capabilities of using satellite precipitation information to directly benefit society."

Marcia Smith, the founder and editor of SpacePolicyOnline.com, told PolitiFact that within the space community, the mission is considered successful. The core observatory is "working with a constellation of other international satellites, and the ones that are in orbit now seem to be working fine, so it's a success story," she said.  

While some of the fruits of the mission's data will advance uncontroversial activities, such as forecasting floods, droughts and hurricanes as well as improving agricultural intelligence, NASA counts on the data also bringing better information about the earth's water cycle and its connection to climate change. That could make the mission a target in a Donald Trump administration that has expressed skepticism about climate change.

For now, though, Obama has presided over the launch of the mission's key piece of hardware -- albeit belatedly -- and it now seems to be functioning well. We rate this a Promise Kept.