frozen orbit造句

• Such an orbit is called a " frozen orbit ".
• For example, a lot of satellites are put into frozen orbits, which are ones that minimize the perturbation that pulls the satellite around.
• Very often a frozen orbit is therefore selected that is slightly higher over the Southern hemisphere than over the Northern hemisphere . " frozen " orbits.
• A large part of this compensation can be done by using a frozen orbit design, but for the fine control manoeuvres with thrusters are needed.
• The classical theory of frozen orbits is essentially based on the analytical perturbation analysis for artificial satellites of Dirk Brouwer made under contract with NASA and published in 1959.
• Fortunately, PFS-1 had been placed, unknown to mission planners at the time, very near to one of only four lunar " frozen orbits ", where a lunar satellite may remain indefinitely.
• These manoeuvres will be very small, typically in the order of a few mm / s of delta-v . If a frozen orbit design is used these very small orbit raising manoeuvres are sufficient to also control the eccentricity vector.
• "' Low Lunar orbit "'( LLO )  orbits below altitude are of particular interest in exploration of the moon, but suffer from gravitational perturbation effects that make most unstable, and leave only a few orbital inclinations possible for indefinite " frozen orbits ", useful for long-term stays in LLO.
• The main perturbing force to be counter-acted to have a frozen orbit is the " J _ 3 \, force ", i . e . the gravitational force caused by an imperfect symmetry north / south of the Earth, and the " classical theory " is based on the closed form expression for this " J _ 3 \, perturbation ".