Ayaks
...that the projected Russian hypersonic aircraft Ayaks was supposed to use novel "magneto-plasmo-chemical engines" capable of working in the mesosphere?
...that the projected <a href="./Russia" id="mwAlQ" rel="mw:WikiLink" title="Russia">Russian</a> <a class="mw-redirect" href="./Hypersonic" id="mwAlU" rel="mw:WikiLink" title="Hypersonic">hypersonic</a> aircraft <b id="mwAlY"><a href="./Ayaks" id="mwAlc" rel="mw:WikiLink" title="Ayaks">Ayaks</a></b> was supposed to use novel "magneto-plasmo-chemical engines" capable of working in the <a href="./Mesosphere" id="mwAlg" rel="mw:WikiLink" title="Mesosphere">mesosphere</a>?