On October 25, NASA celebrated the 10th anniversary of the launching of the STEREO mission to capture a complete image of the sun. To complete the mission two spacecraft, Stereo Ahead and Stereo Behind, were sent to space.
NASA sent both ships in different directions, orbits, and velocities so STEREO-A was sent ahead of the Earth into a smaller orbit and with higher rates of acceleration while STEREO-B went into a larger orbit and slower acceleration behind the Earth.
The mission was expected to last two years of operations using a coronagraph, a telescope that captures images of the sun by blocking its direct light to have a better look of its plasmatic aura, the corona, which resembles a crown.
The coronagraph was created in 1931 by the astronomer, Bernard Lyot, and since its invention, it is used in most of the solar observatories in the world and is an essential instrument for the STEREO missions.
The ships functioned for over eight years until the connection to STEREO-B was lost on October 1, 2014.
Actually, NASA is only using the transmissions from STEREO-A ship which is the only one that is full operating.
The loss of connections with STEREO-A and STEREO-B
STEREO-B lost connections with Earth during a test during a test of the spacecraft’s command loss timer reset. NASA was testing such function to prepare the ship for a solar conjunction, where the spacecraft is behind the sun.
On August 21, almost two years after the loss of communications with STEREO-B, NASA, to recover the spacecraft, recharged its battery with biolinks from the Mission Operations team. ESeven though it was recovered, its signals are weak and intermittent.
STEREO-A only passed four months because of a superior conjunction. When NASA could communicate with the ship again, it automatically sent the information to Earth. Currently, the spacecraft is working at full capacity.
Other missions that explore the sun
STEREO mission is not the only one that studies the sun. Actually, there are other ten missions to explore the sun in many areas from the effects on Earth to the interstellar particles.
DISCOVER was initially planned to give a continued capture of the Earth and check the temperature of the planet,
It was launched on February 11, 2015, and its current mission is to orbit both sun and Earth, check the climate change, and the effects of the sun as a consequence of the damage of the ozone.
The satellite’s duration of the mission is expected to be five years and currently sends pics of the planet to NASA every two hours.
Solar Dynamics Observatory (SDO) studies the activity of the sun. Its purpose is to measure the effects of the sun in the earth and how these affects society. It also studies the atmosphere of the sun.
SDO was launched on November 2, 2011, and its mission is expected to last from 5 to 10 years.
PICARD mission was sent to space on June 15, 2010. It is in charge to measure the irradiation of ultraviolet rays from the sun. Similarly to SDO and DSCOVR missions, PICARD studies the effects of the sun on the Earth.
Solar Monitoring Observatory (SOLAR/SMO) is in operations since February 8, 2008, its mission is to measure the irradiations of the sun and use them for stellar physics and other research.
Hinode (Sunrise) mission was launched on September 22, 2006, in cooperations with JAXA, NASA, and ESA to study the magnet cycles of the sun.
On February 2, 2002, Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) mission was launched to space. It is currently studying the energy release of solar flares and physic particle acceleration of the sun. RHESSI mission was planned to be in space for two years but still is in full operations.
Advanced Composition Explorer (ACE) satellite is in operations since August 5, 1997, and it serves as a weather predictor controlled by the Space Prediction Weather Center to find geomagnetic storms. Also, studies solar energy and interstellar particles.
Solar and Heliospheric Observatory (SOHO) is one of the oldest missions that still in operations to explore the sun. Working in space since December 2, 1995, SOHO studies both the core and corona of the sun. The satellite found that the atmosphere of the sun diminishes the actual effect of the sun irradiations.
Global Geospace Geoscience (GGS) mission was sent to space 22 years ago. It serves as an auxiliary of the STEREO mission by sending database of the sun. Also, measures solar winds and particles emanated from the star.
Source: Phys.org