MESSENGER

Spacecraft· NASAinactive

MESSENGER — first spacecraft to orbit Mercury (2011–2015), mapping the planet in full before impacting its surface.

Open in 3D viewSee MESSENGER in the live, interactive 3D map

Key facts

Current speed

2.29 km/s

Distance from Sun

0.317 AU

Status

Completed

Launched

2004

Mission & specifications

Mission

Operator: NASA
Launched: August 3, 2004
Status: Completed

Trajectory

Current speed: 2.29 km/s
Distance from the Sun: 0.317 AU
Distance from Earth: 1.28 AU
Distance from Mercury: 708,063 km

Cost & funding

Program cost: $4.50 × 10⁸ USD

Mission

MESSENGER was the first spacecraft to orbit Mercury, and it finally gave us a complete picture of the Solar System's smallest, strangest planet. Reaching Mercury is deceptively hard — a craft falling toward the Sun gains enormous speed — so after launching on 3 August 2004, MESSENGER spent six and a half years taking a winding path, using one flyby of Earth, two of Venus and three of Mercury itself to shed energy and slow down. On 18 March 2011 it became the first probe ever to enter orbit around Mercury. Mariner 10 had glimpsed less than half the planet in the 1970s; MESSENGER mapped the whole of it. Its discoveries upended expectations. Despite surface temperatures that soar above 400 °C, it confirmed deposits of water ice hiding in the permanent shadows of polar craters, where sunlight never reaches. It found that Mercury's surface had been shaped by widespread ancient volcanism, that the planet has a surprisingly large iron core, and that it is unexpectedly rich in volatile elements, challenging theories of how it formed. After four years and thousands of orbits, its fuel exhausted, MESSENGER crashed into Mercury's surface on 30 April 2015, adding one more crater to the world it had mapped.

2004Launch toward MercuryLaunch
Sets out on a six-and-a-half-year path using repeated flybys to slow down.
2008First Mercury flybyFlyby
The first of three flybys, imaging terrain Mariner 10 never saw.
2011Mercury orbit insertionArrival
Becomes the first spacecraft ever to orbit Mercury and begins mapping the whole planet.
2012Ice at the closest planet to the SunMilestone
Confirms water ice hiding in permanently shadowed polar craters.
2015Impact on MercuryMission end
Out of fuel, MESSENGER crashes onto the surface, adding a crater to the world it mapped.

Images

MESSENGER Views Rachmaninoff Basin Artist Concept — NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington · NASA Image Library

How Mercury Copland Received Its Name — NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington · NASA Image Library

Waters, Waters Everywhere — NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington · NASA Image Library

You Can Crater on Me — NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington · NASA Image Library

Peak-a-boo Eminescu — NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington · NASA Image Library

Twins Image — NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington · NASA Image Library

Approaching Venus Image #2 — NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington · NASA Image Library

I am the MESSENGER, I Speak for the Crater — NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington · NASA Image Library

Images from open archives · credit shown per image