Andromeda
Log inJoin

NASA spacecraft

Advanced Composition Explorer (ACE)

Also advanced composition explorer · advanced composition explorer ace

Open in OuranosCompare its size

Operating — NOAA's backup solar-wind source behind SOLAR-1 (NOAA SWPC notice, 2026-06-30); its real-time data was flowing on 2026-11-01, when NOAA's feed marked it the active source. At the Sun–Earth L1 point since 1997.

At Earth.

Measured

Agency
NASA
Arrived
1997-12-12
From the Earth today
1,487,403 km
Body, across
1.6 m

How far, from the Earth

1.49 million km. To cross it:

  • Light4.96 seconds
  • Voyager 1's speed1.02 days
  • Driving at 100 km/h20.4 months

Voyager 1 at the speed it moved outward over the year to 2026-10-25 (JPL Horizons). Driving: nonstop, never refuelling.

Facts

  • JPL Horizons trajectory round Earth: worst miss 71 km on the dates it was checked against (median 45 km); between those dates as much as about 214 km. Dates after the data was fetched are Horizons' predictions, which it revises as a mission flies.

Where this comes from

  • NASA/Caltech
  • Spacecraft trajectories: JPL Horizons, NASA/JPL-Caltech; each mission's agency credited on its card.
  • 3D model: Advanced Composition Explorer model: NASA 3D Resources

Every catalogue Ouranos draws is credited on the credits page.