Gravity Probe B
...that scientists are testing Einstein's theory of general relativity with Gravity Probe B, an artificial satellite?
...that scientists are testing <a class="mw-redirect" href="./Einstein" id="mwAnY" rel="mw:WikiLink" title="Einstein">Einstein</a>'s theory of <a href="./General_relativity" id="mwAnc" rel="mw:WikiLink" title="General relativity">general relativity</a> with <b id="mwAng"><a class="mw-redirect" href="./Gravity_B_mission" id="mwAnk" rel="mw:WikiLink" title="Gravity B mission">Gravity Probe B</a></b>, an <a class="mw-redirect" href="./Artificial_satellite" id="mwAno" rel="mw:WikiLink" title="Artificial satellite">artificial satellite</a>?