Экспериментальное определение коэффициента сопротивления конических проникателей и проникателя с плоским передним торцом при сверхзвуковом движении в песчаном грунте

Experimental studies were carried out to determine the coefficient of resistance when conical and cylindrical impactors penetrate into sandy soil. In experiments, the angle of half-solution of the conical tip of the penetrator varied from 10 to 90 deg. The speed of the penetrator changed in the range of 0.2-2.0 km / s. The average values of the drag coefficient are obtained for conical bodies with quasi-stationary supersonic motion in sandy soil with an average humidity of 7-12%, and for impactors with a flat front end - in sandy soil with a humidity of 0 to 16%. A significant dependence of the drag coefficient of thin cones (β < 25◦) on the speed of movement and the absence of such a coefficient (taking into account the experimental error) for blunt cones and a flat-end striker is shown.

Ionosphere disturbance during cosmodrome “Vostochniy” launches

It is known that during spacecraft launches ionospheric plasma properties are modified in the result of impact of shock-acoustic waves generated during carrier rocket supersonic motion. As a rule, investigation of ionospheric plasma variations is carried out by the signals of Global Navigation Satellite Systems GPS/GLONASS that implies ground station network. There is no such a system near the “Vostochniy” cosmodrome that makes it necessary to search for an alternative solution. One of them may be the application of ionosphere vertical and oblique sounding stations. Based on the analysis of such station data, the possibility of evaluation of ionosphere modification during “Vostochniy” cosmodrome launches is shown.

XMM-Newton and Geminga

A deep XMM-Newton/EPIC observation of the field of the Geminga pulsar unveiled the presence of two elongated parallel X-ray tails trailing the neutron star. They are aligned with the object's supersonic motion, extend for ∼ 2′, and have a nonthermal spectrum produced by electron-synchrotron emission in the bow shock between the pulsar wind and the surrounding medium. Such a first ever X-ray detection of a pulsar bow shock allows us to gauge the pulsar electron injection energy and the shock magnetic field while constraining the angle of Geminga's motion and the local matter density.