The 86-year-old was evacuated to Christchurch Hospital from Antarctica last Friday suffering respiratory problems.
Yesterday Aldrin posted a note to his blog about his late friend John Glenn, American aviator and astronaut. Glenn died at the James Cancer Hospital in Columbus, Ohio, where he had been hospitalised for more than a week.
"As I sit in hospital and just heard that my friend John Glenn has passed away, I feel fortunate to be recovering from my own illness, but saddened that we lost another space pioneer and world icon."
Aldrin wrote he was "very saddened" to hear Glenn had been ill over the past year, as he was the last remaining Mercury astronaut. Glenn in 1962 became the first American to orbit the Earth, circling three times.
"I was always lobbying him to encourage the Apollo guys to do regular reunions annually since we're not getting any younger."
Aldrin first met Glenn in 1953 as fighter pilot in South Korea.
"[Glenn] was the Ops officer of the 25th squadron in the 51st fighter group. The next time I learned about him he flew, of course, on his first orbital flight".
Aldrin said when he reported as a Nasa astronaut in 1963, the pair became elders in the same church in Texas.
"Not long after that he left Nasa and, of course, pursued a career in politics while I went on to do my Gemini 12 and Apollo 11 missions."
At 77, Glenn became the oldest to fly in space when he flew again on a shuttle mission.
Buzz said he saw him at "various memorials and astronaut gatherings over the years", but the last time the pair spoke in person was at Neil Armstrong's memorial.
"He [Glenn] will always go down in history as certainly one of the most influential officers in the Marine Corps and of course as one of the original Mercury 7 astronauts."
Buzz added that he would "join that crowd of people and the entire nation and the world in paying homage to his service".
Aldrin's manager Christina Korp posted to Twitter on Monday that Aldrin was on the mend and should be heading home soon.
