SpaceX launches GPS navigation satellite from Cape Canaveral – Spaceflight Now


A Falcon 9 rocket flies into space with the US Space Force’s fourth third-generation GPS navigation satellite. Credit: SpaceX

SpaceX launched a Falcon 9 rocket on Thursday from Cape Canaveral with the US Space Force’s latest third-generation Global Positioning System navigation satellite, helping pave the way for the launch of SpaceX’s first Crew Dragon astronaut operational mission at the end of this month.

More than a month late after a Falcon 9 engine problem grounded the mission, the payload of the GPS navigation exploded in a clear autumn sky at 6:24:23 PM EST (2324:23 GMT) by Thursday.

After departing from Cape Canaveral Air Force Station pad 40 with 1.7 million pounds of thrust, the 229-foot (70-meter) Falcon 9 rocket headed northeast from Florida’s Space Coast on a runway parallel to the east coast of the United States.

The nine main engines of the Merlin 1D rocket shut down and the first stage separates for about two and a half minutes after the start of the flight.

While the single Merlin engine on the upper stage powered the GPS satellite into orbit, the Falcon 9’s reusable first stage repeater dropped to a timely landing on the SpaceX football field-sized drone ship floating in the Atlantic Ocean at approximately 400 miles (630 kilometers) downstream from Cape Canaveral.

The second stage of the Falcon 9 ignited twice to maneuver the US Space Force’s fourth third-generation GPS satellite – designated GPS 3 SV04 – into an egg-shaped transfer orbit with an altitude of approximately 250 miles ( 400 kilometers) and 12,550 miles (20,200 kilometers). ), with an inclination of 55 degrees relative to the equator, according to the tracking data available to the public.

These figures confirm that the Falcon 9 rocket hit its marks before deploying the Lockheed Martin-built GPS 3 SV04 satellite nearly 90 minutes after takeoff, concluding SpaceX’s 20th mission of the year.

Lockheed Martin confirmed in a statement that ground crews at the company’s satellite control center near Denver have made contact with the nearly five-ton GPS spacecraft, which will run its liquid apogee engine more in the coming days. times to reach a circular orbit. 12,550 miles above the Earth.

Ground controllers will send commands to the GPS satellite to deploy its solar panels and energy-generating antennas, perform the checks, then deliver the spacecraft to the Army’s Space Operations Command.

A Falcon 9 rocket takes off Thursday from Pad 40 at Cape Canaveral Air Force Station. Credit: Stephen Clark / Spaceflight Now

The GPS 3 SV04 satellite will join 31 operational spacecraft in the GPS fleet providing positioning, navigation and timing data to billions of military and civilian users around the world, providing information to cell phones, cars, airplanes and ships.

The new satellite will complete its checkout and test program in about a month, and authorities expect the GPS 3 SV04 to be ready for operational use in a few months, according to the Space Force.

“The GPS 3 program continues to make great strides in modernizing the GPS constellation for the US Space Force, while maintaining the gold standard for location, navigation and timing,” said Colonel Edward Byrne, head of the Medium Earth Orbit Space Systems division. of Space Force’s Space and Missile Systems Center.

The GPS 3 Series satellites are designed for 15-year lifetimes, an improvement over the seven-and-a-half-year and 12-year design lives of previous generation GPS satellites.

“The GPS 3 satellites represent a major step forward in terms of both capacity and resilience over previous GPS satellites,” said Byrne. “GPS is a key element for the US military and its allies and provides worldwide services to more than 4 billion civilian users around the world.”

The first of 10 GPS 3 series satellites launched in December 2018, followed by two more GPS 3 satellites in August 2019 and June 30 this year. According to Lockheed Martin, GPS 3 satellites provide three times the accuracy and up to eight times better anti-jamming capabilities than early GPS spacecraft.

The GPS 3 satellites also introduce a new civil L-band signal compatible with other international navigation satellite networks, such as the European Galileo program. Combining signals from GPS, Galileo, and other navigation satellites can improve the accuracy of position measurements in space.

Artistic concept of a GPS 3 satellite in space. Credit: Lockheed Martin

In September, Space Force officials announced they had reached an agreement with SpaceX to launch future GPS 3 satellites on previously piloted Falcon 9 booster rockets. The first booster flown in Thursday night’s mission will be refurbished and used again for the launch of the next GPS 3 satellite in mid-2021, officials said.

Space Force’s Space and Missile Systems Center, or SMC, signed an updated contract with SpaceX in September to cover the deal to fly the next two GPS satellites on reused Falcon 9 repeaters. A reused Falcon 9 first stage will also launch the GPS 3 SV06 mission, which will likely fly in late 2021 or early 2022.

Restructured contracts between Space Force and SpaceX allowed the Falcon 9’s first booster stage to land after the previous GPS satellite launch on June 30. SpaceX also launched the first Series 3 GPS satellite in December 2018, but military officials required the launch company to reserve all of the Falcon 9’s propellant for launching that spacecraft, leaving no residual fuel for descent and landing. .

Space Force loosened their requirements for SpaceX’s upcoming launch with a GPS satellite earlier this year by adjusting the perigee, or lower point, of the target orbit for deploying the GPS payload at an altitude. inferior. This ensured that the Falcon 9 rocket could land the booster on the June 30 mission, saving the Space Force several million dollars.

Taking into account the changes to allow booster recovery on four GPS missions starting June 30th launch, and then reuse of the rocket on two GPS missions starting next year, the updated launch contracts between Space Force and SpaceX have resulted in at savings of $ 52.7 million, officials said.

Next year’s GPS 3 SV05 mission will be the first high-priority homeland security payload to be launched on a Falcon 9 rocket with a previously piloted booster stage. Space Force officials will thoroughly review SpaceX’s rocket refurbishment and reuse procedures and policies before releasing the GPS 3 SV05 satellite for launch aboard a recycled booster next year.

This will help lay the groundwork for the launch of more national security satellites on Falcon rockets with reused first-stage boosters.

“This is our journey to understand how SpaceX performs the refurbishment of previously used hardware,” said Walt Lauderdale, head of SMC’s Falcon Systems and Operations division and mission director for the countdown and launch of GPS 3 SV04. : We would then compare it with qualification. It is learning and then evaluating all the work they do to prepare these boosters to fly again.

“So that requires reviewing a number of different systems and making sure we are good across the board with the previously used hardware, not just this particular booster,” Lauderdale said in a conference call with reporters in September.

With the GPS 3 SV04 satellite safely in orbit, SpaceX’s next mission is the launch of the first regular Crew Dragon astronaut flight to the International Space Station, scheduled to take off November 14 from NASA’s Kennedy Space Center Pad 39A in Florida.

NASA engineers will analyze data from Thursday night’s GPS launch to ensure the Merlin engines are ready to go on the Falcon 9 rocket assigned to the Crew Dragon launch.

SpaceX first tried to launch the GPS 3 SV04 satellite on October 2, but an engine problem forced the automatic shutdown just two seconds before takeoff.

Engineers investigating the October 2 outage found that two of the rocket’s nine first stage engines had a tendency to fire a split second earlier than expected. Inspections showed that a stuck relief valve in the gas generators of the two engines caused the pressure to rise earlier than expected at startup, and the sensors on the engines detected the problem and stopped the countdown.

SpaceX engineers have identified a masking treatment left inadvertently in two Merlin engines as the cause of the interrupted countdown last month. Inspections revealed the substance blocking a line leading to a pressure relief valve in the gas generator on two of the engines originally intended for the GPS mission.

Hans Koenigsmann, SpaceX’s vice president of construction and flight reliability, said the vent port, which means only one-sixteenth of an inch wide, was clogged with a hardened protective paint. He said liquid lacquer – similar to red enamel – is used by a third-party vendor that anodizes aluminum engine components for SpaceX.

The lacquer protects some parts during the anodizing treatment process, but the vendor – which officials have not identified – should remove the material before shipping the components to SpaceX for engine production.

The gas generator on each Merlin engine drives a turbopump that feeds kerosene propellants and liquid oxygen into the main combustion chamber.

SpaceX replaced the two suspicious engines on the Falcon 9 first stage for the GPS 3 SV04 mission, then performed a test launch of the rocket on Saturday at Pad 40 at Cape Canaveral Air Force Station. This gave officials enough confidence to proceed with the GPS launch countdown on Thursday.

A review of the Merlin engines in SpaceX’s rocket fleet found that two of the Falcon 9 rocket engines for the Crew Dragon flight showed similar initial signatures to the launcher’s engines for the GPS mission.

SpaceX said last week that it would replace those two engines on the Falcon 9 launcher for the Crew Dragon mission. The engine problem delayed the launch of Crew Dragon from October 31st to November 14th.

Steve Stich, NASA’s commercial crew program manager, said last week that the agency’s engineers wanted to review engine data from the GPS launch before releasing the Crew Dragon for takeoff later this month.

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Follow Stephen Clark on Twitter: @ StephenClark1.

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