PARIS — The decision by the international Committee on Space Research (COSPAR) to cancel its biennial Scientific Assembly in July — just 12 days before it was to start in Istanbul — is a cautionary tale for any conference organizer with a strong international mandate.

Founded in 1958, COSPAR’s principal mission is to promote global cooperation in space. Its Assemblies typically attract more than 2,000 participants, forcing the organization to select venues four years in advance to secure conference centers.

But while the choice of Turkey — a rising space power at the crossroads of Europe and Asia — might have seemed merely adventurous when the decision was made in 2012, by 2016 it had begun to appear risky.

The Assembly was scheduled for July 30-August 7.

On June 21, reflecting the abundance of caution to which any American receiving U.S. State Department travel advisories becomes accustomed, NASA advised its employees and contractors — including the Jet Propulsion Laboratory — that it would not sponsor travel to Istanbul for COSPAR.

COSPAR President Lennard A. Fisk, a former NASA Associate Administrator for Space Science and Applications, did not accept NASA’s rationale and, with the COSPAR board, decided to push forward with Assembly preparations.

On June 29, a terrorist attack at the Istanbul’s Ataturk Airport left 45 people dead and more than 230 injured. Still, Fisk reasoned, the airport’s security apparatus had succeeded in keeping the terrorists from the airport’s terminal. The meeting was maintained.

On July 14, a terrorist attack in Nice, France, during a a Bastille Day celebration killed 86 people and left 434 injured. Fisk and COSPAR persisted. “We cannot let terrorists dissuade us,” he would say later.

The July 15 attempted military coup in Turkey was the last straw. Fisk wrote COSPAR members on July 18 saying the Assembly had been cancelled.

COSPAR’s experience is an extreme example of issues that confront organizations such as the International Astronautical Congress, whose 67th annual meeting starts this week in Guadalajara, Mexico, and whose 66th meeting last year in Jerusalem was a subject of a safety-related debate.

How should organizations whose reputations are built on their global reach respond to the terrorism issue? Two months after his decision, Fisk concedes there are no easy answers.

Was choosing Istanbul always going to be risky?

COSPAR chose the Istanbul site four years ago. It’s a real challenge for anyone planning meetings of this nature, trying to predict the security environment four years hence.

We were proceeding with the conference well until about January. Attendance was always going to be light because there was a perception that Turkey is in a bad neighborhood.

Still, we were proceeding as we intended, with the belief that we should never let terrorism dissuade us from doing what we want to do.

COSPAR’s reason for being is to promote international cooperation in space research. One of the main ways we do this is to hold an Assembly every two years. We do other things, but our signature product is obviously the Assembly. So we were determined to keep going with this.

How did you view NASA’s pullout?

I think NASA did not know anything special. It was based on an abundance of caution on their part. Nasa deferred to the State Department. Only if NASA had declared it to be mission-critical, a very loosely defined term, could they have perhaps turned that around.

COSPAR was not considered mission critical by NASA. The decision only applied to NASA employees and Nasa contractors. Most U.S. scientists would have been attending on grants from Nasa through their universities. That was not governed by the ban. So there was still going to be a fair amount of attendance from the U.S., but no Nasa employees or contractors.

Then things started really going downhill. We had terrorist attacks in Europe. The thing that drove it through the floor was the bombing at the Istanbul airport. At that point the attendance was sinking fast and we were working with the Turkish organizers to try to to remote access so that people unable or unwilling to come could still find a way to give their talks.

You would have maintained the meeting after the Istanbul airport attack?

We were determined at that point to still make this thing happen. Again, it’s a basic principle: We shouldn’t let terrorism keep us from holding international conferences in the world today.

And then we had the coup attempt — a whole different story. At that point the conference had completely failed. The bottom line: People were not coming and it was not possible to hold a COSPAR conference under those circumstances.

Most scientists who attend COSPAR conferences are sponsored by their governments to do so. Those governments control the attendance of their participants — Chinese, Japanese, Indians, Russians and so forth. And nobody was coming.

So it was cancelled in some ways because it had already failed.

But also it was cancelled because, as president of COSPAR, I have to accept responsibility for the safety of our participants. Even if there were a few intrepid people who wanted to come, I could not accept it, given the environment.

The Assembly was still viable after the airport attack?

Just before the coup attempt were were already suffering. We were struggling to have a quorum to take action at the Assembly. At COSPAR assemblies, you want to have 2,500 people anyway. By the time we got down to the actual cancellation it was down in the hundreds.

I objected strongly to the NASA decision. At the time it was made, there was no reason to assume something was likely to happen. And even airport bombing in Istanbul: In some ways, everything worked like it was supposed to. The terrorists didn’t get inside the airport.

There were also people killed in Brussels from terrorism, and there were more people killed in Paris from terrorism, prior to the coup attempt in Istanbul, than were killed in Istanbul. I attended an American Geophysical Union meeting in Washington, D.C., in 1968. There was smoke.

What conclusions do you draw from this?

Now we’re picking up the pieces. There are working arrangements with the Turkish organizers to undo some of the financial consequences. [COSPAR has told delegates they have until Oct. 1 to seek reimbursement of their registration fees from the Turkish Local Organizing Committee].

For me, the lesson is to fundamentally question whether international societies like COSPAR can do their business in the current state of the world.

There are obviously some places you just judge to be safe and we could always plan to go there. Let’s hope they’re safe four years from now.

Your 2018 Assembly is in Pasadena, a safe bet.

I have every expectation that that’s safe.

All you can do is choose your sites carefully. It takes four years to organize and you cant really change in mid-stream. JPL and Cal Tech are organizing it, and they are very good at this. We are committed to recovering COSPAR’s reputation by having an assembly that is better than any in recent memory.

Does COSPAR seek out what might be called interesting venues?

We haven’t been in the US since 2002. We try to move it around. We have been in China. The purpose of the Assemblies is to facilitate dialogue between developed and developing space nations. We try to have assemblies in places to facilitate [developing space nations’] coming.

Pasadena obviously qualifies for that.

Who are the candidates for the 2020 Assembly?

Shanghai, China; Sydney, Australia; Lausanne, Switzerland; and Prague, Czech Republic. All have made bids and have been evaluated. I think we have a group that meets our criteria of being able to support the major space programs and has the organizational capability to do that. And we’re not going to have the overlay of potential terrorism. We hope to make a decision in November.

Peter B. de Selding was the Paris bureau chief for SpaceNews.