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MMS-4

Catalogued as MMS 4

Magnetospheric Multiscale Mission · NASA

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The fourth and final member of the MMS constellation, completing the tetrahedral formation that makes this mission unique. MMS-4's instruments are duplicates of the other three, providing redundancy and enabling cross-calibration to ensure measurements are consistent across all four spacecraft. Together the quartet has fundamentally changed our understanding of how energy is transferred throughout the solar system and, by extension, throughout the universe — magnetic reconnection powers phenomena from Jupiter's aurora to galaxy-scale particle jets.

Its orbit

Orbit
Highly Ellipticalswings far out, then dives back close to Earth
Altitude
6,628–107,113 mi (10,667–172,381 km)
Inclination
73.1°
One orbit
3.5 days
NORAD ID
40485
Int’l designator
2015-011D
Launched
2015

Orbital elements from CelesTrak, as of 23 Sep 2026.

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