Oechsler, 71, died on June 6 after a two and a half year battle against lung cancer.
According to an online obituary, he «passed away peacefully surrounded by family» in Edgewater, Maryland.
He leaves behind wife Kristen and children Dan, Tracey and Skylar, along with two grandsons and siblings.
Colin Andrews, a well-known British crop circle investigator, told The Sun: «My sincere condolences to the family and friends of well known UFO researcher Bob Oechsler.
«I presented with him on several occasions in a number of countries. Bob’s research was greatly respected.»
Bob worked on the docking collar of the Apollo-Soyuz project, the first international space mission between Russian and the US, plus several other deep space projects.
But his work in the field of UFOlogy in the 1980s and 1990s shot him to worldwide fame as he investigated a series of high-profile cases.
Bob’s ID pass for the space flight center where he worked as a contractor in the 1980s
Bob’s ID pass for the space flight center where he worked as a contractor in the 1980sCredit: Triangle News
Bob was allegedly invited to be a consultant for the Nasa-backed ‘Cosmic Journey Project’, a travelling exhibition featuring a full scale mock-up of a space shuttle and space camp.
One third of the exhibition was to feature UFOs and extraterrestrials, including a 600-seat auditorium that became a Bio-Tech spaceship and a UFO pre-show area with interactive kiosks.
Bob claimed he had meetings with top brass from the Pentagon who backed the project. Recalling an alleged discussion he had with a general in Washington, Bob claimed their talk involved an «exhibit showing an alien/ET corpse in a cryogenic tank».
«The general described the tank as a space-age looking coffin with blue tube lighting inside the clear lexan cover, propped up at an angle so it wouldn’t look so much like a casket,» he said.
«It seems he was concerned about using the real thing versus a mock-up, and he queried me at length about my thoughts on public perception and whether or not the public would believe such an exhibit was real, or how it could be authenticated with official plaques of some sort.»
Bob worked at the Nasa Goddard Space Flight Centre in Maryland
Bob worked at the Nasa Goddard Space Flight Centre in MarylandCredit: Google maps
«I suggested that a companion autopsy report with colour photographs might help the credibility aspect.
«As a matter of fact, I got the impression they had a lot of bodies to choose from!»
Directors denied he ever worked for them as a consultant after the project was scrapped, and claimed it was only ever an exhibition of mock-ups of aliens and flying saucers.
Nasa also denied he visited the places he did and was ever shown UFOs.
In 1989, Bob managed to speak with Admiral Bobby Ray Inman, a former Director of Naval Intelligence and Deputy Director of the CIA, who informed him that the US Government had possession of technology of non-human origin.
Due to COVID-19 restrictions a funeral will be held for Bob at a later date
Due to COVID-19 restrictions a funeral will be held for Bob at a later dateCredit: Triangle News
In a recorded telephone conversation, Bob allegedly asked: «Do you anticipate that any of the recovered vehicles would ever become available for technological research? Outside of the military circles?»
Admiral Inman replied: «I honestly don’t know. Ten years ago the answer would have been no. Whether as time has evolved they are beginning to become more open about it, there’s a possibility.»
Bob also probed video footage of the Chinese lantern shaped objects filmed by builder Ed Walters over his house.
He spent five months analysing the footage using the operational facilities at the NASA Goddard Space Flight Center in Maryland and concluded the UFO was not a radio-controlled model.
Another famous case he probed was the so-called Guardian footage when a family in Canada watched a UFO land in their field.
In an interview with BBC Radio 1 in 2007, he described one UFO he’d been shown, explaining: «It was about a 30 foot diameter disk shaped craft.
«It had a small dome around the centre portion. There were protruding flanges equidistant around the outer edge.»