This has been an incredible decade for space exploration. From telescopes trained on distant stars to Earth observation satellites monitoring our own world, and from Mercury to the distant reaches of our solar system, numerous missions have come to an end over the last 10 years. Here’s a look:
8. Van Allen Probes (August 30, 2012 to October 18, 2019)
This artist’s conception shows the Van Allen Probes in orbit around Earth.
NASA engineers only expected the probes’ electronics to last 2 years in the harsh radiation environment of the Van Allen Belts (regions of charged particles from solar wind, trapped by Earth’s gravity), but the mission stretched to 7 years and only ended because the probes ran out of fuel earlier in 2019. During that time, they gathered data on the radiation in the Van Allen Belts and how it changes with solar activity. That data will eventually help plan for future solar storms and design spacecraft which can survive intense radiation in deep space. Engineers deactivated the first probe in July and the second in October – but they’ll both keep orbiting until sometime in the 2030s, when their orbits decay into twin fiery atmospheric re-entries.
7. Ocean Surface Topography Mission/Jason-2 (June 20, 2008 to October 9, 2019)
OSTM used one instrument to measure the distance from the satellite to the ocean surface, and … [+]
From orbit about 1,300 kilometers (820 miles) above the planet, Jason-2 used radar to measure the height of the ocean’s surface. The satellite’s radar altimeter measured the distance between the water and the satellite with remarkably precision — pinpointing the distance to within a few centimeters across a distance of 1,300 km. That data helped measure global sea level rise: about 5 cm (2 inches) over the course of the mission. It also helped monitor ocean temperatures and currents, which contributed to better hurricane forecasting. The mission was a joint effort between NASA and the French Space Agency.
6 Spirit and Opportunity Rovers (July 7, 2003 to February 13, 2019)
-, SPACE: In this NASA image released 26 January, 2004 the side of a crater surrounding the Mars … [+]
AFP via Getty Images
The rovers Spirit and Opportunity landed about 10,000 km apart on the surface of Mars in 2004. Spirit explored the basalt plains and Columbia Hills of Gusev Crater until 2010, when it got stuck in the sand with its solar panels pointed in the wrong direction to charge properly. Opportunity kept rolling across Meridiani Planum until a dust storm covered its solar panels in late 2018, leaving the rover without enough power to move, communicate, or – probably – keep its instruments warm enough to prevent damage. NASA tried to contact the rover for several months, but finally gave up in early 2019.
5. Kepler Space Telescope (March 7, 2009 to October 30, 2018)
This artist rendering provided by NASA/JPL-Caltech shows some of the 219 new planet candidates, 10 … [+]
NASA’s planet-finding Kepler Space Telescope discovered thousands of planets orbiting other stars during its 9.5-year-mission. The telescope’s extended mission came to an end in late October, 2018 when the telescope ran out of the hydrazine fuel that kept it pointed in the right direction. NASA engineers spent another two weeks downloading data from the telescope before they switched off its radar transmitter, leaving it to stargaze in solitude.
4. Dawn (September 27, 2007 to November 1, 2018)
IN SPACE JULY 24: In this handout from NASA, the giant asteroid Vesta is seen in an image taken … [+]
2011 Getty Images
NASA’s Dawn spacecraft gave us our first close look at the largest objects in the asteroid belt, the protoplanet Vesta and the dwarf planet Ceres. Its thrusters use electricity to accelerate ions out the back end of the spacecraft, and those ion thrusters let Dawn stretch its fuel supply enough to actually orbit Vesta and Ceres instead of just flying past them at close range. But it also used more conventional hydrazine thrusters for fine maneuvers, and their fuel eventually ran out – leaving Dawn dead in orbit around Ceres.
3. Cassini Spacecraft (October 15, 1997 to September 15, 2017)
A model of the Cassini spacecraft is seen at NASA’s Jet Propulsion Laboratory (JPL) September 13, … [+]
AFP via Getty Images
NASA’s Cassini spacecraft revealed Saturn and its complex system of rings and moons in glorious detail. Just after arriving in Saturn’s orbit in late 2004, it deployed the Huygens lander to the surface of Saturn’s moon Titan, giving us our first glimpse of icy shores and liquid methane lakes. Over the next decade, Cassini mapped those methane seas in more detail, monitored the formation of Saturn’s massive storms, and discovered plumes of water erupting from the surface of Enceladus. In its final weeks, Cassini made several daring dives through Saturn’s rings before finally plunging into the gas giant’s upper atmosphere.
2. Messenger (August 3, 2004 to April 30, 2015)
CAPE CANAVERAL, FL – AUGUST 3: A Delta II rocket carrying NASA’s new Messenger spacecraft lifts off … [+]
Mercury looks like a simple Sun-scorched ball of rock, but the first spacecraft to orbit the innermost planet discovered that it’s a surprisingly complex place. Messenger discovered water ice sheltered in the permanent shadow of the planet’s deepest polar craters, evidence of ancient volcanic eruptions, and a strangely offset magnetic field. The spacecraft helped map the surface of Mercury in great detail, estimate the planet’s mass, and measure how quickly its surprisingly water-rich exosphere was giving way to the solar wind. Years from now, future missions will study Messenger’s newly-dug crater on the far side of Mercury to learn more about space weathering.
1. Space Shuttle Program (April 12, 1981 to August 31, 2011)
CAPE CANAVERAL, FL – JULY 31: Space Shuttle Endeavour touches down at the shuttle landing facility … [+]
From the first flight of Columbia in 1981, NASA’s 6 space shuttles flew a total of 135 missions. The shuttles carried the Hubble Space Telescope into orbit, returned with the instrument that saved the mission from a fatal flaw in the telescope’s mirror, and maintained Hubble for years; they launched several modules of the International Space Station and the astronauts to help assemble them; and they flew thousands of science experiments into low Earth orbit. Space shuttles carried the first African-American astronaut, the first female astronaut, and the first Hispanic astronaut into space. The program endured the tragic loss of Challenger during its launch in 1986, but after the loss of Columbia during re-entry in 2003, the political will to maintain the program ran out. Atlantis returned from its final mission on July 21, 2011, and NASA hasn’t launched its own crewed spacecraft since.