SATURN SYSTEM / SATELLITE DOSSIER

Telesto

Telesto is a small, smooth-looking icy moon that travels around Saturn ahead of Tethys on their shared orbit.

Moon view ↗

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Artist’s impression of Telesto

Telesto is a small, smooth-looking icy moon that travels around Saturn ahead of Tethys on their shared orbit.

Environment ↗

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DIAMETER / EARTH0.0019×
EARTHTELESTO
ATMOSPHERE
No substantial atmosphere detectedEffectively airless
SURFACE TEMPERATURE
Cold exposed surface
SURFACE PRESSURE
Effectively airless
HABITABILITYNo life detected
UNPROTECTED HUMANSNot survivable

Interior ↗

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Telesto interiorTelesto's internal structure is unresolved.Unresolved

Moon system ↗

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Saturn moon orbitsSelected moons, ordered outward. Orbit sizes and positions are schematic; relative periods are preserved.SATURNPANDAPHNISATLASPROMETHEUSPANDORAEPIMETHEUSJANUSMIMASENCELADUSTETHYSTELESTOCALYPSODIONEHELENERHEATITANHYPERIONIAPETUSPHOEBE

Landscape ↗

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An imagined ground-level view of Telesto’s muted icy relief. Powder, fragments and the precise hollow are artistic interpretations.
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Rotation ↗

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Telesto rotation compared with EarthThe markers follow equal elapsed time on both worlds. Equal elapsed time and sidereal rotation rates. Polar schematic: sizes, axial tilt and seasons are not shown. Illumination uses a circular mean orbit, not a live sky prediction.SAME ELAPSED TIME · POLAR SCHEMATICTELESTO45.3 hoursSIDEREAL ROTATIONPrograde spinEARTH23.9 hoursSIDEREAL ROTATION≈ 24 h · solar day

Gravity ↗

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GRAVITY UNKNOWNMASS UNCERTAIN

Orbit ↗

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Telesto orbitElliptical orbit viewed along the orbital axis, relative to Saturn. Motion is accelerated, not a live position. Distances are center to center.SATURNTELESTO≈ 295,000 km
Sources ↗
TELESTO

Instrument detail

THE SKY FROM TELESTO

Saturn, in perspective.

SHARED ANGULAR SCALE
Saturn compared with Luna in Earth's skyAt semimajor-axis distance, Saturn spans approximately 23.57 degrees, 45.51 times the apparent diameter of Luna at its mean distance from Earth. Both disks share one angular scale.SATURNOUR MOON≈ 0.52°
Idealized size study · full disks · decorative lighting · rings excluded
ANGULAR DIAMETER
23.57°
OUR MOON'S APPARENT DIAMETER
45.51 ×
CENTER-TO-CENTER DISTANCE
295,000 km

The viewpoint is on Telesto’s nominal spherical surface, directly facing Saturn. The reference is Luna seen from Earth’s center at its mean distance. The reference distance is the orbit’s semimajor axis. Rounded body diameters and orbital elements set the disk sizes; terrain, phases, rings and the actual sky position are not modeled.

Explore Saturn ↗
Telesto orbitElliptical orbit viewed along the orbital axis, relative to Saturn. Motion is accelerated, not a live position. Distances are center to center.SATURNTELESTO≈ 295,000 km
ONE ORBIT1.887802 Earth days around Saturn
Closest to Saturn
294,705 km
Farthest from Saturn
295,295 km

Telesto circles Saturn. Distances are measured between the centers of the two bodies.

Telesto shares Tethys’s orbit around Saturn. The mean ellipse does not simulate libration around the leading L4 region or the relative positions of the three moons.

Telesto rotation compared with EarthThe markers follow equal elapsed time on both worlds. Equal elapsed time and sidereal rotation rates. Polar schematic: sizes, axial tilt and seasons are not shown. Illumination uses a circular mean orbit, not a live sky prediction.SAME ELAPSED TIME · POLAR SCHEMATICTELESTO45.3 hoursSIDEREAL ROTATIONPrograde spinEARTH23.9 hoursSIDEREAL ROTATION≈ 24 h · solar day
Marked longitude · equal time on both worlds
ONE SIDEREAL ROTATION45.3 hours

Turning through space

The comparison uses approximately synchronous rotation: Telesto turns roughly once per orbit and keeps broadly the same hemisphere toward Saturn. Fine orientation variations and axial tilt are omitted.

0 Earth hoursShared clock

Spin comparison only; no solar day is inferred. Sizes and starting longitudes are schematic, not live positions.

Satellite atlasMoons
Saturn moon orbitsSelected moons, ordered outward. Orbit sizes and positions are schematic; relative periods are preserved.SATURNPANDAPHNISATLASPROMETHEUSPANDORAEPIMETHEUSJANUSMIMASENCELADUSTETHYSTELESTOCALYPSODIONEHELENERHEATITANHYPERIONIAPETUSPHOEBE
FEATURED MOONS19
  1. 01Pan ↗0.575051 days
  2. 02Daphnis ↗0.59408 days
  3. 03Atlas ↗0.604602 days
  4. 04Prometheus ↗0.615878 days
  5. 05Pandora ↗0.631369 days
  6. 06Epimetheus ↗0.697012 days
  7. 07Janus ↗0.697353 days
  8. 08Mimas ↗0.9424 days
  9. 09Enceladus ↗1.37 days
  10. 10Tethys ↗1.8878 days
  11. 11Telesto1.887802 days
  12. 12Calypso ↗1.887803 days
  13. 13Dione ↗2.7369 days
  14. 14Helene ↗2.736916 days
  15. 15Rhea ↗4.5175 days
  16. 16Titan ↗15.95 days
  17. 17Hyperion ↗21.2767 days
  18. 18Iapetus ↗79.331 days
  19. 19Phoebe ↗550.3039 days

Saturn’s moon system includes hazy Titan and icy Enceladus. Methane lakes on Titan and water jets from Enceladus make these worlds compelling destinations in their own right. Saturn itself takes about 29.4 Earth years to complete an orbit.

Janus and Epimetheus share nearly the same orbital distance and exchange inner and outer positions. Their separated tracks here are schematic; this view does not simulate that exchange. Telesto and Calypso share Tethys’s orbit, roughly 60 degrees ahead and behind. Their tracks and positions are also separated schematically here; co-orbital libration is not simulated. Helene similarly shares Dione’s orbit in the leading region.

GRAVITY UNKNOWNMASS UNCERTAIN
SURFACE GRAVITYUnknown

Mass remains uncertain

The cited mass estimate depends on an assumed density. No measured mass is adopted here, so a numerical surface-gravity or jump comparison is not shown.

Telesto interiorTelesto's internal structure is unresolved.Unresolved

Beyond the surface

Telesto’s internal structure is unresolved. Its external shape does not establish separate ice and rock layers or a present-day ocean.

    Artist’s impression of Telesto

    Soft contours on a small world.

    Telesto’s irregular outline encloses a relatively smooth icy exterior. Cassini images show broad hollows without the dense, sharp crater pattern familiar from many larger moons. Fine terrain in the landscape illustrations is reconstructed.

    Sixty degrees ahead.

    Telesto leads Tethys by roughly 60 degrees around Saturn, near the L4 region of their co-orbital arrangement. Calypso is the trailing companion. Telesto orbits Saturn, not Tethys. The system display separates tracks for readability and does not reproduce this shared geometry.

    A surface is not an interior map.

    The adopted mean diameter is about 24.8 kilometers. Published mass estimates can depend on assumed density; no measured mass is adopted for the gravity instrument. The distribution of ice, rock and empty space remains unresolved.

    A shared circuit in forty-five hours.

    The mean orbital scale is about 295,000 kilometers, with a period of 1.887802 Earth days. The spin comparison uses approximately synchronous rotation. The orbital instrument omits libration around the leading co-orbital region.

    DIAMETER / EARTH0.0019×
    EARTHTELESTO
    EARTH
    12,742 km
    TELESTO
    24.8 km
    Mean diameters · circles share one scale

    24.8 km is the adopted mean diameter. Telesto is irregularly shaped; this circle represents equivalent size, not its longest dimension.

    ATMOSPHERE
    No substantial atmosphere detectedEffectively airless

    Telesto is effectively airless. No substantial atmosphere is known to provide breathable air or surface pressure.

    SURFACE TEMPERATURE
    Cold exposed surface
    SURFACE PRESSURE
    Effectively airless
    HABITABILITYNo life detected

    No life has been detected, and a habitable environment has not been established.

    UNPROTECTED HUMANSNot survivable

    The exposed surface requires oxygen, pressure protection and thermal control.

    Planet and landscape images are artistic interpretations.

    • NASA ↗
      • Classification and orbital data
      • Rotation and internal structure constraints
      • Size, physical data and atmospheric constraints
      • Natural conditions and human survival
      • Landscape
      • Companions
    • NASA ↗
      • Parent-body diameter for the angular sky comparison
    • www.sai.msu.ru ↗
      • Mass and gravity constraints
      • Interior
    • NASA / JPL ↗
      • Mean orbital dimensions; distances from parent center
      • Orbit
    • naif.jpl.nasa.gov ↗
      • Rotation model and synchronous or independent spin
    An imagined ground-level view of Telesto’s muted icy relief. Powder, fragments and the precise hollow are artistic interpretations.

    Across a smooth hollow

    An imagined ground-level view of Telesto’s muted icy relief. Powder, fragments and the precise hollow are artistic interpretations.

    A landscape study inspired by Telesto’s smooth appearance. Local slopes and shallow grooves are imagined rather than mapped features.

    Along a rounded ridge

    A landscape study inspired by Telesto’s smooth appearance. Local slopes and shallow grooves are imagined rather than mapped features.

    A single rounded pale icy block half submerged in smooth powder. An artistic reconstruction of Telesto; local detail, lighting and viewpoint are imagined.

    Surface fragments in close view

    A single rounded pale icy block half submerged in smooth powder. An artistic reconstruction of Telesto; local detail, lighting and viewpoint are imagined.