Mission Requirements Document
EXP-TESS-RQMT-0001
Rev #DRAFT
National Aeronautics and
Space Administration
Effective Date: TBD: DRAFT
Expiration Date: TBD: DRAFT
Goddard Space Flight Center
Greenbelt, Maryland
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Mission Requirements Document
EXP-TESS-RQMT-0001
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This document is a TESS controlled document. Changes to this document require prior approval from the TESS Program Office. Proposed changes shall be submitted to the TESS Configuration
Management Office (CMO), along with supportive material justifying the proposed change.
Questions or comments concerning this document should be addressed to:
EHPD Configuration Management Office
Mail Stop 460
Goddard Space Flight Center
Greenbelt, Maryland 20771
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Mission Requirements Document
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Prepared by:
/electronic signature on file/
Benjamin Cichy
TESS Systems Engineer
Code 599
Reviewed by:
/electronic signature on file/
George Ricker
TESS Principle Investigator
MKI
/electronic signature on file/
TBD
TBD: SMA
TBD
_______
Date
_______
Date
_______
Date
/electronic signature on file/
TBD
TBD: MKI/LL
TBD
Approved by:
_______
Date
/electronic signature on file/ _______
Jeff Volosin
TESS Project Manager
Date
Code 401
/electronic signature on file/
TBD
TESS Project Scientist
Code TBD
/electronic signature on file/
TBD
TBD: OSC
TBD
/electronic signature on file/
TBD
TBD
TBD
All reviews and approvals are electronic via the TESS MIS at:
_______
Date
_______
Date
_______
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Mission Requirements Document
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Level
Description of Change
Baseline Document
Approved By
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Date
Approved
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Mission Requirements Document
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REQ ID Description
MRD_12 Stars per observation period . TBD on how to handle the number of stars per observation period. Waiting on flow-down from revised L1 requirements.
MRD_13 Stray light.
TBD on how to handle the stray light requirement and Earth/Moon interference.
MRD_14 Long duration targets.
TBD on how to handle
MRD_16 Measurement time tag precision . TBR on value required by science. Potential driver to S/C
MRD_17 Measurement time tag accuracy . TBR on value required by science. Potential driver to S/C and GND.
MRD_19 Measurement sensitivity . TBR on star brightness, currently I=12
MRD_23 Fine pointing stability . TBR on value. Pending resolution of pointing budget.
MRD_24 Instrument Interface Temperature Stability .
Pending resolution of pointing budget.
Owner
Vanderspek
Hynes
Vanderspek
Vanderspek
Vanderspek
Vanderspek
Hynes
Hynes
Due Date
MRD_25 Instrument Interface Distortion . TBD req
MRD_26 Instrument Solar Heat Flux . TBD req
MRD_29 Science Downlink Data Allocation . TBR as to whether to add margin.
Hynes
Hynes
Cichy
MRD_30 Ground Based Follow-Up Observation Program .
TBD # of targets.
MRD_31 Reconnaissance Spectroscopy . TBD # of targets.
MRD_32 Doppler Spectroscopy . Need # of targets.
MRD_53 Avoidance of Geosynchronous Orbit . TBD as to whether requirement applies to TESS
MRD_54 Launch Period . TBR on # days in lunar cycle
Vanderspek
Vanderspek
Vanderspek
Hynes
Mendelsohn
MRD_55 Launch Window . TBR on duration
MRD_59 Orbit Determination during ascent . TBD m
Mendelsohn
Mendelsohn
MRD_60 Orbit Determination during science orbits . TBD m Mendelsohn
MRD_63 Delta-V Maneuver Accuracy . TBR % Mendelsohn
11/22
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Mission Requirements Document
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1.0 Introduction ................................................................................................................................. 1
1.1
Mission Overview................................................................................................................................... 1
1.2
Requirements Architecture ............................................................................................................... 1
2.0 Mission Description ................................................................................................................... 1
3.0 Requirements .............................................................................................................................. 1
3.1
General Requirements ......................................................................................................................... 1
3.2
Science Requirements .......................................................................................................................... 1
3.3
Mission Phase Requirements ............................................................................................................ 1
3.3.1
Prelaunch .......................................................................................................................................................... 1
3.3.2
Launch ................................................................................................................................................................ 1
3.3.3
Ascent and Commissioning ........................................................................................................................ 1
3.3.4
Science Operations ........................................................................................................................................ 2
3.3.5
Decommissioning .......................................................................................................................................... 2
3.4
Mission Design and Navigation Requirements ........................................................................... 2
3.5
Mission Operations Requirements .................................................................................................. 1
3.6
Mission Robustness and Safety Requirement ............................................................................. 2
3.7
Data Handling Processing and Archiving ...................................................................................... 2
3.8
Project Interfaces ................................................................................................................................... 2
4.0 Appendix A Definitions ............................................................................................................. 2
5.0 Appendix B Requirements Verification Matrix ................................................................ 3
6.0 Appendix C Requirements Linkage Audit .......................................................................... 4
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Mission Requirements Document
1.0 Introduction
TBD
1.1 Mission Overview
TBD: include scientific objectives from L1s
1.2 Requirements Architecture
TBD
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2.0 Mission Description
TBD
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3.0 Requirements
3.1 General Requirements
MRD_3 Environmental Requirements
The TESS Project shall meet the requirements in the Environmental Requirements
Document (ERD).
Rationale : Levy requirements from LV environments and on-orbit environments. ERD will include LV and transportation mechanical & thermal environments, as well as radiation on-orbit thermal requirements
MRD_4 Contamination Control
The TESS Project shall deliver an Observatory with contamination levels consistent with the objectives of the mission.
Rationale : Parent for contamination requirements at L3 and L4. The TESS Project
Contamination Control Plan outlines the processes that will be followed to achieve these requirements.
MRD_5 Orbital Debris
The TESS Project shall prevent the release of any orbital debris during nominal
Observatory deployment, operations, and disposal.
Rationale : Elminates need for TESS to demonstrate mitigations to released debris per
NASA Standard Process for Limiting Orbital Debris (NASA-STD-8719.14).
MRD_6 Probability of Accidental Explosion
The TESS Project shall have an integrated probability of explosion for all credible failure modes of the Observatory and Launch Vehicle less than 0.001 (excluding small particle impacts).
Rationale : Required per NASA Standard Process for Limiting Orbital Debris (NASA-
STD-8719.14). Requirement 4.4.2.1.1.
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Mission Requirements Document
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MRD_7 Common Reference Frames
The TESS Project shall comply with the reference frames in Figure 1.
Rationale : Good practice that all elements use the same reference frames
3.2 Science Requirements
MRD_9 Instrument Accommodation
The TESS Project shall accommodate a wide field imaging photometer (the Instrument).
Rationale : Parent for L3 accommodation requirements.
MRD_10 Observation Period
The TESS Project shall observe each candidate host star for a total observation period of
25 days.
Rationale : L1.3 requires 25 days of total observation.
MRD_11 Instrument FOV
The TESS Project Instrument field of view (FOV) shall be at least 23 deg x 90 deg oriented from ecliptic plane to ecliptic pole.
Rationale : L1.1 requires distribution of targets over celestial sphere. This requirement ensures that during the 2 year mission TESS will be able to observe a large fraction of the sky.
MRD_12 Targets per Observation Period
The TESS Project shall be capable of observing at least [20250 TBR] candidate host stars per Observation Period distributed over the Instrument FOV. (TBD)
Rationale : L1 requirement for 500,000 stars over mission divide by expected number of segments (26) yields 20,000 stars per Observation period. Additional 250 stars provide margin for stars lost due to Earth/Moon interference.
MRD_13 Stray Light
The TESS Project shall limit observations degraded by stray light (e.g. from the Earth and Moon) to [5 TBR] % of total observed targets. (TBD)
Rationale : Loss due to interference is specified over the course of the full mission.
During certain orbits more than 5% of targets may be lost to Earth/Moon interference.
MRD_14 Long Duration Targets
The Project shall be capable of observing [10000 TBR] candidate host stars distributed near the celestial poles for [5] consecutive Observation Periods. (TBD)
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Rationale : L1 requirement is on 120 days of continuous observation for 10,000 targets.
120 days = 4.4 observation periods.
MRD_15 Primary Science Measurement
The TESS Project shall generate photometric measurements centered on each candidate host star every 60 seconds during the observation period.
Rationale : L1.6 requires 1 minute time resolution. See section E.6.3 and "Observing time resolution" on page E-6 of CSR
MRD_16 Measurement Time Precision
The TESS Project shall align measurements made of a candidate host star on adjacent orbits with a relative precision of +/- [10 TBR] sec.
Rationale : Roland to provide (TBD)
MRD_17 Measurement Time Tag Accuracy
The TESS Project shall timetag measurements with an accuracy of +/- [50 TBR] ms relative to UTC.
Rationale : Roland to provide (TBD)
MRD_18 Full Images
The TESS Project shall collect full frame images from the Instrument.
Rationale : Primarily for diagnostic purposes. CSR specifies 12 per day, however frequency will be specified in operations.
MRD_19 Measurement Sensitivity
The TESS Instrument shall have an effective collecting area of at least 50 cm^2, for candidate stars in the spectral range F5-M5 brighter than I=[12 TBR].
Rationale : L1 - Allow the detection of a rich sample of superearths around bright stars.
The transit signal from small planets is inherently small, and the ability to detect the transit events is limited by the effective area of the individual telescopes within the instrument. The requirement as stated above leads to an expected yield of ~500 Super-
Earth or smaller planets.
MRD_20 Coarse Pointing Control
The Observatory shall point the Instrument to within 120 arc-sec 3-sigma without the use of the Instrument.
Rationale : The Instrument does not support a lost-in-space attitude solution. Coarse pointing is required to get the instrument on to the correct guide stars.
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MRD_21 Fine Pointing Control
The Observatory shall point the Instrument to within 40 arc-sec 3-sigma when using the
Instrument as an attitude reference.
Rationale : 40 arc-sec corresponds to two-pixels in the reference camera design. This ensures that a 10x10 postage stamp data product includes the desired 6x6 pixel photometric aperture of a bright star.
MRD_22 Fine Pointing Attitude Estimation
The Instrument shall estimate the inertial attitude of each camera at > 1 Hz frequency with a 3-sigma accuracy of 0.6 arc-sec line-of-sight, and 3 arc-sec in roll.
Rationale : Instrument used for fine pointing attitude knowledge to eliminate need to fly additional star trackers on spacecraft
MRD_23 Fine Pointing Stability
The Observatory shall point the Camera Structure Assembly with [5.5 TBR] arc-sec stability 3-sigma for boresight and roll axes over [1] hour.
Rationale : Allocation of 60 ppm systematic noise to Spacecraft.
MRD_24 Instrument Interface Temperature Stability
The Observatory shall limit the temperature rate of change at the interface to the Camera
Structure Assembly to < [2] deg C per hour during HASO. (TBD)
Rationale :
MRD_25 Instrument Interface Distortion
The Observatory shall limit distortion at the interface to the Camera Structure Assembly to [0.01 TBR] inch displacement and [0.001 TBR] rad rotation per hour. (TBD)
Rationale :
MRD_26 Instrument Solar Heat Flux
The Observatory shall limit the solar flux on the Camera Structure Assembly to [6 TBR]
W/m^2 at sun angles up to 90 degrees. (TBD)
Rationale : To maintain a stable thermal environment for the instrument during science operations, and limit thermal transients during LAHO. Does not apply during fault conditions where sun angles may be greater than 90 degrees.
MRD_27 Instrument Systematic Noise
The Instrument shall limit systematic errors to < 60 ppm, as measured by the excess noise observed in a 1 hour integration during High Altitude Science Operations (HASO) given the pointing and thermal stability environment of the Camera Structure Assembly.
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Rationale : Flowdown of L1 to allow for detection of Earth sized planet transits.
Instrument owns bookeeping of systematic noise, given the sensors sensitivity to the stability of the observatory.
MRD_28 Science and Ancillary Data
The TESS Project shall collect, transmit, and archive Ancillary Spacecraft data and
Instrument Houskeeping data to support science analysis.
Rationale : Ancillary data allows ground post-processing of science data.
MRD_29 Science Downlink Data Allocation
The Observatory shall generate no more than [92 TBR] GB of Science, Ancillary
Spacecraft data, and Instrument Houskeeping data to be downlinked per orbit.
Rationale : Downlink constraints preclude downlinking all raw data. Data must be reduced onboard to a volume that can be downlinked in a nominal DSN downlink pass.
MRD_30 Ground Based Follow-Up Observation Program
The TESS Project shall perform direct imaging and high S/N transit photometry followup observations for [TBD] targets.
Rationale : Agreements from CSR
MRD_31 Reconnaissance Spectroscopy
The TESS Project shall perform spectroscopic follow-up observations for [TBD] targets.
Rationale : Agreements from CSR
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MRD_32 Doppler Spectroscopy
The TESS Project shall perform Doppler spectroscopic follow-up observations for [TBD] targets.
Rationale : Agreements from CSR
3.3 Mission Phase Requirements
3.3.1 Prelaunch
MRD_35 Integration and Test
The TESS Project shall be designed to support Observatory Integration, Test, and Launch
Site operations.
Rationale : The project must design for test, integration, and launch in addition to on orbit operations. Hardware and software design must account for safe operations in all environments.
3.3.2 Launch
MRD_37 Telemetry During Launch
The TESS Project shall transmit telemetry during launch through the Launch Vehicle.
Rationale : Provides data pathway for Spacecraft telemetry while attached to the launch vehicle.
MRD_38 Initial Acquisition
The TESS Project shall acquire telemetry from the Observatory no later than separation +
1 minute.
Rationale : Spacecraft transmitter must be powered OFF during launch due to LV constraints. This requirement sets the time at which first contact with the spacecraft can be established. 1 minute chosen to minimize telemetry outage duration around LV sep critical event.
MRD_39 Post Launch Autonomy
The Spacecraft shall autonomously achieve a thermally stable and power positive state after separation from the Launch Vehicle.
Rationale : Any critical deployments must happen autonomously so that the health of the vehicle does not depend on the ability of the ground to command the vehicle.
3.3.3 Ascent and Commissioning
MRD_41 Commissioning
The TESS Project shall characterize the health and performance of the Observatory within 2 months after launch.
Rationale : Enables project to evaluate end-to-end system operation, and troubleshoot any issues early in operations.
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MRD_42 Operational Orbit
The TESS Project shall achieve the operational science orbit within 2 months after launch.
Rationale : Allows for a full 2 year science mission
3.3.4 Science Operations
MRD_44 HASO
The Observatory High Altitude Science Operations (HASO) shall be greater than [12.5] days.
Rationale : L1 science requires 25 day observation period
MRD_45 HASO Telemetry
The TESS Project shall be designed to receive state of health telemetry during HASO.
Rationale :
MRD_46 LAHO
The Observatory Low Altitude Housekeeping Operations (LAHO) shall be not greater than 16 hours.
Rationale : L1.3 requires 95% continuity on observations over full 25 day observation period. LAHO interrupts the observation. By limiting LAHO to 16 hours, the observation time drops to 97.5% (16hr/25day), yielding 2.4% margin (~15 hours) for other interruptions.
MRD_47 Target Specification
The Observatory shall point the Instrument at a ground specified inertial target.
Rationale : Observing strategy will be based on pointing the instrument boresight at 26 different intertial targets to define observation sectors.
3.3.5 Decommissioning
MRD_49 Decommissioning
The TESS Project shall be designed to decommission and passivate the Observatory at the end of the mission.
Rationale : Required per NASA Standard Process for Limiting Orbital Debris (NASA-
STD-8719.14)
3.4 Mission Design and Navigation Requirements
MRD_51 Mission Orbit
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The TESS Project shall achieve an operational orbit that is a 2:1 lunar resonance High
Earth Orbit.
Rationale : This orbit provides long science view periods, periods that are close to the earth for downlink & is, to first order, stable with respect to lunar perturbations.
MRD_52 Mission Orbit Max Perigee
The TESS Project shall operate the Observatory in orbits with perigee less than 22 Re for the mission life.
Rationale : Allows for balance of Transmitter power, downlink rate & pass duration using standard DSN 34m dishes
MRD_53 Avoidance of Geosynchronous Orbit
The TESS Project shall achieve an operational orbit with a predicted minimum perigee of
GEO +200 km (35,986 km) for a period of at least 100 years after end of mission. (TBD)
Rationale : Required per NASA Standard Process for Limiting Orbital Debris (NASA-
STD-8719.14). Requirement 4.6.2.2 specifies disposal at EOM to be above GEO for at least 100 years. Requirement 4.6.2.4 specifies a probability of success of 0.9 for disposal operations. The latter is satisfied by operating the mission during nominal ops in the desired disposal orbit (dispose in place).
MRD_54 Launch Period
The TESS Project shall have launch opportunities on [25 TBR] days of any given Lunar cycle.
Rationale : Maximize the probability of launch within a given lunar cycle. 25 days ~=
90%
MRD_55 Launch Window
The TESS Project shall provide for launch windows of at least [30 TBR] minutes during each day of the launch period.
Rationale :
MRD_56 Eclipse Frequency and Duration
The TESS Project shall limit the total number of eclipses during the nominal mission to
16 with each eclipse having a maximum duration of 6 hours.
Rationale : Allows power system sizing for reasonable battery size while providing adequate flexibility in mission design targeting of lunar fly-by and launch day of year constraints.
MRD_57 Observatory Sun Angle
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The TESS Project shall collect science data over the range +/-15° between the Instrument boresight angle projected onto the ecliptic plane and the anti-sun vector.
Rationale : Constrains science operations to allow for thermal and power limits. Mission design requires 13.5 degrees. 15 degrees provides approximately 10 percent margin over requirement for variations in orbital period.
MRD_58 Observatory Pitch Angle
The TESS Project shall collect science data at pitch angles from 45° to 67.5° measured from the ecliptic plane
Rationale : Nominal operations will always be at 45 degrees. 67.5 degrees for off nominal case where camera closest to celestial pole fails, and operations team must reorient the
Observatory in order to meet threshold coverage of long-duration targets.
MRD_59 Orbit Determination during ascent
The TESS Project shall determine the orbit ephemerides during ascent to less than [TBD] m (X,Y, Z J2000, 3sigma)
Rationale : Allow for pointing of DSN antennas & dV maneuver planning
MRD_60 Orbit Determination during science orbits
The TESS Project shall determine the orbit ephemerides during the science orbit to less than [TBD] m (X,Y, Z J2000, 3sigma)
Rationale : Allow for pointing of DSN antennas and control of orbit
MRD_61 Slew Performance
The Spacecraft shall be capable of slewing >0.3°/sec with a control accuracy of ≤5° (3 sigma, per axis).
Rationale :
MRD_62 Delta-V Attitude Accuracy
The Spacecraft shall control the Observatory thrust axis during ∆V maneuvers to within
5° of the desired target.
Rationale :
MRD_63 Delta-V Manuever Accuracy
The Spacecraft shall perform ∆V manuevers with an accuracy of +/- [5 TBR]%.
Rationale :
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MRD_64 Missed Maneuver
The TESS Project shall be able to achieve the operational orbit in the presence of any single missed or aborted maneuver.
Rationale : Allows the manuevers to be handled as nominal operations rather than mission critical events. Reduces the availability requirements on the ground and flight system.
3.5 Mission Operations Requirements
MRD_66 Real time commands
The TESS Project shall generate, transmit, and execute real time commands to the
Observatory.
Rationale : Real time commands are required for testing, engineering operations, and to diagnose and recover from anomalies on orbit.
MRD_67 Stored commands
The TESS Project shall generate, transmit, store, and execute command sequences constructed with either absolute or relative execution times.
Rationale : The Observatory will be out of ground contact for much of the science orbit.
Stored commands are required to manage operations during this time.
MRD_68 Telemetry
The TESS project shall provide Observatory state data to determine Spacecraft and
Instrument health, support science operations, and diagnose anomalies during all mission phases.
Rationale : Telemetry required from observatory to determine spacecraft health on orbit, readiness to launch on the pad, etc…
MRD_69 Recorded Telemetry
The TESS Project shall be capable of downlinking real-time and recorded Observatory
Housekeeping data during all S-band contacts.
Rationale : Allows for operations team to debug spacecraft outside of LAHO, potentially enabling recovery prior to the next LAHO and thereby minimizing lost science.
MRD_70 CCSDS Protocols
The TESS Project shall utilize Consultative Committee for Space Data Systems (CCSDS) protocols for command and telemetry links.
Rationale : Provides interoperability for flight and ground systems.
MRD_71 Downlink Performance
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The TESS Project shall be capable of downlinking two Orbits of Spacecraft and
Instrument Data in a 4 hour communication pass.
Rationale : Bounds minimum amount of DSN contact time required to downlink all science data from the previous two orbits
MRD_72 Data Retransmit
The TESS Project shall retransmit the current and prior orbit's Instrument Data in each comm pass.
Rationale : L1 requires 95% of data collected by the spacecraft to be returned to the ground. This approach allows for >97.5% of data to be returned in the presence of DSN outages and weather.
MRD_73 Unattended operation
The TESS Project shall be capable of operating the Observatory, including collecting science data, without ground intervention for 2 orbits.
Rationale : Communication passes may be lost due to ground station issues or weather.
Under the scenario where we are unable to communicate with the Observatory during an individual LAHO, we do not want to sit idle for the subsequent orbit.
MRD_74 Common Time Format
The TESS project shall utilize the CCSDS Time code format.
Rationale : Consistent time code format across elements minimizes confusion
MRD_75 Mission Critical Telemetry and Commanding
The TESS Project shall maintain continuous telemetry and command coverage during all mission-critical events.
Rationale : Gold Rule 1.14. Continuous telemetry coverage shall be maintained during all mission-critical events. Mission-critical events shall be defined to include separation from the launch vehicle; power-up of major components or subsystems; deployment of mechanisms and/or mission-critical appendages; and all planned propulsive maneuvers required to establish mission orbit and/or achieve safe attitude. After separation from the launch vehicle, continuous command coverage shall be maintained during all following mission-critical events.
With continuous telemetry and command capability, operators can prevent anomalous events from propagating to mission loss. Also, flight data will be available for anomaly investigations.
MRD_76 Commandability
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The Observatory shall be capable of receiving and executing real-time commands at all times after launch vehicle separation subject to RF constraints identified in the Spacecraft to Ground ICD.
Rationale : To support anomaly recovery, the ground should always have the capability to command the spacecraft.
MRD_77 Modification of flight software
The TESS Project shall allow for modification of all flight computer flight software images.
Rationale : On-orbit modification of software provides the mission some robustness to unanticipated operational conditions and scenarios.
3.6 Mission Robustness and Safety Requirement
MRD_79 Fault Tolerance
The TESS Project shall be designed to mitigate credible single point failures that would prevent the Project from achieving minimum mission success.
Rationale : Even though TESS is a single-string mission, critical single point failures that prevent the project from achieving minimum mission success must be mitigated through the use of high reliability parts, selective redundancy, graceful degradation, etc…
MRD_80 Safe Hold Mode
The Observatory shall detect anomalous conditions that threaten the health or consumables of the Observatory and autonomously enter a minimum safe operating state
(Safe Hold) that maintains the health, consumables, and commandability of the
Observatory.
Rationale : Gold Rule 1.17. Safe mode provides a state that requires fewer resources and is more robust than operational mode
MRD_81 Safe Hold Duration
The Observatory shall autonomously maintain Safe Hold mode indefinitely, or until all propellant resources have been expended.
Rationale : It may take multiple orbits for the ground to diagnose and recover the spacecraft from an onboard anomaly. During this time commandability may be limited, thus the spacecraft must autonomously maintain vehicle health. This includes performing momentum management, which requires propellant.
MRD_82 Catastrophic Hazards
The TESS project shall mitigate any failure which leads to a Catastrophic Hazard with three independent verifiable inhibits.
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Rationale : Gold Rule 1.24. Catastrophic Hazard A condition that may cause death or permanently disabling injury, major system or facility destruction on the ground, or vehicle during the mission.
MRD_83 Critical Hazards
The TESS Project shall mitigate any failure which leads to a Critical Hazard with two independent verifiable inhibits.
Rationale : Gold Rule 1.24. Critical Hazard A condition that may cause severe injury or occupational illness, or major property damage to facilities, systems, or flight hardware.
MRD_84 Inadvertent Commanding
The TESS Project shall protect against the inadvertent generation, transmission, and execution of commands that may result in damage to the Observatory or loss of mission.
Rationale : Gold Rule 1.23 In a single string Spacecraft, or a redundant Spacecraft with a failure, no single command shall result in Spacecraft "OFF
MRD_85 Instrument Sun/Earth Sensitivity
The Instrument shall be capable of pointing at any target, including the Sun and the
Earth, indefinitely with no damage or permanent impact to performance.
Rationale : Allows for flexibility in mission design and spacecraft safing responses. No expectation that the instrument will be able to collect science data when pointed at the
Sun - see requirement on Sun Angle for science operating range.
MRD_86 Instrument Robustness
The Instrument shall preserve science and engineering data across a power cycle.
Rationale : In certain fault conditions the Spacecraft may remove power from the instrument. In these cases we do not want to lose science data
3.7 Data Handling Processing and Archiving
MRD_88 Science Data Retention
The TESS Project shall deliver >= 95% of Instrument data collected to the project archive.
Rationale : In this requirement, collected refers to data that has been successfully stored within the Instrument onboard the spacecraft. This allocation allows for potential loss of data in transmission and handling.
MRD_89 Science Data Delivery Latency
The TESS Project shall deliver raw and calibrated Instrument data to the Mikulski
Archive for Space Telescopes (MAST) within 6 months of downlink.
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Rationale :
MRD_90 Final Science Data Archive
The TESS Project shall deliver the final science data set and high-level science data products to the MAST within 6 months following the end of mission.
Rationale : Allows the public access to TESS data within 6 months of the end of the baseline mission.
3.8 Project Interfaces
MRD_92 Launch Vehicle Interface
The Observatory shall comply with the LV Interface Requirements Document (LVIRD).
Rationale : LV IRD creates requirements on the interface between the LV & spacecraft
MRD_93 DSN S-Band Uplink and Downlink
The TESS Project shall use S-band through the Deep Space Network for nominal command and telemetry.
Rationale : Need large dishes to communicate efficiently with TESS
MRD_94 DSN Ka-Band Science Downlink
The TESS Project shall use Ka-band through the Deep Space Network for nominal
Instrument Data transmission.
Rationale : Bandwidth is too large for X-band, rate is too high for S-band hence Ka-band
MRD_95 Space Network S-Band Uplink and Downlink
The TESS Project shall use S-band through the Space Network TDRS constellation for contingency commanding and telemetry.
Rationale : TDRS provides contact for phasing orbits at perigee and for critical burns.
Critical operations may not match DSN coverage.
MRD_96 Mission Data Archive
The TESS Project shall archive all Science and supporting data to the Mikulski Archive for Space Telescopes (MAST).
Rationale :
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Mission Requirements Document
4.0 Appendix A Definitions
This section will be completed at a later date.
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Mission Requirements Document
5.0 Appendix B Requirements Verification Matrix
This section will be completed at a later date.
ID Short Title Requirement Rationale
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Allocation Verification
Method
Verification Approach
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Mission Requirements Document
6.0 Appendix C Requirements Linkage Audit
This section will be completed at a later date.
EXP-TESS-RQMT-0001
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