The <a href="https://en.wikipedia.org/wiki/Soviet_Union" id="mw_Q" rel="mw:WikiLink" title="Soviet Union">Soviet</a> probe <a href="https://en.wikipedia.org/wiki/Venera_4" id="mw_g" rel="mw:WikiLink" title="Venera 4">Venera 4</a> reaches <a href="https://en.wikipedia.org/wiki/Venus" id="mw_w" rel="mw:WikiLink" title="Venus">Venus</a> and becomes the first spacecraft to measure the atmosphere of another planet.