PARIS — The head of Russia’s Roscosmos space agency on March 31 rebutted claims from amateur satellite watchers that the Proton rocket’s upper stage came apart in orbit March 14 shortly after releasing the Euro-Russian ExoMars satellite.

Briefing reporters in Moscow, Igor A. Komarov reiterated statements made by Proton prime contractor Khrunichev Space Center of Moscow, saying the Breeze-M upper stage separated ExoMars without incident and then proceeded with the standard passivation and collision-avoidance maneuvers.

Komarov said he had seen photos taken from a Brazilian ground telescope that appeared to show small objects in the vicinity of the Breeze-M stage and ExoMars.

“I do have these pictures, provided by the Brazilian observatory, showing the ExoMars spacecraft surrounded by some dimly illuminated objects reportedly related to the upper stage,” Komarov said.

“Telemetry and other objectively verifiable data available to us, covering the entire time from the separation and the contamination and collision avoidance maneuvers to the passivation of the upper stage, show that all these steps have been performed successfully, without any anomalies,” Komarov said. “There is absolutely no indication of an upper-stage explosion or breakup.”

Komarov did not offer an alternative explanation for the suspected debris, but said all indications from the stage, and from the European Space Agency’s ExoMars satellite, are that nothing notable happened.

Reputable skywatchers have been at pains to explain what they saw without some high-energy occurrence on the Breeze-M, but they said they had no information that would contradict Khrunichev or Roscosmos. If the on-board energy sources were passivated, there remains the possibility of the Breeze-M being hit by an object, or that the Brazilian observatory’s visual data somehow gave an inaccurate impression of events.

One expert, saying he was speaking informally, said the photos from the Brazilian observatory seem at first glance to show “objects drifting with the rocket body.”

“But as I look more closely, I see a number of single pixels ‘moving’ along with it. These actually look suspiciously like hot pixels,” this official said, which could be a product of the observing instrument.

“They appear to move because the original images appear to have been taken with the upper stage fixed in the image – the camera was tracking the upper stage. … The result, while a logical attempt to show the booster moving through the stars, introduces a bias to the observer that these other ‘objects’ are actually moving through the stars, too, when in reality they could be artifacts of the camera system.”

The 22-nation ESA has said ExoMars was released on target by the Breeze-M vehicle and is functioning normally on its way to Mars orbit and that there are no indications of any on-board issues.

Initial reports from respected space watchers strongly suggested that an event occurred with the Breeze-M that resulted in the ejection of several observable pieces.

In response to these reports, Khrunichev initially released a statement saying it had successfully conducted all the safety procedures suggested by international guidelines to avoid debris proliferation.

It was not so much the debris issue but the performance of the Breeze-M that created concern. The stage is used to launch many types of missions, including commercial geostationary-orbit satellites whose launches are managed by International Launch Services (ILS) of Reston, Virginia.

The next commercial Proton launch is of an Intelsat satellite, scheduled for May. An Intelsat official said the company has been given no information suggesting a problem with Breeze-M.

The commercial launches are usually insured, meaning satellite owners have an obligation to report any anomalous behavior that was not factored into to the insurance policy.

Khrunichev, in its statement, said the Breeze-M propellant tanks and other sources of stored energy were “passivated,” meaning emptied of fuel or otherwise drained of power, with no anomalies during the procedures. Telemetry received post-passivation, Khrunichev said, likewise indicated no trouble.

“We do have precise information about the exact time when the first burn of the contamination and collision maneuver was performed; we also have the same information about the second burn – when it was executed, as well as the timing of the passivation operations,” Komarov said, according to a translation of his remarks provided by ILS.

“After that we recorded an end to telemetry operations as the upper stage operations were completed. We have accurate data about the distances between the upper stage and the spacecraft at the moment of all of these operations.”

In an indication of Roscosmos’s desire to put the issue to rest, Komarov went so far as to say that Khrunichev’s full report on the launch, signed by the company’s director-general, would be available for public inspection.

Komarov also said during the briefing that Roscosmos and ESA were continuing their assessment of whether the ExoMars 2018 mission, the second half of the ExoMars program, would in fact be ready for launch in 2018 or would need to await the next launch Earth-to-Mars launch window in 2020.

More than ExoMars 2016, the 2018 mission features a deep intermingling of European and Russian contributions. Government and industry officials have said that neither can launch without the other.