Carpenter suffered complications after a fall . John Glenn is the lone survivor of the Mercury 7 . ` ` We have lost a true hero , '' says NASA administrator . He was a backup pilot for John Glenn ahead of America 's first manned orbital space flight in February 1962 . Carpenter was the second American to orbit Mercury .
Carpenter suffered complications after a fall . John Glenn is the lone survivor of the Mercury 7 . ` ` We have lost a true hero , '' says NASA administrator . Carpenter was the second American to orbit Mercury .