Mortuary officials at an Air Force Base twice offered shocked inspectors “a peek” at the body of US astronaut and icon John Glenn as it awaited burial.

Reports say an investigation is underway in to what officials said was “clearly inappropriate and personally shocking” behaviour.

The Military Times said the incidents happened at Dover Air Force Base in Delaware. Glenn died in December 2016, but the body of the man who was the first American to orbit the earth and the oldest to fly in space, was not buried in Arlington Cemetery until 6 April 2017.

Astronaut Jack Fischer admires the view from space

That marked the wedding anniversary with his wife, Annie. His body was kept at Dover in the interim.

Pentagon officials have now launched a high level investigation to determine whether misconduct was committed.

John Glenn was the first American to orbit the Earth in 1962 (Roberto Schmidt/Getty)

A memo, written by Deborah Skillman, the Defence Department’s director of casualty and mortuary affairs, states the employee’s alleged actions were “clearly inappropriate and personally shocking”. The document is dated May 2017.

Glenn died at the age of 95. His 1962 flight as the first US astronaut to orbit the Earth made him an all-American hero and propelled him to a long career in the US Senate.

In 1998, he flew aboard the shuttle Discovery, making him at age 77 the oldest person in space.

After his death, his family asked that the military take care of his remains until burial, a request that was granted to “ensure an increased level of privacy and security for a renowned public servant, Marine Corps officer, and pioneer of space exploration”.

Twice during the time that Glenn body was being held at Dover, mortuary officials offered inspectors a chance to view the deceased, the internal memo said.