When a damaged Apollo 13 and its crew were careening to Earth, mission control director Gene Kranz famously told the assembled NASA team that “failure is not an option.” Actually, the actor playing Kranz in the “Apollo 13” movie spoke those words, but by all accounts Kranz and his team lived that phrase, with a drive that became a reality.
That kind of hard-driving confidence now seems to be built into NASA’s DNA, and with some tragic exceptions it has served the agency well in its myriad high-precision and high-drama ventures.
So it was somewhat surprising (and a bit refreshing) to read the recent blog post from Thomas Zurbuchen, NASA’s Associate Administrator for the Space Science Directorate, on the subject of the scheduled November launch of the James Webb Space Telescope.
“Those who are not worried or even terrified about (the challenges facing the JWST mission) are not understanding what we are trying to do,” he wrote.
“For most missions, launch contributes the majority of mission risk – if the spacecraft is in space, most risk is behind us. There are few types of missions that are very much different with most risk coming after launch.
“We have already performed one such mission in February when we landed on Mars. For the Perseverance rover, only 10-20% of the risk was retired during launch, perhaps 50% during the landing, and we are in the middle of the residual risk burn down as we are getting ready to drill and collect the precious Mars samples with the most complex mechanical system ever sent to another planet.
“The second such mission this year is Webb. Like a transformer in the movies, about 50 deployments need to occur after launch to set up the huge system. With 344 so-called single point failures – individual steps that have to work for the mission to be a success – this deployment after launch will keep us on edge for 3 weeks or so. For comparison, this exceeds single point failures for landing on Mars by a factor of 3, and that landing lasted only 7 minutes.”
Zurbuchen is confident that the Webb team and technology is up to the challenge but still, that is quite a risk profile.… Read more