Mission Requirements Document (MRD) Hierarchy
		1	Science Requirements	4	Spacecraft Requirements
		1.1	Science Observations	4.1	Structural /Thermal
		1.2	Data Capture & Completeness	4.1.1	Launch Vehicle Accommodation
		1.3	Angular Resolution & Coverage	4.1.2	S/C & Instr Accom.
		1.5	Precision, Acc, & Dyn Range	4.1.3	Thermal Monitoring and Control
		1.6	Cadence	4.1.4	Instrument Optical Bench
				4.2	Attitude Control & Determination
		2	Mission Implementation	4.2.1	Acquisition
		2.1	Orbit	4.2.2	Pointing Knowledge
		2.2	Mission Life	4.2.3	Attitude Control and Stability
		2.3	Environment	4.2.4	Propulsion & Delta-V
		2.4	Launch Vehicle (LV)	4.2.5	Momentum Management
		2.5	Mission Implem/ Ops Concept	4.2.6	Safehold
		2.6	Standard Spacecraft Services	4.3	Power
		2.7	Development Approach	4.3.1	Power Generation
				4.3.2	Power Storage
		3	Instrument Requirements	4.3.3	Power Distribution
		3.1	EVE	4.3.4	Load Shedding
		3.1.1	Alignment, Jitter & Stability	4.3.5	Constraints
		3.1.2	Spectral Resolution	4.4	Comm & Data System
		3.1.3	Timing	4.4.1	S-Band Communications
		3.1.4	Data Completeness	4.4.2	Ka-Band Communications
		3.1.5	Interface Requirements	4.4.3	Data System Functions
		3.2	HMI	4.5	HGA Assembly
		3.2.1	Alignment & Jitter	4.5.1	Operation, Pointing and Stability
		3.2.2	Angular Resolution	4.6	Deploy Actuation and Verif
		3.2.3	Timing	4.6.1	Solar Array Deploy and Verif
		3.2.4	Data Completeness	4.6.2	HGA Deployment and Verification
		3.2.5	Interface Requirements
		3.3	SHARPP	5	Ground Segment Requirements
		3.3.1	Alignment & Jitter	5.1	Integration and Test (I&T)
		3.3.2	Angular Resolution	5.1.1	High Rate Science GSE
		3.3.3	Timing	5.1.2	Low Rate GSE
		3.3.4	Data Completeness	5.2	Ground Station Implementation
		3.3.5	Interface Requirements	5.2.1	Dedicated Site Requirements
		3.3.6	Dynamic Range	5.2.2	Ancillary Site Requirements
				5.2.3	Commanding
				5.2.4	Housekeeping Telemetry
				5.2.5	Tracking
				5.2.6	Science Telemetry
				5.3	Mission Operations Center (MOC)
				5.3.1	Cmd and Tlm Functions
				5.3.2	Data Products
				5.4	Science Operations Center (SOC)
				5.4.1	Ops
				5.4.2	Archive
				5.4.3	Data Products
		APS- Antenna Pointing System		INSTR- Instruments (EVE, HMI, SHARPP)
		C&DH- Command & Data Handling Subsystem		LV- Launch Vehicle
		CONTAM- Contamination Subsystem		MECH- Mechanical Subsystem
		DEPLOY- Deployment Subsystem		PARTS- Parts Subsystem
		ELEC- Electrical Systems		PROP- Propulsion Subsystem
		FLT DYN- Flight Dynamics Subsystem		PWR- Power Subsystem
		FSW- Flight Software Subsystem		RAD- Radiation Effects Subsystem
		GN&C- Guidance, Navigation and Control Subsystem		RF- RF Communications Subsystem
		GND- Ground Segment		THERM- Thermal Subsystem
		GSE- Ground Support Equipment Subsystem
		Observatory = Combination of Spacecraft flight segment and Instrument flight segments
		Instruments = EVE, HMI, & SHARPP Flight segments
		SOC = Science Operations Center
		Ground System = Command and control facility and equipment located in the Mission Operations Center (MOC)
		Ground Station = Remotely located antenna site and data distribution facility
		Ground Segment = All ground elements, including ground system, Instrument SOCs, SDO ground station, and any ancillary ground stations
#	Last modified	Title	Functional Requirement	Performance Requirement	Comments	Subsystem Allocation	Trace From	Verify Method
1		Science Requirements
1.1		Science Observations	The science mission shall perform solar observations sufficient to characterize solar activity as the sun exits from a period of solar minimum and progresses to a period of solar maximum	N/A	N/A	N/A	N/A
1.1.1				The SDO Observatory will launch during or shortly after solar minimum (June 2007 to August 2008 (TBR)) in order to permit observations as the solar cycle progresses towards solar maximum	Defines launch requirement within a range that allows initial observations at end of solar minimum	Project	Lev.1 [Science Objectives, Mission Timeline Success Criteria in 4.1.1]
1.1.2				Science observations shall cover 5 years of the progression from solar minimum to solar maximum to meet full mission success science requirements	Comments: Minimum success will be achieved with a series of observations spanning both minimum and maximum conditions, ideally met with a 3-year observation period (c.f. : Level 1 Science Requirements Document for full details).	ALL	Lev.1 [Science Objectives, Mission Timeline Success Criteria in 4.1.1]
1.2		Data Capture & Completeness	The end-to-end system of the SDO Instrument, Spacecraft, and Ground System shall obtain and deliver solar observations to the Investigator’s SOCs of sufficient quality to achieve the mission science objectives.	N/A	N/A	N/A	N/A
1.2.1				The end-to-end HMI Data Capture budget requires 95% of all possible science data over the SDO mission, including delivery of these data to the SOCs.  The EVE and SHARPP data capture budgets require 90% of all possible science data.	For minimum mission success, the Observatory shall return 80% of SHARPP and EVE data, while a completeness of up to 95% (depending on the campaign) is specified in the HMI Science Observation Requirements table in the Level 1 Science Requirements Document. Note that HMI is the driver of this requirement as well as the completeness requirement.  Requirement addressed through the use of a configured data capture budget.  Is this requirement quantifiable?	INSTR, C&DH, GN&C, APS, RF, GND	Lev.1 [Science Meas. 1 in 4.1.1]
1.2.2				The combined HMI Instrument, Spacecraft, and Ground System shall provide an end-to-end data completeness of 99.99% over periods of minutes to hours.The requirement for EVE and SHARPP is 99.9% (TBR).	The HMI observable construction requires minimizing data loss in order to calculate Dopplergrams and magnetograms from a series of filtergrams. The completeness value for EVE and SHARPP will be reviewed to ensure that this value does not unnecessarily drive BER for the instruments.	INSTR, C&DH,  RF, GND	Lev.1 [Science Meas. 1 in 4.1.1]
1.2.3				Individual solar observations shall consist of a minimum of TBD (8??) hours of continuous observation with no planned data gaps greater than TBD (2.5??) minutes in length	Requirement addressed minimum HMI Dopplergram observation size as well as largest observation gap that can be interpolated through before splitting into 2 distinct observations (based on 5 mission feature periodicity).  Affects allowable HGA handover time	INSTR, C&DH, APS, RF, GND	Lev.1 [Science Meas. 1 in 4.1.1]
1.2.4				A data interruption of more than TBD (2.5 minutes??) is considered a data gap and results in the beginning of a separate science observation		INSTR, C&DH, APS, RF, GND	Lev.1 [Science Meas. 1 in 4.1.1]
1.2.5				Data interuptions less than that specified in 1.2.4  are considered a data gap if they are not preceded by TBD times (10x??) the duration of the interruption both prior to and after the event, thereby resulting in the beginning of a separate science observation		INSTR, C&DH, APS, RF, GND	Lev.1 [Science Meas. 1 in 4.1.1]
1.3		Angular Resolution & Coverage	The Instruments shall provide adequate angular resolution and image field of view to meet the Level 1 Science Requirements	N/A	N/A	N/A	N/A
1.3.1				Dopplergrams shall cover the full disk with a sampling of about 0.5 arcsec per pixel, and image quality and stability that enable a resolution of <1.5 arcsec.	Drives high frequency jitter and instrument resolution. Full disk image defines FOV, absolute pointing, and data rate. Using the Rayleigh criterion for diffraction limited resolution, 0.5 arcsec pixels would give 1.2 arcsec angular resolution that would then increase for non perfect optics, pointing, photon statistics, charge spreading, etc.	HMI	Lev.1 [Science Meas. 1 in 4.1.1]
1.3.2				Longitudinal and vector magnetograms shall cover the full disk with a sampling of about 0.5 arcsec per pixel, and image quality and stability that enable a resolution of <1.5 arcsec.	Drives high frequency jitter and instrument resolution. Full disk image defines FOV, absolute pointing, and data rate. Using the Rayleigh criterion for diffraction limited resolution, 0.5 arcsec pixels would give 1.2 arcsec angular resolution that would then increase for non perfect optics, pointing, photon statistics, charge spreading, etc.	HMI	Lev.1 [Science Meas. 2 in 4.1.1]
1.3.3				Atmospheric images shall cover the sun out to 1.4 solar radii with a sampling of 0.66 arcseconds per pixel	Drives jitter but not pointing. 1.32 arcsecond resolution stems from the requirement that a resolved feature should be less than 2 pixels wide (0.66 arcseconds/pixel).	SHARPP	Lev.1 [Science Meas. 4 in 4.1.1]
1.3.4				Coronographic images shall cover the sun from 2 to 15 solar radii with a sampling of 15 arcseconds per pixel	Drives pointing. 30 arcsecond resolution stems from the requirement that a resolved feature should be less than 2 pixels wide (15 arcsecond/pixel)	SHARPP	Lev.1 [Science Meas. 6 in 4.1.1]
1.3.5				Spectral Irradiance measurements must consist of integrated disk measurements over a field of view extending to 1.5 (?TBR) solar radii from the center of the solar disk.	Ensures overlap of EVE and SHARPP measurements.	EVE	Lev.1 [Science Meas. 6 in 4.1.1]
1.4		Spectral Resolution & Wavelength Range	The Instruments shall provide adequate spectral resolution and range to meet Level 1 spectral irradiance and atmospheric imaging measurements	N/A	N/A	N/A	N/A
1.4.1				Solar Spectral irradiance measurements shall be performed in the 0.1 to 105 nm range	For minimum mission success, 6 or more emissions to specify the chromosphere, TR, and corona, plus the He II 30.4 nm emission.	EVE	Lev.1 [Science Meas. 5 in 4.1.1]
1.4.2				Spectral resolution of 0.1 nm for a minimum of 18 emission lines shall be achieved	For minimum mission success, .2 nm for 6 emissions.	EVE	Lev.1 [Science Meas. 5 in 4.1.1]
1.4.3				Spectral resolution of 5 nm for other emission lines shall be achieved	No corresponding measurements for minimum mission.	EVE	Lev.1 [Science Meas. 5 in 4.1.1]
1.4.4				Atmospheric images shall cover the  temperature range spanning 20,000 to 3,000,000 K with 7 wavebands	AIA requirement: 7 telescopes for 7 different wavebands	SHARPP	Lev.1 [Science Meas. 4 in 4.1.1]
1.5		Precision, Accuracy, & Dynamic Range	The Instruments shall provide adequate measurement accuracy over the require measurement range to meet the Level 1 Requirements	N/A	N/A	N/A	N/A
1.5.1				The Dopplergram velocity noise level shall be <25 m/sec over a period of 50 sec.	This flows down to a requirement that images be co-aligned on an HMI sensor to 0.1 arcsec (3-sigma) over the 50-second interval needed for one set of images to limit noise from intensity gradients and image shifts. Note that 15 Km/sec Doppler shift only possible in orbits where Doppler shift is small between observations, such as GEO or L1 orbits.	HMI	Lev.1 [Science Meas. 1 in 4.1.1]
1.5.2				Longitudinal magnetograms shall have a zero point error of <0.3 Gauss.	Do we need a definition of zero point error?	HMI	Lev.1 [Science Meas. 2 in 4.1.1]
1.5.3				Longitudinal magnetograms shall have a noise level of < 5 Gauss over a period of 10 minutes.	This flows down to a requirement that images be co-aligned on an HMI sensor to 0.1 arcsec (3-sigma) over the 50-second interval needed for one set of images to limit noise from intensity gradients and image shifts. Note that 15 Km/sec Doppler shift only possible in orbits where Doppler shift is small between observations, such as GEO or L1 orbits.	HMI	Lev.1 [Science Meas. 2 in 4.1.1]
1.5.4				Longitudinal and vector magnetograms shall have a dynamic measurement range of +-3 kGauss		HMI	Lev.1 [Science Meas. 2, 3 in 4.1.1]
1.5.5				The polarimetric precision in Q, U, and V should be better than 0.3% in 10 minutes.	Q, U, and V are the basic polarimetry measurements from which the vector magnetic field is derived. The noise level and systematic errors of vector magnetic field measurements are complicated functions of solar conditions and Q, U, and V. This also flows down to the image stability requirement of 0.1 arcsec (3 sigma).	HMI	Lev.1 [Science Meas. 2 in 4.1.1]
1.5.6				Calibration of the intensity of the atmospheric images shall be 10%. This absolute calibration is defined to be the daily averaged integrated solar disk intensity.	Minimum mission success shall be 20% (TBR). SHARPP calibration requirements should not exceed those of EVE.	SHARPP	Lev.1 [Science Meas. 4 in 4.1.1]
1.5.7				Signal to noise of atmospheric images shall be 8 in quiet sun, 20 in active sun	6 in quiet sun, 15 inactive sun for minimum mission success.	SHARPP	Lev.1 [Science Meas. 4 in 4.1.1]
1.5.8				Coronagraphic images shall have a calibrated intensity precision (absolute accuracy) of 10%	20% for minimum mission success.	SHARPP	Lev.1 [Science Meas. 6 in 4.1.1]
1.5.9				Spectral irradiance measurements shall have an absolute accuracy of 10% for 5 nm intervals and daily average	20% for minimum mission success.	EVE	Lev.1 [Science Meas. 5 in 4.1.1]
1.5.10				Spectral irradiance measurements shall have a precision of 2% per year	5% for minimum mission success.	EVE	Lev.1 [Science Meas. 5 in 4.1.1]
1.6		Cadence	The Instruments shall provide data sets with adequate cadence to study solar phenomena on appropriate time scales	N/A	N/A	N/A	N/A
1.6.1				The dopplergrams shall have an observation cadence of no higher than 50 seconds	Drives instr observation timing, instr processing & data rate	HMI	Lev.1 [Science Meas. 1 in 4.1.1]
1.6.2				The longitudinal magnetograms shall have an observation cadence of no higher than 50 seconds	Drives instr observation timing, instr processing & data rate	HMI	Lev.1 [Science Meas. 2 in 4.1.1]
1.6.3				The vector magnetograms shall have an observation cadence of no higher than 5 minutes	Drives instr observation timing, instr processing & data rate	HMI	Lev.1 [Science Meas. 3 in 4.1.1]
1.6.4				The atmospheric images shall have an observation cadence of no higher than 10 seconds	20 seconds for minimum success. Drives instr observation timing, instr processing & data rate	SHARPP	Lev.1 [Science Meas. 4 in 4.1.1]
1.6.5				The coronagraphic images shall have an observation cadence of no higher than 60 seconds	80 seconds for minimum success. Drives instr observation timing, instr processing & data rate	SHARPP	Lev.1 [Science Meas. 6 in 4.1.1]
1.6.6				The spectral irradiance measurements shall have an observation cadence of no higher than 20 seconds	60 seconds for minimum success. Drives instr observation timing, instr processing & data rate	EVE	Lev.1 [Science Meas. 5 in 4.1.1]
2		Mission Implementation
2.1		Orbit	SDO orbit shall be selected to support the instrument science requirements and overall ops concept	N/A	N/A	N/A	N/A
2.1.1				Geosynchronous orbit with an initial RAAN of 200 +/- 7.5 degrees longitude	Geo orbit allows continuous ground contact for high rate downlink and introduces an acceptable orbital Doppler shift and orbital period for HMI measurements;  RAAN selection minimizes eclipse season impacts to science data collection; also has impacts on antenna FOV and handovers in degraded mode. Tolerance on RAAN defines launch window (each 1 hour widening of window results in 15 deg RAAN shift).  Launch window opens at 192.5 degrees	LV, GN&C, PROP, FLT DYN	Lev.1 [Science Meas. 1], 1.2.1 (Data Capture & Comp.), 1.5.1 (Dopplergram accuracy), 1.6 (Cadence)
2.1.2				The Observatory shall be designed to support operations in an orbit with two yearly eclipse seasons with a maximum duration of 23 days, each with a maximum daily shadow of 72 minutes	Eclipse seasons indicated in AO. Orbit eclipse characteristics derived from RAAN selection	GN&C, FLT, DYN, PROP, MECH, THERM, PWR	Lev.1 [Science Meas.], 1.2.1 (Data Capture & Compl)
2.1.3				The orbit shall be selected to have an average longitudinal stationkeeping position within a range of 100-110 deg W longitude	Based on gravity well at specified position which minimizes stationkeeping maneuvers	LV, GN&C, FLT, DYN, PROP	Lev.1 [Science Meas.], 1.2.1 (Data Capture & Compl)
2.1.4				The Observatory shall maintain a stationkeeping position within +/- 0.5 deg of its allocated average longitudinal position	Based typical longitudinal orbit slot for Geo Spacecraft	GN&C, FLT, DYN, PROP, GND	Lev.1 [Science Meas.], 1.2.1 (Data Capture & Compl)
2.1.5				The mission shall be designed to remain within a maximum orbital eccentricity of 0.005 (TBR) over the course of a 5 year mission	Defines orbit characteristics- does not place prohibitive reqs on orbit; Affects HGA/ground station pointing angle (minimizes antenna pointing angles) & Delta-V stationkeeping budget; Eccentricity provides predictable range for HMI doppler effects; Keeps observatory above outer Van Allen belt	GN&C, FLT, DYN, PROP, GND	Lev.1 [Science Meas.], 1.2.1 (Data Capture & Comp.), 1.5.1 (Dopplergram accuracy)
2.1.6				The Observatory and mission shall be designed for a maximum orbital inclination of < 30 (TBR) over the 5 year mission life	Initial inclination at launch planned to be 28.7 deg; Affects HGA/ground station pointing angle & Delta-V stationkeeping budget	GN&C, FLT, DYN, PROP, GND	Lev.1 [Science Meas.], 1.2.1 (Data Capture & Comp.)
2.2		Mission Life	Mission life shall be sufficient to achieve science data collection to meet fundamental science requirements	N/A	N/A	N/A	N/A
2.2.1				5 Year Mission Life (after reaching on-station GEO orbit and post commissioning activities)	Derived from Level 1 Reqs; Level 1 doc indicates three years as minimum mission life.	ALL	Lev.1 [Science Objectives, Mission Timeline Success Criteria in 4.1.1], 1.1.2 (Science Observ)
2.2.2			The SDO Spacecraft shall be designed to be tolerant to a single fault tolerant and still meet minimum mission success criteria or shall employ sufficient testing or analysis to ensure system reliability where fault tolerance and graceful degradation does not exist		Project guidelines direct the design of the most robust and fault tolerant system within the constraints of allocated resources.  Requirement reflects accepted design practice commensurate with mission scope; spacecraft will employ the use of redundancy, cross-strapping and spacecraft system design that promotes graceful degradation of the SDO spacecraft functions in the event of an anomaly or failure to allow spacecraft to meet 5 year goal; Anticipate that the redundancy implementation required to meet project-level reliability requirements for a 5 year mission	ALL	1.1.2 (Science Observ), 2.2.1 (