Another trick question! Two ways to find the answer: count the satellites on the globe or review the list under Missions. But the trick is that the GRACE-FO mission is comprised of twin satellites. Not all NASA Earth satellites are shown in Earth Now. The graphic to the right shows more missions in space and planned for the future.

Trick question! The International Space Station has been in orbit about a year longer, but Terra studies the land. After more than 20 years orbiting at 705 km above Earth's surface and routinely crossing the equator at approximately the same time every day, Terra is now drifting nearing the end of its mission studying Earth. With no maneuvers planned to sustain Terra's altitude and crossing time, Terra will slowly get closer and closer to Earth - crossing the equator earlier and earlier as time passes. However, despite impacts to some of Terra's nearly 100 data products, Terra's five sensors continue to collect meaningful scientific data, producing one of the longest continuous climate data records collected by satellite.

Use Missions > Missions Menu > ISS > then click the blue button to reveal all the details for the International Space Station. The ISS circles Earth in about 92 minutes, which equals 15.5 orbits per day.

The GRACE missions measure small month-to-month variations in gravity over Earth's surface arising from the constant redistribution of mass. Changes in how mass is distributed within and between Earth’s atmosphere, oceans, groundwater and ice sheets are fundamental indicators of the large-scale dynamics of the planet. Monitoring changes in ice sheets and glaciers, near-surface and underground water storage, the amount of water in large lakes and rivers, as well as changes in sea level and ocean currents provides an integrated global view of how Earth’s water cycle and energy balance are evolving — measurements that have far-reaching impact on our understanding of the Earth system and important applications for everyday life.

This is a tough one! You must spin the globe and compare the cities. And Christchurch, New Zealand is just a bit closer to the south pole than the others. While you’re doing this, look at all the swirling cloud patterns around Antarctica. Did you know that this area of open water, an “ocean basin” has recently been named the Southern Ocean?

Select the Sea Level data set and look at the color bar. The color red indicated 88+ mm and transitions into white at 176 mm of sea level. These colors indicate regions of sea level greater than average over the last month. Sea levels rise as the ocean is heated and the sea water expands, as well as from the addition of melting ice into the ocean

Select the Carbon Dioxide data set and learn about OCO-2. The Orbiting Carbon Observatory 2, or OCO-2, is an Earth satellite mission designed to study the sources and sinks of carbon dioxide globally and provide scientists with a better idea of how carbon is contributing to climate change.