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The NOAA/NASA portion is called the Joint Polar Satellite System (JPSS). The first satellite in the program – originally called JPSS-1, but now known as NOAA-20 – was constructed by Ball Aerospace & Technologies Corp. , under a fixed price contract of $248 million with a performance period through Feb. 1, 2015. [ 8 ]
The geographic poles are defined by the points on the surface of Earth that are intersected by the axis of rotation. The pole shift hypothesis describes a change in location of these poles with respect to the underlying surface – a phenomenon distinct from the changes in axial orientation with respect to the plane of the ecliptic that are caused by precession and nutation, and is an ...
Through analysis of seafloor magnetic anomalies and dating of reversal sequences on land, paleomagnetists have been developing a Geomagnetic Polarity Time Scale. The current time scale contains 184 polarity intervals in the last 83 million years (and therefore 183 reversals).
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As an example, with a = 7200 km, i.e., for an altitude a − R E ≈ 800 km of the spacecraft over Earth's surface, this formula gives a Sun-synchronous inclination of 98.7°. Note that according to this approximation cos i equals −1 when the semi-major axis equals 12 352 km , which means that only lower orbits can be Sun-synchronous.
The trajectories that enabled NASA's twin Voyager spacecraft to tour the four gas giant planets and achieve velocity to escape our solar system In astrodynamics a gravity assist maneuver, gravitational slingshot or swing-by is the use of the relative movement and gravity of a planet or other celestial body to alter the trajectory of a ...
A geomagnetic excursion, like a geomagnetic reversal, is a significant change in the Earth's magnetic field.Unlike reversals, an excursion is not a long-term re-orientation of the large-scale field, but rather represents a dramatic, typically a (geologically) short-lived change in field intensity, with a variation in pole orientation of up to 45° from the previous position.
Examples of degenerate cases—with the non-linear terms in the Navier–Stokes equations equal to zero—are Poiseuille flow, Couette flow and the oscillatory Stokes boundary layer. But also, more interesting examples, solutions to the full non-linear equations, exist, such as Jeffery–Hamel flow , Von Kármán swirling flow , stagnation ...