Method of releasing artificial satellites in earth's orbit

Abstract

A method of releasing artificial satellites into Earth's orbit includes providing an orbital transport spacecraft able to move at orbital height and comprising a cargo area, hooking a plurality of satellites in said cargo area, housing said orbital transport spacecraft in a space launcher configured to reach an orbital height, releasing said orbital transport spacecraft at orbital height, when said space launcher reaches orbital height, by imparting a separation thrust to said orbital transport spacecraft, releasing satellites in sequence from the cargo area. The release of each satellite from the cargo area occurs in a respective predetermined direction and upon the orbital transport spacecraft has reached a respective predetermined position.

Claims

1. A method of releasing artificial satellites into Earth's orbit, comprising the steps of: providing an orbital transport spacecraft able to move at orbital height and comprising a cargo area; providing a plurality of release systems housed in said cargo area, wherein each release system comprises a POD (Picosatellite Orbital Deployer); housing a plurality of satellites inside said PODs, wherein said PODs are configured for housing, transporting and releasing said plurality of satellites; housing said orbital transport spacecraft in a space launcher configured to reach an orbital height; releasing said orbital transport spacecraft at orbital height, when said space launcher reaches orbital height, by imparting a separation thrust to said orbital transport spacecraft; releasing satellites in sequence from the cargo area through said PODs; wherein the release of each satellite from the cargo area occurs in a respective predetermined direction and upon the orbital transport spacecraft has reached a respective predetermined position; and wherein each two satellites released successively of the plurality of satellites are released in substantially mutually opposite directions, wherein a first satellite of the two satellites is released in a direction contrary to an orbital direction of advance of the orbital transport spacecraft and the second satellite of the two satellites is released in a direction matching the orbital direction of advance of the orbital transport spacecraft.

2. A method of releasing artificial satellites into Earth's orbit, comprising the steps of: providing an orbital transport spacecraft able to move at orbital height and comprising a cargo area; providing a plurality of release systems housed in said cargo area; securing a plurality of satellites in said cargo area; housing said orbital transport spacecraft in a space launcher configured to reach an orbital height; releasing said orbital transport spacecraft at orbital height, when said space launcher reaches orbital height, by imparting a separation thrust to said orbital transport spacecraft; releasing satellites in sequence from the cargo area; wherein the release of each satellite from the cargo area occurs in a respective predetermined direction and upon the orbital transport spacecraft has reached a respective predetermined position; wherein each two satellites released successively of the plurality of satellites are released in substantially mutually opposite directions, wherein a first satellite of the two satellites is released in a direction contrary to an orbital direction of advance of the orbital transport spacecraft and the second satellite of the two satellites is released in a direction matching the orbital direction of advance of the orbital transport spacecraft.

3. The method according to claim 2, wherein an attitude of said orbital transport spacecraft is adjusted prior to the release of each satellite.

4. The method according to claim 2, wherein each satellite is released with respective separation speeds; wherein each separation speed is predetermined such that the released satellite reaches a predetermined orbital position.

5. The method according to claim 2, wherein each release system of said plurality of release systems comprises a POD (Picosatellite Orbital Deployer) configured for housing, transporting and releasing one or more satellites of said plurality of satellites.

6. The method according to claim 5, wherein said PODs are arranged side by side so as to form a matrix of PODs.

7. The method according to claim 5, wherein each POD is provided with a containment casing, an opening door and actuator members to expel the one or more satellites by imparting a predetermined thrust to them.

8. The method according to claim 5, wherein each POD houses more than one satellite of said plurality of satellites.

9. The method according to claim 2, wherein each of said plurality of satellites are released according to a predetermined release pattern.

10. The method according to claim 2, comprising activating a propulsion system for the orbital transport spacecraft to position the orbital transport spacecraft in predetermined and subsequent orbital positions every time one satellite of said plurality of satellites is released.

11. The method according to claim 2, comprising moving the orbital transport spacecraft in an atmospheric entry trajectory after having released all of the plurality of satellites.

Description

DESCRIPTION OF THE DRAWINGS

(1) Further characteristics and advantages of the present invention will become clearer from the following detailed description of some preferred embodiments thereof, with reference to the appended drawings and provided by way of indicative and non-limiting example. In such drawings:

(2) FIG. 1 schematically shows a space launcher;

(3) FIG. 2 schematically shows an orbital transport spacecraft;

(4) FIG. 3 schematically shows a first component of the orbital transport spacecraft of FIG. 2;

(5) FIG. 4 shows a detail of the component of FIG. 3;

(6) FIG. 5 schematically shows a second component of the orbital transport spacecraft of FIG. 2;

(7) FIG. 6 schematically shows to arrangement of nanosatellites inside the component of FIG. 3; and

(8) FIGS. 7 and 8 show two examples of orbital positioning of satellites according to the present invention.

DETAILED DESCRIPTION

(9) In FIG. 1, the number 100 indicates a space launcher able to reach an orbital height around the Earth. The space launcher 100 can be a space launch vehicle of the type with vertical take-off which from the Earth's surface is able to reach an orbit around the Earth or a vehicle that, released from an aircraft, is able to reach an orbit around the Earth.

(10) Preferably, the orbital height reached is a low Earth orbit (LEO), i.e. a circular orbit around the Earth at a height between the Earth's atmosphere and the Van Allen belt, between 200 km and 2000 km from the surface of the Earth.

(11) The space launch vehicle 100 comprises a propulsion system 101 (for example a chemical propellant), control and guidance systems (not shown) and a housing compartment 102 for a payload.

(12) Said payload can for example comprise a main satellite 103 and a plurality of secondary satellites 104.

(13) At least one orbital transport spacecraft 1 finds storage space and is housed inside the housing compartment 102.

(14) The orbital transport spacecraft 1 is connected to the space launcher 100 through a conventional orbital separation system 105 configured to release with a predetermined thrust the orbital transport spacecraft 1 once the space launcher 100 reaches a predetermined orbital height.

(15) Preferably, said orbital height is the one adapted for the release of the main satellite 103, i.e. of the main payload of the space launcher 100.

(16) The orbital transport spacecraft 1 comprises a satellite platform 2 which contains all the subsystems necessary for the control and management of a satellite. Said subsystems (not shown or further described because they are conventional) are redundant, i.e. they are duplicated to increase their reliability.

(17) As schematically shown in FIG. 5, the satellite platform 2 further comprises a command and control module 3 powered by a source of electricity 4 (for example a battery) preferably dedicated to the command and control module 3.

(18) The command and control module 3 comprises a signal transmitter 5 able to send signals on the Earth's surface and a signal receiver 6 able to receive signals from the Earth's surface.

(19) The command and control module 3 further comprises a timer 7 and a plurality of driver boards 8 configured to generate and send driver signals 8 to actuator members 15.

(20) The satellite platform 2 further comprises at least one conventional propulsion system 9 configured to move the orbital transport spacecraft 1 along an orbit or to move it to a different orbit. The propulsion system 9 is further configured to correct and/or change the attitude of the orbital transport spacecraft 1.

(21) The orbital transport spacecraft 1 further comprises a mechanical interface 10 whereby the orbital transport spacecraft 1 is connected to the space launcher 100.

(22) The orbital transport spacecraft 1 further comprises a plurality of release systems 20. Each release system 20 comprises a POD (Picosatellite Orbital Deployer) 11 inside which are housed one or more satellites 12. The PODs serve as releasing pipes, with the function of storing, transporting and releasing the satellites 12 that have to be placed in orbit and are preferably housed in a cargo bay 12a of the orbital transport spacecraft 1.

(23) The PODs 11 are modular and independent of each other. By way of example, the orbital transport spacecraft 1 can transport 48 Cubesats each of 1 unit (1 Cubesat unit is defined by a volume of 10×10×10 cm), or 16 Cubesats each of 3 units or else 8 Cubesats each of 6 units, or 4 Cubesats each of 12 units and mixed configurations thereof.

(24) FIG. 6 shows an example of mixed configuration of Cubesats transported by the orbital transport spacecraft 1, in which A1 and C1 represent respective 6-unit Cubesats, A3, A4, B1, B2, C1, D1, D3, D4 represent respective rows of three Cubesats of 1 unit, B3 represents a 12-unit Cubesat.

(25) FIG. 3 shows a plurality of PODs 11 in which each POD is able to house a 3-unit Cubesat. The PODs 11 can be powered by photovoltaic panels 11a installed on the structure of the PODs themselves, or, more preferably, they are powered by the satellite platform 2 of the orbital transport spacecraft 1.

(26) As shown in FIG. 4 (which shows a POD for the transport and release of a 3-unit Cubesat), each POD is provided with a containment casing 13, an opening door 14 and actuator members 15 to expel the Cubesats transported imparting a predetermined thrust to them.

(27) Said actuator members 15 can for example be springs preloaded according to the thrust to be imparted to the satellite at the time of the release.

(28) The PODs 11 are arranged mutually side by side to form a matrix of PODs in which, preferably, all opening doors 14 lie with the same orientation and are coplanar, as shown in FIG. 3.

(29) According to the method of the present invention, the orbital transport spacecraft 1 is equipped with the satellites 12 inserted in the PODs 11 and then housed in the space launcher 100.

(30) The space launcher 100 is placed in orbit around the Earth. The orbital height and the position reached by the space launcher 100 is usually the one specifically prescribed for the release of the main satellite 103 which represents the most important payload of the space launcher and for which the space mission was mainly conceived.

(31) At this point, the orbital transport spacecraft 1 is released by the space launcher 100. The releasing step occurs imparting a separation thrust to the orbital transport spacecraft 1 able to remove the orbital transport spacecraft 1 from the space launcher 100. Said thrust gives the transport spacecraft 1 a momentum that, depending on current regulations and/or on the mission parameters, is able to move the orbital transport spacecraft 1 into the orbit reached for a time interval of a few days (usually 2 or 3 days).

(32) Note that in this step the propulsion system 9 of the orbital transport spacecraft 1 is not activated.

(33) Alternatively, if the orbital transport spacecraft 1 has to reach a different orbital height or if it is necessary to impart to the orbital transport spacecraft 1 a greater momentum than that imparted by the separation thrust, the propulsion system 9 is activated.

(34) In any case, the orbital transport spacecraft 1 then moves away from the space launcher 100.

(35) When the orbital transport spacecraft 1 reaches a first predetermined position, a first satellite 12 is released.

(36) Said predetermined position is calculated according to the position in which the satellite 12 has to be placed in orbit.

(37) The satellite 12 is released imparting a separation thrust thereto. Said separation thrust can for example be imparted by the actuator members 15 of the POD. Said separation thrust is preferably predetermined when planning the mission and then pre-set. Alternatively, said separation thrust can be determined at the time of release of the satellite 12 according to the exact position reached by the orbital transport spacecraft 1 (which could differ from the positions specified when planning the mission).

(38) In any case, the satellite 12 moves away from the orbital transport spacecraft 1 in a pre-set and pre-calculated direction, with a separation speed that assures the attainment of the desired position without requiring additional manoeuvres. In this way, the satellite 12 can be positioned even if it is not provided with an autonomous propulsion system.

(39) Before the release of the satellite 12, to assure that said satellite moves away in the selected direction, the propulsion system 9 of the orbital transport spacecraft 1 is activated to correct the attitude of the orbital transport spacecraft 1.

(40) In the preferred embodiment of the invention, the satellite 12 is released in a direction opposite to that of the movement of the orbital transport spacecraft 1.

(41) Once the first satellite is released, the orbital transport spacecraft 1 reaches a new release position and the operations for releasing an additional satellite 12 are repeated as described above.

(42) In this way, a gradual release of the satellites 12 in a direction opposite to that of the movement of the orbital transport spacecraft 1 along the orbit is assured, without requiring additional manoeuvres on the part of the satellites 12 (as shown schematically in FIG. 7). This allows to have a release, for example, of 16 satellites in approximately 88 days.

(43) The release sequence of the satellites 12 can be pre-set or decided case by case according to the needs of the operator of the satellites 12.

(44) Alternatively, two satellites 12 released successively are released in substantially mutually opposite directions. Each release follows the steps described above, with the difference that the second satellite 12 is released in a direction matching the orbital direction of advance of the orbital transport spacecraft 1, after reorienting the orbital transport spacecraft 1, as schematically shown in FIG. 8.

(45) The Applicant has calculated that in this way it is possible to reduce the total release time of the satellites 12 by 35% compared to a release sequence in which the directions of removal of the satellites are always directed in the opposite direction to that of advance of the orbital transport spacecraft 1.

(46) The separation thrusts and the correlated separation speeds of the satellites 12 can be different from each other and, as stated, they are selected to assure the correct positioning of the satellites 12 in the shortest possible time.

(47) At the end of the positioning of the satellites 12, the orbital transport spacecraft 1 is placed on an atmospheric entry trajectory, avoiding its becoming a dangerous, uncontrolled object in orbit.

(48) This operation can be carried out using the residual propellant and the propulsion system used for manoeuvres in orbit or using a dedicated propulsion system configured to carry out only the atmospheric re-entry operations.

(49) Obviously, a person skilled in the art, to meet specific and contingent needs, may make numerous modifications and variants to the invention described above, without thereby departing from the scope of protection of the present invention as defined by the following claims.