gun-launched probes Ballistic Research Laboratories 0V6P BaMOS , Md. and Gerald V. Bull Space Research Institute, Inc. Northfield, Vt.

Abstract 90 km were obtained by means of chemical releases. The use of 5- and 16-inch guns for vertical soundings Early in 1965, the altitude performance of the 16-inch over Barbados is described. Five-inch gun soundings gun was increased from 108 km to 144 km by the addi- have obtained numerous measurements of winds up to tion of a 50 ft long muzzle extension (Fig. 2). With 60 km and have made a few temperature measurements this extension, the gun is 119 ft long and weighs 200 with the development of appropriate sensors. Projectiles tons. By means of an improved ignition system and a launched from the 16-inch gun have made 67 measure- modified M-8 propellant, an identical gun at Yuma ments of winds above 85 km and these results have been Proving Ground, , has reached 180 km (Murphy correlated with ground based radio frequency mea- and Bull, 1966, 1967). surements to increase our understanding of Sporadic-E The Barbados gun work was initiated by McGill layers. University with the aid of a small U. S. Army contract which allowed the supply of a large quantity of surplus 1. Introduction U. S. equipment including the guns themselves. Addi- In the summer of 1962, the U. S. Army landing ship, tional financial support came from the Army during the the Lt. Col. John D. Page, moved through a hole blasted preliminary work up to July 1964. At this time, a three in the reef at Foul Bay on the Southeast coast of Bar- year joint U. S.-Canadian program called HARP-McGill bados and beached itself high on the sand. Two 140 was established. With the conclusion of this program, ton 16-inch gun barrels with associated mount parts budgetary pressures forced the Army to terminate its were unloaded and moved over land in flat cars on support and McGill University has withdrawn from temporary track two miles to a plateau 70 ft beneath the work. A nonprofit corporation, Space Research In- the East end of the jet runway at Seawell Airport stitute, Inc., has been set up under the control of Nor- (Fig. 1). In January 1963, first proof flights were made wich University and the Army has transferred most of by projectiles from this 16-inch gun and the island of its equipment to this company. The Barbados range as Barbados became the site of a new operational range well as an engineering test site at Highwater, , for scientific soundings. are being operated by this company (Bull, 1968). During 1963 and 1964, a number of successful firings of the 185 lb finned projectiles called Martlet 2's were made and first measurements of nighttime winds above

Fio. 1. Barbados launch site. FIG. 2. Barbados 16-inch and 5-inch guns.

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Unauthenticated | Downloaded 10/05/21 07:08 PM UTC Bulletin American Meteorological Society In this paper, some of the more interesting scientific and 13 successful temperature measuring flights. In results obtained from probes fired from the Barbados the period January 1966 to July 1967, 98 firings of 16-inch gun and its associated 5-inch gun, which was the Barbados five-inch gun were made with 60 success- installed in January 1966, will be presented. Before ful wind measurements. Although some of the nondata- considering this work, we should give the advantages of gathering flights were caused by radar malfunctions, a gun probe system in comparison with the more con- most of these unsuccessful flights were due to a faulty ventional sounding rocket approach. These can be sum- ejection system which has been modified. All of these marized by the two words, economy and accuracy. The data have been published in the appropriate MRN economy of this method is based on the consideration Data Report. of the gun barrel as a reusable first stage booster. The The wind sensor used in these flights was an alu- accuracy can be expressed as a 2 Yuma Proving Ground, Ariz. As of 1 January 1968, these guns have made 221 successful wind measuring flights * $36.00 a year from the U. S. Government Printing Office.

FIG. 4. Ambient air temperature measured by parachute supported 250 MHz telemeter with 10 mil bead thermistor. FIG. 3. Average winds for February 1966 measured by alu- A segment of the mean tropical atmosphere (Jordan, 1958) minized parachutes ejected from 5-inch projectiles is shown above and below the tropopause. 641

Unauthenticated | Downloaded 10/05/21 07:08 PM UTC Vol. 49, No. 6, June 1968 the interval 20-55 km. We see that the winds in this During a firing series, simultaneous measurements of interval are predominately easterlies with a maximum the ionosphere are made by a C-4 ionosonde located near 42 km. An interesting feature of this profile is the near the gun site and correlations between the loca- direction reversal to westerlies above 50 km. These tion of Sporadic E layers and the observed winds are qualitative features of the Barbados (13N) profiles are sought (Wright et al., 1967). A spaced array of receivers also seen at Panama Canal Zone (7N) and at Antiqua is also located near the ionosonde to measure move- (17N). ment of irregularities in the E-layer by comparison of Although the wind sensors are passive and quite re- the arrival time of signals at the different receivers. sistant to the large accelerations associated with gun These ionospheric drifts are compared with the neutral launch, temperature sensors are much more delicate wind profiles to improve our use of the radio frequency and usually require an operating telemetry system. sounding techniques (Wright et al., 1966). Finally, spec- Telemetry transmitters for 250 MHz as well as the me- trographs of twilight trails have been taken to corre- teorological frequency of 1680 MHz have been devel- late spectrum intensity at various wavelengths with oped to withstand gun acceleration as high as 50,000 g's height above ground, depression of the Sun below the and a small number of successful flights with a 10 mil horizon, and time after the initial release of the chemi- bead thermistor have been made (Mermagen et al cal (Millman, 1966). 1966). A temperature telemeter unit has only recently In Fig. 5, a sample wind profile is shown together reached an acceptable level of reliability and an addi- with the location of two Sporadic E layers which were tional number of flights are required to validate this present at the time of this measurement. The coinci- reliability. These telemeters weigh about 260 gm and dence of the Sporadic E layers with the maximum shear are attached to the two-meter parachutes replacing the of the zonal wind should be noted since this is a pre- usual metal weights. Most flights have been made with diction of a simplified wind shear model for the pro- the 250 MHz unit, so increased developmental effort duction of a Sporadic E layer. The high amplitude is being made on the 1680 MHz unit as well as on fluctuations of wind components with height is also the successful gun-launch of the more sophisticated characteristic of ionospheric winds. thin film resistors. In Fig. 4, temperature profiles for three successful flights over Barbados during the month of June 1967 are given. Although ejection occurred above 55 km for all flights, the bead thermistors were initially at 25C and required as much as 10 km of fall to yield good values of the ambient air temperature. The flight on 19 June suffered from RF interference from some unknown source and only partial data was obtained. The flights reflect the low temperatures of the tropical tropopause (Jordan, 1958).

3. Ionospheric winds The basic scientific measurements made by projectiles launched from the 16-inch gun were wind profiles be- tween 85 and 140 km. In the three year period July 1964 to June 1967, 67 successful measurements have been made of winds in this altitude interval (Murphy et al1966, 1967). The actual profiles are published in appendices which appear in the January and June MRN Data Reports, starting with the January 1967 issue. The winds at these altitudes are measured by the continuous release of 2.5 kg of a liquid mixture of tri- methyl-aluminum and tri-ethyl-aluminum which reacts with the atomic oxygen found above 85 km to yield a luminous trail (Rosenberg et al1963). This trail can be seen at night over distances as great as 300 km and persists as long as 15 min. K-46 camera sites are located on Barbados and the neighboring islands of Tobago, Grenada, and St. Vincent. Photographs from any pair of sites can be used to determine the trail as a space curve and two such determinations separated by 60 sec FIG. 5. Wind components measured by release of TMA/TEA can be used to provide the wind profiles. from 16-inch projectile.

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FIG. 6. Meridional wind contours for 23-24 February 1966.

FIG. 8. Average wind profiles for four nights over Barbados.

clouds of electrons by explosive release of Cesium (Murphy et al1967), to measure directly electron densities and electron temperatures by Langmuir probes and on-board telemetry (Block et al., 1965), and to mea- sure the Earth's electric field by the release of a cloud of Barium ions (Mead et al., 1967). Although the Lang- muir probe and Barium release experiments are still under development, the explosive release of Cesium did create an observable cloud of electrons which persisted for about 16 min. Our experience with these experi- ments has given us confidence that any interesting mea- FIG. 7. Zonal wind contours for 23-24 February 1966. surement can be designed for gun launch if a sufficient number of repetitive experiments is planned to justify The variation of the winds through a night can be the increased developmental cost incurred by the need best shown by means of a pair of contour plots (Figs. for resistance to the high launch accelerations of a gun 6-7). Here the times and altitude intervals of each mea- system. surement are shown as vertical line segments and con- tours of constant component speed drawn as curves in Acknowledgment. The authors are especially grateful a time-altitude plane. As can be seen from these figures, to the Government of Barbados for its encouragement the winds at a given altitude vary by large amounts and many acts of direct support to the sounding pro- throughout a night. For example, Fig. 6 shows that the gram described in this paper. meridional component at 105 km varies from a southerly of 80 m sec"1 at 7:30 p.m. Atlantic Standard Time (AST) References to a northerly of 100 m sec"1 at 3:30 a.m. These rapid Block, A. V., A. Kodis and L. C. Smith, 1965: High altitude fluctuations mean that the average circulation can only gun probes (development of Langmuir Probes). G.C.A. TR be measured by averaging a number of measurements 65-16-G, AD 633920. at the same altitude throughout a night. Boyer, E. D., 1966: Five-inch HARP tests at Barbados, West In Fig. 8, average profiles of this type are constructed Indies, January-February 1966. BRL MR 1771, AD 640438. for data from four different night firing series. From Bull, G. V., 1968: Project HARP. Ordnance, 52, 482-486. this figure, we see no order in the meridional com- Cox, R. N., 1967: The case for gun-launched space probes. ponents but do see a definite reversal of the zonal New Scientist, 36, 337-340. components between the September 1965 night and the Jordan, C. L., 1958: Mean soundings for the West Indies three winter nights in November 1965 and February area. J. Meteor15, 91-97. 1966. Verification of this reversal is awaiting the com- Mead, J. B., E. H. Parkison and L. Witten, 1967: Measure- ment of geo-electric fields and upper atmosphere parame- plete analysis of two more nights in September 1966 and ters by release of barium vapors. Martin-Marietta Co., February 1967, respectively. AD 662066. 4. Other atmospheric measurements Mermagen, W. H., W. J. Cruikshank and F. Vrataric, 1966: VHF and UHF high-G telemetry for HARP vehicles. The In addition to the measurements of ionospheric winds, Fluid Dynamic Aspects of Ballistics, AGARD CP 10, AD 16-inch projectiles have been used to create artificial 805753. (See also BRL MR 1768, AD 640596.)

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Unauthenticated | Downloaded 10/05/21 07:08 PM UTC Vol. 49, No. 6, June 1968 The Meteorological Rocket Network, IRIG Document 111-64, measured by gun launched projectiles. J. Geophys. Res., Feb. 1965, AD 464583. 71, 4535-4545. Millman, P. M., 1966: Big gun on Barbados. Sky and Tele- , , and J. W. Wright, 1967: Motions of an electron scope, 32, 64-67. cloud released from a gun-launched projectile. J. Geophys. Murphy, C. H., and G. V. Bull, 1967: HARP 5-inch and 16- Res., 72, 3511-3514. inch guns at Yuma Proving Ground, Arizona. BRL MR Rosenberg, N. W., D. Golomb, and E. F. Allen, 1963: Chemi- 1825, AD 654123. luminescence of tri-methyl-aluminum released into the , and , 1966: Review of the High Altitude Re- upper atmosphere. J. Geophys. Res., 68, 5895-5898. search Program. The Fluid Dynamics Aspects of Ballistics, Wright, J. W., and L. S. Fedor, 1966: Comparison of iono- AGARD CP10, AD 805753. (See also BRL R 1327, AD spheric drift velocities by spaced receiver technique with 645284.) neutral winds from luminous rocket trails. Space Research , and , 1967: Night-time variation of ionospheric VII, North-Holland Publishing Co., Amsterdam, 67-72. winds over Barbados, W. I. J. Geophys. Res., 72, 4831- , C. H. Murphy, and G. V. Bull, 1967: Sporadic E and 4837. the wind structure of the E region. J. Geophys. Res., 72, , , and H. D. Edwards, 1966: Ionospheric winds 1443-1460.

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JAM editor appointed A graduate of Massachusetts Institute of Technology, Dr. Hilst obtained his S.M. in meteorology at MIT in 1949 and Dr. Glenn R. Hilst has been his Ph.D. in meteorology at the University of Chicago in named editor of the JOURNAL 1957. Before going to Travelers in 1960, he was manager of OF APPLIED METEOROLOGY, the Atmospheric Physics Operation at Hanford Atomic Prod- succeeding Prof. Richard J. ucts, General Electric Company (1954-1960) and from 1949 Reed of the University of to 1952, a research meteorologist in the Hanford radiological Washington, who served as protection program. In 1952-1954 he was a research asso- JAM editor from early 1966. ciate with the AEC's Argonne National Laboratory. Dr. Hilst has been an asso- Dr. Hilst is currently an AMS councilor and serves on the ciate editor of JAM since Committee on Scientific Communications and the Fund Rais- 1962 and is also an associate ing Committee. He was treasurer of the Society in 1966, editor of METEOROLOGICAL secretary of the Council in 1967, and has served on the MONOGRAPHS. He is currently Committee on Air Pollution and the Committee on Atmo- vice president of The Trav- spheric Turbulence and Diffusion. elers Research Center, Inc., Manuscripts for the JOURNAL OF APPLIED METEOROLOGY and director of the Center's should now be sent to Dr. Glenn R. Hilst, Editor of J. Appl. Environmental Sciences De- Meteor., partment, where he is re- The Travelers Research Center, Inc., 250 Constitu- sponsible for the scientific tion Plaza, Hartford, Conn. 06103. and technological programs in air and water resources. (More announcements on page 673)

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