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A satellite whose orbital period is an integer fraction of a day (e.g., 24 hours, 12 hours, 8 hours, etc.) will follow roughly the same ground track every day. This ground track is shifted east or west depending on the longitude of the ascending node, which can vary over time due to perturbations of the orbit. If the period of the satellite is ...
The ground pressure of motorized vehicles is often compared with the ground pressure of a human foot, which can be 60 – 80 kPa while walking or as much as 13 MPa for a person in spike heels. [ 3 ] Increasing the size of the contact area on the ground (the footprint ) in relation to the weight decreases the unit ground pressure.
Ground track example from Heavens-Above.An observer in Sicily can see the International Space Station when it enters the circle at 9:26 p.m. The observer would see a bright object appear in the northwest, which would move across the sky to a point almost overhead, where it disappears from view, in the space of three minutes.
The radar ground stations determine the position of the vehicle C-band transponder by measuring range, azimuth angle, and elevation angle. Range is derived from pulse travel time, and angle tracking is accomplished by amplitude-comparison monopulse techniques. As many as four radar stations may track the beacon simultaneously.
On the other hand, the various perturbations can be orchestrated by clever astrodynamicists to assist with orbit maintenance tasks, such as station-keeping, ground track maintenance or adjustment, or phasing of perigee to cover selected targets at low altitude.
The laser array is rotated 2 degrees from the satellite's ground track so that a beam pair track is separated by about 90 m (300 ft). The laser pulse rate combined with satellite speed results in ATLAS taking an elevation measurement every 70 cm (28 in) along the satellite's ground path. [17] [19] [20] The laser fires at a rate of 10 kHz.
Instruments used to plot a course on a nautical chart. In navigation, the course of a watercraft or aircraft is the cardinal direction in which the craft is to be steered.The course is to be distinguished from the heading, which is the direction where the watercraft's bow or the aircraft's nose is pointed.
1.1.1 Flat ground. 1.1.2 Uneven ground. 1.1.3 Angle of impact. ... irregularities in the projectile's shape and weight distribution tend to be cancelled out.