PARIS — SpaceX’s silence on the schedule delays of its Falcon 9 Upgrade rocket, whose inaugural flight on Dec. 21 was a success, is causing ripples of concern among commercial customers, which like NASA are counting on a high launch cadence in 2016 to meet these companies’ schedule milestones, industry officials said.

The next flight of the Falcon 9 Upgrade, also known as Falcon 9 v1.2, is ostensibly dedicated to the 5,300-kilogram SES-9 telecommunications satellite, headed to geostationary transfer orbit.

That mission, scheduled for September, has been repeatedly delayed as Hawthorne, California-based SpaceX made final checks on the new-version rocket, which provides 30 percent more power than the Falcon 9 v1.1 rocket it is replacing.

The new power will enable the rocket to carry sufficient fuel to take large telecommunications satellites to geostationary transfer orbit while retaining enough propellant to return the first stage for refurbishment and reuse – a key SpaceX goal to reduce launch costs.

Luxembourg-based SES and SpaceX in October agreed to allow SpaceX to first test the Falcon 9 Upgrade on a lighter-weight, low-orbit mission, carrying 11 machine-to-machine messaging satellites for Orbcomm Inc. of Rochelle Park, New Jersey.

The Dec. 21 mission went off smoothly, both in separating the Orbcomm satellites in the correct orbit and returning the first stage to a landing point near the launch pad at Cape Canaveral Air Force Station, Florida.

Importantly for commercial geostationary satellite owners, SpaceX said the mission also featured a full-duration re-ignition of the Falcon 9 rocket’s upper-stage engine to demonstrate the coast-and-restart function needed for the heavier telecommunications payloads.

After telling investors to expect SES-9 in October and then November, SES said it hoped for a late-December launch on the heels of the successful Orbcomm mission. That schedule came and went, and the company focused on January.

Industry officials are now openly speculating that the launch will not occur until March. The effect of another month’s delay might be minimal for SES – although the company’s 2016 revenue forecast includes substantial SES-9 revenue. But the knock-on effects on the rest of the SpaceX manifest for 2016 may be more important.

In response to SpaceNews inquiries, SES on Jan. 29 said it is awaiting word from SpaceX to determine when the SES-9 launch would occur. The company specifically declined to say whether March was a more likely launch at this point but said that the satellite, built by Boeing Space and Intelligence Systems of El Segundo, California, was in good health and was not blocking the launch.

Many companies are hoping for a 2016 launch from SpaceX. Some are more anxious than others. With each passing week without a launch, their announced schedules become less and less tenable.

Spacecom of Israel, in what industry officials characterized as a highly optimistic announcement, on Jan. 26 announced that its Amos-6 telecommunications satellite would be launched aboard the Falcon 9 in May.

Eutelsat of Paris and ABS of Bermuda are awaiting the launch of their two Boeing-built satellites, Eutelsat’s 117 West B and the ABS 3A satellites, together on a Falcon 9 Upgrade rocket. Both companies have said they expect a launch by March, although it is unclear whether one or two NASA space station cargo missions might immediately follow SES-9. That would make March less likely.

In addition to a heavy Falcon 9 Upgrade manifest for 2016, SpaceX is scheduled to introduce its Falcon Heavy – three Falcon 9 first stages tied together with a single second stage atop the middle lower stage.

SpaceX has said it would conduct a demonstration flight of Falcon Heavy before proceeding with any payloads. The second launch had been dedicated to the U.S. Air Force’s Space Test Program-2 (STP-2) satellite as the main payload.

Among the commercial customers on the Falcon Heavy manifest, ViaSat Inc. of Carlsbad, California, is perhaps the most financially exposed to any launch delay. The large ViaSat-2 Ka-band broadband satellite, once in service, will allow ViaSat to reopen broadband subscriptions to U.S. customers in regions where the current ViaSat-1 satellite’s beams are full.

ViaSat-2 also extends ViaSat’s Exeded broadband service to the North Atlantic air and maritime corridors. ViaSat has told investors to expect a 2016 launch.

On Jan. 30, SpaceX Chief Executive Elon Musk, in remarks at Texas A&M University on the SpaceX-backed competition to design future fast passenger ground transportation, said the Falcon Heavy “is supposed to launch toward the end of this year. I’d say maybe late September.”

SpaceX declined to respond to inquiries about the Falcon schedule.