Natural and sail-displaced doubly-symmetric Lagrange point orbits for polar coverage

This paper proposes the use of doubly-symmetric, eight-shaped orbits in the circular restricted three-body problem for continuous coverage of the high-latitude regions of the Earth. These orbits, for a range of amplitudes, spend a large fraction of their period above either pole of the Earth. It is shown that they complement Sun-synchronous polar and highly eccentric Molniya orbits, and present a possible alternative to low thrust pole-sitter orbits. Both natural and solar-sail displaced orbits are considered. Continuation methods are described and used to generate families of these orbits. Starting from ballistic orbits, other families are created either by increasing the sail lightness number, varying the period or changing the sail attitude. Some representative orbits are then chosen to demonstrate the visibility of high-latitude regions throughout the year. A stability analysis is also performed, revealing that the orbits are unstable: it is found that for particular orbits, a solar sail can reduce their instability. A preliminary design of a linear quadratic regulator is presented as a solution to stabilize the system by using the solar sail only. Finally, invariant manifolds are exploited to identify orbits that present the opportunity of a ballistic transfer directly from low Earth orbit

Extension of Earth-Moon libration point orbits with solar sail propulsion

This paper presents families of libration point orbits in the Earth-Moon system that originate from complementing the classical circular restricted three-body problem with a solar sail. Through the use of a differential correction scheme in combination with a continuation on the solar sail induced acceleration, families of Lyapunov, halo, vertical Lyapunov, Earth-centred, and distant retrograde orbits are created. As the solar sail circular restricted three-body problem is non-autonomous, a constraint defined within the differential correction scheme ensures that all orbits are periodic with the Sun’s motion around the Earth-Moon system. The continuation method then starts from a classical libration point orbit with a suitable period and increases the solar sail acceleration magnitude to obtain families of orbits that are parametrised by this acceleration. Furthermore, different solar sail steering laws are considered (both in-plane and out-of-plane, and either fixed in the synodic frame or fixed with respect to the direction of sunlight), adding to the wealth of families of solar sail enabled libration point orbits presented. Finally, the linear stability properties of the generated orbits are investigated to assess the need for active orbital control. It is shown that the solar sail induced acceleration can have a positive effect on the stability of some orbit families, especially those at the L2 point, but that it most often (further) destabilises the orbit. Active control will therefore be needed to ensure long-term survivability of these orbits

Solar kites for Earth magneto-tail monitoring

Solar Sails have been studied in the past as an alternative means of propulsion for spacecraft. Recent advances in Solar Sail technology and the miniaturisation of technology can drive these systems much smaller (<5 kg mass, <10m sail diameter) than existing sails, while still having a high delta-V and acceleration capability. With these unique capabilities of miniature Solar Sails, called Solar Kites, some very unique space science missions can be achieved which are difficult to be implemented using conventional propulsion techniques. One such unique candidate mission is to study the Earth's magnetotail. The paper lays out the main design features and technologies of a Solar Kite mission/platform and demonstrates that a cluster of Solar Kites with science payloads can provide multiple, in-situ measurments of the dynamic evolution of energetic particle distributions of the rotating geomagnetic tail of Earth. With a unique design, a Solar Kite proves to be an efficient, affordable and versatile solution for the mission analysed with a significant science return

A solar kite mission to study the Earth's magneto-tail

Solar Sails have been studied in the past as an alternative means of propulsion for spacecraft. Recent advances in Solar Sail technology and the miniaturisation of technology can drive these systems much smaller (< 5 kg mass, < 10m sail diameter) than existing sails, while still having a high delta-V and acceleration capability. With these unique capabilities of miniature Solar Sails, called Solar Kites, some very unique space science missions can be achieved which are difficult to be implemented using conventional propulsion techniques. One such unique candidate mission is to study the Earth's magnetotail. The paper lays out the main design features and technologies of a Solar Kite mission/platform and demonstrates that a cluster of Solar Kites with science payloads can provide multiple, in-situ measurements of the dynamic evolution of energetic particle distributions of the rotating geomagnetic tail of Earth. With a unique design, a Solar Kite proves to be an efficient, affordable and versatile solution for the mission analysed with a significant science return

Introduction

The first integrated circuits date back to the 1950s. From that moment, humanity witnessed an impressive growth of electronics presence in everyday life. This growth is not going to stop, and will also involve innovative applications that, contrary to most product nowadays, will not be based on high computational power or ultra-fast mobile data communication