NASA C-130B Aircraft Source/Platform Document

NASA C-130B Aircraft, C-130B

The retired NASA C-130B is a low- and medium-altitude, moderate-speed aircraft. With a maximum performance altitude of 25,000 feet and a nominal performance altitude of 22,000 feet, the NASA C-130B flies from approximately 150 to 330 knots with a range of 2,200 nautical miles.

NASA C-130B Aircraft (138 kb)

The NASA C-130B aircraft is operated through the NASA Earth Resources Aircraft Program at NASA Ames Research Center in Moffett Field, California.

In operation since January 1980, the NASA C-130B aircraft has been part of NASA's Airborne Science and Applications Program and has been used to acquire data for Earth science research (e.g., forest canopy surveys, soil transpiration studies, oceanographic exploration, biomass combustion studies, satellite instrument calibration). The aircraft serves as a platform for a variety of sensors that collect data in support of NASA-sponsored scientific projects as well as projects involving other Federal Government, State, university, and commercial investigators. The NASA C-130B aircraft is part of a fleet of airborne platforms that provide or that have provided support to the Earth Science Enterprise initiative.

Data are collected over selected areas of the United States, Alaska, and Hawaii. The NASA C-130B aircraft also has been deployed to the United States territory of Puerto Rico and to international sites, including Africa, Australia, Bermuda, France, Germany, Austria, and Italy.

The NASA C130-B aircraft's automatic flight control system limits deviations in pitch, yaw, and roll by monitoring speed, altitude, and weight. The system also provides automatic elevator trim, coordinated turn, and constant barometric altitude control.

When cruising at a constant speed and altitude, the NASA C130-B aircraft flies at a 1- to 3-degree, nose-up attitude. The nominal attitude value is 1.5 degrees; however, the actual angle depends on a combination of gross weight, altitude (altitude decreases as fuel is consumed), and true airspeed. When parked, the aircraft rests at a 1.5-degree, nose-down attitude. During the installation or calibration of equipment, the aircraft can be leveled to zero degrees by elevating the nose.

The frequency ranges of various NASA C-130B navigation, radio, and radar units are provided to experimenters, who are subsequently cautioned to engineer equipment in a manner that prevents spurious response at given frequencies. Experimenters are also directed to limit sensor telemetry output to 100 milliwatts maximum.

The Inertial Navigation System (INS) sends serial digital and analog outputs to a C-130 Automated Digital Data System (CADDS), including latitude, longitude, true heading, drift angle, ground speed, wind speed, wind direction, distance and time between waypoints or reference points, track and track-angle error information, pitch and roll angles, and cross-track distance. A stream of 12 INS values is received during a 600-millisecond interval with each parameter separated by a 50-millisecond interval. Pitch and roll values are averaged together to produce one set of output values per second.

Altitude data collected from above the local mean terrain are sent in a serial digital format to the CADDS from a radar altimeter at 80-millisecond intervals. The CADDS also receives barometric pressure readings although the radar altimeter is a more accurate source for readings above the local mean terrain. An onboard computer system provides synchronized analog outputs for wind computations, and a sensor measures ambient free air outside the aircraft for total air temperature calculations. A precision radiation thermometer measures gross apparent radiation in an 8- to 14-micrometer range with its optical head nadir-mounted and roughly boresighted to the NS-001 multispectral scanner, while a two-stage hygrometer measures prevailing dew point and frost point temperatures. Data are time stamped with a code provided by a Datum time code generator. Though collected in millisecond intervals, some of the values gathered through the CADDS are averaged, usually to produce one set of output values per second per instrument or sensor (i.e., if 10 values for total air temperature are acquired each second, then the CADDS averages these values to produce one value per second). Data may be distributed to onboard experimenter stations in real time.

A wide variety of sensors and instruments may be carried aboard the NASA C-130B aircraft, including:

• ASAS -- Advanced Solid-State Array Spectroradiometeri
• C-SCAT -- C-Band Radar Scatterometer
• Frost Dew Point Hygrometer
• MAS -- Moderate-Resolution Imaging Spectroradiometer (MODIS) Airborne Simulator
• NS-001 Multispectral Scanner
• NUSCAT -- K-Band Radar Scatterometer
• PBMR -- Pushbroom Microwave Radiometer
• PRT-5 -- Precision Thermal Radiometer
• TIMS -- Thermal Infrared Multispectral Scanner
• Zeiss Cameras

Experiment teams are involved in all phases of mission integration and operation at the NASA Ames Research Center, including pre-flight and post-flight activities. Experimenters are present for the pre-flight assembly, installation, examination, and operation of their experiments although NASA C-130B personnel ultimately transport and install the equipment on board the aircraft. In some cases, technicians at NASA Ames Research Center also assist with the interfaces between experiments and aircraft systems, but support of the experimental equipment is the responsibility of the experimenter. All equipment is laboratory inspected before installation on the aircraft.

Prior to flight missions, the Mission Manager may conduct flight checks, simulating mission conditions. During flight checks, experimenters verify operation of their equipment and become familiar with flight procedures and the flight environment. Post-flight activities include removing the equipment or experiments under the supervision of the Mission Manager. The Mission Manager also holds debriefing sessions to review mission results, complete requests for aircraft systems data, and to arrange for post-mission science reviews if required by the experimenters. Published research results are to be provided by the experimenter for documentation of scientific accomplishments.

The CADDS processes housekeeping data, including avionics and environmental sensor data, in real time. The data are then distributed to experimenter stations for use by investigators. The CADDS also archives both raw and processed housekeeping data onto personal-computer-compatible cartridges in a Small Computer System Interface format.

The CADDS transfers a full complement of aircraft housekeeping data (referred to as a type-1 data block) to onboard experiment stations in ASCII-formatted engineering units at 1-second intervals. A subset of values, including pitch and roll angles, radar altitude, and time code (referred to as a type-2 data block), is sent four times between transmission of type-1 data blocks at a rate of one block each 200 milliseconds. The type-2 data blocks provide a better history of aircraft position than is provided with the type-1 data.

Not applicable. Crossing times vary, because the NASA C-130B aircraft is a mission-oriented airborne platform.

National Aeronautics and Space Administration, 1991, C-130 flight summary report--Maricopa, Arizona, site [number] 9129, flight [number] 91-010-06: Moffett Field, California, NASA Ames Research Center, [18] p.

National Aeronautics and Space Administration, [n.d.], C-130 airborne laboratory experimenter's handbook: [Moffett Field, California, NASA Ames Research Center].

National Aeronautics and Space Administration, [n.d.], NASA 707 C-130B, in C-130 Earth resources aircraft--about the NASA C-130: [Moffett Field, California], NASA Ames Research Center.

Disclaimer: Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

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