Bjoern Gimle wrote: > If RCS is indicative of true cross-sectional area, drag force increases with > RCS. > But the EFFECT of the force decreases with more mass of the affected object. Exactly speaking (in equations): spacecraft decelaration is given as a = (1/2).cx.(A/m).rho(h).v.v where cx - aerodynamic coefficient (depending on shape of object) A - effective cross-sectional area of spacecraft m - mass of spacecraft rho(h) - atmospheric density at given height h v.v - velocity (squared) For a circular orbit with major semiaxis a, the change (decay) of semiaxis per orbit is given as delta a = -2.PI.cx.(A/m).rho(h).a.a Consequences: for spacecraft of silimilar shape the decay is proportional to the A and inversely proportional to the m (PI is Ludolph number, 3.14159265....) -- Mgr. Antonin Vitek, CSc. Office: Main Library, Academy of Sciences of the Czech Republic Narodni 3, CZ-11522 Praha 1 - Phone: +420(2)21403255, fax +420(2)24240611 Home: Kytin 127, CZ-25210 Mnisek p. B., Czech Republic Phone: +420(305)592865 - Coord.: 14.2194 deg E, 49.8488 deg N, 442 m ASL My satellite home page: http://www.lib.cas.cz/www/space.40/index.html ----------------------------------------------------------------- Unsubscribe from SeeSat-L by sending a message with 'unsubscribe' in the SUBJECT to SeeSat-L-request@lists.satellite.eu.org http://www2.satellite.eu.org/seesat/seesatindex.html
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