UPPER AIR ROCKET SUMMARY                                                                       V-2
                                                                                                                           NO. 20
IDENTIFICATION                                                                            20 February 1947

    Agency: Air Research and Development Command
    Time: 1116 MST
    Altitude: 68.0 miles


    Pressure-temperature: Ram pressure at nose tip with ion gage and pressure on cone with four
        ion type gages (Univ. of Michigan).
    Ionosphere: Vertical incidence propagation transmitters (AFCRC). Bipolar probe measurement
        of ion current flow (Univ. of Michigan).
    Sky brightness: Photomultiplier tubes with filters (AFCRC).
    Biological: Rye seeds, cotton seeds, and fruit flies.
    Other: Voltage breakdown measurements (AFCRC).


    Telemeter: PXTA-501 channel NRL PPM/AM system
    Physical recovery: Separation of forward portion of rocket with TNT and prima cord. (New
        Mexico School of Mines). Blossom, ejection of canister and lowering by parachute
            (Cambridge Field Station).


    Firing Range
        Theodolites: Two Mitchell and six Askania stations
        Cameras: Two Ballistic and three Bowen-Knapp stations
        Telescopes: One station
        Radar: Two modified SCR-584 S-Band stations
        Doppler: Four stations
        Impact location: None.

        Beacon: AN/APN-55, (XE-2), S-Band transponder.
        Doppler: DOVAP transceiver
        Radio Cutoff: AN/ARW-17 FM control receiver for command fuel cutoff
        Aspect: Four AAF K-25 cameras in midsection (WPAFB)
        Other: Routine rocket propulsion and control performance instruments. (G. E. Co.).


    Firing angle:
    Program angle:
    Time to burnout: 58.0 sec.
    Altitude at burnout: 17 miles
    Velocity at burnout: 4062 ft. per sec.
    Time to zenith: 190 sec.
    Altitude at zenith: 68 miles
    Time to blowoff: 285 sec.
    Altitude at blowoff: 40 miles
    Flight duration: 419 sec.
    Impact Coordinates: 13.4 miles North and 14.4 miles West
    Payload weight:
    Unfueled rocket weight: 9390 lbs.
    Unfueled rocket C. G.: 243.1 inches
    Gross weight at takeoff: 28,455 lbs.


    Theodolites: Satisfactory Mitchell and Askania operation
    Cameras: Satisfactory data from two Ballistic and three Bowen-Knapp stations
    Telescopes: Satisfactory images 0 to 100 sec.
    Radar: Fair tracking to impact, poor 180 to 240 sec. telemeter interference with beacon
    Doppler: Good data 0 to 285 sec.


    Telemeter: Good record 0 to 260 sec. intermittent thereafter from roll
    Physical recovery: Nose separation failed, rocket exploded at impact. Parachute recovery
        very good. Aspect cameras no recovered.


    Ionosphere: Propagation transmitters failed after burnout, no data. Bipolar probe data in
        good agreement with expected electron density values, interpretation of data in doubt.
    Pressure-temperature: Pressure data from 55.3 to 66.5 miles. Temperature lower than
        NACA standard.
    Sky brightness: Satisfactory equipment operation, data poor after 40 sec. due to rocket roll
    Biological: Seeds recovered and flies still alive.
    Voltage breakdown: Data questionable.


    Rocket performance: Excellent performance 0 to 27 sec., at this time pitch motion disturbance
        occurred. Roll began at 37.4 sec. and increased to 1 r.p.s. by burnout. Combustion
            chamber pressure began to drop at 55.5 sec. Jet vane 3 did not operate normally.
    Ballistics: Optical instruments hampered by sun's position, haze, and clouds.


    Preliminary Report of V-2 Firing No. 20, ORDBS White Sands Proving Ground, dated
        24 Feb. 1947
    Report on A-4 (V-2 Rocket No. 20), Prepared by Physical Science Laboratory, New
        Mexico College of Agriculture and Mechanic Arts for Ballistic Research Laboratories, Aberdeen
            Proving Ground.
    Telemetering Report, A-4 Rocket No. 20, Prepared by Physical Science Laboratory, New
        Mexico College of Agriculture and Mechanic Arts, for Naval Research Laboratory.
    "Atmospheric Pressure and Temperature Measurements Between the Altitudes of 40 and 110
        Kilometers," Upper Air Research Program Report No. 2, Engineering Research Institute,
            University of Michigan, Contract W33-038 ac-14050(15719).
    "Upper Air Research Program, Report No. 1, Air Material, Command, Cambridge Field Station,
        1 September 1947.
    "University of Michigan BiPolar Probe Experiment," Phys. Rev. 76:987, 1949.
    "Dynamic Probe Measurements in the Ionosphere," Upper Air Research Program Report No.
        3, Engineering Research Institute, University of Michigan.
    Report No. 695, by H. P. Hitchcock, Ballistics Research Laboratories, Aberdeen Proving Ground,
        April 1949.
    "Panel Report No. 20," Minutes of Meeting of the Upper Atmosphere Rocket Research Panel
        on 21 April 1949.
    "Final Report, Project Hermes V-2 Missile Program," by L. D. White, Report No. R52A0510,
        General Electric Company, September 1952.