WASHINGTON — When the Falcon 9 first stage used to loft six Orbcomm satellites made a soft landing in the Atlantic Ocean after launch July 14, Space Exploration Technologies Corp. was not the only one watching.

NASA too had eyes on the falling booster, hoping to snap some infrared images of its engines relighting as the rocket stage screamed back to Earth at supersonic speeds. Reconnaissance like that, the agency maintains, could provide valuable insight into the propulsive landing of massive payloads — something essential for putting humans on Mars one day.

SpaceX got the footage it was looking for. The company released an 80-second video July 22, taken from one of Falcon 9’s onboard cameras, that shows the rocket’s liquid-fueled first stage executing the second of two planned engine burns, then extending its landing legs for a simulated landing at sea.

NASA, which was watching Falcon 9’s landing spot in the Atlantic from a Martin WB-57 twin-jet airplane, was not as lucky.

The crew aboard the NASA-operated aircraft, circling about 15 kilometers above the expected splash zone, caught sight of the Falcon 9 as it ascended, and of the first stage as it plummeted toward the ocean, but was unable to get a good shot of the descending stage’s first engine burn.

The WB-57 crew had the plane’s midwave infrared imager trained on the falling stage, but was “unable to obtain the external thermal imagery of the rocket engines relighting,” according to NASA spokesman David Steitz.

Steitz compared imaging a falling rocket stage with “trying to find something while looking through a soda straw,” and added that clouds in the area further complicated the effort.

It is the second time NASA has tried, and failed, to snap a shot of a descending SpaceX rocket stage.

The first time, the agency’s plan was spoiled when a plane set to observe the booster’s ocean landing after an April 18 cargo launch to the international space station was not able to get off the ground due to icy conditions at the runway near NASA’s Langley Research Center in Hampton, Virginia.

NASA’s next chance to record Falcon 9’s engine relighting will be during the company’s next NASA-sponsored cargo resupply mission to the international space station, currently scheduled to lift of Sept. 12 from Cape Canaveral Air Force Station in Florida.

SpaceX has two missions on the slate before September, but both are flying to geostationary transfer orbit for Hong Kong-based telecommunications satellite fleet operator AsiaSat and will require all the fuel Falcon 9 can carry, the company said in a July 22 note on its website. That means no booster-flyback attempt until the next ISS resupply mission.

That attempt, which SpaceX says has only a “low probability of success,” will be Falcon 9’s final attempted water-landing before SpaceX tries later this year to land the booster on a solid surface — either terra firma or a floating platform, SpaceX said in the July 22 note.

SpaceX says the July 14 test confirmed that Falcon 9’s liquid-oxygen and -kerosene-fueled booster “is able consistently to reenter from space at hypersonic velocity, restart main engines twice, deploy landing legs and touch down at near zero velocity.” The test marked the second time SpaceX has guided the Falcon 9’s first-stage booster to a near-zero-velocity splashdown with landing legs deployed.