Micro-cathode arc thruster

Patent metadata

Field	Value
Publication number	US-10738768-B2
Application number	US-201715630545-A
Country	US
Kind code	B2
Filing date	Jun 22, 2017
Priority date	Jun 22, 2016
Publication date	Aug 11, 2020
Grant date	Aug 11, 2020

Abstract

A satellite thruster increases satellite efficiency. The Linear Actuated μCAT has a stepper motor to move the ablative electrode forward. A LabVIEW program and Arduino microcontroller are used to analyze the Linear Actuated μCAT to determine how many steps are required for re-ignition, arc current, and the validity of the feed system. Results from testing show that micro-stepping the stepper motor is an effective way to replenish the cannibalized electrode for propellant.

First claim

The invention claimed is:

1. An arc thruster comprising:
an anode;
a cathode;
an advancement apparatus attached to the cathode comprising:
a motion generator;
a coupling device fixedly connected to said motion generator and movably connected to said cathode; and
a linear guide member slidably connected to said cathode to linearly move the cathode with respect to the anode and prevent said cathode from rotating with respect to said anode.

2. The arc thruster of claim 1 , further comprising a dielectric insulator between the cathode and the anode, said dielectric insulator insulating the cathode and the anode, wherein the anode surrounds at least a portion of the cathode.

3. The arc thruster of claim 1 , wherein said anode surrounds said cathode, and further comprising a sensor that detects a position of a distal end face of said cathode and a controller for controlling movement of said advancement apparatus, wherein said controller receives the position and controls the motion generator to move said cathode upon sensing that the distal end face of said cathode cathode is greater than a pre-determined distance from a distal end face of said anode.

4. The arc thruster of claim 3 , wherein said controller moves the distal end face of the cathode toward the distal end face of said anode until the distal end face of the cathode is substantially level with the distal end face of said anode.

5. The arc thruster of claim 1 , wherein said coupling device has a coupling device threaded portion and said cathode has a cathode threaded portion, wherein the coupling device threaded portion of said coupling device is threadably connected to the cathode threaded portion of said cathode.

6. The arc thruster of claim 5 , wherein said motion generator comprises a motor which rotates said coupling device to screw or unscrew said coupling device from said cathode.

7. The arc thruster of claim 1 , wherein said cathode comprises a rod and said coupling device comprises a tube.

8. The arc thruster of claim 1 , wherein the anode comprises one of Iron, Titanium, Tungsten or Copper.

9. The arc thruster of claim 1 , wherein the cathode comprises one of Iron, Titanium, Tungsten or Copper.

10. The arc thruster of claim 1 , wherein the dielectric insulator comprises one of a ceramic material, Boron Nitride, Mica, or Alumina.

11. The arc thruster of claim 1 , further comprising a frame having a proximal end and a distal end opposite the proximal end, wherein said motion generator is connected at the proximal end and a thruster head is connected at the distal end.

12. The arc thruster of claim 11 , wherein a distal end face of said anode and a distal end face of said cathode are aligned at the thruster head and provide an arc discharge at the thruster head.

13. The arc thruster of claim 1 , further comprising a housing, said advancement apparatus connected to said housing, whereby said motion generator rotates said coupling device with respect to said housing, and wherein said linear guide member is fixedly connected to said housing.

14. The arc thruster of claim 1 , said cathode having a guide section with at least one flat surface, said guide section engaging said linear guide member to prevent rotation of said cathode with respect to said anode.

15. A method of operating an arc thruster having a cathode, an anode insulated by a dielectric insulator, a stepping motor and a rod, the method comprising:
providing impulse bits to the cathode and the anode insulated by the dielectric insulator to generate an arc;
sensing a level of ablation of the cathode;
activating the stepping motor connected to the cathode through the rod to actuate the cathode to move linearly forward to compensate for the ablation upon sensing the level of the cathode is below a pre-determined value,
while preventing rotation of the cathode with respect to the anode.

16. The method of operating the arc thruster of claim 15 , wherein the rod and the cathode are engaged via helical ridges formed on a surface of an end of the rod and additional helical ridges formed on a surface of an end of the cathode, wherein upon activation of the stepping motor, the helical ridges and the additional helical ridges engage transforming a rotary motion of the rod into a linear motion to actuate the cathode, and wherein a guide member prevents rotation of the cathode with respect to the anode.

17. The method of operating the arc thruster of claim 15 , wherein the predetermined value is a value in relation to a level of the anode.

18. The method of operating the arc thruster of claim 17 , wherein the stepping motor is activated until the cathode is level with the anode.

19. The method of operating the arc thruster of claim 15 , wherein the impulse bits are of approximately 1 uNs or higher.

20. An arc thruster comprising:
a frame having a frame proximal end and a frame distal end;
a thruster head connected to the frame distal end;
a cathode having a cathode distal end with a cathode distal end face;
an anode having an anode distal end with an anode distal end face, said anode surrounding said cathode;
a coupling device movably connected to said cathode;
a motor connected to the frame proximal end and connected to said coupling device, wherein said motor moves said coupling device with respect to said anode whereby said anode distal end face is level with said cathode distal end face; and
further comprising a guide member movably connected to said cathode to move said cathode with respect to said anode and to prevent rotation of said cathode with respect to said anode.

Assignees

• Univ George Washington

Inventors

• Keidar Michael
• Teel George
• Hurley Samantha A

Classifications

• B64G1/413

  Ion or plasma engines · CPC title

• F03H1/0012 Primary

  Means for supplying the propellant · CPC title

• F03H1/0087

  Electro-dynamic thrusters, e.g. pulsed plasma thrusters · CPC title

• B64G1/1021

  Earth observation satellites · CPC title

• F03H1/0081 Primary

  Electromagnetic plasma thrusters · CPC title