On Mariner 9

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On Mariner 9

Postby mxsquid » 24 Jun 2008, 10:52

Remember when 36 billion computations a day seemed like a lot?

Mariner 9 provided almost twelve times more planetary data than all previous planetary missions combined and it demonstrated the ability to perform a type of orbital operation in which information from any orbital pass could be used to develop an operations plan for the rest of the orbital passes.

The 3 major components of the Mariner Mars 1971 mission sucess:

1. Spacecraft System, for the actual spacecraft hardware that performed precisely timed program and ground commanded activities;

2. Tracking and Data System, for tracking the spacecraft, transmitting the necessary commands
to each spacecraft, and receiving and transmitting information between the tracking stations and the Space Flight Operations Facility; and

3. Mission Operations System, for commanding and controlling each spacecraft during the phases of cruise and orbit.

Analyzing, implementing, testing, documenting the mission interfaces was among the necessary requirements for the success of the Mariner Project.

The following major Mission Operating System (MOS) programs were developed for the 360/175 and the 1108 systems:

(1) ICG (Injection Conditions Generator Program). Computes injection time, velocity, radius; coordinates flight path angle and launch azimuth, using launch time and a polynomial approximation equation.

(2) DPTRAJ (Double Precision Trajectory Program). Integrates equations of spacecraft motion from epoch to desired point using input from ODE, ICG, or nominal data. Provides listings and SAVE tape of position, velocity, look angles, DSS view periods, etc.

(3) ODE (Orbit Data Editor). Prepares DP orbit data file from the real time tracking data master file by selection, compression, correction, or calibration, etc.

(4) DPODP (Double Precision Orbit Determination Program). Calculates best orbit from ODE file data using weighted least-squares trajectory fit. Maps statistical errors to encounter. Also may solve for physical constants, DSS locations, perturbing forces, etc.

(5) SATODP (Satellite Orbit Determination Program). Calculates and maps trajectory and errors as above
from orbital data located in the ODE file.

(6) MOPS (Maneuver Operations Programming System). Calculates maneuver capabilities, maneuver values and commands required for midcourse maneuver, orbit insertion, and orbit trim.

(7) POGASIS (Planetary Observation Geometry and Science Instruments Scan Program). Determines the
orbital science strategy that optimizes science data return and computes for the spacecraft the required scan platform angles and instrument viewing times. Conversely, computes actual coverage and observation conditions based on data received from SPOP (platform orientation and time).

(8) AMPS (Adaptive Mode Planning System). Automates the operation of a set of programs, i.e., POGASIS,
SPOP, SCISIM, COMGEN, SOEGEN, required for the adaptive planning of orbital operations.

(9) LIBSET (Science Library Index System). Automates the operation of a set of programs, i.e., POGASIS,
SPOP, SCISIM, required for producing the science library index.

(10) COMGEN (Command Generation Program). Assembles and checks CC&S programs, simulates the CC&S action
on the program, and forms spacecraft command messages for loading CC&S memory from this assembly or other sequences provided by SCISIM and SPOP.

(11) SCISIM (Science Subsystem Event Simulator Program). Generates flight command subsystem and CC&S
commands and timing for COMGEN in order to accomplish specified data automation subsystem sequences. Simulates data automation subsystem sequencing, and predicts time of occurrences of actual science events in any specified time base.

(12) SOEGEN (Sequence of Events Generator). Generates and displays a time-ordered sequence of events from file or card input, with capability to display or output by mission, tracking station number, etc.

(13) SPOP (Scan Platform Operations Program). Provides commands to COMGEN based on data received from
SCALP or POGASIS. Determines best estimate of platform positioning angles from data received from

(14) IRIS (Infrared Interferometer Spectrometer Program). Accepts experiment data record tape of engineering and interferogram data, processes data and parity information to provide spectral plots and listings, instrument coverage, and performance.

(15) SCILIB (Science Library Program). Provides an index of science measurements for all instruments, including coordinates of planetary "footprints", slant ranges, and illumination angles.

(16) UVS/IRR (Ultraviolet Spectrometer/Infrared Radiometer Program). Provides calibration and formatting of ultraviolet spectrometer and infrared radiometer science telemetry data for display purposes.

(17) OCCULTATION (Occultation Science Program). Accepts received doppler tracking data, calculates
residuals from SATODP or predicted values, and analyzes the data in relation to the spacecraft trajectory derived from DPTRAJ to compute planetary atmospheric parameters.

(18) PSOP (Propulsion Subsystem Operations and Performance Program). Predicts subsystem performance based on propellant/pressurant subsystem analysis; spacecraft mass distribution and thrust vector orientation based on gimbal actuator pre-aim data.

(19) P A P (Telecommunications Performance and Prediction Program). Computes predicted channel performance from antenna pattern data,spacecraft and ground system characteristics and trajectory data. Computes actual performance from real-time telemetry data and ground system, and compares with predicted data.

(20) CELREF (Celestial Reference Program). Computes sensor performance vs clock angle; lists acquirable
objects using sensor characteristics and trajectory data. Calculates spacecraft attitude relative to Sun, planets, or selected stars; and outputs cone and clock angles of celestial objects.

(21) SCALP (Scan Calibration Program). Provides corrections to SPOP for improving accuracy of scan platform pointing, based on calibration data derived from television pictures of stars and actual scan platform angles.

This statement seems so dated now:

"Because of the complexity of the missions and the requirement for rapid processing of great amounts of data, greater use will be made of electronic computers for Mariner Mars 1971 than for any previous planetary project. During orbital operations, these electronic computers will perform about 36 billion computations each day 7 days per week."

http://ntrs.nasa.gov/archive/nasa/casi. ... 029190.pdf
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