The spacecraft behind CME Tracker

The Solar and Heliospheric Observatory is the grandfather of the fleet. Designed for a two year mission, it has now watched the Sun for three decades. Its LASCO coronagraphs block out the Sun's disk with a small occulting disk, the way you'd block the Sun with your thumb, so the faint outer atmosphere becomes visible. That is where CMEs are first seen: a bright cloud leaving the Sun at hundreds or thousands of kilometers per second.

For a decade the Deep Space Climate Observatory was the craft the world watched for storms. It sits in the solar wind's path and simply reports what is flowing past: how fast, how dense, and which way the magnetic field is pointing. Because it's a million miles upstream, its readings arrive 30 to 60 minutes before the same wind hits Earth. That hour is the entire basis of short term storm warnings. In 2026 NOAA handed that job to SOLAR-1; DSCOVR is still at L1.

NOAA's first satellite built purely for space weather. It launched in September 2025 sharing a rocket with IMAP, reached L1 in January 2026, and after checkout took over from DSCOVR as the operational solar wind monitor in the spring. It carries the same kind of instruments as its predecessors, a plasma sensor and a magnetometer, plus two things DSCOVR never had: an energetic particle detector and CCOR-2, a compact coronagraph, so a single craft can now both see a CME leave the Sun and feel it arrive.

The Interstellar Mapping and Acceleration Probe's main job is far bigger than Earth: it maps the boundary where the Sun's wind meets interstellar space, by catching neutral atoms that drift in from the edge of the heliosphere. But it sits at L1 with a full set of solar wind and particle instruments, and NASA built it a real time data stream specifically so forecasters could use it. That makes it the first science mission designed from the start to double as a space weather sentinel.

The Advanced Composition Explorer was built to study what the solar wind is made of, atom by atom, but it became famous for something else: for eighteen years it was the world's real time solar wind monitor, the craft whose readings NOAA watched to see storms coming. DSCOVR took over that job in 2016 and SOLAR-1 in 2026. ACE is still flying, nearly thirty years on, and still streams as a backup.

The GOES satellites are the weather satellites behind every hurricane image on the news, and they carry a second set of eyes pointed at the Sun. An X-ray sensor measures the Sun's X-ray brightness every second; when it spikes, that's a solar flare, and its height gives the flare its class (C, M or X). Particle detectors count the protons that arrive after big flares, the radiation storms that matter to astronauts and airline crews over the poles.

The Solar Dynamics Observatory is the Sun's portrait photographer. It takes a full disk image every 12 seconds in ten wavelengths, from visible light (where you see sunspots) to extreme ultraviolet (where you see the million degree corona, loops of magnetic field, and flares as they erupt). It sends home more data every day than most missions do in their lifetime.

A coronagraph on the Earth side of the Sun has a problem: a CME coming straight at us looks like a ring growing in all directions, and you can't tell how fast it's really moving toward you. STEREO-A solves this by looking from the side. It's on its own orbit around the Sun, slowly lapping Earth, so it sees the same CME from a different angle. Two angles give you the true direction and speed. Its twin, STEREO-B, was lost in 2014.

Parker is the fastest object humans have ever built, and the first to fly through the Sun's corona. Its closest passes bring it inside 10 solar radii, where it's protected by a carbon foam shield that faces 1,400°C while the instruments behind it sit near room temperature. It samples the solar wind at its birthplace, before it has had time to mix and cool, which is how we're learning why the wind is fast in some places and slow in others.

Solar Orbiter does two jobs at once: it photographs the Sun from as close as 0.28 AU with the sharpest cameras ever flown there, and it samples the wind flowing past at the same time, so what it sees and what it feels can be matched up. Each Venus flyby tips its orbit further out of the flat plane the planets live in. By the end of the decade it will look down on the Sun's poles, which no camera has ever seen.