Commercial Space Operations Noise and Sonic Boom Measurements (2020)

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Commercial Space Operations Noise and Sonic Boom Measurements 19 3 Community Noise Measurement Protocol Introduction The community noise measurement protocol was developed to provide guidelines for conducting community and near-field noise measurements for commercial space operations propulsion noise and sonic booms. Accurate, reliable, and repeatable noise measurements from standardized noise measurement procedures will help ensure confidence in the data used to verify and validate modeling and prediction tools for noise impact assessments. The protocol addresses several important parameters such as recording system requirements, measurement methods, data analysis, and data reporting. The measurement methods include notional microphone layouts for a range of launch and re-entry vehicles (as shown in Figure 1) and operations. The language presented in this protocol is taken in large part from ANSI/ASA S12.75-2012 [2] American National Standard Methods for the Measurement of Noise Emissions from High Performance Military Jet Aircraft. Blue Ridge Research and Consulting, LLC (BRRC) and Brigham Young University (BYU) personnel, as members of the working group, coauthored ANSI/ASA S12.75 [2]. This protocol leverages the guidance adopted in ANSI/ASA S12.75, as it is a well-known industry standard with similarities to commercial space operations acoustic measurements. Note: The procedures in this protocol have not been approved by an accredited standards committee for commercial space operations. However, the purpose of developing the protocol is to begin the process toward future standardization of measurement procedures. Terms and Definitions For the purposes of this protocol, the terms and definitions given in ANSI S1.1 [3] and the following apply: A-weighting: A-weighting refers to a standardized filter meant to mimic the nonuniform frequency response of the human ear for relatively quiet sounds. Bandwidth: The bandwidth of a transducer or system is defined as the frequency range over which the frequency response is relatively flat. Bandwidth is usually expressed along with the decibel rolloff at the edges, e.g., -3 dB. C-weighting: C-weighting refers to a standardized filter meant to mimic the nonuniform frequency response of the human ear for relatively loud sounds. Directivity (of the source): Spectral and amplitude behavior, as a function of angle, from the centerline axis of the vehicle. Down-track: A location along the ground track relative to the vehicle initiation point in the direction of flight. Dynamic Range: The minimum sound pressure level recorded and reported to the maximum sound pressure level recorded and reported.

Commercial Space Operations Noise and Sonic Boom Measurements 20 Flight Path: Trajectory of the air vehicle. The curve defined by the tangent of the velocity vector of the vehicle as a function of time. Free-field Microphone: A microphone designed for use in measuring normally incident sound fields. Frequency Response: The frequency response of a transducer or system is the relative gain (in dB) of its response to a uniform input as a function of frequency. Geometric Far-field: Distances greater than 150 nozzle diameters from the nozzle plane. Geometric Near-field: Distances less than 150 nozzle diameters from the nozzle plane. Grazing Incidence: The microphone oriented so that the sound wave propagation direction is parallel to the microphone diaphragm; i.e., 90° incidence angle. Ground Track: Projection of the flight path onto the ground. Maximum Radiation Angle: The angle of maximum OASPL relative to the thrust angle. Maximum Sound Level (Lmax): Maximum sound level refers to the greatest value of the OASPL that varies with time, such as with the passage of a vehicle. Noise: Unwanted or undesired sound. Normal Incidence: The microphone oriented so that the sound wave propagation direction is perpendicular to the microphone diaphragm, i.e., 0° incidence angle. Nozzle Diameter: Diameter of the nozzle at the engine or motor nozzle plane. Nozzle Exit Plane: Plane through the outer or aft-most tips of the nozzle. One-third Octave (OTO) Band: OTO band analysis refers to calculating the amount of energy within a band that, in frequency, is one-third of an octave wide. The octave represents a frequency doubling. The OTO band widths are such that they are equally large on a logarithmic frequency scale. Band center frequencies and widths are standardized. Overall Sound Pressure Level (OASPL): The OASPL is the SPL of the time-dependent root-mean-square pressure. It may also be defined as the summation over frequency of the mean-square pressure spectrum (the autospectrum). Peak Overpressure (Δp): The Δp refers to the magnitude of the front pressure shock relative to the ambient pressure. It is one of the primary metrics used to describe a sonic boom. Pressure Microphone: A microphone that responds to sound pressure without any orientation corrections. Sonic Boom: The impulsive sound heard on the ground as a “sonic boom” is the sudden onset and release of pressure after the buildup by the shock wave or “peak overpressure” generated by an object traveling faster than the speed of sound.

Commercial Space Operations Noise and Sonic Boom Measurements 21 Sound Exposure Level (SEL): The sound exposure level is a measure of the total sound energy received during some time interval. SEL is calculated as 10 log10(∫𝑝𝑝2(𝑡𝑡)𝑑𝑑𝑡𝑡 /4 × 10−10Pa2 ∙ s) and is expressed as a decibel. Sound Pressure Level (SPL): The SPL is defined as 𝑆𝑆𝑆𝑆𝑆𝑆 = 20 log10(|𝑝𝑝𝑅𝑅𝑅𝑅𝑅𝑅|/20 𝜇𝜇Pa) and is measured in decibels, where p represents the instantaneous waveform pressure. Spectrum: The distribution of energy as a function of frequency for a particular sound. Vehicle Centerline: The longitudinal axis through the geometric center of the vehicle. Windscreen: A removable protective covering of foam, plastic, fabric, or wire mesh held at a distance from the microphone diaphragm used to reduce effects of wind. The windscreen is used in addition to the integral microphone protection grid. Noise Data Acquisition System Requirements The recording system shall be a digital recording system with associated microphones, preamplifiers, cables, and amplifiers with the following characteristics. 3.3.1 Noise recording systems Recording systems The recording systems shall have a minimum of 16-bit resolution (24-bit preferred) and shall be linear over the reported measurement dynamic range. A sample rate of 51,200 samples per second and per- channel bandwidth of 4 Hz to 20 kHz is recommended for propulsion noise, and a sample rate of 30,000 samples per second and per-channel bandwidth of 0.1 Hz to 10 kHz is recommended for sonic booms. Note, the recommended frequency bandwidth may be relaxed if a reduced bandwidth captures the significant acoustic energy of the event. Recording systems that produce OTO band levels should meet the requirements of ANSI/ASA S1.4 Part 1-2014 [4]. Anti-aliasing filters should be used before performing analog-to-digital conversion to restrict the bandwidth of a signal to satisfy the Nyquist-Shannon sampling theorem over the band of interest, with the goal of attenuating unwanted signals to the point that they do not adversely affect the signal. The recording systems should be time synchronized using IRIG timecodes or at a minimum, synchronizing the system’s internal clocks to GPS time. Signal-to-noise ratio The recording system noise floor must be sufficiently low to ensure the signal-to-noise ratio (SNR) for propulsive noise is greater than 10 dB on an OTO band basis. For sonic boom peak estimation, a 20 dB SNR is required for less than 10% error (~1 dB) and a 30 dB SNR is preferred for 3% error (~0.3 dB). Signal measurement peak handling For propulsion noise, the peak signal handling capacity of the signal measurement chain shall be at least 15 dB above the root-mean-square (rms) level of the Lmax to prevent clipping. For the case of sonic booms, the peak handling capacity of the signal measurement chain needs to be larger than the maximum instantaneous sound pressure level.

Commercial Space Operations Noise and Sonic Boom Measurements 22 3.3.2 Microphones and preamplifiers Specifications All microphones shall exceed the requirements of ANSI/ASA S1.15-1997 (R 2011) [5] for Type 1. A microphone frequency response of 4 Hz to 20 kHz for propulsion noise and 0.1 Hz to 10 kHz for sonic booms is recommended. Note, the recommended response may be relaxed if a reduced frequency response captures the significant acoustic energy of the event. Note, the sensitivity, bandwidth, maximum SPL capability and noise floor characteristics of all microphones must be appropriate for the measurement location, frequency range, and acoustic levels. Frequency response laboratory calibration All microphones shall be calibrated for frequency response. All preamplifiers shall be calibrated at the same time as the associated microphone. Calibration procedures shall be traceable to National Institute of Standards and Technology (NIST). The most recent calibration data shall be recorded and made available upon request. Before each field test, microphones should be tested to ensure their sensitivity is within ±6% (corresponding to a ±0.5 dB change in SPL relative to the stated sensitivity). If a microphone’s sensitivity is found to vary more than 6%, then a complete calibration shall be required before the microphone should be used. Windscreens Windscreens may be used to reduce the airflow-generated noise and help isolate microphones in “wet” conditions. Measurement Methods The measurement methods include guidelines and considerations for collecting propulsion noise, sonic boom, vehicle, and weather data. 3.4.1 Propulsion noise and sonic boom Recording system location Determination of the location of the measurement stations (microphone and recording systems) during the measurement period is critical. A Global Positioning System or other similarly accurate tracking instrumentation may be used to record the location of the recording system(s). For the desired microphone layout (see Section 3.4.2), determination of the location of the measurement stations shall consider the following:  Access permission and restrictions,  Safety of measurement personnel and equipment,  Event-based triggering for locations within the hazard zone or other un-manned locations,  External power requirements,  Terrain,  Ambient noise levels,  Exposure to extreme temperatures/vibration, and  Minimizing cable lengths.

Commercial Space Operations Noise and Sonic Boom Measurements 23 Terrain Ideally, the test site terrain shall permit direct line-of-sight from each microphone location to the source over the duration of the event. In areas where the initial direct line-of-site is not feasible, the microphone locations should be selected so that the duration of the line-of-sight blockage is minimized. Ideally, the test site terrain shall be flat and homogeneous within a 75-foot radius circle centered on the measurement location(s), and the closest vertical reflecting surface 100 square feet or larger shall be at least 200 feet from the measurement location(s). Any significant ground consistency or terrain changes should be avoided. However, when required, deviations from these guidelines shall be documented in the test report. Weather requirements Care should be taken to ensure that the instrumentation is operated within their specific environmental limitations. The expected environmental conditions (i.e., temperature, humidity, and precipitation) shall be considered when selecting equipment. Microphone height and orientation Two different microphone heights and orientations are used in this protocol: microphones at ground height mounted over a hard surface and microphones a minimum of 5 feet above the ground. Ground- plane microphones are preferred to minimize the effects of interference between the direct and reflected waves. The ground microphones should be placed with their diaphragms directed at the ground (inverted) and at a height which is equivalent to one-half the microphone diameter above the ground. Alternatively, ground-plane microphones can utilize flush-mounted ground boards. However, if the chance of rain and/or moisture is expected, inverted ground microphones are recommended. Microphones off the ground shall be placed at heights greater than or equal to 5 feet above ground level on a stationary stand such as a tripod. Pressure microphone diaphragms shall be oriented at grazing incidence and free-field microphone diaphragms at normal incidence to the estimated maximum emission point. Field gain check (daily pre and post-test) Once microphones are connected to the data acquisition system, a gain check shall be conducted before and after the test to verify that the pressure signals are valid. A field calibrator conforming with ANSI/ASA S1.40-2006 (R2011) [6] and of known frequency and level shall be placed on each microphone and the channel recorded for at least 10 seconds. If a microphone’s sensitivity is found to vary more than 6% from the most recent laboratory calibration, the microphone and cabling route for that microphone should be inspected and fixed or replaced. Ambient acoustic background measurement The ambient acoustic background at the test site shall be measured and reported for each OTO band at each microphone location. Ambient sound levels shall be averaged for a minimum of 30 seconds. This measurement shall be accomplished as close to the beginning and end of the measurement period as practical. These background ambient sound levels shall be used as the noise floor in the analysis. For propulsion noise measurements, the ambient level should be at least 10 dB less than the expected measured noise levels during the maximum emission portion of the event. For sonic boom peak estimation, the ambient level is required to be 20 dB less than the measured sonic boom level to achieve less than 10% error and 30 dB for 3% error.

Commercial Space Operations Noise and Sonic Boom Measurements 24 3.4.2 Microphone layout The following sections provide guidance on the minimum recommended number of measurement arrays and microphones. Additional measurement locations are desirable to increase the spatial resolution and extent of the data available for model validation. Conducting measurements at specific points of interest (e.g., launch viewing areas) should also be considered. Far-field community noise of vertical launch/landing Far-field noise from vertical launches and landings is best measured using line arrays along different radials extending from the pad as shown in Figure 5. The minimum number of recommended radials is three but could be increased in the case of significant terrain variation or wind.  180° line array: One array should be set 180° to the trajectory heading (i.e., directly behind the engine exhaust) with microphone locations starting from the hazard zone to progressively doubled distances from the launch pad. This provides a convenient check of the propagation relative to spherical spreading (-6 dB/doubling-of-distance). A minimum of three microphones should be used.  Perpendicular line array: Two other arrays that are perpendicular to the 180° array should be used. One of these should have comparable resolution to the 180° array. The opposite array should include at least two microphones to capture any wind-induced propagation effects. Additional microphones may be placed along the radials within the hazard zone to increase the spatial extent available for model validation. Figure 5. Notional microphone layout for far-field community noise measurements of vertical launch/landing.

Commercial Space Operations Noise and Sonic Boom Measurements 25 Far-field community noise of horizontal launch/landing Far-field community noise from horizontal launches should be measured at a minimum of two arrays as shown in Figure 6.  Centerline array: One array should be directly under the flight path with a minimum of three microphones. The microphones should be equidistant from one another.  Perpendicular line array: The other array should be perpendicular to the flight path and centered on the centerline array (the two arrays will be in the formation of a cross). A minimum of four microphones should be used (not including the centerline microphone). The majority of the microphones should be placed at progressively doubled distances from the center at one side of the cross. The opposite side can be placed with half as many microphones which should mirror a location on the primary side to capture any wind-induced propagation effects. Measurement should be performed on the side of the cross that has a ground surface that is more homogeneous, flat, and least obstructed. If both sides are similar, the downwind side is preferable. Figure 6. Notional microphone layout for far-field community noise measurements of horizontal launch/landing. Sonic boom of vertical launch/horizontal launch/horizontal landing Sonic booms from vertical launches, horizontal launches, or horizontal landings are best measured using line arrays aligned with the estimated focal region, as shown in Figure 7. Ideally, a centerline array and another at 45° should be used. If measurements along these arrays are not feasible because they are located over the ocean (typical of vertical launches), alternate locations over land shall be selected based on the predicted sonic boom footprint.  Centerline array: One array should be directly under the flight path, with microphone locations starting before the estimated focal region and then at progressively increasing distances down-track. The maximum distance down-track measured should be informed by predictions. A minimum of four microphones should be used.  45° line array: The 45° array should start at the estimated focal region and extend down-track. The farthest down-track location should align with the farthest down-track centerline array location. A minimum of two microphones should be used.

Commercial Space Operations Noise and Sonic Boom Measurements 26 Figure 7. Notional microphone layout for sonic boom measurements of vertical launch/horizontal launch/horizontal landing. Sonic boom of vertical landing Sonic booms from vertical landings are best measured using line arrays along different radials extending from the landing pad as shown in Figure 8. The minimum number of recommended radials is two but could be increased in the case of significant wind.  180° line array: One array should be set 180° to the landing flight path with microphone locations starting from the hazard zone to progressively doubled distances from the landing pad. The maximum distance measured from the landing pad should be informed by the predicted sonic boom footprint. A minimum of three microphones should be used.  Perpendicular line array: One other array that is perpendicular to the 180° array should be used and have comparable resolution to the 180° array. An additional opposite array can be placed with half as many microphones to capture any wind-induced propagation effects. If the vehicle landing occurs in quick secession of a launch, the microphone layouts associated with the far-field community noise of a vertical launch/landing shall be leveraged to co-locate as many measurement systems as possible to record both events. Figure 8. Notional microphone layout for sonic boom measurements of vertical landing.

Commercial Space Operations Noise and Sonic Boom Measurements 27 Far-field community noise of static vertical engine firing Far-field community noise measurements of a static vertical engine firing shall be carried out in the same manner as for vertical launches as shown in Figure 9. However, additional microphone arrays should be considered to increase angular resolution, particularly near the hazard zone.  180° line array: One array should be set 180° from the deflected plume direction, starting from the hazard zone and then at progressively doubled distances. A minimum of three microphones should be used.  Perpendicular line array: Two other arrays that are perpendicular to the 180° array should be used. One of these should have comparable resolution to the 180° array. The opposite array can be placed with half as many microphones to capture any wind-induced propagation effects. Because a vertically fired plume with flame trenches or other test pad obstructions may lessen the symmetry of the noise radiation, a circular arc at the edge of the hazard zone with microphones at 30° resolution should be considered. These arc locations can also serve as the closest microphone for radials extending from the test pad to the community. Figure 9. Notional microphone layout for community noise measurements of static vertical engine firing. Far-field community noise of static horizontal engine firing Far-field radial line arrays are best suited to these types of measurements as shown in Figure 10.  Radial line arrays: To produce reasonable estimates of community noise, at least two radial line arrays with microphones at three different distances shall be used – one near the maximum radiation angle (~65°) and one in the direction of the nearest community – where all angles are with respect to the engine exhaust direction. If asymmetry will exist in the measurement because of wind or significant terrain shielding, additional radials should be placed on the opposite side of the plume. Additional arrays may be considered to capture source directivity for model validation.

Commercial Space Operations Noise and Sonic Boom Measurements 28 Figure 10. Notional microphone layout for far-field community noise measurements of static horizontal engine firing. Near-field source characterization of static vertical engine firing Directional microphone arrays are recommended to carry out the acoustic source characterization of an impinging, vertical plume environment.  Beamforming array: A far-field beamforming array is the only researched approach for obtaining the noise sources from a vertical plume with impingement.  Intensity-probe array: A line array of intensity probes can also yield information about the radiation and reflections present. Near-field source characterization of static horizontal engine firing A line array of microphones that spans the source region is best suited to these types of measurements. Vector acoustic intensity probes would improve source amplitude and directivity information and should be considered as an option.  Shear layer aligned array: The line array should be laid out so as to be approximately parallel to the plume shear layer. The estimated spread of the shear layer should be based on the engine operating condition and is generally ~15° from the plume centerline. The recommended offset distance from the shear layer to the array is 5-10 nozzle diameters. To adequately span the source region and account for the plume noise source directivity at both low and high frequencies, array elements should be located starting at least 10 diameters upstream of the nozzle to 60 diameters downstream and with a linear spacing of at most 10 nozzle dimeters. If additional spatial resolution is desired, microphones should be added between 10 and 30 diameters downstream of the nozzle, e.g., at 15 and 25 diameters. Directivity of static horizontal engine firing A far-field arc of microphones that spans as much of the polar angular aperture as possible is best suited to these types of measurements.

Commercial Space Operations Noise and Sonic Boom Measurements 29  Far-field arc array: The far-field arc should consist of microphones located at an angular resolution of at least 10°. When possible, finer resolution should be sought in the 45°-75° from plume centerline region to improve characterization of the principal radiation lobe. The arc reference point should be located at a distance of 17 nozzle diameters [7] downstream of the nozzle exit plane and along the plume centerline. The arc radius should be a minimum of 150 nozzle diameters to limit bias errors (caused by displacement of the maximum source region and the reference point at the lower and upper band frequency limits). 3.4.3 Vehicle data recording requirements Vehicle and engine At a minimum, vehicle weight, length, nozzle diameter, number of nozzles, and propellant type shall be reported. Vehicle and engine parameters necessary to validate propulsion noise or sonic boom models include weight, length, thrust (as a function of time), and nozzle diameter. Trajectory At a minimum, vehicle location (i.e., latitude, longitude, and altitude) shall be recorded at a rate of at least one sample per second. Any available additional trajectory information should be recorded, if possible. Trajectory parameters desired to perform propulsion noise or sonic boom model validation include geographic location, velocity, acceleration, jerk, attitude (i.e., roll, pitch, and yaw), flight path azimuth, flight path heading, thrust, weight, and drag. Additionally, stage separation information including time and vehicle configuration is desired. 3.4.4 Weather recording requirements Weather instrumentation Temperature, humidity, ambient pressure, and wind velocity (speed and direction) shall be recorded near the site of the event. The weather data shall be recorded at a minimum of one sample per second. The wind direction reference shall be specified. Additionally, available weather balloon data from the nearest radiosonde to the launch/test site should be collected to capture the temperature and wind speed profile. To supplement local weather station data, or in lieu of these data, additional locations may be utilized for weather data collection. Data Analysis Data analysis guidelines are presented for propulsion noise and sonic boom measurements. 3.5.1 Propulsion noise data analysis One-third octave-band time histories Spectral analysis using OTO digital filters shall be used for analyzing the OTO band SPL time histories. The digital filters must conform to the requirements for Class 1 given in ANSI/ASA S1.11 - 2014 [8] and use preferred frequencies and band numbers conforming to ANSI/ASA S1.6 - 1984 (R2011) [9]. Alternately, spectral analysis can be performed using fast Fourier transform (FFT) analysis. A Hann window should be applied to the time domain signals before performing the FFT analysis. When summing FFT-based spectral lines to obtain OTO bands, each spectral line shall be assumed to represent a uniform spectral density across its width. FFT spectral lines on the frequency boundaries between OTO bands shall be apportioned

Commercial Space Operations Noise and Sonic Boom Measurements 30 according to the band-filter skirt shapes in ANSI/ASA S1.11-2014 [8]. OTO band levels that are not at least 10 dB higher than the ambient or microphone noise levels measured should be so noted and will be considered unreliable. Overall levels Unweighted, A-weighted, and C-weighted OASPL as functions of time at one-second intervals shall be computed and reported along with the OTO band time-history data. SEL (only for non-static events) and unweighted, A-weighted, and C-weighted Lmax shall be reported in the summary file. Acoustic reference levels shall conform to ANSI/ASA S1.8 2016 [10] and the A-weighting and C-weighting shall conform to ANSI/ASA S1.42-2001 (R2016) [11]. 3.5.2 Sonic boom data analysis Pressure time histories – pressure vs. time The pressure vs. time-history for each microphone shall be reported. Overall levels Peak Overpressure and SEL shall be computed for each microphone and reported in the summary file. Acoustic reference levels shall conform to ANSI/ASA S1.8 2016 [10] and the C-weighting shall conform to ANSI/ASA S1.42-2001 (R2016) [11]. Reporting and Test Documentation The reporting and test documentation shall include the short report, database description document, noise data, vehicle data, and weather data. 3.6.1 Short report The short report shall briefly summarize the acoustic measurements and resultant dataset. The acoustic measurement summary shall include a description of the event, figure of the measurement layout, table of microphone locations, and photographic documentation of all recording locations. The resultant dataset summary shall include a description of the files in the database and their associated filename format. For data not approved for public release, contact information shall be provided to direct data requests. 3.6.2 Database description document The test description document (e.g., spreadsheet) shall describe the test with sufficient detail to allow for the measurement to be repeated. Information describing the test shall include:  Event details describing the vehicle and mission;  Instrumentation setup for every microphone, pre-amplifier, and recording channel; and  Test location data describing the physical arrangement of the microphones and recorders. The information in the database description document shall be mirrored in the header of the noise data files. The header format will support the addition of custom lines relevant to a specific event.

Commercial Space Operations Noise and Sonic Boom Measurements 31 3.6.3 Noise data Individual transducer file data format Each transducer shall have a unique file for each measurement event. The filename shall contain the unique number identifying each transducer (e.g., channel number). The file format shall contain an ASCII header mirroring the information in the database description document followed by the transducer data. The ASCII header shall be composed of 82-byte lines where the first byte is a semicolon and bytes 81 and 82 are either repeated line feeds (0x0A 0x0A) or carriage return line feed (0x0D 0x0A). Header lines shall consist of a descriptor separated from its value by a colon. The first header line shall have a descriptor denoting the number of lines in the header. An example of an ASCII header is presented in Figure 11 for an example propulsion noise event. For propulsion noise from launches, landings, or static fires, the transducer data shall contain the weighted overall levels and OTO band spectral time histories. For sonic booms, the transducer data shall contain pressure time histories. Time should be recorded in Coordinated Universal Time (or UTC) and the data shall be written as single precision real numbers. Summary file data format A summary file shall be prepared for each measurement event. The file format shall contain an ASCII header that mirrors the event information in the database description document followed by the summary data. The summary file shall contain overall levels as described in Section 4.4.1 for propulsion noise and sonic booms. The data shall be written as single precision real numbers. 3.6.4 Vehicle data Vehicle data, as defined in Section 3.4.3, shall be reported and documented. 3.6.5 Weather data Weather data, as defined in Section 3.4.4, shall be reported and documented.

Commercial Space Operations Noise and Sonic Boom Measurements 32 ;HEADER SIZE..................: 42 ;RUN..........................: RUN0001 ;MISSION NAME.................: CYGNUS CRS OA-8E ;MISSION TYPE.................: ISS Resupply ;MISSION OPERATOR.............: NASA ;MISSION CONTRACTOR...........: ORBITAL ATK ;EVENT DESCRIPTION............: LAUNCH ;EVENT DATE...................: 12 NOVEMBER 2017 ;EVENT TIME...................: 07:19:51 A.M. EST ;EVENT SITE...................: MARS PAD 0A, WALLOPS FLIGHT FACILITY, VA ;PAD LATITUDE.................: 37.833864 ;PAD LONGITUDE................: -75.487683 ;VEHICLE......................: ANTARES 230 ;VEHICLE CONFIGURATION........: VERTICAL LAUNCH ;NOMINAL TRAJECTORY AZIMUTH...: 107 ;ORGANIZATION.................: BRRC & BYU ;RECORDER LOCATION............: OLD FERRY DOCK ;RECORDER LOCATION SHORT NAME.: OF1 ;START TIME (UTC ZULU SEC AM).: 44391.000 ;START TIME (UTC ZULU)........: 12:19:51.000 ;END TIME (UTC ZULU SEC AM)...: 44511.000 ;END TIME (UTC ZULU)..........: 12:21:51.000 ;RUN NOTES....................: NONE ;CH NUMBER....................: CH402 ;CH DESCRIPTION...............: 1/2“ MICROPHONE PRES-FIELD ;TRANSDUCER MODEL.............: GRAS 46AO ;TRANSDUCER SN................: 307161 ;TRACEABLE SENS (mV/Pa).......: 11.09 ;MEAS SENS (mV/Pa)............: 11.06 ;TRANSDUCER SUPPLY............: 2 mA ;ORIENTATION..................: GRAZING ;WINDSCREEN...................: YES ;PREAMP MODEL.................: GRAS 26CA ;PREAMP SN....................: 307161 ;RECORDER TYPE................: NI-9233 ;POSITION.....................: 11654R_287D_005G ;COORDINATES..................: GEOGRAPHIC ;DATUM........................: WGS 84 ;LATITUDE.....................: 37.842901 ;LONGITUDE....................: -75.525762 ;ALTITUDE AGL FT..............: 05 ;UNITS........................: dB ;CH NOTES.....................: NONE Figure 11. Example of an ASCII header mirroring the contents of the database description document.