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Abstract:

The report considers the idea of reducing near-Earth space debris by releasing the spent additional fuel tank (AFT) and the booster's central block (CB) into the Earth's atmosphere during the insertion phase to the target orbit. The spacecraft transfer from a reference circular orbit of an artificial Earth satellite to a target elliptical orbit is optimized. The transition maneuvers are carried out using a booster with a high limited-thrust engine and the AFT. The second zonal harmonic of the Earth's gravitational field is taken into account. The first series of transition maneuvers of a spacecraft to the target orbit is performed using fuel from the AFT. After exhausting this fuel, the spacecraft is in an orbit touching the conditional boundary of the Earth's atmosphere (with a perigee altitude of 100 km). On the passive flight segment, lasting 120 s, the AFT is released. The spacecraft returns to a safe orbit (with a perigee altitude of 200 km) by an additional activation of the spacecraft engine. This activation, as well as the subsequent ones, are performed using fuel from the CB's main tank. After performing the second series of maneuvers, the spacecraft is in a target orbit from which the characteristic velocity of final ascent maneuvers to the GEO is bounded by a given value. The objective functional is the payload mass, i.e., the mass of the spacecraft remaining in the target orbit after undocking the CB. Initially, trajectories with low overhead costs of releasing AFT and CB are identified in the impulse statement. In the next step, based on the hierarchy methodology, Pontryagin extremals are constructed for problems with high-limited thrust. A comparison is carried out between the Pontryagin extremals and the trajectories of the simple control scheme, in which the thrust vector direction on each active segment is defined by two angles that depend linearly on time.