The Iranian government refused a formal request by the U.S. on Tuesday to return an unmanned surveillance drone that was captured by Iran’s military earlier this month. Instead, Iranian officials insisted the U.S. apologize for invading its airspace. Iranian television broadcast images of the RQ-170 Sentinel on Monday night, saying scientists were collecting data from the drone. U.S. officials say the drone malfunctioned, countering Iran’s claim that electronic warfare brought down the drone. The U.S. says this is the latest provocation of the West by Iran, following an alleged plot to assassinate the Saudi ambassador to the U.S., and the storming of the British embassy in Tehran. (See a video of the drone after the jump.) Chris Day is an engineering specialist from the firm Magna Parva, with over 30 years of experience in drone technology. He discusses what Iran might learn about the U.S. technology and what possibly went wrong.