Conversation so far:
How did Sergei get started in his career?
After graduation, Sergei Korolev worked with some of the best Soviet designers at the 4th Experimental Section aircraft design bureau OPO-4 headed by Paul Aimé Richard
Where did working with some of the best Soviet designers at the 4th Experimental Section aircraft design bureau OPO-4 headed by Paul Aimé Richardlead Sergei Korolev?
Sergei Korolev did not stand out in this group, but while so employed he also worked independently to design a glider capable of performing aerobatics.
Was Sergei Korolev successful in the design of a glider capable of performing aerobatics?
Did Sergei Korolev land a job after working on glider capable of performing aerobatics?
In 1930 Sergei Korolev became interested in the possibilities of liquid-fueled rocket engines to propel airplanes while working as a lead engineer on the Tupolev TB-3 heavy bomber.
What did Sergei Korolev do with that interest in the possibilities of liquid-fueled rocket engines to propel airplanes?
Sergei Korolev earned his pilot's license and explored the operational limits of the aircraft he piloted, wondering what was beyond his plane's altitude limit and how he could get there.
Did exploring limits of the aircraft he piloted, wondering what was beyond his plane's altitude limit and how he could get there help Sergei Korolev design?
Many believe this was the start of Sergei Korolev's interest in space

Question: What project did he take on from there?
Self-contained rewrite: What project did Sergei Korolev take on from exploring limits of the aircraft he piloted, wondering what was beyond his plane's altitude limit and how he could get there help?