Congrats to NASA and its astronauts for the safe return of the shuttle yesterday. Here are a few interesting comments I have come across on the mission.

Senator Kay Bailey Hutchison, Republican of Texas and chairwoman of the Senate Commerce subcommittee on science and space, called the mission “an important milestone in our nation’s space exploration history.” (link)

Expectations for the space program have really gone down if simply returning astronauts safely is interpreted as an important milestone. On the other hand, it might be a good sign if such a view reflected an honest appraisal of the risks of spaceflight. Call me a cynic, but I doubt this latter explanation explains comments like those of Senator Hutchinson, which probably reflect diminishing expectations more than anything else.

“We don’t have any slack,” [NASA Administrator Michael Grifin] said. “We have just enough shuttle flights left to do the job, so we can’t afford to mess up.” (link)

Planning with no “slack” is called “success-oriented planning” and has plagued NASA for decades. Why in the world would NASA create plans with absolutely no slack? As has been seen time and time again, this is a recipe for schedule disruption, cost overruns, and performance shortfalls. Griffin also says: “I think the words ‘routine human space flight’ don’t go in the same sentence. Every one of these (missions) is experimental.” In such a circumstance, isn’t a little slack desirable? It is not really going out on a limb to expect that the next 16 missions won’t be carried out as planned today.

“The shuttle remains a fragile, delicate, temperamental vehicle and needs to be operated with extreme care,” said John Logsdon, who heads the Space Policy Institute at George Washington University . . . “I think that the most likely future is one in which the shuttle flies out its remaining missions and gets its job done.” (link)

If the risks of losing an orbiter are 1 in 100, then there is about a 15% chance of losing an orbiter over its last 16 flights. As I have written before, this is just about the same odds as playing Russian Roulette. If the odds are less in NASA’s favor, then the chances go up. Given NASA’s history, I dount that Logsdon is correct about the most likely future. This doesn’t mean that there will be a catastrophic loss of an orbiter, but the chances of the less likely futures are not insignificant and they come with a few outcomes with extreme consequences. A more likely future will involve unexpected technical, schedule, and costs issues that disrupt the plans set at any given time.