A method and apparatus uses a VLF transmitter, a VLF receiver, and/or a low earth orbit satellite including a rocket engine. A VLF wave transmitted into space is converted to an ambient wave. The ambient wave acts as a signal wave for a whistler traveling wave parametric amplifier. Rocket exhaust is generated in atmospheric plasma. The rocket exhaust includes kinetic energy acting as a Lower Hybrid wave source. The Lower Hybrid wave source produces a Lower Hybrid wave, which acts as a pump wave for the parametric amplifier. Nonlinear mixing of the signal wave and the pump wave in the atmospheric plasma simultaneously parametrically amplifies the ambient wave and generates an idler wave and a parametrically amplified wave. The parametrically amplified wave (1) reduces the density of energetic protons or killer electrons in the Van Allen radiation belt, and (2) improves communications between the VLF transmitter and VLF receiver.

Antenna apparatus and spacecraft to be deployed in a more compactly stored state are disclosed. In an example of the disclosed technology, a spacecraft includes: a main-reflection unit configured to reflect and emit a radio wave outside, a sub-reflection unit configured to face the main-reflection unit, a radiator arranged to face the sub-reflection unit and configured to radiate the radio wave in a direction of the sub-reflection unit, a main body configured to be able to accommodate at least one part of the sub-reflection unit therein, and a delivery device connected to the sub-reflection unit and configured to deliver the sub-reflection unit, at least one part of which is accommodated in the main body, to a position where the sub-reflection unit is able to reflect the radio wave radiated from the radiator to the main-reflection unit and cause the main-reflection unit to radiate the radio wave outside.

In a satellite constellation forming system, each satellite in an orbit satellite group includes a propulsion device to change velocity of each satellite in the orbit satellite group. A satellite constellation forming unit causes propulsion devices of satellites in the orbit satellite group to operate in synchronization, for each orbital plane of the plurality of orbital planes. The satellite constellation forming unit causes each satellite in an orbit satellite group in a first orbital plane of the plurality of orbital planes to perform an acceleration and deceleration process of repeating operation of accelerating for a first time period and then decelerating for the first time period. The satellite constellation forming unit causes each satellite in an orbit satellite group in an orbital plane adjacent to the first orbital plane to start the acceleration and deceleration process after a delay of a second time period.

A satellite constellation forming system forms a satellite constellation (20) including two orbital planes each having a different normal direction and in each of which the same number of satellites fly. A satellite constellation forming unit gradually changes an orbital altitude of at least one orbital plane of the two orbital planes from a state in which satellite passage timings of satellites flying in the two orbital planes do not coincide with each other at an intersection neighborhood point (Pc) between the two orbital planes in each of the two orbital planes, while maintaining the state in which the satellite passage timings do not coincide with each other.

Retrofittable satellite systems for an in-orbit host satellite comprising an enhancement module for adding a capability to the in-orbit host satellite, modifying the function of the in-orbit host satellite, and/or extending the function of the in-orbit host satellite. The in-orbit, retrofittable satellite system comprises a transfer vehicle for transferring the enhancement module from a first to a second location and a service vehicle for receiving the enhancement module from the transfer vehicle and installing the enhancement module on the in-orbit host satellite. In-orbit space situational awareness systems, comprising one or more in-orbit host satellites having one or more enhancement modules attached thereto, the enhancement modules comprising sensors such as satellite spatial location/position sensors, range sensors, navigation sensors, and/or proximity sensors for detecting other objects in-orbit, their location, speed, acceleration, orbital trajectory or the like, wherein the enhancement modules communicate to create a mesh network between the satellites.

An information processing device calculates a communication available period for communication between a satellite station and an earth station on the basis of orbit information regarding the satellite station and location information regarding the earth station, and performs reservation processing for reserving a communication reservation period for the communication between the satellite station and the earth station, among reservation target periods selected from the communication available period.

A satellite system can include one or more satellites that orbit the Earth. The one or more satellites may have satellite buses that support antenna arrays. The antenna arrays may include space fed arrays. Each space fed array may have an antenna feed array and an inner array that is coupled to a direct radiating array. The direct radiating array may operate in the same satellite band as the space fed array, or upconversion and downconversion circuitry may be used to communicatively couple a direct radiating array that operates in a different satellite band to the space fed array. The satellites may have peripheral walls with corner fittings that can be selected to provide the satellite bus with particular leg strengths. This can reduce overall mass of the satellites in a payload fairing while accommodating different types of antenna arrays.

A satellite system may have a constellation of communications satellites in orbits such as highly inclined eccentric geosynchronous orbits and low earth orbits. To place satellites in inclined eccentric geosynchronous orbits, a series of launch vehicles may be launched. Each launch vehicle may be used to place a set of satellites, such as a set of three satellites, into a common orbital plane with distinct longitude of ascending node values. To place satellites in low earth orbits, a series of launch vehicles may be launched, each of which releases satellites in sequence from a stack of satellites into a common orbital plane. After desired separations have been produced between the released satellites, circularization procedures may be performed using the propulsion systems of the satellites to place the satellites into final orbit.

Methods, systems, and devices are described for providing dynamic spatial allocation of satellite capacity based on aircraft load forecasting. In embodiments, a satellite communications system provides network access service over a service area via a plurality of satellite user beams, predicts spatial network resource demand for the service area over one or more service periods based at least in part on forecasted travel paths of a plurality of mobile multi-user terminals over the one or more service periods and respective predicted service demands for the plurality of mobile multi-user terminals, determines a satellite capacity resource configuration for the plurality of satellite user beams for the one or more service periods based on the predicted spatial network resource demand, and then adapts at least one characteristic of the plurality of satellite user beams for the one or more service periods based on the determined satellite capacity resource configuration.

A universal test port is connected to the different functional sub-systems of a spacecraft, allowing the sub-systems to be tested from a single location of an assembled spacecraft. The universal test port is mounted on an external surface of the spacecraft and configured to connect to the different functional sub-systems (such as power, propulsion, and command and data handling, for example) of the assembled spacecraft, allowing for the streamlining of testing operations by electrical ground system equipment during assembly, integration, and test (AIT) operations and reducing the risk of collateral damage to spacecraft hardware during testing in AIT.