Astronomical specifications:

Orbital characteristics:
Distance from Galatic Center ~2.5 x 1017 km
Orbital periode about Galatic Center 225-250 million years
Orbital Speed ~220 km/s
Physical characteristics:
Diameter 1,392,000 km
Surface area 6.0877 x 1012 km²
Volume 1.4122 x 1018 km³
Mass 1.9891 x 1030 kg
Density 1.409 g/cm³
Equatorial gravity 274.0 m/s²
Escape velocity 617.7 km/s
Rotation period 25.38 hours
Axial tilt to the ecliptic 7.25 deg
Surface temperature 5,778 K

The Sun by the Atmospheric Imaging Assembly of NASA's Solar Dynamics Observatory


Early history:

Space race:

Solar missions:

Name Launch
Launch rocket Weight
Pioneer 5 (USA) 11-Mar-60 Thor-Able 43 kg First deep-space probe, returned data from a distance of 36.5 million km.
Pioneer 6 (USA) 16-Dec-65 Delta 61 kg Solar probe, orbiting Sun inside Earth's orbit.
Pioneer 7 (USA) 17-Aug-66 Delta 61 kg Solar probe, orbiting Sun outside Earth's orbit.
Pioneer 8 (USA) 13-Dec-67 Delta 66 kg Solar probe, orbiting Sun outside Earth's orbit.
Pioneer 9 (USA) 08-Nov-68 Delta 67 kg Solar probe, orbiting Sun inside Earth's orbit.
Pioneer E (USA) 27-Aug-69 Delta 67 kg Solar probe, failed to achieve Earth orbit.
Explorer49 (US)
(RAE 2)
10-Jun-73 Delta-1913 328 kg Solar physics mission, in lunar orbit 15 June 1973.
Helios 1 (US/FRG) 10-Dec-74 Titan-Centaur 370 kg Solar probe orbiting within 0.3 AU of Sun.
Helios 2 (US/FRG) 15-Jan-76 Titan-Centaur 376 kg Solar probe orbiting within 0.29 AU of Sun.
ICE (USA) 12-Aug-78 Delta-2914 469 kg Originally launched as International Sun-Earth Explorer 3 (ISEE-3). Transfer to escape trajectory and renamed International Comet Explorer.
SMM (US) 14-Feb-80 Delta-3910 2315 kg Studied solar eruption in the year of the most important solar activity.
Ulysses (ESA/US) 06-Oct-90 Shuttle/IUS 371 kg Jupiter gravity assist International Solar Polar Mission (ISPM). First craft to pass over the poles of the Sun (south pole in mid-1994, north pole in mid-1995)
Solar-A (Japan) 30-Aug-91 M-3S-2 - Japanese mission to study solar flares from Earth orbit.
Wind 1 (USA) 01-Nov-94 Delta II 1.195 kg Solar probe, orbiting Sun inside Earth's orbit.
SOHO (ESA) 02-Dec-95 Atlas-2AS - kg European solar observatory in solar orbit. The SOHO solar observatory, orbiting the Earth-Sun L1 point, has been lost due to an apparent gyroscope problem.
TRACE 02-Apr-98 Pegasus-XL 213 kg Will explore the connections between fine-scale magnetic fields and the associated plasma structures of the Sun.
Genesis (USA) 08-Aug-01 Delta-2 636 kg This robotic probe will park for 2½ years about a million miles away to collect samples of the solar wind. The Genesis spacecraft completed orbital correction on August 9, August 29 and September 6, 2004 as it approched Earth. The spacecraft re-entry capsule separated from the spacecraft bus on September 8, 2004 and crashed into the Utah desert floor.
Stereo-A, Stereo-B (USA) 26-Oct-06 Delta-7925 620 kg These are identical satellites which orbit the sun, Stereo-A(head) of the Earth and Stereo-B(ehind) the Earth. They will create stereo images of the sun used to predict Coronal Mass Ejections headed for the Earth.
Herschel/Planck (ESA) 14-May-09 Ariane-5ECA 3402/1921 kg In May 2009 the Herschel infrared space telescope and the Planck microwave background observatory were launched, and were stationed at the Earth-Sun L2 Lagrange Point 1.5 million km towards midnight.
Aug 2013: After completing their very successful missions, the spacecrafts have now been sent into solar orbit and will be deactivated.
Herschel departed L2 on Apr 1, 2013 and was turned off on Jun 17; it is in a 1.04 x 1.06 AU x 0.19 deg solar orbit.
Planck departed L2 on Aug 14, 2013 for a 1.00 x 1.10 AU x 0.1 deg orbit and will be switched off on Oct 23.
Akatsuki (Japan) 20-May-10 H-2A-202 640 kg The craft failed to enter Venus orbit in December 2010 and remains in solar orbit.
Ikaros (Japan) 20-May-10 H-2A-202 315 kg Solar sail.
UNITEC 1 (Japan) 20-May-10 H-2A-202 16 kg In solar orbit.
PROCYON (Japan) 03-Dec-14 H-2A-202 65 kg In solar orbit (May 2015)

Ref.: #7(JR684), #98, #214 - update: 09.10.13 Home