Telescoping Boom

Abstract

A boom which is carried inside a reentry vehicle during launch and flight ereof and extended from the aft of the reentry vehicle during reentry of the vehicle into the atmosphere. Instrumentation is carried by the boom for making certain experiments and for making direct measurements of flow properties in the recirculation region and hypersonic wake behind the reentry vehicle.

Description

BACKGROUND OF THE INVENTION

The boom is basically an instrument carrier which is stored inside the reentry vehicle during the launch and is extended therefrom after the reentry vehicle is separated from the launch vehicle, but before it is spun up. The boom contains such instruments as pressure gages, electrostatic probes, acoustic sensors, radiometers, a wake seeding device, a spectrometer, a base diffusion experiment, etc. The apparatus permits localized (point) measurements over portions of near wake, recirculation region, and expansion region for relatively long periods of time during reentry, and at well fixed geometric points. It also permits direct wake seeding experiments to be performed without involving the recirculation region.

SUMMARY OF THE INVENTION

The boom structure includes a boom guide tube having the boom, with its instrumentation carried thereon, carried in the guide tube. An explosive "pin puller" retains the boom in the stowed position. At the desired time a small electric motor extends the boom out of the boom guide and the reentry vehicle. Electric cable secured to an instrument package in the vehicle and the instruments on the boom is extended with the boom and a cable drum and negator spring is provided to insure that the electric cable does not become entangled during deployment of the boom. The instrument package receives signals, through the cables, from the instruments. The signals are recorded or transmitted, as desired.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevational view of the boom assembly in stowed position in a reentry vehicle.

FIG. 2 is a sectional view along line 2--2 of FIG. 1.

FIG. 3 is a sectional view along line 3--3 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT

As shown in FIG. 1, a boom 10 is carried in a cylindrical boom guide 12 in stowed position in a reentry vehicle 14. The aft end 16 of the boom rests in a cylindrical bearing 18 in a support sleeve 20 which in turn is threaded into a structural member 21 of the vehicle. A flange 22 of a structural support tube 24 of the instrument package 26, for the experiments is secured to structural member 21. The forward end 27 of the boom rests similarly in a support tube 28. At the aft end 16, an explosive "pin puller" 30 extends through the boom guide 12 for engagement with the boom to provide a stowed position lock.

Electrical wiring 34 extending from the instrument carried by the boom 10 is molded together in a flat cable and is carried over a rotating drum 36 and extends back to the instrument package 26, running in an annular space 38 between boom 10 and support tube 12. The cable 34 is guided by an arrangement of longitudinal lands 40 (FIGS. 2 and 3) in the supporting tube wall. Lands 40, together with matching cut-outs 42 in the boom sliding surfaces, provide an indexing feature which prevents the boom from rotating in the support tube and thus makes the boom position in relation to the reentry vehicle known even in the extended position.

The cable drum 36 is attached to a negator spring (not shown) located in the forward end 27 of the support tube. The spring provides a constant stretch load through the drum 36 onto the wire cable 34 reglardless of the longitudinal position of the boom during its deployment thus preventing tangling of the electrical cable and slack in the actuating cable.

The instruments mounted inside the boom are supported on a central fiber glass-epoxy one-piece shelf 44 (FIGS. 3 and 4) which runs from end to end of the boom. The shelf slides on two parallel lands 46 and 48 brazed into the boom. Surface contact between shelf and boom lands is minimized for heat conduction and function considerations by small intermittant inserts of teflon 50 in the groves on the shelf. Furthermore, the instruments on the shelf are protected from radiant heat from the boom walls by thin half cylinders of fiber glass epoxy sheet 52 on each side of the shelf. Holes and windows 53 in the boom wall are required for all instruments.

Deployment of the boom to the extended position takes place after separation of the reentry vehicle from the launch vehicle in a near zero g condition. A small electric motor (not shown) with a reduction gear drives a cable drum 54 with a wire 56 running from the drum to the forward end of the boom thus pulling the boom out to the deployed position. When the boom reaches the fully deployed position, three spring-loaded locks 58 (FIG. 2) in the forward end of the boom snap into position in a grove 60 (FIG. 1) in the sleeve 20 forming a position lock. At the same time, two conical shoulders 62 (FIG. 1) on the boom end 27 come to rest against corresponding shoulders 64 on the inside periphery of the sleeve forming a firm seat for the boom which is now cantilevered out from the reentry vehicle. A microswitch (not shown) shuts off the electric motor drive at the end position.

Claims

We claim:

1. A telescoping boom comprising:

a. boom support means;

b. a guide member secured to said boom support means;

c. a boom carried in said guide member in telescoping relation therewith;

d. releasable locking means for securing said boom in a nonextended position and for release thereof for movement to an extended position;

e. means for extending said boom out of said guide member and said support means;

f. locking means for securing said boom in the extended position; and;

g. an instrument package carried in said boom support means having electric cables connected thereto and to said instruments, cable tension mechanism carried in said boom guide to prevent entanglement of said cables responsive to boom deployment, and, means for guiding said electric cable from said instrument package to said cable tension mechanism including adjacent longitudinally extending lands provided in said boom and said guide member.

2. A telescoping boom as in claim 1 wherein said guide member is a tubular member having said boom slidably mounted therein.

3. A telescoping boom as in claim 1 wherein said means for extending said boom includes an electric motor driven boom actuator drum and a wire connected to the forward end of said boom and said drum whereby responsive to rotation of said drum said wire extends said boom out of said guide member.

4. A telescoping boom as set forth in claim 3 wherein said means for retention of said boom in the extended position includes an annular groove disposed in said support member and ball lock means carried on said boom at the forward end thereof, said ball lock means including a plurality of balls carried in biased relation in said boom for locked engagement in said annular groove responsive to said boom reaching the extended position.

5. A telescoping boom as set forth in claim 4 wherein said support means is a reentry vehicle and said boom is provided with instrument support means for support of instruments thereon for measurements of conditions in the wake of said reentry vehicle.

6. A telescoping boom as in claim 5 wherein said means for securing said boom in the non-extended position and for release thereof for movement to an extended position includes an explosive retaining means extending through said boom guide in engagement with said boom.