After 2nd World War, the most priority projects were on military domain. A YU engineer has developed everything needed for military airplanes. It is well known that a lot of researches were spending on IRBM missiles. Space program is just between these two domains.
A lot of people see Yugoslavia like a country completely devastated and in ruin. It's now true & it's starts to fall apart since TITO's death in 1980 but after WW2 Yugoslavia was pretty strong especially military & a lot of money went to R&D in order to insure high technologies military level.
"nation that gave the world that engineering marvel called the Yugo"
Yes Yugo came from Yugoslavia. I agree that were bad car but commercially it was a big success. Few hundred thousand were sold in US & other country. For us (Yugoslavian) it was only a way to obtain a lot of $ for extremely cheap car. At that time US market needed a car like that one so they imported it.
Let’s compare it again with China: The whole world buy cheap products
Made in China and everyone know that is bad quality but for China it's a source of money, a lot of money.
Around that secret base (Object 505, ZELJAVA,
http://www.zeljava-lybi.com/Zeljava-index2_eng.html ) 15 or 20km were well protected by police. It was just enough to stop a car for 2 min & police will chase you rapidly out. Everybody knows something happens there but nobody was enough stupid to ask too much questions.
Naturally protected walleye by High Mountain it was perfect place to test a lot of weapons & aircraft hidden from radars beams.
By the way, during 1st war in Iraq, UN sent some Yugoslav troops and tanks there. Our tanks had a good reputation because they hadn’t problems with sand in Iraq desert. Oh, I forget, a few Saddam's anti-atomic bunkers were made by.... Yugoslavian engineers. During NATO strike on Yugoslavia in 1999, YU army just shut down US stealth bomber F117.
For radars operators he was not stealth enough... so they shut him down. It was very first loose of stealth plane.