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Helios

Mission index · dated sources

Spacecraft as evidence, not decoration

Helios connects each planet portrait to a mission that materially changed what can be said about that world. Status labels are kept with their source context; this page is not a live operations console.

Explore the systemRead the data policy
Editorial records
9
Planet systems
8
Source rule
Official record

Selected missions

Eight worlds, different kinds of encounter

Orbiters, flybys, atmospheric probes and Earth-observing platforms answer different questions. The cards preserve that distinction instead of flattening every mission into the same achievement list.

  1. 01

    Mercury

    MESSENGER

    Completed orbiterHistorical

    The first spacecraft to orbit Mercury mapped the planet, studied its composition and magnetic field, and verified water-ice-dominated polar deposits.

  2. 02

    Venus

    Magellan

    Completed radar orbiterHistorical

    Magellan used synthetic-aperture radar to map Venus through its clouds and produced the first near-global view of its surface.

  3. 03

    Venus

    DAVINCI

    Future atmospheric probeLatest available

    DAVINCI is designed to examine Venus from above the clouds to the surface, including atmospheric chemistry, pressure, temperature and descent imaging.

  4. 04

    Earth

    Terra

    Earth-observing orbiterLatest available

    Terra studies interactions among land, atmosphere, oceans and radiant energy, reinforcing the page's view of Earth as a connected system.

  5. 05

    Mars

    Mars 2020 · Perseverance

    Mars rover missionLatest available

    Perseverance explores Jezero Crater for evidence of past habitability, seeks signs of ancient microbial life and collects rock and regolith samples for possible future return.

  6. 06

    Jupiter

    Juno

    Jupiter orbiterLatest available

    Juno probes beneath Jupiter's clouds to study its origin, interior, magnetic field, atmosphere and polar storms.

  7. 07

    Saturn

    Cassini-Huygens

    Completed Saturn system missionHistorical

    Cassini spent thirteen years at Saturn, studying the planet, rings, magnetosphere and moons while Huygens descended through Titan's atmosphere.

  8. 08

    Uranus

    Voyager 2

    Completed flybyHistorical

    Voyager 2 remains the only spacecraft to have studied Uranus at close range, discovering new moons and rings during its 1986 encounter.

  9. 09

    Neptune

    Voyager 2

    Completed flybyHistorical

    Voyager 2 is the only spacecraft to have visited Neptune, revealing moons, rings and the Great Dark Spot during the 1989 encounter.

Reading the catalogue

Status is dated context

“Historical” identifies a completed record. “Latest available” means the linked official page is the newest reviewed source in the repository; it does not imply live telemetry or a guaranteed future schedule.

Mission records remain deliberately selective. They explain why a planet page emphasizes radar mapping, atmospheric descent, polar storms or close-range flyby evidence without claiming to inventory every spacecraft ever launched.