A refurbished SpaceX’s Falcon 9 rocket sent two gravity-mapping satellites and five satellites for Iridium’s next-generation telecommunications network into orbit today on its second go-round.

The soot-smudged first-stage booster previously flew in January to launch Zuma — a secret national security satellite project that apparently went awry after ascent due to a problem with a payload adapter that was provided by Northrop Grumman, the satellite’s manufacturer.

No such problem arose with the booster, back then or today. The rocket rose from Vandenberg Air Force Base in California at 12:47 p.m. PT after a problem-free countdown.

SpaceX, which is transitioning to a new generation of its workhorse Falcon 9, made no plans to recover the first-stage booster after today’s launch. However, it sent a net-equipped ship out into the Pacific to try making a “catcher’s mitt” recovery of hardware from the rocket’s nose cone, or fairing.

Launch commentator John Insprucker said the recovery ship, nicknamed Mr. Steven, “came very close” to recovering fairing hardware, “but not quite.”

The payloads for this launch support government-funded science as well as privately funded commerce.

GRACE-FO: Tracking gravity and water

Two satellites for the Gravity Recovery and Climate Experiment Follow-On mission, or GRACE-FO, were deployed about 11 minutes after launch. The GRACE-FO is jointly supported by NASA and the German Research Center for Geosciences, and as the mission’s name suggests, it follows up on the 15-year GRACE mission to track gravitational shifts in Earth’s mass distribution.

Gravity readings from GRACE have shown how water is being transported around the globe, primarily due to changes in climate and weather patterns. Just last week, scientists took advantage of GRACE data to publish a study suggesting that wet regions in the high latitudes and the tropics are getting wetter, while dry regions in mid-latitudes are getting drier.

“The pattern of wet-getting-wetter, dry-getting-drier during the rest of the 21st century is predicted by the Intergovernmental Panel on Climate Change models, but we’ll need a much longer data set to be able to definitively say whether climate change is responsible for the emergence of any similar pattern in the GRACE data,” study co-author Jay Famiglietti of NASA’s Jet Propulsion Laboratory said in a news release.

The original GRACE mission ended last October. GRACE-FO is expected to take the handoff.

Iridium NEXT: The upgrade continues

A little more than an hour after launch, five satellites were added to the Iridium NEXT telecommunications constellation. SpaceX had already put 50 of the satellites into low Earth orbit for Iridium. Today’s deployment gets Iridium closer to its full strength of 66 operational satellites and nine on-orbit spares.

Iridium NEXT has been called one of the biggest tech upgrades in history. The $3 billion satellite constellation will replace Iridium’s existing network and open the way for enhanced data services.

Iridium’s Certus platform provides broadband access for specialized applications ranging from maritime emergency communications, to in-flight entertainment and high-speed internet access on airplanes, to high-quality satellite voice calls.

During a Kratos podcast interview, Iridium CEO Matt Desch said the Internet of Things is the fastest-growing application for satellite communications.

“A lot of people think of Iridium as a satellite phone, but in fact, more than half of our subscribers are really connecting devices to machines, to things, vehicles and whatnot,” he said. “It’s the perfect thing to do that.”