Senator John Glenn, the first US astronaut to orbit the earth in 1962, is to become the oldest at 77 when he will be launched into space again next October.
The decision by NASA to send Mr Glenn back into space was announced yesterday. He will orbit the earth for 10 days as a crew member of the Discovery shuttle as part of a study of the effects of age on humans experiencing the weightlessness of space travel.
Mr Glenn, a Democratic senator from Ohio since 1974, has been seeking NASA's consent to make a last trip in space for the past two years. He plans to retire from politics at next November's election.
The senator is said to be remarkably fit for his age and to have passed "the most exhausting medical examination ever endured by a crew member in shuttle history". He flies his own plane between Washington and Ohio at least once a week.
While the decision to allow Mr Glenn to renew his astronaut career after 36 years has been welcomed widely in America, there is also some criticism that there is not enough scientific basis to justify sending him into space. It is asked why NASA has up to now made astronauts retire at 60 if it was really interested in the effect of weightlessness on the ageing process.
Mr Glenn told a press conference that he was "excited" to be back in space travel. He hoped that this experiment would lead to a better knowledge of the ageing process. Young astronauts quickly recover from the "ageing" effects of weightlessness such as diminished bone mass and weaker muscles, he pointed out. Now NASA could make tests on an old person experiencing weightlessness and make comparisons with him at a younger age.
NASA director Mr Dan Goldin denied that there was any connection between this decision and Mr Glenn's strong support for President Clinton and the White House during the recent Senate hearings on abuses in Democratic party fund-raising. Mr Glenn also strongly rejected this allegation.