President-elect Donald Trump recognized the death of famous astronaut John Glenn, declaring him an American hero.

“Today we lost a great pioneer of air and space in John Glenn,” he wrote briefly on Twitter. “He was a hero and inspired generations of future explorers. He will be missed.”

Glenn, the first American to orbit the earth in 1962 and the oldest person in space in 1998 died on Thursday.

Later, Donald Trump spoke about Glenn during his visit to Ohio on Thursday afternoon.

“I met him on two separate occasions. Liked him, always liked him,” he told reporters. “But he was indeed an American hero.”