SDO Project Specifications
This section provides details about the SDO spacecraft, when it will be launched, and SDO's planned orbit. Please note that details in the design will change as the mission matures.
The science of the Solar Dynamics Observatory will be performed on a spacecraft that allows both nearly continuous observations of the Sun and a science data downlink rate over of 100 Megabits per second (Mbps). These two requirements determined the orbit and spacecraft design as well as the definition of the SDO Mission.
- 3-Axis stabilized & robust spacecraft.
- Launch mass of 3100 kg (weight of 6800 lbs); 270 kg payload, 1400 kg fuel.
- Spacecraft is 2.2 x 2.2 x 4.5 m, solar panels are 6.5 m across when extended.
- Solar panels cover an area of 6.6 m², producing 1450 W of power. The homeplate shape prevents the solar panel from blocking the high-gain antennas.
- Science data is sent to the ground at a rate of ~130 Mbps on a continuous, high rate data stream at a Ka-Band frequency of ~26 GHz.
- SDO will be ready on February 11, 2010, 10:23 am EST for a launch on an Atlas V from SLC 41 at Cape Canaveral.
- The observatory will be delivered into a geosynchronous transfer orbit (GTO) by the Atlas V. SDO's propulsion system will then perform a circularization maneuver to boost the spacecraft into geosynchronous orbit (GEO).
- SDO's main engine is a bi-propellant system using monomethyl hydrazine (MMH) fuel and nitrogen tetroxide (NTO) oxidizer. Thrusters using the same fuel and oxidizer mix will keep SDO in the correct orbit during the mission.
- The rapid cadence and continuous coverage required for SDO observations led to placing the satellite into an inclined geosynchronous orbit. This allows for a nearly-continuous, high-data-rate, contact with a single, dedicated, ground station.
- Nearly continuous observations of the Sun can be obtained from other orbits, such as low Earth orbit (LEO). If SDO were placed into an LEO it would be necessary to store large volumes of scientific data onboard until a downlink opportunity. The large data rate of SDO, along with the difficulties in managing a large on-board storage system, resulted in a requirement of continuous contact.
- The disadvantges of this orbit include higher launch and orbit acquisition costs (relative to LEO) and eclipse (Earth shadow) seasons twice annually, During these 2-3 week eclipse periods, SDO will experience a daily interruption of solar observations. There will also be three lunar shadow events each year from this orbit.
- This orbit is located on the outer reaches of the Earth's radiation belt where the radiation dose can be quite high. Additional shielding was added to the instruments and electronics to reduce the problems caused by exposure to radiation. Because this a a Space Weather effect, SDO is affected by the very processes it is designed to study!
Project Organization Chart
Integration & Testing Photos
SDO is three years into our five year prime mission, observing the Sun
almost 24 hours a day each day. Almost 130 million images are in the SDO
data archives and 1000 research papers have appeared describing the
science of SDO.
- March 3-8, 2013
- 2013 LWS Solar Dynamics Observatory Science Workshop: "Exploring the Network of SDO Science", Cambridge, MD
- November 12 - 16, 2012
- GONG 2012/LWS/SDO-5/SOHO 27, Eclipse on the Coral Sea: Cycle 24 Ascending, Palm Cove, Queensland, Australia
- March 12-16, 2012
- SDO-4/IRIS/Hinode Workshop, Dynamics and energetics of the coupled solar atmosphere
- October 31-November 4, 2011
- LWS/SDO-3/SOHO-26/GONG-2011 Workshop, Solar Dynamics and Magnetism from the Interior to the Atmosphere, Stanford, CA
- July 25-29, 2011
- Stereo-4/SDO-2/SOHO-25 Workshop, The Sun 360, Kiel, Germany
- May 1-6, 2011
- LWS/SDO-1 Science Workshop, The Many Spectra of Solar Activity - Squaw Valley, CA
- May 1, 2010
- Transition to Phase E
The SDO observatory was launched on February 11, 2010, 10:23 am EST. SDO is
now in the "Launch and Early Operations" phase of mission development,
during which the instruments and spacecraft are turned on and tested on
orbit. At the same time, ground system is used to control the spacecraft and
accept the data from the instruments and subsystems. Once the spacecraft and
instruments are commissioned SDO will begin its observing of the Sun. This
prime observing phase of SDO is planned to last five years - almost half a
solar cycle - with the possibility of a 5-year extension.
- April 21, 1010
- First Light Press Conference, Newseum, Washington, DC
- February 11, 2010, 10:23 am EST
- Launch of SDO
- July 21-22, 2009
- Flight Operations Readiness Review
- June 4, 2009
- Pre-ship Review II
- January 21-22, 2009
- Pre-ship Review I
- December 18, 2009
- SDO passes its Mission Readiness Briefing at NASA HQ
- July 29-August 16, 2008
- SDO passed the Thermal Vacuum Test in the SES chamber
- July 16-25, 2008
- SDO passed the Thermal Balance Test in the SES chamber
- May 25-June 2, 2008
- SDO passed the Vibration and Acoustic tests in Building 10 at Goddard
- April 13-20, 2008
- SDO passed the EMI/EMC Tests in Building 7 at Goddard
- January 5, 2008
- Instrument installed on spacecraft bus, SDO becomes an observatory!
- November 30, 2007
- AIA instrument arrived
- November 14, 2007
- HMI instrument arrived
- October 27, 2007
- Propulsion module placed inside spacecraft bus.
- September 25, 2007
- EVE instrument arrived
- April 5-7, 2005
- Passed Critical Design Review (CDR) at GSFC
- June 1, 2004
- SDO/LWS Confirmation Review at NASA HQ, Transition to Phase C
- March 22-26, 2004
- First SDO Science Workshop in Boulder, CO
- March 9-12, 2004
- Preliminary Design Review
- September 3, 2003
- Initial Confirmation Review at NASA HQ (SDO Project), transition to Phase B
- April 8-11, 2003
- Systems Concept Review (SDO Project with instrument team participation) in Greenbelt, MD
- December 3-5, 2002
- SDO Project Mission Definition Retreat (GSFC project and instrument teams) NASA GSFC
- November 13-15, 2002
- 2nd LWS Community Workshop at JHUAPL
- March 7, 2002
- SDO Science Kick-off Meeting
- January 18, 2002
- SDO Announcement of Opportunity Released: AO-02-OSS-01
- July 2001
- SDO Science Definition Team Report Released
- April 24, 2001
- SDO Announcement of Opportunity Proposals Due
- November 2000 - July 2001
- SDO Definition Team Activities
- July 2000
- LWS Preformulation Study Released
- May 10-12, 2000
- 1st LWS Community Workshop at GSFC