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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.

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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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WB-57 - JSC

Current Status:
#926Major Ops Inspection (ends 09/30/20)
#927Inactive (Starting 09/02/20: Demo-2 Imaging Mission)

The NASA Johnson Space Center (JSC) in Houston, Texas is the home of the NASA WB-57 High Altitude Research Program. Three fully operational WB-57 aircraft are based near JSC at Ellington Field. The aircraft have been flying research missions since the early 1970's, and continue to be an asset to the scientific community with professional, reliable, customer-oriented service designed to meet all scientific objectives.

The WB-57 is a mid-wing, long-range aircraft capable of operation for extended periods of time from sea level to altitudes in excess of 60,000 feet. Two crew members are positioned at separate tandem stations in the forward section of the fuselage. The pilot station contains all the essential equipment for flying the aircraft while the sensor equipment operator (SEO) station contains both navigational equipment and controls for the operation of the payloads that are located throughout the aircraft. The WB-57 can fly for approximately 6.5 hours, has a range of approximately 2500 miles, and can carry up to 8,800 lbs of payload.

NASA Johnson Space Center
Conventional Aircraft
7 hours (payload and weather dependent)
Useful Payload: 
8 800 lbs
Gross Take-off Weight: 
72 000 lbs
Onboard Operators: 
2 (Pilot and SEO)
Max Altitude: 
60,000 ft and above (payload dependent)
Air Speed: 
410 knots
2 500 Nmi
110V/60Hz AC, 110V/400Hz AC, and 28 VDC
Point(s) of Contact: 

Derek Rutovic

Mobile: (832) 205-3854
Work: (281) 244-9871

WB-57 Ascent Video Experiment

The WB-57 Ascent Video Experiment (WAVE) provides both ascent and entry imagery and enables better observation of the Shuttle on days of heavier cloud cover and areas obscured from ground cameras by the launch exhaust plume. WAVE comprises a 32-inch-ball turret system mounted on the nose of two WB-57 aircraft. The turret houses an optical bench, providing installation of both HDTV and infrared cameras. Optics consist of an 11-inch-diameter, 4.2 meter fixed-focal-length lens. The system can be operated in both auto track and manual modes.

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Methane Near IR Tunable Diode Laser Absorption Spectrometer

The tunable diode laser (TDL) absorption instrument consists of a very high resolution scanning near-infrared diode laser spectrometer. The laser diode is a 3 mW single-mode distributed feedback (DFB) InGaAsP/InP laser that is cooled and temperature stabilized via a Peltier cooler. The laser is scanned in frequency by varying the injection current linearly. The resulting frequency scan covers the entire CH4 R(3) ro-vibrational transition in the 2ν3 overtone band at 1.653 μm.

Because the line strengths are very weak for this overtone transition, the laser beam is multipassed through a custom designed low volume astigmatic Herriott cell yielding a total optical pathlength of 245 m. The transmitted light is detected by a dc-coupled InGaAsP detector and digitized by a custom 20-bit A/D converter. This ADC is synchronized to the 16-bit software generated laser scan waveform running in continuous DMA mode. The laser scans continuously over the methane absorption at a rate of 0.25 - 0.5 KHz and coadds typically 100 scans in a 2 second integration time.

By use of the Beer-Lambert law, the methane number density is calculated from the direct absorption measurements. This calculation is performed by a non-linear least squares Voigt fitting program. The program constraints include the measured cell temperature and pressure in addition to the known absorption line strengths and pressure broadening coefficients associated with the three transitions that make up the R(3) lineshape.

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Leica RC-30 metric camera

The RC-30 is an airborne film camera system, using color infrared, natural color and black and white film, to obtain high resolution earth imagery.

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Forward Scattering Spectrometer Probe

The FSSP is of that general class of instruments called optical particle counters (OPCs) that detect single particles and size them by measuring the intensity of light that the particle scatters when passing through a light beam. A Helium Neon laser beam is focused to a diameter of 0.2 mm at the center of an inlet that faces into the oncoming airstream. This laser beam is blocked on the opposite side of the inlet with an optical stop, a "dump spot" to prevent the beam from entering the collection optics. Particles that encounter this beam scatter light in all directions and some of that scattered in the forward direction is directed by a right angle prism though a condensing lens and onto a beam splitter. The "dump spot" on the prism and aperture of the condensing lens define a collection angle from about 4º - 12º.

The beam splitter divides the scattered light into two components, each of which impinge on a photodetector. One of these detectors, however, is optically masked to receive only scattered light when the particles pass through the laser beam displaced greater than approximately 1.5 mm either side of the center of focus. Particles that fall in that region are rejected when the signal from the masked detector exceeds that from the unmasked detector. This defines the sample volume needed to calculate particle concentrations.

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Single Particle Soot Photometer (NOAA)

The SP2 is a laser-induced incandescence instrument primarily used for measuring the refractory BC  (rBC) mass content of individual accumulation-mode aerosol particles. It is able to provide this data product independently of the total particle morphology and mixing state, and thus delivers detailed information not only about BC loadings, but also size distributions, even in exceptionally clean air. The instrument can also provide the optical size of individual particles containing rBC, and identify the presence of materials associated with the BC fraction (i.e. identify the rBC’s mixing state). Since its introduction in 2003, the SP2 has been substantially improved, and now can be considered a highly competent instrument for assessing BC loadings and mixing state in situ.  NOAA deploys multiple SP2s with different designs: the first was built for the WB-57F research aircraft. Two others are rack-mounted units customized at NOAA; one of the rack mounted units can be humidified, and has been deployed with a paired dry rack-mounted SP2 as the "Humidified-Dual SP2" (HD-SP2). The rack mounted units are suitable for in-cabin operations.

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Unmanned Aerial System Laser Hygrometer

ULH measures water vapor at high accuracy in the upper troposphere and lower stratosphere to meet the following science objectives:

1. validation and scientific collaboration with NASA earth-monitoring satellite missions, principally the Aura satellite, http://aura.gsfc.nasa.gov/

2. observations of stratospheric trace gases in the upper troposphere and lower stratosphere from the mid-latitudes into the tropics,

3. sampling of polar stratospheric air and the break-up fragments of the air that move into the mid-latitudes, The ULH flights on Global Hawk will advance the state of the art technologically with remote command and control. ULH will provide real-time in-situ stratospheric water vapor measurements from Global Hawk. Additionally, ULH will make continuous measurements during long-duration flights up to 33 hours, which would be impossible with manned aircraft.

The advantages of ULH over other hygrometers are:

• Small and lightweight instrument package,
• No outgassing (achieved by mounting the open-path optical cell in the free air stream),
• Fast time response measurements in and out of clouds, without contamination,
• Accurate with a low detection limit <1 ppmv.

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Whole Air Sampler

The Whole Air Sampler (WAS) collects samples from airborne platforms for detailed analysis of a wide range of trace gases. The compounds that are typically measured from the WAS includes trace gases with sources from industrial midlatitude emissions, from biomass burning, and from the marine boundary layer, with certain compounds (e.g. organic nitrates) that have a unique source in the equatorial surface ocean. The use of a broad suite of tracers with different sources and lifetimes provides powerful diagnostic information on air mass history and chemical processing that currently is only available from measurements from whole air samples. Previous deployments of the whole air sampler have shown that the sampling and analytical procedures employed by our group are capable of accessing the wide range of mixing ratios at sufficient precision to be used for tracer studies. Thus, routine measurement of species, such as methyl iodide, at <= 0.1 x 10-12 mole fraction, or NMHC at levels of a few x 10-12 mole fraction are possible. In addition to the tracer aspects of the whole air sampler measurements, we measure a full suite of halocarbon species that provide information on the role of short-lived halocarbons in the tropical UT/LS region, on halogen budgets in the UT/LS region, and on continuing increasing temporal trends of HFCs (such as 134a), HCFCs (such as HCFC 141b), PFCs (such as C2F6), as well as declining levels of some of the major CFCs and halogenated solvents. The measurements of those species that are changing rapidly in the troposphere also give direct indications of the age and origin of air entering the stratosphere.

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