relative orbit
81Space debris — populations seen from outside geosynchronous orbit (GEO). Note the two primary debris fields, the ring of objects in GEO, and the cloud of objects in low earth orbit (LEO) …
82Gravitational two-body problem — The gravitational two body problem concerns the motion of two point particles that interact only with each other, due to gravity. This means that influences from any third body are neglected. For approximate results that is often suitable. It… …
83India — /in dee euh/, n. 1. Hindi, Bharat. a republic in S Asia: a union comprising 25 states and 7 union territories; formerly a British colony; gained independence Aug. 15, 1947; became a republic within the Commonwealth of Nations Jan. 26, 1950.… …
84relativity — /rel euh tiv i tee/, n. 1. the state or fact of being relative. 2. Physics. a theory, formulated essentially by Albert Einstein, that all motion must be defined relative to a frame of reference and that space and time are relative, rather than… …
85spaceflight — /spays fluyt /, n. the flying of manned or unmanned spacecraft into or in outer space. Also, space flight. [1945 50; SPACE + FLIGHT1] * * * Introduction flight beyond Earth s atmosphere. This article deals with the basic concepts associated with …
86Mercury (planet) — Mercury  ☿ …
87Double star — For other uses, see Double star (disambiguation). In observational astronomy, a double star is a pair of stars that appear close to each other in the sky as seen from Earth when viewed through an optical telescope. This can happen either because… …
88Sundial — A sundial is a device that measures time by the position of the Sun. In common designs such as the horizontal sundial, the sun casts a shadow from its style (a thin rod or a sharp, straight edge) onto a flat surface marked with lines indicating… …
89Delta-v budget — (or velocity change budget) is an astrogation term used in astrodynamics and aerospace industry for total delta v (or total velocity change) requirements for the various propulsive tasks and orbital maneuvers over phases of a space mission.… …
90Newton's theorem of revolving orbits — Figure 1: An attractive force F(r) causes the blue planet to move on the cyan circle. The green planet moves three times faster and thus requires a stronger centripetal force, which is supplied by adding an attractive inverse cube force. The …
