Multiple space vehicle launch system

Abstract

A space vehicle system, a method of manufacturing a multiple space vehicle launch system, and a method to transmit a launch load between space vehicles during a launch are disclosed. The space vehicle system may include a first space vehicle including a first core structure, a second space vehicle including a second core structure releasably attached to the first space vehicle in a stacked configuration, a first solar array supported by the first core structure, the first core structure extending beyond a lower edge of the first solar array, and a second solar array supported by the second core structure, the second core structure extending beyond an upper edge of the second solar array.

Description

BACKGROUND

The present disclosure is directed to space vehicle launch systems and, more particularly, to space vehicle launch systems for launching multiple payloads.

Typical launch vehicles are very expensive. Further, each kilogram of payload that is to be launched into Earth orbit may require as much as ten kilograms of fuel. Accordingly, it may be desirable to minimize payload mass in order to reduce overall cost and fuel requirements. One mechanism for reducing payload mass may be to eliminate any unnecessary structure from the payload.

As a result of such cost concerns, it may be desirable to launch two or more discrete payloads with a single launch vehicle. Such multiple payloads may be in the form of space vehicles, such as satellites. Typically, such satellites themselves may require and incorporate chemical rocket motors to increase orbital altitude and to make altitude adjustments once the desired orbital altitude is achieved.

Such chemically powered space vehicles are relatively heavy. Due to space constraints within the payload region of the fairing, it is often necessary to orient such space vehicles in a linear or stacked column that may extend along a central longitudinal axis of the launch vehicle. When such a launch vehicle is on a launch pad, and after lift-off, the orientation of such space vehicles is substantially vertical.

As a result, the weight, or gravitational force of the mass, of an upper space vehicle may bear down upon a lower space vehicle in such a vertical configuration. When the launch vehicle lifts off the launch pad, this gravitational force is multiplied as a result of the acceleration of the launch vehicle into Earth orbit. Because of the mass of the space vehicles, especially if equipped with chemical rocket motors, the lower space vehicle may not be able to withstand the gravitational force and launch load of the upper space vehicle. Accordingly, a support structure is required.

One example of such support structure is a dual-launch structure denoted in French as Systeme de Lancement Double Ariane (Sylda), or in English this is known as a Double Ariane Launch System, as employed on the Ariane 4 and Ariane 5 rockets. A Sylda may be made of carbon fiber and be in the form of a hollow structure that encloses the lower space vehicle and engages and supports the upper space vehicle. Gravitational forces and launch loads may be transmitted from the upper space vehicle, to the Sylda, and from the Sylda to the support base of the fairing. Thus, the lower space vehicle does not have to support the mass and launch load of the upper space vehicle.

A disadvantage of such an arrangement may be that the use of a Sylda adds to the overall payload mass, which may increase the fuel requirement and/or reduce the available size of a payload that is to be launched into orbit by a given launch vehicle. Accordingly, there is a need for a multiple space vehicle launch system that minimizes or eliminates the need for such support structure.

SUMMARY

The present disclosure is directed to a multiple space vehicle launch system that may include a first space vehicle, and a second space vehicle releasably attached to the first space vehicle and oriented relative to the first space vehicle such that, when placed within a fairing, a launch load from the first space vehicle is transmitted to and borne by the second space vehicle, thereby eliminating the need for Sylda or other reinforcing or support structure. In an embodiment, the first and second space vehicles each may include one of an electrical propulsion motor and a hybrid chemical and electrical propulsion motor. By utilizing electrical propulsion motors in the space vehicles, the total mass of the space vehicle may be significantly reduced when compared to a space vehicle having a chemical propulsion motor, which may enable support structures such as Sylda to be eliminated.

According to an embodiment, a method of manufacturing a space vehicle system is disclosed. The method comprises disposing a first space vehicle having an upper core structure upon a second space vehicle having a lower core structure such that loads of the first space vehicle may be transmitted to the lower core structure of the second space vehicle.

In another embodiment, a method of assembling a space vehicle system is disclosed. The method comprises disposing a first space vehicle having an upper core structure upon a second space vehicle having a lower core structure such that loads of the first space vehicle may be transmitted to the lower core structure of the second space vehicle. The method further comprises disposing the first space vehicle and the second space vehicle into a payload region of a launch vehicle.

In yet another embodiment, a space vehicle system is disclosed. The space vehicle system may include a first space vehicle having an upper core structure and a second space vehicle having a lower core structure. The first space vehicle is disposed upon the second space vehicle such that loads of the first space vehicle may be transmitted to the lower core structure of the second space vehicle.

In another embodiment, a method of launching a space vehicle system is disclosed. The space vehicle system may include a first space vehicle having an upper core structure disposed upon a second space vehicle having a lower core structure. The method comprises causing loads associated with the first space vehicle to be transmitted to and borne by the lower core structure of the second space vehicle. The method further comprises launching the first space vehicle and the second space vehicle.

In yet another embodiment, a space vehicle system is disclosed. The space vehicle system may include a first space vehicle having an upper core structure and a second space vehicle having a lower core structure. The first space vehicle is disposed upon the second space vehicle prior to deployment of the space vehicle system such that loads of the first space vehicle may be transmitted to the lower core structure of the second space vehicle. The first space vehicle and the second space vehicle may be separated from one another during the deployment of the space vehicle system.

In the embodiments described above and others, the use of traditional inter-launch vehicle fairing, Sylda, and inter-fairing separation systems may be eliminated. This reduces the non-revenue generating payload mass and may reserve more available mass for revenue generating payload. Other objects and advantages will be apparent from the following description, the accompanying drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic, side elevation in section of an embodiment of the multiple space vehicle launch system of the present disclosure;

FIG. 2 is a schematic, perspective view of two space vehicles depicted in FIG. 1; and

FIG. 3 is a schematic, side elevation in section of the space vehicles depicted in FIG. 1.

DETAILED DESCRIPTION

As shown in FIG. 1, the multiple space vehicle launch system, generally designated 10, is used with a launch vehicle 12 having a fairing 14. The system 10 may include a first or upper space vehicle, generally designated 16, and a second or lower space vehicle, generally designated 18. The space vehicles are positioned within a payload region 20 of the fairing 14. It should be noted that, although FIG. 1 shows a space vehicle launch system 10 having two space vehicles 16, 18, it is within the scope of the disclosure to provide a space vehicle launch system having three or more space vehicles.

Regardless of the number of space vehicles 16, 18 employed in the launch system, the arrangement of space vehicles within the fairing 14 may be in a stacked, vertical configuration as shown in FIG. 1. The term “vertical” as used herein refers to the orientation of the stacked space vehicles 16, 18 relative to a launch pad (not shown) supporting the launch vehicle 12 when the launch vehicle is oriented in a vertical position, or a vertically stacked manner, relative to the Earth. In an embodiment, the stacked space vehicles 16, 18 may be aligned with, and may coincide with, a central longitudinal axis of the fairing 14 and/or launch vehicle 12. The lower space vehicle 18 may rest upon a base 22 that may be a part of the fairing 14.

As shown in FIGS. 2 and 3, the space vehicles 16, 18 may be satellites. In various embodiments, the space vehicles 16, 18 may be geosynchronous satellites, interplanetary probes, combinations thereof, or any type of space vehicle having a propulsion system that is launched by a launch vehicle 12 (FIG. 1).

The space vehicles 16, 18 may include antenna reflectors 24, 26, respectively, and deployable solar arrays 28, 30, respectively. As best shown in FIG. 3, the space vehicles 16, 18 may include shear load panels 32, 34 that are mounted on core structures 36, 38, respectively.

The core structures 36, 38 may be cylindrical in shape and hollow. Core structures may be of other shapes and not depart from the scope of this disclosure. Core structure 36 may be made of a strong, light material such as graphite, and in one embodiment have a wall thickness of 0.09″. Core structure 38 also may be made of a strong, light material such as graphite, and in one embodiment have a wall thickness of 0.45″. The shear panels 32, 34 may support the solar arrays 28, 30 of the space vehicles 16, 18, respectively.

In the embodiment shown in FIGS. 2 and 3, the space vehicles 16, 18 each may include an electric propulsion unit such as an electric propulsion motor, generally designated 40, 42, respectively. Electric propulsion motors 40, 42 may consist of an ion/plasma motor that utilizes Xenon gas as a propellant that is stored in tanks 44, 46 that may be positioned within core structures 36, 38, respectively. The electric propulsion motors 40, 42 also may include exhaust nozzles 48, 50, respectively.

In the embodiment shown in FIGS. 2 and 3, the space vehicles 16, 18 each may include a single electric propulsion motor 40, 42 that may constitute the sole source of propulsion and navigation for that space vehicle; no other propulsion source may be included. The components 40, 42 of space vehicles 16, 18 also may represent other types of electric propulsion motors, as well as hybrid electric/chemical propulsion units such as hybrid electric/chemical propulsion motors. It is also within the scope of the disclosure to provide space vehicle 16 with an electric propulsion motor 40 and provide space vehicle 18 with a hybrid electric/chemical propulsion motor 42. Use of electric propulsion motors 40, 42, or hybrid electric/chemical propulsion motors may be advantageous because they reduce the overall mass of the space vehicles 16, 18 in comparison to chemical propulsion motors.

In one embodiment, the upper space vehicle 16 may be connected to the lower space vehicle 18 by a pre-tensioned release band 52 that connects the core structure 36 of the upper vehicle with the core structure 38 of the lower vehicle. As shown in the figures, the core structure 38 of the lower vehicle 18 may extend upwardly above the upper edge of the solar arrays 30 of the lower vehicle to engage the core structure 36 which, in the embodiment shown, may not extend beyond the lower edge of the solar arrays 28 of the upper space vehicle.

In operation, the upper and lower space vehicles 16, 18, respectively, first may be attached to each other by the pre-tensioned release band 52. The combined space vehicles 16, 18 may be placed within the fairing 14 of a launch vehicle 12, as shown in FIG. 1, so that the lower space vehicle rests upon the base 22 of the fairing.

When the launch vehicle is standing on the launch pad (not shown), the launch vehicle 12, fairing 14 and space vehicles 16, 18 may be oriented vertically relative to the Earth. In this configuration, the downward gravitational force of the upper space vehicle 16 may be transmitted to and borne entirely by the lower space vehicle 18. In the embodiment shown, this gravitational force may be transmitted entirely from the core structure 36 of the upper space vehicle 16 to the core structure 38 of the lower space vehicle 18.

During liftoff of the launch vehicle 12, the acceleration forces of the upper space vehicle 16 likewise may be transmitted through the core structure 36 to the core structure 38 of the lower space vehicle 18. In the embodiment shown, the upper and lower space vehicles 16, 18 may be linearly and vertically aligned in a vertically stacked configuration so that the gravitational and launch loads of the upper space vehicle 16 are efficiently transmitted to and borne entirely by the lower space vehicle 18.

In conclusion, two configuration features of the disclosed space vehicle launch system combine to provide a reduction in overall launch system mass. First, the individual space vehicles do not use conventional chemical propellant, but instead use electric propulsion, in one embodiment, which has a higher efficiency and thus requires significantly less propellant mass. In another embodiment, the space vehicles may use a hybrid electric/chemical propulsion motor. Second, the space vehicles may be stacked, one on top of the other, so that the launch loads from the upper space vehicle may pass through the lower space vehicle.

The upper and lower space vehicles may include a compatible mounting structure for releasably mounting adjacent spacecraft. This structure may eliminate the need for an inner fairing structure or a fairing separation system, which otherwise might be necessary for multiple manifested spacecraft. The disclosed vehicle launch system may eliminate a significant amount of mass that is not required to fulfill the primary spacecraft mission, which allows more available mass for revenue-generating payload. Further, minimizing propellant mass and non-functional structure mass from the launch vehicle optimizes the overall system mass.

While the forms of apparatus and methods herein described constitute preferred embodiments of this invention, it is to be understood that the invention is not limited to these precise forms of apparatus and methods, and that changes may be made therein without departing from the scope of the invention.

Claims

1. A space vehicle system, comprising: a first space vehicle including a first core structure having a first wall thickness;a second space vehicle including a second core structure having a second wall thickness more than twice the first wall thickness, the second core structure releasably attached to the first space vehicle in a stacked configuration, at least one of the first core structure or the second core structure made of graphite;a first solar array supported by the first core structure, the first core structure having a first end and a second end, the first end extending below a first upper edge of the first solar array, the second end extending beyond a lower edge of the first solar array; anda second solar array supported by the second core structure, the second core structure extending beyond a second upper edge of the second solar array.

2. The space vehicle system of claim 1, wherein the first core structure and the second core structure are hollow cylindrical structures.

3. The space vehicle system of claim 1, further including a fairing shaped to enclose the first and the second space vehicles, the fairing including a base shaped to support the second space vehicle.

4. The space vehicle system of claim 1, wherein the second space vehicle is attached to the first space vehicle such that a launch load from the first space vehicle is transmitted entirely to, and borne entirely by, the second space vehicle through the first core structure and the second core structure.

5. The space vehicle system of claim 1, wherein the first space vehicle includes a first electric propulsion unit including a first electric propulsion motor and the second space vehicle includes a second electric propulsion unit including a second electric propulsion motor, the first electric propulsion motor constitutes the sole source of propulsion for the first space vehicle and the second electric propulsion motor constitutes the sole source of propulsion for the second space vehicle.

6. The space vehicle system of claim 5, wherein at least one of the first electric propulsion unit or the second electric propulsion unit is an ion/plasma propulsion unit.

7. The space vehicle system of claim 1, wherein the second core structure is releasably attached to the first space vehicle with a release band.

8. The space vehicle system of claim 1, wherein the first space vehicle includes a first propulsion unit and a first tank to store first propellant for the first propulsion unit and the second space vehicle includes a second propulsion unit and a second tank to store second propellant for the second propulsion unit.

9. The space vehicle system of claim 8, wherein the first core structure includes the first tank and the second core structure includes the second tank.

10. A method of manufacturing a multiple space vehicle launch system, the method comprising: attaching a first core structure of a first space vehicle to a second core structure of a second space vehicle along a central longitudinal axis of a launch vehicle, the first core structure having a first wall thickness, the second core structure having a second wall thickness more than twice the first wall thickness, at least one of the first core structure or the second core structure made of graphite;mounting a first solar array on the first core structure, the first core structure extending below an upper edge of the first solar array and beyond a lower edge of the first solar array;mounting a second solar array on the second core structure; anddisposing the first core structure and the second core structure in a fairing of the launch vehicle such that the second core structure rests upon a base of the launch vehicle.

11. The method of claim 10, wherein the first core structure is releasably attached to the second core structure with a release band.

12. The method of claim 10, wherein disposing the first core structure and the second core structure includes orienting the first core structure and the second core structure in a stacked configuration within a payload region of the fairing.

13. The method of claim 12, wherein the stacked configuration is a vertically stacked configuration, a launch load of the first space vehicle is transmitted to and borne by the second space vehicle by orienting the first core structure and the second core structure in the vertically stacked configuration.

14. The method of claim 10, wherein mounting the first solar array and the second solar array includes: mounting a first shear load panel on the first core structure;supporting the first solar array on the first shear load panel;mounting a second shear load panel on the second core structure; andsupporting the second solar array on the second shear load panel.

15. The method of claim 10, wherein the upper edge is a first upper edge, the second solar array defines a second upper edge, the second core structure extends upwardly above the second upper edge of the second solar array to engage the first core structure.

16. A method to transmit a launch load between space vehicles during a launch, the method comprising: initiating a liftoff of a launch vehicle, the launch vehicle including: a first space vehicle including a first core structure and a first solar array, the first core structure having a first wall thickness, the first solar array coupled to the first core structure, the first core structure extending below an upper edge of the first solar array and beyond a lower edge of the first solar array; anda second space vehicle attached to the first space vehicle in a stacked configuration, the second space vehicle including a second core structure having a second wall thickness more than twice the first wall thickness, at least one of the first core structure or the second core structure made of graphite, the first space vehicle and the second space vehicle disposed upon a base of a fairing of the launch vehicle; andin response to the initiation of the liftoff, transmitting a launch load of the first space vehicle to the second space vehicle.

17. The method of claim 16, wherein the launch load is borne by the second space vehicle during the liftoff.

18. The method of claim 16, wherein attaching the first space vehicle to the second space vehicle includes attaching the first core structure to the second core structure of the second space vehicle.

19. The method of claim 18, wherein the first core structure and the second core structure are attached such that forces associated with the launch load of the first space vehicle is transmitted to the second core structure.

20. The method of claim 18, wherein forces from the first core structure are transmitted to the second core structure during the liftoff.

21. A method, comprising: disposing a first space vehicle including an upper core structure upon a second space vehicle including a lower core structure in a stacked configuration in a launch vehicle, the upper core structure releasably attached to the lower core structure via a release band, the upper core structure having a first wall thickness, the lower core structure having a second wall thickness more than the first wall thickness, at least one of the lower core structure or the upper core structure made of graphite;mounting a first solar array on the upper core structure, the upper core structure extending below a first upper edge of the first solar array and past a lower edge of the first solar array; andmounting a second solar array on the lower core structure, the lower core structure extending upwardly above a second upper edge of the second solar array to engage the upper core structure.

22. The method of claim 21, wherein the first space vehicle and the second space vehicle are disposed in a fairing of the launch vehicle.

23. The method of claim 21, wherein mounting the first solar array and the second solar array includes: mounting a first shear load panel on the upper core structure and mounting the first solar array on the first shear load panel; andmounting a second shear load panel on the lower core structure and mounting the second solar array on the second shear load panel.

24. The method of claim 21, wherein the lower edge is a first lower edge, and the lower core structure extends below a second lower edge of the second solar array.

25. The space vehicle system of claim 1, wherein at least one of the first space vehicle or the second space vehicle is a geosynchronous satellite or an interplanetary probe.

26. The space vehicle system of claim 1, wherein the first wall thickness is uniform throughout the first core structure and the second wall thickness is uniform throughout the second core structure.

27. The space vehicle system of claim 1, wherein the first wall thickness and the second wall thickness are based on the stacked configuration.

28. The method of claim 21, wherein at least one of the first space vehicle or the second space vehicle is a geosynchronous satellite or an interplanetary probe.