A NASA veteran has stated that aliens are real, but he emphasized that no extraterrestrial life has ever visited Earth.

Dr. Gentry Lee, who began his career with NASA in 1968 and designed probes that landed on distant planets, spoke at an AAAS gathering. He said, “There exists nothing today that says any alien or any alien machine has ever landed on the planet Earth,” adding that people who believe otherwise have been misled.

Dr. Lee also highlighted the likelihood of life elsewhere in the universe, saying, “We are going to find life of some kind somewhere else.”

His remarks came after former U.S. President Barack Obama stated, “Aliens are real,” though he later clarified he had seen no evidence of extraterrestrial life on Earth during his presidency. Current U.S. President Donald Trump has asked the government to prepare the release of files on aliens and UFOs.

Experts say planets with Earth-like conditions are the most promising for discovering alien life. One example is the Earth-sized planet TRAPPIST-1e, located just 40 light-years away, which is considered a strong candidate for hosting extraterrestrial life.

Dr. Lee, now chief engineer for the Solar System Exploration Directorate at NASA’s Jet Propulsion Laboratory, urged astronauts to be ready for alien life that could be very different from life on Earth.