Fuel-free spacecraft propelling system based on spatial atomic oxygen and propelling method

The present invention is a U.S. national phase of PCT/CN2013/075242 filed May 7, 2013, and claims priority from Chinese patent application Serial No. 201210159715.2 filed May 22, 2012 and Chinese patent application Serial No. 201210270034.3 filed Aug. 1, 2012, the subject matter of which are incorporated herein by reference.

The invention relates to the technical field of spacecraft propulsion, and more particularly relates to a fuel-free orbit spacecraft propulsion system based on space atomic oxygen and a method for propelling an orbit spacecraft continuous movement based on the system.

Space propulsion techniques can be divided into a chemical propulsion and an electric propulsion, as well as some other propulsion techniques (such as solar sail, tethered propulsion and the like). At present, most main thrusters of spacecraft employ chemical propulsion. But as an advanced propulsion technique, electric propulsion is getting more and more attention.

Chemical propulsion is a kind of propulsion technique using chemical energy to send the spacecraft into the reserved space orbit and realizes orbit maneuver. The most prominent feature of chemical propulsion is high propulsion, which is the most used technique in the space field. A chemical engine is used in the present long-life tri-axial attitude control stabilized satellite and spin satellite as a controlling and executing assembly. There are two work modes of the chemical engine: pulsating work and stability work. The pulsating work is mostly used in satellite attitude-adjusting and position-retaining; while the stability work is mostly used in satellite-orbit maneuver.

An electric propulsion system provides energy to a propellant using electricity generated by a solar panel or a nuclear reactor, to make the propellant produce a jet velocity far more than a common chemical thruster. High specific impulse of electric propulsion can reduce the system quality, save the propellant, improve the lifetime and increase payload. Besides applying in a long-life communication satellite to improve the performance of the satellite platform, the electric propulsion can complete the tasks which a common propulsion system is unable to do.

Both chemical propulsion and electric propulsion need to carry certain propellants, which not only occupy the weight of a spacecraft platform but also greatly increase the launch costs. Meanwhile in-orbit maneuver life of a spacecraft mainly depends on the quantity of carried fuel. A propulsion mode depends on the carried fuels and seriously restricts the spacecraft platform function extension and service life prolongation. So, the present international space field is actively developing all kinds of propulsion techniques based on the use of space environment. All the new techniques, including solar sail, magnetic sail, magnetic engine or the like, are developed based on the use of space environment using light, electric, magnetic and the like.

The invention solves the problem that the propulsion method of the present spacecraft carrying fuels has high-cost launch. The spacecraft orbit life depends on an amount of carried fuels resulting in the restriction of spacecraft orbit life. The invention uses space atomic oxygen as a propellant, thereby making in-orbit maneuver of the spacecraft in space environment a continuous space rotation movement without any influence by tiny resistance in space environment.

To solve the aforementioned problem, the invention adopts the following technical scheme.

A fuel-free spacecraft propulsion system based on space atomic oxygen, comprises an outer cylinder of a propulsion device, the outer cylinger having a first open end and a second open end, in which an atomic oxygen collecting device, an RF generating device and an ion cyclotron wave heating device are arranged orderly. The atomic oxygen collecting device is arranged at the first open end of the outer cylinder of the propulsion device for propelling forwardly, and is hermetically connected with one end of the RF generating device through a first magnetic confinement device while the other end of the RF generating device is connected with the ion cyclotron wave heating device through a second magnetic confinement device. The inlet and outlet of a spiral wave discharge oxygen plasma in the ion cyclotron wave heating device are respectively provided with a third and fourth magnetic confinement device. The atomic oxygen collecting device is used for pressurizing space atomic oxygen flowing into the first end of the outer cylinder of the propulsion device for propelling forwards. The pressurized space atomic oxygen is ionized in a spiral wave discharge mode in the RF generation device. The oxygen ions of the ionized oxygen plasma in the ion cyclotron wave heating device absorbs the energy of the cyclotron wave and lead to an increase in kinetic energy. Magnetic field configuration (shape and distribution of magnetic flux) of a sprayer is changed by adjusting the third and fourth magnetic confinement device inside the ion cyclotron wave heating device so that circumferential motion of the oxygen ions is transformed into parallel motion, and a propulsion three is provided for the spacecraft after the oxygen ions are sprayed out of the sprayer.

Further, the aforementioned atomic oxygen collecting device has a gradually diminished sectional area, preferably a trumpet-type atomic oxygen collecting device.

Further, the spiral wave discharge mode of the RF generating device is produced by the RF discharging, and the ion cyclotron wave of the ion cyclotron wave heating device is produced by the RF device.

Further, the magnetic field is changed into a divergent magnetic field.

In a use of the propulsion system, the propulsion system is arranged at both sides of a spacecraft. The atomic oxygen in orbit space environment is used as a propellant, ionized in spiral wave mode, heated by ion cyclotron, and then sprayed out at a high speed so as to propel in-orbit maneuver of the spacecraft.

In comparison with traditional electric propulsion techniques, the propulsion of the invention does not need to carry the propellant, which greatly reduces the launch costs, enables a spacecraft to work in an orbit in the whole life circle work and is greatly advantageous.

FIG. 1 illustrates a schematic view of the fuel-free spacecraft propulsion system based on space atomic oxygen.

In FIG. 1 , the following numbers indicate the respective components: 1 —space atomic oxygen; 2 —an outer cylinder of the propulsion device; 3 —an atomic oxygen collecting device; 4 —an RF generating device; 5 —a magnetic confinement device; 6 —a spiral wave discharge oxygen plasma; 7 —an ion cyclotron wave heating device; 8 —a magnetic confinement device; 9 —an ion spraying flame.

Embodiments of the present fuel-free spacecraft propulsion system based on space atomic oxygen of the invention now will be described more fully with reference to the accompanying drawings. These embodiments are provided for example, and the invention should not be construed as limited to the embodiments.

In FIG. 1 , a fuel-free spacecraft propulsion system based on space atomic oxygen of the invention, comprises an outer cylinder 2 of a propulsion device with both ends open, an atomic oxygen collecting device 3 , an RF generating device 4 and an ion cyclotron wave heating device 7 inside the outer cylinder of the propulsion device 2 . The atomic oxygen collecting device 3 is arranged at the front end of the outer cylinder 2 of propulsion device propelling forwardly following an orbit spacecraft. Space atomic oxygen 1 enters the atomic oxygen collecting device 3 with the orbit spacecraft being propelled forward. The atomic oxygen collecting device 3 is hermetically connected with one end of the RF generating device 4 through a first magnetic confinement device 8 arranged at both ends of the RF generating device 4 . The other end of the RF generating device 4 is hermetically connected with the ion cyclotron wave heating device 7 through a second magnetic confinement device arranged at the end. From the entering end of the space atomic oxygen 1 to the entering end through which the space atomic oxygen enter the RF generating device 4 , the atomic oxygen collecting device 3 has a gradually diminished sectional area, such as trumpet-type atomic oxygen collecting device. The atomic oxygen collecting device 3 is used for pressurizing the space atomic oxygen entering the first end of the outer cylinder of the propulsion device while the spacecraft is moving forward. The pressurized space atomic oxygen is ionized in a spiral wave discharge mode in the RF generating device 4 . A spiral wave discharge oxygen plasma 6 from the RF generating device 4 enters the ion cyclotron wave heating device 7 . An inlet and an outlet of the spiral wave discharge oxygen plasma 6 in the heating device are respectively provided with a third and fourth magnetic confinement device 8 . The oxygen ions of the ionized oxygen plasma in the ion cyclotron wave heating device absorb the energy of the cyclotron wave and result in the kinetic energy increase. The magnetic field configuration of a sprayer is changed by adjusting the magnetic confinement device inside the ion cyclotron wave heating device 8 . The magnetic field configuration means the shape and distribution of the magnetic flux. Circumferential motion of the oxygen ions is transformed into parallel motion, and a propulsion force is provided for the spacecraft after the oxygen ions are sprayed out of the sprayer. The spraying plasma is the ion spraying flame. The magnetic field is changed to a divergent magnetic field. The divergent magnetic field is that the magnetic lines of it extend radially from an interior of the ion cyclotron wave heating device to the oxygen ions sprayer.

A fuel-free spacecraft propulsion system based on space atomic oxygen of the invention specially applies to propel in-orbit maneuver of a spacecraft in space environment. When using the propulsion system, the propulsion system is arranged at both sides of the spacecraft. The atomic oxygen in orbit space environment is used as a propellant, ionized in a spiral wave mode, heated by an ion cyclotron, then sprayed after acceleration to propel in-orbit maneuver of the spacecraft.

To simply explain the process of the present fuel-free spacecraft propulsion system, the system is a cylindrical space particles collecting device, arranged at a special position of the spacecraft, to collect atomic oxygen of orbit space environment as the spacecraft is moving. The 300 km orbit space environment exists about the atomic oxygen. AO density of 10 15 /m 3 , of which average thermal motion speed can be ignored compared with speed of the spacecraft, so atomic oxygen AO in orbit can be regarded as static. The relative speed of both is the speed of the spacecraft, about 8 km/s (a first cosmic speed).

Atomic oxygen AO is discharged as ion oxygen. If its kinetic energy is increased to 1 KeV by the RF heating mode, Ft=Δ(mv),

v = 2 ⁢ E m ,

we can see that:

Ft =√{square root over (2 mE )}

An O + can gain the impulse of about 0.3×10 −20 (N.S).

Supposing that the spacecraft carries an AO collecting device with 1 m 2 sectional area, the collecting atomic oxygen amount per unit time is:

N=nV=nSvt

Wherein, in is orbit AO atomic oxygen density (10 15 /m 3 ), S is a collecting sectional area (1 m 2 ), and v is a spacecraft motion speed (about 8 km/s), the collecting atomic oxygen AO amount per unit time is 8×10 18 .

From Ft=Δ (MV)=Δ (nmv), we can see that, when the particle's accelerating energy is constant, a propulsion force gained by using space and atomic oxygen is proportional to its ionization rate. Currently, an American organization that adopts the spiral wave discharge mode, under certain conditions, can gain the 100% discharged plasma. As a reference, all the collected atomic oxygen AO is ionized, the oxygen ions are accelerated to 1 KeV, the entire gained impulse Ft is 2.4×10 −2 (N·S), and the gained propulsion force is 24 mN.

The fuel-free spacecraft propulsion is based on the space atomic oxygen. The gained propulsion force is proportional to the collecting atomic oxygen flux density per unit time, the ionization rate and the ion heating energy. If the radii of the collecting device is 1 m, the atomic oxygen is 100% ionized per unit time, and the oxygen ions are heated to 1 KeV and the gained propulsion force is 70 mN. Even when the ionization rate is 50%, the gained propulsion force is 35 mN.

While the invention has been described in conjunction with the exemplary embodiments described above, many equivalent modifications and variations will be apparent to those skilled in the art when given this disclosure. Accordingly, the exemplary embodiments of the invention set forth above are considered to be illustrative and not limiting. Various changes to the described embodiments may be made without departing from the spirit and scope of the invention.