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The first adsorbed layers of helium.
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Also Elastic Scattering of Electrons and Positrons.
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First spacecraft beyond the orbit of Neptune (first spacecraft to pass beyond all Solar System planets)
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First Infrared orbital observatory
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Also Coulomb Scattering of Relativistic Electrons.
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Also measurement of Heat Capacity of Microscopic Particles at Low Temperatures.
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Also theoretical Analysis of Buildup of Current in Transient Townsend Discharge.
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First ICBM
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First artificial satellite in Earth orbit
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First animal in orbit
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First solar probe
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First communications satellite (lasted 12 days)[1]
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First Reusable manned spacecraft (orbital)
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First Venus soil samples & sound recording of another world
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Ultraviolet orbital observatory