# US 8,464,640 B2 · Controllable digital solid state cluster thrusters for rocket propulsion and gas generation

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- Number: US 8,464,640 B2
- Document ID: US8464640B2
- Status: Granted
- Kind: B2
- Application number: 13/101,934
- Filed: 2011-05-05
- Published: 2012-06-07
- Granted: 2013-06-18
- Earliest claimed: 2004-12-17
- Assignees: Digital Solid State Propulsion, LLC
- Applicants: Wayne N. Sawka
- Inventors: Wayne N. Sawka
- Web page: https://patentgrep.com/patent/US8464640B2

## CPC

- C06B 45/00: Compositions or products which are defined by structure or arrangement of component of product (explosive charges of particular form or shape F42B1/00, F42B3/00)
- F02K 9/10: Shape or structure of solid propellant charges
- F02K 9/26: Burning control {(F02K9/10, F02K9/34, F02K9/86, F02K9/92 and F02K9/94 take precedence)}
- F02K 9/95: characterised by starting or ignition means or arrangements (safety devices F02K9/38)
- Y10T 29/49346: Rocket or jet device making
- C06B: EXPLOSIVES OR THERMIC COMPOSITIONS (blasting F42D); MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES (compounds in general C01, C07 or C08; {demolition agents based on cementitious or like materials C04B41/0009})
- F02K: JET-PROPULSION PLANTS (features of jet-propulsion plants common to gas-turbine plants, air intakes or fuel supply control of air-breathing jet-propulsion plants F02C7/00, F02C9/00)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A thruster stack assembly and method for manufacturing the same is provided. The thruster stack assembly includes a plurality of grain elements having a common core region (e.g., a channel or passageway), where each grain element comprises a volume of electrically ignitable propellant. The thruster stack assembly further includes electrodes associated with the plurality of grain elements, the electrodes adapted for selectively igniting the plurality of grain elements. In one example, one or more of the grain elements may be ignited and combusted without igniting or damaging adjacent grain elements of the stack. The core region serves to channel combustion gases and exhaust from the thruster stack. Multiple stacks may be assembled together to form three-dimensional thruster arrays.

## Claims

### Claim 1

A thruster stack assembly, comprising:
a plurality of grain elements having a common core region, each grain element comprising a volume of electrically ignitable propellant, wherein:
the electrically ignitable propellant is ignitable in response to the application of electrical power there through, and
the common core region comprises a passageway adjacent a portion of each of the plurality of grain elements for the passage of combustion gas; and
electrodes associated with the plurality of grain elements, the electrodes adapted for selectively igniting the plurality of grain elements.

### Claim 2 (depends on 1)

The assembly of claim 1, wherein an insulation layer is disposed between two adjacent grain elements.

### Claim 3 (depends on 1)

The assembly of claim 1, wherein an electrode is disposed between two adjacent grain elements.

### Claim 4 (depends on 1)

The assembly of claim 1, wherein two adjacent grain elements are disposed in direct contact with each other.

### Claim 5 (depends on 1)

The assembly of claim 1, wherein at least two grain elements comprise two coaxially aligned rings of the electrically ignitable propellant.

### Claim 6 (depends on 1)

The assembly of claim 1, further comprising a plurality of stacked thrusters, each thruster having a plurality of grain elements, thereby forming a three-dimensional array of addressable grain elements.

### Claim 7 (depends on 1)

The assembly of claim 1, wherein the common core region communicates with at least one exhaust port.

### Claim 8 (depends on 1)

The assembly of claim 1, wherein the plurality of grain elements are stacked along a vertical dimension and the common core region is disposed along the vertical dimension.