NATIONAL AERONAUTICS AND SPACE ADMINISTRATION WASHINGTON, D.C. 20546 REPLY TO ATTN OF: GP TO: KSI/Scientific & Technical Information Division Attn: Miss Winnie M. Morgan FROM: GP/Office of Assistant General Counsel for Patent Matters SUBJECT: Announcement of NASA-Owned U.S. Patents in STAR In accordance with the procedures agreed upon by Code GP and Code KSI, the attached NASA-owned U.S. Patent is being forwarded for abstracting and announcement in NASA STAR. The following information is provided: U.S. Patent No. 4.080.901 Government or Corporate Employee U.S. Government Supplementary Corporate Source (if applicable) NASA Patent Case No. LAR-12.018-1 NOTE - If this patent covers an invention made by a corporate employee of a NASA Contractor, the following is applicable: YES // NO /A / Pursuant to Section 305(a) of the National Aeronautics and Space Act, the name of the Administrator of NASA appears on the first page of the patent; however, the name of the actual inventor (author) appears at the heading of column No. 1 of the Specification, following the words "...with respect to an invention of ..." <.^ *• Bonnie L. Henderson Enclosure United States Patent 4,080,901 Heier et al. [45] Mar. 28, 1978 [54] MOLDED COMPOSITE PYROGEN IGNITER Primary Examiner—Harold Tudor FOR ROCKET MOTORS Attorney. Agent, or Firm—Wallace J. Nelson; Howard J. [75] Inventors: Wilbur C. Heier, Hampton; Melvin Osborn; John R. Manning H. Lucy, Virginia Beach, both of Va. [57] ABSTRACT [73] Assignee: The United States of America as A lightweight pyrogen igniter assembly including an represented by the Aministrator of the elongated molded plastic tube adapted to contain a National Aeronautics and Space pyrogen charge and to be inserted into a rocket motor Administration, Washington, D.C. casing for ignition of the rocket motor charge with a [21] Appl. No.: 678,520 molded plastic closure cap provided for the elongated [22] Filed: Apr. 20, 1976 tube and including an ignition charge within the cap for igniting the pyrogen charge and an electrically actuated 2 [51] Int. a. F42B 15/10 ignition squib within the cap for igniting the ignition [52] U.S. a 102/49.7; 60/39.82 E; charge. The ignition charge is contained within a por- 102/39; 102/70 R; 285/192 tion of the closure cap and it is retained therein by a [58] Field of Search 102/70 R, 39, 70.2 A, noncorrosive ignition pellet retainer or screen which is 102/43 D, 49.7; 60/39.82 R, 39.82 E, 256; adapted to rest on a shoulder of the elongated tube 220/288; 285/192, 220, 212; 403/195, 201, 238, when the closure cap and tube are assembled together. 239 The interior of the closure cap and the exterior of the [56] References Cited elongated tube are provided with matching tapered U.S. PATENT DOCUMENTS spiral buttress threads to serve as the attachment means therefor. A circumferentially disposed metal ring is 2,462,135 2/1949 Skinner 102/70.2 A provided along the external circumference of the clo- 2,561,670 7/1951 Miller et al 102/70.2 A X 3,031,842 5/1962 Ledwith 62/234 sure cap and is molded or captured within the plastic 3,129,561 4/1964 Priapi 60/39.82 E X cap in the molding process to provide, along with O- 3,151,447 10/1964 Bornstein 102/70 X ring seals, a leakproof rotary joint as part of the contain- 3,190,372 6/1965 Johnson 102/49.7 X ing wall with the rocket motor casing when the igniter 3,529,418 9/1970 Puckett et al 60/256 X assembly is installed within the rocket motor casing.. 3,581,662 6/1971 Grebert : 102/70.2 A 3,780,151 12/1973 Heier 425/355 3,906,720 9/1975 Boydston 102/49.7 12 Claims, 6 Drawing Figures 34 30 35 tttA$ArCase-L A E -12 018-. 1) •, MG|p.f D' N78-2U275 PYS6GEN IGNITER FOR ROCKET tiaTO'BS Pafemt (NASA) 10 p '/•GS-.CI- 2-1-B"; Onelas U.S. Patent March 28, 1978 Sheet 1 of 3 4,080,901 34 30 53 61 FIG. 2 FIG. 1 FIG. 3 ent 1978 Sheet 2 of3 4>080,9Qi PIG. 4 PIG. U.S. Patent March 28, 1978 Sheet 3 of 3 4,080,901 20 *•! 34 FIG. 6 4,080,901 igniter of the present invention is itself a miniature solid MOLDED COMPOSITE PYROGEN IGNITER FOR rocket motor that burns for short duration and consists ROCKET MOTORS of very few inert components and a pyrotechnic train. The inert components in presently used igniters of this ORIGIN OF THE INVENTION 5 type consist of numerous parts. The caps or rocket The invention described herein was made by employ- motor case closures are generally fabricated from steel, ees of the United States Government and may be manu- titanium, or aluminum held in place within the rocket factured and used by or for the Government for govern- motor casing by a steel snap-ring or machined threads mental purposes without the payment of any royalties and this cap must be heavily insulated to protect it dur- thereon or therefor. 10 ing rocket motor burning. These known caps or clo- sures contain provisions for initiators and pressure mon- BACKGROUND OF THE INVENTION itoring ports as well as O-ring seals. The pyrogen case This invention relates generally to rocket motor ignit- or pressure vessel in presently used igniters usually ers and relates in particular to a molded plastics com- consist of a steel, titanium, aluminum or fiberglass shell posite rocket motor pyrogen igniter assembly that may 15 that is also heavily insulated inside and out to protect it be produced on a production line basis and is readily when the pyrogen and the rocket motor are burning. adaptable for all present day existing and anticipated The insulation material is generally a molded phenolic- rocket motors that may be employed by the National /asbestos or rubber/asbestos compound. The hot gases Aeronautics and Space Administration for sounding exhausted from the pyrogen must pass through one or rocket vehicles and in various military rocket motors as 20 more nozzles at the end of the shell with the nozzles well as for anticipated space shuttle payload rocket being generally made from molded phenolic/glass, as- launches and the like. bestos or graphite material. A steel or titanium slotted In the field of rocket .motor ignition where solid pro- plate or screen is usually included to retain the pyro- pellant grains are utilized, it is the general practice to technic ignition pellet charge within the igniter and the employ an igniter assembly that includes a pyrogen 25 inside surface of the pyrogen case insulator generally propellant material and an initiator for the pyrogen with receives a coating of a rubber liner material to insure the igniter assembly being, in some instances, formed of good adhesion between the insulator and the solid pro- a two-piece system wherein the initiator charge is re- pellant charge placed in the pyrogen tube. movable from the rocket motor while the pyrogen ma- These non-standard pyrogen igniters have proved terial is permanently installed and maintained within the 30 sufficient for present day needs; however, they impose combustion chamber adjacent the solid propellant unnecessary penalties on the overall systems that use rocket charge. Unitary or single piece non-standard solid propellant rocket motors with pyrogen igniters. igniter assemblies have been employed but these, as in These present day pyrogen igniters contain numerous, the two-piece construction, must be individually ma- complex, massive, relatively expensive, heavily insu- chined and fabricated for each different rocket motor. 35 lated metal and non-metal parts that must be fabricated This individual machining of the metallic parts em- individually and that require many man hours for fabri- ployed in constructing the igniter increases the cost of cation and assembly and meticulous inspection through- the igniter assembly as well as provides unnecessary out for quality control. There is no common or univer- weight to the rocket motor. In propelling payloads, sal design for the various igniters employed by different such for example in the anticipated space shuttle mis- 40 rocket motor manufacturers and each new design must sions, and in various sounding rockets and other space be evaluated and qualified. Thus, proven reliability applications, the additional weight utilized in the igniter suffers because of the relatively few number of devices serves to reduce the prospective payload weight that that are tested and used. could be transported by the solid propellant rocket All molded pyrogen igniter designs of the present motor. The firm users identified to date would be the 45 invention can be incorporated into their respective solid NASA Scout launch vehicle which employs solid motors during normal operational use and this can be rocket motors consisting of Algol III, Castor II-A, done as part of routine surveillance testing, product Antares, Altair III, and the proposed higher energy improvements, or new procurements or developments. versions of each of these which are presently under It is therefore an object of the present invention to study; the NASA Delta and Japanese N launch vehicles 50 provide a novel molded composite rocket motor pyro- using solid motors consisting of the Castor II-A, and gen igniter assembly. It is a further object of the present TE-364; the Air Force Block Five Launch Vehicle, and invention to provide a molded composite rocket motor the Astrobee "F" sounding rocket vehicle. Other poten- pyrogen igniter assembly that is light in weight and less tial users include the second stage Minuteman, Terrier expensive to construct than presently used igniter as- Malemute and the Navy HARM missiles.