P-3 Orion
NASA P-3 Orion - WFF
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P-3 Orion - WFF

NASA Goddard Space Flight Center’s (GSFC) Wallops Flight Facility (WFF) Aircraft Office operates the NASA Airborne Science Program's P-3 Orion (N426NA). The P-3 is a self-sufficient, four-engine turboprop aircraft designed for endurance and range. This aircraft operates out of civilian and military airfields supporting scientific research in remote areas of the world. WFF has operated the P-3 since 1991 for a wide range of scientific activities, including ecology, meteorology, atmospheric chemistry, cryospheric research, oceanography, soil science, biology, and satellite calibration/validation. The P-3 is also used as a technology test bed for new airborne and satellite instrumentation.

The P-3 has been extensively modified to support airborne scientific research. Features include zenith ports, three nadir ports (aft of the wings), and seven P-3 and DC-8 style windows that have been modified to provide externally mounted experiments. Additionally, there is are tail cone ports, nose radome ports, and ten mounting locations on the wings. Most of the fuselage ports are contained within the pressurized cabin environment while a custom fairing allows the unpressurized bomb bay to be converted into experimenter ports. This fairing creates two large nadir ports and several oblique ports for large sensors and antennas. When the bomb bay fairing is removed and the bomb bay doors installed, the doors are functional in flight to support aerial deployments. Dropsonde and sonobuoy deployment systems are also available.

The P-3 is an all-weather aircraft with modern avionics. Along with an upgraded cockpit, the P-3 has an Airborne Science Program network providing data and video throughout the cabin. This data system is connected to two satellite constellations providing uplink/downlink capability, internet access, flight tracking, and instant messaging between other aircraft and ground assets. Several sensors are connected to the data system to provide meteorological and aircraft positional data to researchers.

The GSFC/WFF Aircraft Office is committed to providing safe, reliable, and cost-effective platforms for airborne research.

* The performance numbers presented below are based on a 135,000lb Maximum Normal Take Off Weight. However, 139,760lbs is the Maximum Gross Take Off Weight.

** Airspeed indicated below is Knots Indicated Airspeed (KIAS). Maximum values shown, aircraft typically limited to 300KIAS to reduce fatigue.

Current Status:
NASA GSFC Wallops Flight Facility
Conventional Aircraft
12.0 hours (payload and weather dependent)
Useful Payload: 
18 000 lbs
Gross Take-off Weight: 
135 000 lbs
Onboard Operators: 
24 (including flight crew)
Max Altitude: 
32,000 feet (payload weight and weather dependent)
Air Speed: 
405 knots
3 800 Nmi
90KVA of 115VAC 60Hz single phase & 400Hz 3 phase; 28V DC
NASA SMD User Fee per Hour: 
Point(s) of Contact: 

Mike Cropper

Work: (757) 824-2140

Lidar Atmosphere Sensing Experiment

The Differential Absorption Lidar uses the backscatter of two simultaneous laser wavelengths through zenith and nadir windows to measure the vertical profiles of H2O and aerosols/clouds.

NASA's Lidar Atmospheric Sensing Experiment (LASE) system is an airborne DIAL (Differential Absorption Lidar) system used to measure water vapor, aerosols, and clouds throughout the troposphere. LASE probes the atmosphere using lasers to transmit light in the 815-nm absorption band of water vapor. Pulses of laser light are fired vertically below the aircraft. A small fraction of the transmitted laser light is reflected from the atmosphere back to the aircraft and collected with a telescope receiver. The received light indicates the amount of water vapor along the path of the laser beam.

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Langley Aerosol Research Group Experiment

Langley Aerosol Research Group Experiment (LARGE).  The "classic" suite of instrumenation measures in-situ aerosol micrphysical and optical properties. The package can be tailored for specific science objectives and to operate on a variety of aircraft. Depending on the aircraft, measurments are made from either a shrouded single-diffuser "Clarke" inlet, from a BMI (Brechtel Manufacturing Inc.) isokinetic inlet, or from a HIML inlet. Primary measurements include:

1.) total and non-volatile particle concentrations (3nm and 10nm nominal size cuts),
2.) dry size distributions from 3nm to 5µm diameter using a combination of mobilty-optical-aerodynamic sizing techniques,
3.) dry and humidified scattering coefficients (at 450, 550, and 700nm wavelength), and
4.) dry absorption coefficients (470, 532, and 670nm wavelength). 

LARGE derived products include particle size statistics (integrated number, surface area, and volume concentrations for ultrafine, accumulation, and coarse modes), dry and ambient aerosol extinction coefficients, single scattering albedo, angstrom exponent coefficients, and scattering hygroscopicity parameter f(RH).

DC-8 - AFRC, C-130H - WFF, P-3 Orion - WFF, HU-25 Falcon - LaRC, King Air B-200 - LaRC, Twin Otter - CIRPAS - NPS
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High Volume Precipitation Spectrometer

SPEC previously built the Version 1 and Version 2 HVPS probes that have now been discontinued due to obsolete parts and significant advances in technology. The HVPS-3 uses the same 128-photodiode array and electronics that are used in the 2D-S and 2D-128 probes. The optics are configured for 150 micron pixel resolution, resulting in a maximum field of view of 1.92 cm (i.e., particles up to 1.92 cm are completely imaged, although even larger particles can be sized in the direction of flight).

Sample volume of the HVPS-3 is 400 L s-1 at 100 m s-1. The 2D-S or 2D-128 and HVPS make an excellent pair of probes that completely image particles from 10 microns to 1.92 cm.

Point(s) of Contact: 

Cloud Droplet Probe

The Cloud Droplet Probe (CDP), manufactured by Droplet Measurement Technologies, measures the concentration and size distribution of cloud droplets in the size range from 2-50 µm. The instrument counts and sizes individual droplets by detecting pulses of light scattered from a laser beam in the near-forward direction, using a sample area of 0.24 mm2 or a sample rate of 48 cm3 at a flight speed of 200 m/s. The probe is mounted in an underwing canister and is designed to operate at up to 200 m/s; the G-V often exceeds this flight speed, but usually not in penetrations of clouds containing cloud droplets. Droplet sizes are accumulated in 30 bins with variable sizes, as specied in the header of the netCDF data files. Measurements are usually provided at a rate of 1 Hz in the standard data files but can be made available at 10 Hz in special high-rate processing. The instrument is similar to, and might be considered a high-speed replacement for, the Forward Scattering Spectrometer Probe. At high droplet concentration (> 500 cm-3), coincidence losses have been observed with this probe, and these are especially serious at G-V flight speeds. The probe is designed for cloud droplets, and its response to ice crystals is not intended to be quantitative; measurements in ice clouds should not be used except as qualitative indications of cloud.

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Langley Wideband Integrated Bioaerosol Sensor

Wideband Integrated Bioaerosol Sensor (WIBS-4A) - Droplet Measurement Technologies.  Dectection of Fluorescent Biological Aerosol Particle (FBAP) number concentrations.  Single particle analysis using dual wavelength (280nm and 370nm by xenon lamps) excitation on two parallel broadband visible-wavelength detectors (310-400nm and 420-650nm). Particles are classified by a combination of fluorescence excitation and emission characteristics, as well as their optical size measured by forward-scattering using a 635nm continuous-wave diode laser.    

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Frequency Modulated Continuous Wave Snow Thickness Radar

The Center for Remote Sensing of Ice Sheets has developed an ultra-wideband radar that operates over the frequency from 2 to 8 GHz to map near-surface internal layers in polar firn with fine vertical resolution. The radar has also been used to measure thickness of snow over sea ice. Information about snow thickness is essential to estimate sea ice thickness from ice freeboard measurements performed with satellite radar and laser altimeters. This radar has been successfully flown on NASA P-3 and DC-8 aircraft.

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Particle Into Liquid Sampler

The Particle Into Liquid Sampler (PILS) was developed for rapid automated on-line and continuous measurement of ambient aerosol bulk composition. The general approach is based on earlier devices in which ambient particles are mixed with saturated water vapor to produce droplets easily collected by inertial techniques. The resulting liquid stream is analyzed with an ion chromatograph to quantitatively measure the bulk aerosol ionic components. In this instrument, a modified version of a particle size magnifier is employed to activate and grow particles comprising the fine aerosol mass. A single jet inertial impactor is used to collect the droplets onto a vertical glass plate that is continually washed with a constant water diluent flow of nominally 0.10 ml min-1. The flow is divided and then analyzed by a dual channel ion chromatograph. In its current form, 4.3 min integrated samples were measured every 7 min. The instrument provides bulk composition measurements with a detection limit of approximately 0.1 µg m-3 for chloride, nitrate, sulfate, sodium, ammonium, calcium, and potassium.

Instrument Type: 
Na, NH4, K, Mg, Ca+2, Cl, NO2, NO3, SO4, PO4, Br-, WSOC
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Langley Single Particle Soot Photometer

Droplet Measurement Technologies (DMT) Single Particle Soot Photometer (SP2). Signle particle measurement of accumulation-mode refractory black carbon (rBC) mass concentrations based on laser-induced incancescence.   

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