SpaceX scrubs Sunday launch try with Intelsat send satellite

A computer-triggered cancel halted a countdown of a Falcon 9 rocket Sunday during NASA’s Kennedy Space Center in Florida, pulling behind a subsequent goal in SpaceX’s launch swell until during slightest Monday.

The 229-foot-tall Falcon 9 rocket was counting down to liftoff with an Intelsat communications satellite during 7:36 p.m. EDT (2336 GMT) Monday, and an iffy afternoon continue foresee gave approach to transparent skies as clocks ticked toward launch.

An involuntary sequencer sent commands to bucket a two-stage rocket with super-chilled RP-1 kerosene and glass oxygen propellants, and a Falcon 9’s engines were prepared for ignition and a fuel tanks pressurized for launch during a final mins of Sunday’s countdown.

But clocks stopped during T-minus 9 seconds after a mechanism overseeing preset criteria in a rocket’s guidance, navigation and control complement systematic an involuntary abort. SpaceX’s launch executive scrubbed Sunday’s launch try a few mins after as engineers investigated a problem.

“We had a car cancel criteria disregarded during T-minus 10 seconds, a GNC (guidance, navigation and control) criteria,” a launch executive said. “We’re still looking into what that is during this time.

“We’re not going to be means to get a recycle in currently though going past a finish of a window, so we’re strictly scrubbed,” he said. “Go forward and put a 24-hour recycle into work.”

SpaceX began removal a Falcon 9’s diesel tanks during launch pad 39A shortly after a scrub.

If SpaceX’s launch group can know a problem, and scold it if necessary, a Falcon 9 rocket could be fueled again Monday for a 58-minute launch window that opens during 7:37 p.m. EDT (2337 GMT).

The launch of a Intelsat 35e communications satellite is a third in a array of Falcon 9 flights over a final dual weeks. If a rocket bloody off Sunday, it would have been a third Falcon 9 launch in a small over 9 days, and a second from a same launch pad in Florida.

The hectic gait of activity during SpaceX’s Cape Canaveral comforts seeks to mangle a record for a fastest turnaround between launches during pad 39A. SpaceX and Intelsat are fervent to get a rocket off a belligerent before a U.S. Air Force’s Eastern Range becomes taken to support a launch after a Jul 4 holiday.

The Falcon 9 rocket reserved to Intelsat 35e’s goal conducted a immobile glow exam Thursday dusk during pad 39A, reduction than 72 hours before a opening of Sunday’s launch window. Ground crews rolled behind a Falcon 9 to a hangar Friday afternoon and trustworthy a Intelsat 35e satellite to a rocket in time to lapse to a pad in a predawn hours Sunday.

“We had to supplement additional resources to try to spin around a campaigns in such a brief time,” pronounced Ken Lee, Intelsat’s comparison clamp boss of space systems, in an talk Sunday during Cape Canaveral. “More manpower — a lot of vigour — though as common a group is mission-oriented, so when they see a aim they’re going to do a best they can do accommodate that date.

“They’ve been operative roughly around-the-clock, and we brought in additional engineers to make certain that we did a work that we indispensable to do though any shortcuts.”

Credit: Stephen Clark/Spaceflight Now

The 14,905-pound (6,761-kilogram) Intelsat 35e communications satellite, built by Boeing, is a heaviest booster ever launched by SpaceX toward a roost in geostationary orbit, a round loop some-more than 22,000 miles (nearly 36,000 kilometers) above Earth’s equator ordinarily used by promote and information send stations.

At that altitude, orbital mechanics need a satellite to fly around Earth during a same speed it rotates, permitting a booster to float over a bound geographic location, an ideal conditions for communications applications.

The complicated weight of Intelsat 35e effectively “maxes out” a Falcon 9’s capability to lift a cargo going to that form of orbit, Lee said.

SpaceX has budgeted all of a Falcon 9’s kerosene and glass oxygen diesel to send Intelsat 35e into as high of an circuit as possible. That means a initial theatre will not lapse to land on a boat during sea, and a top stage’s singular Merlin engine is automatic to glow as prolonged as it can, instead of aiming for a specific fixed altitude.

The goal is designed to leave as small leftover diesel as probable in a second stage, called a “minimum residual shutdown.”

“There is a smallest orbital aim that we are sharpened for, and if there is additional fuel on a rocket, afterwards we’re going to continue to bake until we exhaust all a fuel,” Lee said.

Lee pronounced there is a operation of probable orbits a Falcon 9 could muster Intelsat 35e into, though a smallest approaching rise altitude, or apogee, when a satellite separates from a top theatre is 19,405 miles (31,230 kilometers), according to Lee.

The low point, or perigee, of a send circuit is approaching to be around 155 miles (250 kilometers), and Intelsat 35e’s trail around Earth will be slanted 26 degrees to a equator.

If a launcher releases a Intelsat 35e satellite in that orbit, a booster will still have adequate on-board diesel for a designed 15-year operational life. Intelsat and Boeing concluded to bucket some-more fuel into a booster to make adult for a probable altitude shortfall.

“Everything else will be gravy in terms of a use life,” Lee said, referring to a advantage of going into a aloft initial orbit.

When it blasts off, a Falcon 9 could broach additional opening for Intelsat 35e, and a probable operation of a satellite’s initial round altitude runs above 22,000 miles, a regime called “supersynchronous” send orbit, Lee said.

The aloft a orbit, a improved for a satellite in terms of goal lifetime since Intelsat 35e will have to bake reduction of a possess fuel to scheme into a final position.

“The operation we are anticipating for tonight, we have a smallest number, and we have a limit number, that would be a somewhat supersynchronous (transfer) orbit,” Lee said.

“We are maxing out (the Falcon 9) and over since we are doing a MRS (Minimum Residual Shutdown) mission, and we are not recuperating this rocket.”

Intelsat 35e’s possess engine will glow mixed times in weeks after launch to circularize a satellite’s circuit a geostationary altitude. Lee pronounced a booster should ever use in a second half of August, lucent signals opposite a Americas, a Caribbean, Latin America, Europe and Africa for wireless network providers and radio broadcasters.

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