Glenn and six crewmates, including a Japanese flier and Spain's first astronaut, are scheduled to take off aboard Discovery on Oct. 29. Glenn was added to the crew in January by Administrator Daniel Goldin to carry out a battery of experiments to learn more about aging and the possible treatment of various ailments affecting the elderly.
In 1962, Glenn became the first American in orbit. At the end of the month, he will become the oldest person to fly in space when he makes his second flight in 36 years.
While public support for Glenn's mission appears high, at least two former astronauts have criticized the assignment, saying the 77-year-old senator is not physically up to the challenge of certain emergency scenarios and thus poses a threat to his crewmates.
They also have questioned the statistical significance of Glenn's research, saying data collected on a single subject cannot be applied to a broad population.
Writing in the Sept. 21 edition of Aviation Week & Space Technology magazine, former astronaut Michael Mullane, a veteran of three shuttle flights, said, "The shuttle is not an airliner. The threat of various, severe emergencies is very real."
"Visualize a launch pad emergency, in-flight bailout or a crash landing," he said."Trying to escape from a shuttle in a time-critical situation with 83 pounds of equipment strapped to your body requires muscle and lightning fast reactions. I am particularly concerned about a ground egress that would require Glenn (sitting downstairs) to negotiate (in a full pressure suit) the narrow, seven-foot ladder up to the cockpit, then climb onto the shuttle roof and rappel over the side of the orbiter."
As for Glenn's research agenda, Mullane wrote, "If such research is needed, you would think NASA would have selected more senior citizens or a doctor of geriatric studies from the latest astronaut class. A 'one data point' Glenn mission doesn't sound like good science."
Former astronaut Story Musgrave, who set the current age record when he blasted off on his sixth flight at age 61, said Glenn's mission makes sense from a historical perspective, "but we need to be honest about it," he told The Lexington Herald-Leader. "We are flying a legislative passenger, as we have in the past. It's John Glenn. Marvelous. But it is a legislative passenger."
As such, Musgrave said, Glenn's Senate duties prevented him from focusing solely on crew training.
"I am bothered by the fact that Senator Glenn is not giving it all he's got, that he's takng a part-time approach to it," Musgrave said. "It should've been put off until he was done with his Senate duties."
Glenn, as one would expect, strongly disagreed. During a news conference at launch pad 39B Thursday, the senator told a throng of reporters that his critics are off base, saying, "I've been adequately trained for this mission as any payload specialist is."
"I'm not back as a legislative passenger," he insisted. "I'm back as a science passenger. And that was the basis on which I was selected, the basis on which I have trained. And that's what my objective is on my flight. If there are others who have a different view of that, well I'd just ask them to look at what we've been doing, look at the training, look at the experiments in detail and then make their judgments, not make it on some preconceived idea they may have had earlier. I just disagree entirely with that statement."
As for the value of his research program, Glenn said, "The people that have said there wasn't any science on this, when I have talked to them or sent them material to review about the science we're doing on this ... they have changed their minds. I wish all the people had looked at some of these things before they made some of their public statements."
Glenn said, "Any normally healthy person could do the kind of training we've been doing." But he said space travel should not be opened up to civilians "unless there's a scientific reason for them going."
"When I talked to [NASA Administrator] Dan Goldin originally, when he was thinking about my going up, it was on the basis of we're going to have a good science base for this thing that the National Institute of Aging was behind and NASA was behind. That was the basis for it. I didn't look at myself as just the average civilian coming back in. I had had experience, albeit a long time ago. I was coming back in for a very specific purpose.
"I know it's easy to report the 'oh, gee whiz' of the personal aspects of this thing, but this is science at its very best, out there on the cutting edge, and I'd sure invite you to get in there and report that."
Glenn and his six crewmates - commander Curt Brown, pilot Steven Lindsey, Scott Parazynski, Stephen Robinson, Spaniard Pedro Duque and Japanese flier Chiaki Mukai - flew to Florida Tuesday to participate in a terminal countdown demonstration test, or TCDT. The crew practiced emergency procedures Wednesday and Thursday in case of pre-launch problems that could force them to attempt an emergency evacuation at the pad. Early Friday, all seven astronauts plan to strap in aboard Discovery for the final hours of a dress-rehearsal countdown.
The next major milestone is scheduled for Oct. 15 in Houston when NASA stages traditional pre-launch news briefings, including a final crew news conference. A detailed mission overview will be posted here as soon as possible after next week' briefings.