scientific initiative
...that from 1955 to 1973, the United States conducted a scientific initiative aimed at producing gravity-manipulation technology?
...that from 1955 to 1973, the <a href="./United_States" id="mwAuE" rel="mw:WikiLink" title="United States">United States</a> conducted a <b id="mwAuI"><a class="mw-redirect" href="./United_States_gravity_control_propulsion_initiative" id="mwAuM" rel="mw:WikiLink" title="United States gravity control propulsion initiative">scientific initiative</a></b> aimed at producing <a href="./Gravity" id="mwAuQ" rel="mw:WikiLink" title="Gravity">gravity</a>-manipulation technology?