STEREO

Encyclopedia excerpt

STEREO (Solar TErrestrial RElations Observatory) is a solar observation mission. Two nearly identical spacecraft (STEREO-A, STEREO-B) were launched in 2006 into orbits around the Sun that cause them to respectively pull farther ahead of and fall gradually behind the Earth. This enabled stereoscopic imaging of the Sun and solar phenomena, such as coronal mass ejections. Contact with STEREO-B was lost in 2014 after it entered an uncontrolled spin preventing its solar panels from generating enough power. It was briefly resumed in 2016 before being interrupted and eventually declared lost.

Orbital Period · P

10,721 yr

v(q)

39.6 km/s

v(Q)

0 km/s

T_J

-0.4

Eccentricity · e

0.9977

Orbit and dynamics

Between its closest point (1.129 AU) and its farthest (971.3 AU), the heliocentric distance changes by 970.2 AU over every revolution.

One full revolution takes 10,721 yr (3,915,729 days), computed from the semi-major axis of 486.2 AU.

The high eccentricity (0.998) produces a strongly elongated orbit, so the object spends most of its time far from the Sun.

A steep inclination of 108.3° carries it well above and below the ecliptic plane.

By the vis-viva equation its orbital speed rises to 39.6 km/s at perihelion and falls to 0 km/s at aphelion.

Its Tisserand parameter with respect to Jupiter is T_J = -0.4, a standard discriminator between asteroidal and cometary dynamics.

Size and surface

Neither a measured diameter nor a reliable absolute magnitude is available for STEREO, so its physical size remains unconstrained.

Observation record and orbit quality

Astrometry from 119 individual observations underpins this orbit; the fit leaves an RMS residual of 0.7366 arcseconds.

About these computed values

Orbital periods, perihelion and aphelion speeds, and diameter estimates on this page are computed by SpaceAtlas from the JPL SBDB orbital elements. They are derived quantities, not values copied from the source catalogue.

Orbital Parameters

Semi-Major Axis

486.2 AU

Eccentricity

0.9977

Perihelion

1.129 AU

Aphelion

971.28174 AU

Inclination

108.31°

Orbital Period

— yr

Epoch

2454960.5

Mean Anomaly

0.0°

Orbit diagram

The Sun sits at the focus (orange). Earth's orbit is the grey circle at 1 AU. The red dot marks the object's position at the catalog epoch.

3D orbit (interactive)

Drag to rotate; scroll or pinch to zoom. The Sun is at the focus (orange), Earth's orbit is the grey ring at 1 AU, and the red dot marks the object's current position.

Close approaches

No close approaches to Earth are currently on record for this object.

Physical Parameters

Diameter

— km

Albedo

—

Density

— g/cm³

Rotation Period

— h

Absolute Magnitude

—

Orbit Quality

RMS

0.73656

Condition

—

Orbit ID

—

Data source: NASA JPL Small-Body Database . Orbital periods, perihelion and aphelion speeds, and diameter estimates on this page are computed by SpaceAtlas from the JPL SBDB orbital elements. They are derived quantities, not values copied from the source catalogue.

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