Time of firing: 1442 MST
    Agency: Air Research and Development Command
    Altitude: 65 miles

UPPER AIR INSTRUMENTS

    Density-pressure-temperature: One ion type pressure gage to measure ram pres-
        sure on truncated cone. Four ion type pressure gages on side of cone. One
        Pirani type pressure gage on side of cone. One Pirani type pressure gage a few
        inches forward of No. 1 fin. Aspect camera for pressure gage interpretation.
        (Michigan U.)
    Skin temperature measurements: AC resistance bridge with commutator to measure
        temperature change in nickel temperature-sensing elements distributed along
        rocket skin (Boston University)
    Solar soft x-ray studies: Densitometer packets with x-ray type photographic film
        behind filters of varying thicknesses of evaporated aluminum (of the order of a
        few microns) which are opaque to visible light
    Vertical incidence ionosphere propagation experiment: Synchronized ground and
        rocketborne equipment to measure delay time of low-frequency pulse traveling
        through the E layer by comparison with travel time of undelayed high-frequency
        signal (AFCRC)
    Oblique incidence ionosphere propagation experiment: Gound-trnsmitted signal
        travels over very long path. Receivers both in rocket and on ground. Rocket
        transmitter retransmits signal received in rocket to ground receiver. Measures
        attenuation of wave passing downward through E layer reflected from F layer
        (Boston University)
    Aspect project: Four still cameras and three motion picture cameras to record data
        of rocket aspect; cameras are housed in containers to be lowered by parachute
        on ejection (WADC and FILRAD)
    Sky brightness project: Twelve photomultiplier tubes installed on warhead doors,
        with one door on east side and one door on west side (AFCRC)

ROCKET PERFORMANCE INSTRUMENTS

    Heliograph altitude recorder: Heliograph recorders installed in Fins II, III, and IV
        for cinematographic record of apparent position of sun and horizon as seen from
        rocket fins (SCEL)
    Beacon triangulation system: Track rocket by electronic triangulation system
        (AFCRC)
    Voltage breakdown: Three sets of electrodes at varying spacing mounted on surface
        of rocket nose cone

DATA RECOVERY INSTRUMENTS

    Telemeter: NRL PPM-AM telemetering system - transmitter with frequency of
        1025 Mc was located in control compartment of missile
    Physical recovery: Separation of warhead from body of missile. Separation of four
        aluminum cylindrical containers approximately 11 inches in diameter and 13
        inches in length. These canisters are lowered to earth by an 8-foot nylon ribbon
        chute.

BALLISTIC INSTRUMENTS

    Firing Range
        Theodolites: Two Mitchell and four Askania stations
        Cameras: Two Ballistic and three Bowen-Knapp stations
        Telescopes: Two stations
        Radar: Two S-band radars were used

    Airborne
        Beacon: Ionosphere beacon in warhead. A radar beacon, AN/APN-55 (XE),
            located in tail section of rocket.
        Radio cutoff: Two ARW-17 radio receivers at 40.780 Mc located in control
            compartment for fuel cutoff and warhead blowoff
        Other: Routine rocket performance (G. E.)

ROCKET INFORMATION

    Unfueled rocket weight: 9485 lb
    Gross weight at takeoff: 29,050 lb

ROCKET PERFORMANCE

    Program angle: Seven degrees
    Time to burnout: 65 sec
    Velocity at burnout: 3939 ft/sec
    Altitude at burnout: 16-17 miles
    Time to zenith: 180 sec
    Altitude at zenith: 65 miles
    Time to tail blowoff: 300 sec (approximate)
    Altitude at tail blowoff: 22.4 miles
    Flight duration: 340 sec to warhead impact (estimated
    Impact coordinates: Approximately 28 mi north of firing site and 1/2 mi east

BALLISTIC DATA

    Theodolites: Mitchell to near peak, Askania to impact
    Cameras: Ballistic film plates good. All Bowen-Knapp camera operations satis-
        factory.
    Telescopes: Telescope I tracked to impact, but had intermittent jams. Warhead
        blowoff was photographed. Telescope II lost rocket prior to peak.
    Radar: Both radars tracked rocket for approximately 315 sec. They indicated that
        the rocket drifted slightly to east after blowoff.
    Beacon triangulation system: Tracking beacon worked satisfactorily after canister
        separation
    Aspect: Data from the three aspect cameras mounted in the mid-body clearly show
        the motion of the rocket in roll, pitch, and yaw. A slow roll with a period of
        approximately 80 sec was indicated, and this was substantiated by the action of
        the ionization gages. The aspect camera information shows rather irregular
        motions in both pitch and yaw.

DATA RECOVERY

    Telemeter: A good telemetering record was obtained until approximately 310 sec,
        which ws shortly after the warhead blowoff
    Physical recovery: rocket body was minus warhead and tail fins at impact; con-
        ponents scattered on violet impact. two aspect canisters found in rocket mid-
        body at impact. Blossom parachute minus canister located approximately 15
        miles from rocket impact. Canister smashed by impact. Fourth parachute
        from aspect canister found, minus canister, approximately 22 miles from
        impact. One 16-mm movie camera from aspect canister found 1/2 miles south
        of rocket impact. One heliograph, in good condition, found approximately 1/2
        mile south of rocket impact.

EXPERIMENTAL DATA

    Sky brightness experiment: Scattered light measurements made with interference
        filters that were peaked at 4280, 4720, 5350, 5670 and 6150A obtained from
        ground to 35 km verified magnitude of intensities and correlation with atmos-
        pheric density as obtained from previous flight
    Solar soft x-ray studies: Two packets installed in rocket; one recovered, but foil
        was missing, eliminating results
    Skin temperature experiment: Temperature-time curves obtained. Test flight of
        equipment; low accuracy.
    Voltage breakdown: Data were obtained only in the altitude interval of 12 km to 22
        km. Density data computed in this interval was in agreement with known
        densities within experimental error. After fuel burnout no data were obtained
        due to some failure.
    Pressure and temperature experiment: Pressure data obtained from 46 km to 100
        km. Temperatures computed by means of barometric equation are consistently
        lower value than the NACA mean standard.
    Oblique incidence ionosphere propagation experiment: Rocket flight too low for
        penetration into E layer; some propagation patterns obtained for very long path
    Vertical incidence ionosphere propagation experiment: Equipment worked well; data
        obtained only for lower part of E layer because of low altitude

COMMENTS

    Rocket performance: Exceptionally stable flight. Held calculated course, but failed
        to obtain calculated maximum altitude.

REPORTS AND PAPERS

    WSPG Report of V-2 Firing No. 28, ORDBS 471.94 (a), 15 December 1947
    Telemetering Report, A-4 Rocket 28, prepared by Physical Science Lab., New Mexico
        College of A. & M.A. for BRL, Aberdeen Proving Ground, Contract N173S-11218
        December 8, 1947
    "Upper Air Research Program," Report No. 1 by the Navigation Laboratory, AMC,
        Cambridge Field Station, 1 September 1947
    "Atmospheric Pressure & Temperature Measurements Between the Altitudes of 40
        and 110 Kilometers," Upper Air Research Program Progress Report No. 2,
        1 July 1948, Engineering Research Institute, University of Michigan, Contract
        W33-038-ac-14050
    "Upper Air Research Program," Report No 3 by the Upper Air Laboratory, ERHU,
        AMC, Cambridge Field Station, 1 April 1949
    Final Report No. P-2106-11 Blossom Series, W. F. Gould, The Franklin Institute
        Laboratories for Research and Development, 1 March 1950, Contract
        AF19(122)-33
    "Dynamic Probe Measurements in the Ionosphere," A. Reifman and W. G. Dow,
        Phys. Rev. 76:987 (1949)
    "Day Sky Brightness Measured by Rocketborne Photoelectric Photometers," H. A.
        Miley, et al., Trans. Am. Geophys. Union (in press)