このエピソードについて
This week's mini-episode comes from a May 2023 interview with Dr. Alan Stern. Today, Dr. Stern is an aerospace executive and remains a planetary scientist. In 2015, he was the Principal Investigator on the historic New Horizons mission to Pluto. In that role, he had ultimate responsibility for the entire research project, overseeing its scientific, technical, and administrative aspects.
The situationIn 2015, after a nine-year journey, the New Horizons spacecraft was poised to complete its an historic flyby of Pluto. But success was not guaranteed. For the New Horizons' mission to be successful, all of the spacecraft's data-gathering instruments had to work flawlessly starting seven days before reaching its closest point to the planet and for at least two days after. All of the maneuvering of the seven data-gathering instruments – what they would look at, what they would measure – had to be preprogrammed into the craft's computer. There was simply no way someone back at Mission Control could drive the spacecraft in real time, because by 2015 New Horizons was three billion miles from Earth. A signal traveling at the speed of light would take 4.5 hours to reach the speeding spacecraft. In that amount of time, whatever Mission Control had been directing the spacecraft to photograph or measure would likely have passed.
But preprogramming didn't guarantee success either. New Horizons, traveling at 35,000 miles an hour, had to reach a specific point in space within a nine-minute window, or "the box," as the team referred to it. If the craft were early or late to that point, the computer would be directing the instruments to look at or measure something during the critical flyby period that wasn't centered in their field of view – or potentially not there at all. And there would be no time to recalibrate them. Orbiting Pluto for a redo was out of the question because the spacecraft didn't have the necessary fuel to execute such a move. Orbiting Pluto wasn't even in the mission plan. If the box were missed, the potential to collect data would be lost. The mission would have failed.
A grace period of only nine minutes. 540 seconds. After three billion miles. And nine years.
The good news is that Mission Control scientists were carefully monitoring the spacecraft as it approached the ideal central point and calculated that it was less than two minutes off – way inside the nine-minute box. Everyone in Mission Control breathed a sigh of relief.
But what if we…?
Scientists and engineers are, however, perfectionists, so the question quickly arose, "Do we make a correction? Do we scratch back a few more important seconds to make sure our instruments are pointing where we want them to point?" Days before the critical flyby, there was still time to do so. It was a tempting proposition. Dr. Stern picks up the story.
Once we got in the box, the navigation teams recommended that we do one more engine firing to really put it in the middle of the box. And we had an analysis done that showed that if we didn't change anything if we stayed where we were, didn't go to the middle of the box but we're just in the box, we would get every single scientific observation One that we had set out to do. And yet they were recommending, and in fact, the engineering and science teams, were recommending that we just nail it, we go right down the middle of the pike. And I rejected that as the leader of the mission. Because at that point, we were going to get everything we came for. And while we might have done a few things a little bit better, the risk that that engine burn might have gone haywire, or sent the spacecraft into some fetal position where it needed help from Mama back on Earth before or we could carry out the flyby was real. And I didn't want to take any risk. Once we were in the box. You know, there's an old saying Better is the enemy of good knife. Yeah, right. It was good enough. And as you've seen from the results, we really nailed it. So I'm glad that we, we backed away from that, because it looks to me like more risk than reward,
To summarize, as the mission leader, Dr. Stern gathered everyone on his team together to review the navigation calculations, and then took three powerful steps:
1. Stern asked each of his team members to voice their opinion on the wisdom of making the correction. One by one, around the table, each leader of a critical aspect of the program voiced "Go," recommending the correction.
2. Stern waited and took notes until everyone had the opportunity to voice his or her opinion. He then made the decision: "No go."
3. He then asked a critical question, "Is there a must-do reason to make the correction when we're already safely within the box?" He went back around the room and asked each section leader to respond. After hearing from everyone, Stern stood with his original "No go." It was simply not worth the risk of introducing a potential programming error this late in the game.
New Horizons soon flew past Pluto at 35,000 miles an hour, a mere 7,500 miles above the dwarf planet's surface. As the spacecraft began to "phone home" amazing images and other data, it was clear that New Horizons – the first mission to Pluto – was an unqualified success. "Good enough" was truly good enough.
The idea
Leaders typically struggle with three questions in scenarios like the one before the New Horizons team, and they do so because they feel "All eyes are on me."
• Do they feel they need to make the immediate call without input because they're the leader, or do they ask to hear from all members of their team on the critical question?
• Do they speak first because they're the leader, or do they weigh input from the team and speak last? And finally,
• Do they push for "better," or do they stand pat when there is evidence that "good enough" is truly good enough?
Here's Dr. Stern's further rationale for the process.
I always speak last. As the mission leader, I'm a firm believer that, well, I might set the table, I might start a meeting off, here are our objectives, here's what we should consider that the final gonna go on my part should be considered one, having heard from all the experts that know more than me about each individual area, my job is to go broad, and make sure that the mission carries out all of his objectives. And their job is to go deep, and make sure that each little piece is operating properly. So I was last in that poll. And I did reject what was a unanimous decision by everyone else. And it was a little lonely, but you know what, I was confident in it. And it worked out just fine.
Dr. Melissa Hughes, a neuroscience geek researcher and author of Happier Hour with Einstein, Another Round, reinforces Dr. Stern's steps as a meaningful way to avoid "groupthink," which she defined as "a psychological phenomenon that happens when people in a group willingly or unconsciously commit to decisions they don't necessarily agree with to avoid creating emotional tension or conflict with their colleagues."
In Dr. Stern's case, no one on his team wanted to be the only "No go" and buck the "groupthink." The consequences of groupthink, as Dr. Hughes describes, can be significant: "When people…put harmony and cohesion above the critical evaluation and analysis of the outcome, they stifle their thoughts, refrain from asking the hard questions and avoid exposing potential pitfalls. This often leads to irrational or problematic decisions."
In New Horizons' case, the consequences of groupthink could have been disastrous.
A program note: If you're a space geek like I am, I've included a couple of illustrations of the mission in the shownotes on my website.
