ARTEMIS (THEMIS-B and -C)
ARTEMIS — two of NASA's five THEMIS magnetosphere satellites (launched 17 February 2007), sent to the Moon from 2009 once their Earth mission was done. ARTEMIS-P1 was the first spacecraft to orbit an Earth–Moon Lagrange point, in August 2010; in 2011 both moved into orbits around the Moon, where they study the solar wind, the Moon's wake and Earth's magnetic tail. (Shown at P1's position; P2 flies a similar orbit.)
Key facts
Mission & specifications
Mission
- Operator
- NASA / UC Berkeley
- Launched
- February 17, 2007
- Status
- Active
Trajectory
- Speed rel. the Moon
- 406 m/s
- Computed from the cached state vector, relative to the Moon
- Distance from the Sun
- 0.996 AU
- Computed from the cached position
- Distance from Earth
- 0.116 AU
- Computed from cached positions
- Distance from Venus
- 0.276 AU
- Computed from cached positions
Mission
ARTEMIS began as part of THEMIS, five identical NASA satellites launched together on 17 February 2007 to find out what triggers the sudden brightenings of the aurora. In 2009 two of them, THEMIS-B and THEMIS-C, were given a new mission and a new name: ARTEMIS (Acceleration, Reconnection, Turbulence and Electrodynamics of the Moon's Interaction with the Sun). From July 2009 they used the fuel they had left to make their way to the Moon, a journey of more than a year. ARTEMIS-P1 reached the Earth–Moon L2 point, beyond the far side, on 25 August 2010 — the first spacecraft to orbit an Earth–Moon Lagrange point — and ARTEMIS-P2 reached L1, between Earth and the Moon, on 22 October 2010. In 2011 both moved into elongated orbits around the Moon's equator, about 100 km above the surface at their lowest and 19,000 km at their highest, once every 26 hours: P1 on 27 June and P2 on 17 July. From there they measure how the solar wind flows around the Moon and fills in its wake, how particles are accelerated, and how turbulence develops in the solar wind and in Earth's magnetic tail, which the Moon crosses once a month. (Its position here is JPL Horizons' for P1.)
- 2007THEMIS launches on a Delta II rocketLaunch
Five identical satellites, two of which later became ARTEMIS.
- 2010P1 at the Earth–Moon L2 pointArrival
Beyond the far side: the first spacecraft to orbit an Earth–Moon Lagrange point.
- 2010P2 at the Earth–Moon L1 pointArrival
Between Earth and the Moon.
- 2011P1 in orbit around the MoonArrival
About 100 km above the surface at its lowest and 19,000 km at its highest.
- 2011P2 in orbit around the MoonArrival
Joining P1 in a similar orbit around the Moon's equator.
Images
Images from open archives · credit shown per image