FIELD

The present disclosure relates to converging/diverging nozzles and, more particularly, relates to a converging/diverging magnetic nozzle employing magnetic fields generated by permanent magnets to define a converging/diverging flow structure.

BACKGROUND AND SUMMARY

This section provides background information related to the present disclosure which is not necessarily prior art. This section further provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.

Small satellites are changing the nature of spacecraft and space-based science. Their smaller size (less than or equal to 750 kg) allows them to be developed at a lower cost and on a more rapid development cycle. Nanosatellites (about 1 to about 10 kg) in particular have caught the attention of scientific and commercial entities alike for a wide range of tasks from imagery to space weather. The rapid emergence of nanosatellites has spawned the need for primary propulsion in these spacecraft. Chemical propulsion requires far more propellant mass than can be stored in such a small craft while conventional electric propulsion devices such as Hall thrusters and ion engines lose effectiveness when scaled down. This technological gap requires a new sort of electric propulsion device designed to be small (less than about 1000 cm3), low mass (less than about 1 kg), and low power (less than about 50 W). The CubeSAT Ambipolar Thruster (CAT) described in connection with the principles of the present teachings is designed specifically to fulfill these requirements.

Since their introduction about 10 years ago, CubeSATs and their P-POD deployers have come to be the dominant nanosatellite design. A single CubeSAT unit (U) is a cube with 10 cm sides with satellites consisting of some multiple or fraction of U's (1 U, 0.5 U, 3 U, etc.). P-PODs are the deployment hardware that is attached to the launch vehicle, typically as secondary payload. It is specifically designed to protect the launch vehicle and primary payload while delivering the CubeSAT(s) safely into orbit. Because of the adoption of this standard, construction costs have been reduced, standardized hardware can be manufactured, and flight heritage can be established across the many programs that use CubeSATs. These programs include those of industry, universities, and countries without large space programs as well as large budget agencies such as NASA and the ESA.

CubeSAT propulsion is less advanced than other nanosatellite technologies because of the difficulties in miniaturizing conventional thruster designs. Monopropellant and bipropellant systems exist or are in development with thrusts less than about 1 N and small ΔV capabilities of 10 s of m/s. For moderate ΔVs (>100 m/s), electric propulsion is needed. A wide variety of electric thrusters are in development, with predicted ΔV capabilities up to 300 m/s. These thrusters will be suitable for station keeping, formation flying, and deorbiting.

With a thruster capable of providing large ΔV (>1 km/s) to a CubeSAT, a huge variety of new missions would become available. They would no longer be restricted to the orbit of the launch vehicle but could maneuver themselves into highly elliptical orbits, geostationary orbit, or polar orbits. With enough ΔV, CubeSATs could reach the Earth-Moon or Earth-Sun Lagrange points. Significant cost savings would come from being able to deploy an array of satellites from a single launch vehicle, fanning them out to create a global network. Other possibilities include cluster formation flying and long-lived low altitude orbits.

In order to provide the necessary structure for such thruster systems, the present teachings set forth one aspect of the present system, namely a magnetic nozzle system.

According to the principles of the present teachings, the magnetic nozzle system is provided that defines a magnetic field structure equivalent to a physical de Laval nozzle (seeFIG. 1). In a de Laval nozzle thermal energy of an impinging gas is converted into directed kinetic energy in the converging subsonic region. In the throat of the nozzle, the propellant is accelerated to the sound speed of the gas (i.e. the sonic speed, or Mach 1). As the propellant continuous through a diverging section of a de Laval nozzle, it accelerates to super-sonic velocities (Mach>1). According to the present teachings, a magnetic nozzle generated by permanent magnets uses the same converging/diverging contour shape to convert the thermal energy of a propellant into directed kinetic energy, but uses magnetic fields instead of a physical boundary to direct the flow of plasma (as opposed to hot gases).

Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

