The study of the Sun has long been an important part ofastronomy and the recent successful launch of theSunrise Telescope helped to move this forward by producing stunning images of the Sun’s surface. The Sunrise Telescope is launched into the stratosphere carried by a giant helium balloon and will only spend a limited time observing the Sun. However NASA is also planning a more permanent observatory which will be launched into orbit around Earth. This new mission is known as the Solar Dynamics Observatory (SDO) and the design and build phase of the instrument is nearing completion. With a launch date for the mission currently planned for early 2010, our knowledge of the Sun is about to take a giant leap forward.
The SDO mission is the first in NASA’s scientific program called Living With a Star(LWS). This program is being put in place to further our knowledge of solar variability and the impacts that this has on our planet. The SDO mission itself was designed with the aim of studying the solar atmosphere in an attempt to understand its influence on Earth and near-Earth space.
The planning and development of the project is being undertaken by NASA’s Goddard Space Flight Centre and they will also be responsible for managing the operational phase of the mission once its gets underway. Important milestones in recent months have included moving the instrument to Kennedy Space Centre where it is undergoing final testing to ensure it can withstand the rigors of being launched into space and also the conditions it will face during its life orbiting the Earth. A launch date is expected in early 2010 with the mission planned to run for an initial 5 year period.
The aim of the SDO mission is to study how the magnetic field of the Sun is generated and converted into solar activity which comprises solar flares, solar wind and coronal mass ejections. Solar flares and coronal mass ejections can discharge millions of tons of charged particles and solar material into interplanetary space at millions of miles per hour and this can stream towards Earth on the solar wind. This is generally known as space weather and can be potentially dangerous to astronauts in outer space as well as posing problems for technology on and around Earth including satellite communications, electricity supply and navigation systems.
The observatory will be put into an orbit where it can monitor the Sun continuously during its 5 year mission and the three scientific instruments on board will be capable of taking a range of measurements. These instruments will work simultaneously and they include the Extreme Ultraviolet Variability Experiment (EVE) which will measure the Sun’s ultraviolet brightness as often as every ten seconds to record changes in this. The Helioseismic and Magnetic Imager (HMI) will measure sound waves bouncing around the interior of the Sun and also the strength and direction of magnetic fields on its surface which should allow a picture of the Sun’s interior to be built up. The Atmospheric Imaging Assembly (AIA) will take pictures of the various layers in the Sun’s atmosphere in an effort to understand how changing magnetic fields release the energy which leads to solar flares and coronal mass ejections.
Together the suite of instruments on SDO will result in observations that should help scientists gain a much fuller understanding of the complex solar dynamics which impact on Earth and the near-Earth environment. Ultimately this should lead to the development of a capability for assessing and predicting solar variations and this should help to provide an early warning to any potential problems heading our way as a result of solar activity. 2010 should be an exciting year in the continued study of the Sun and with the recent success of the Sunrise Telescope and the operational capabilities of the Solar Dynamics Observatory our knowledge of the Sun could take a giant leap forward in the near future.
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