PARIS — Europe’s Arianespace launch-service provider — the only one of the three principal commercial launch operators not grounded by rocket problems — might be able to add a supplemental heavy-lift Ariane 5 vehicle to its 2017 manifest if market conditions demand it, Arianespace Chief Executive Stephane Israel said Sept. 8.

In an interview, Israel said the Evry, France-based company would finish this year with a seventh Ariane 5 campaign, not eight as originally planned. The company’s 2016 Ariane 5 manifest was upset by the non-availability of Japan’s DSN-1/Superbird-8 satellite, which was damaged en route to the launch site.

Israel said the company would be able to catch up on its backlog by early 2017 and was already planning seven Ariane 5 campaigns for the year. Earlier plans were to launch six Ariane 5 rockets in 2017.

“We are now looking to see whether we can add an eighth launch in the event an upper-berth passenger is available given the evolution of the market,” Israel said.

By “market evolution” Israel was referring to the Sept. 1 failure of competitor SpaceX’s Falcon 9 rocket during a static firing, and to the fact that Russia’s Proton rocket will be grounded until at least mid-November following a June anomaly.

The June event did not result in a mission failure, but was judged serious enough by Proton manufacturer Khrunichev Space Center of Moscow to suspend launches since then.

Ariane 6: Expendable and not ashamed of it

In a Sept. 7 interview with France Info radio, Israel reiterated his confidence in what he portrayed as Arianespace’s more plodding, deliberative — and higher-cost — approach to launches when compared to SpaceX.

Arianespace does not want a reusable rocket for the moment, he said, because it’s not certain that reusability can reduce costs and maintain reliability. The Ariane 6 rocket, to operate starting in 2020, will not be reusable. The company also is wary of the Silicon Valley ethos that champions constant iteration, which he said has been a feature of Hawthorne, California-based SpaceX as well.

“We think that the more a launch resembles the preceding launch, the better we are for our customers because we remain in the ‘explored domain’ where everything is understood,” Israel said.

Unlike its two principal competitors, Arianespace’s Ariane 5 business model depends mainly on pairing lighter and heavier satellites for its launches.

The Evry, France-based company struggles in periods when the commercial market favors one or the other satellite model. For now, the stand-down of Falcon 9 and Proton could cause owners of heavier satellites to seek a slot on Ariane 5’s upper berth.

The rocket’s lower berth is reserved for the higher of the two spacecraft.

Building heavy-lift rockets is not like building automobiles. A manufacturer cannot react quickly to market opportunities created by a competitor’s failure.

Soyuz option for small telecom satellites

For very light telecommunications satellites, Arianespace has a second option, which it has not used so far, in the Europeanized Russian Soyuz rocket. Operating from Europe’s equatorial Guiana Space Center on the northeast coast of South America, the Europeanized Soyuz can carry a satellite weighing around 3,300 kilograms, and perhaps a bit more, into geostationary-transfer orbit.

Israel stressed that whatever fresh capacity the company made available in 2017 would not provoke launch delays for customers that have already booked with Arianespace.

In his largely diplomatic remarks on SpaceX’s failure — “failures? Everyone has had them, including us,” he said — Israel sought to distinguish Arianespace from SpaceX’s corporate culture from that of Arianespace and its industrial contractors.

“It is very difficult to do innovate with each launch, increase launch cadence and avoid failure all at the same time,” Israel said.

Falcon 9 Full Thrust is a new vehicle; Ariane 5 was once, too

It is not clear how much near-term tinkering SpaceX plans for the current Falcon 9 Full Thrust vehicle, which has made only eight flights, all successful, since it was introduced in December 2015. Its first flight to geostationary transfer orbit was in March.

The June 2015 Falcon 9 failure was of the vehicle’s earlier version, since discontinued. The Sept. 1 failure, which destroyed the $200 million Amos-6 satellite owned by Spacecomm of Israel, was not during a launch but during a prelaunch test firing.

It is not yet clear whether that failure was due to ground support equipment, or the rocket, or some combination of the two. If the investigation points to a rocket issue, the Falcon 9 could be grounded for several months. It took nearly six months after the June 2015 failure for SpaceX to resume flights.

The Ariane 5 rocket was introduced in 1996 and suffered a spectacular low-altitude failure on its inaugural flight. A partial failure occurred in 1997, and still another in 2001 before a full failure in 2002. Since then the rocket has racked up 73 consecutive successes.

Looking back, European government and industry launch officials agree that it took nearly six years for them to fully stabilize the Ariane 5 launch system.