ULA rubs off Atlas 5 launch as SpaceX repairs rocket for GPS mission – Spaceflight Now

A United Launch Alliance Atlas 5 rocket lands on Pad 41 at Cape Canaveral Air Force Station on Tuesday, November 3. Credit: United Launch Alliance

The United Launch Alliance called for a planned launch of the Atlas 5 rocket at Cape Canaveral on Wednesday to fix the valve problem on the launch pad, while a SpaceX team to the south prepared Day Mail for a lift on Thursday evening. With GPS navigation satellite.

The ULA’s launch team canceled an attempt to launch the Atlas 5 at 6pm EST (2300 GMT) on Wednesday, before unsuccessful attempts to resolve the Valve issue, first remotely and then with a team of technicians launching the Atlas 5 offshore. Departed for launch pad.

The Atlas 5 rocket will line up a classified payload for the US government’s spy agency, the National Reconnaissance Office. The launch has been named NRL-1 101ated, and the NRO has not provided any clarification on the payroll mission, in addition to assisting the agency in gathering and disseminating information to government intelligence agencies.

The ULA did not launch the Atlas 5 countdown Wednesday morning, launched the rocket, and proceeded with testing of the guidance system and other checkouts before loading the cryogenic propellants into the launcher ahead of the planned lift at 5:54 a.m. EST (2254 GMT). Done.

However, the initial team stopped the countdown clock “after a sudden response from a remotely commanded ground system liquid oxygen valve,” the ULA said in a statement.

“The team continues to analyze the system and will defend our next start-up effort before November 6,” the ULA said.

The next opportunity to launch the Atlas 5 rocket will be on Friday, the ULA said. The exact time of Friday’s initial effort was not immediately announced, but the start time of the mission has been increased to four minutes per day. It will set Friday’s start time at around 5:46 pm EST (2246 GMT).

The launch of the Atlas 5 was originally scheduled for Tuesday, but the ULA has launched a rocket to replace the top-secret NRO payload at the top of the 206-foot-high (63) rocket to replace the duct-feeding environmental control system. Returned to their vertical hanger nearby. -M) vehicle.

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Ground crews returned the Atlas 5 to its launch pad late Tuesday in preparation for the initial effort on Wednesday.

Ahead of the launch of the next Atlas 5, SpaceX plans to launch a Falcon 9 rocket from nearby Pad 40 during the opening of a 15-minute window at 6:24 pm EST (2324 GMT) on Thursday.

The 229-foot-long (70-meter) Falcon 9 rocket landed on the 40 Wednesday pad in preparation for launch Thursday evening. Pad 40 is located about a mile (2.5 km) south of the Atlas 5 launch pad at Cape Canaveral.

A SpaceX Falcon 9 rocket lands on Pad 40 at Cape Canaveral Air Force Station on November 4. Credit: Stephen Clark / Spaceflight Now

The Falcon 9 rocket is designed to lift the GPS 3 SV04 navigation satellite for the US space force, filling the fleet of space and time stations used by billions of military and civilian users around the world.

SpaceX attempted to launch the GPS satellite on October 2, but an engine problem forced an automatic abortion just two seconds before the lift.

Engineers investigating the October 2 abortion found that the rocket had a tendency to set fire to the split-second before the first of the nine nine-stage engines expected. Investigations showed that an interruption in the gas generators of both engines was due to the pressure rising faster than the pressure created at the start valve, and the engines and sensors detected the problem and stopped the countdown.

SpaceX Engineer Identified a masking treatment Last month, two of Merlin’s engines were unknowingly overlooked.

“When we look at the statistics, we see that two engines tried to start early, and the auto abortion stopped it,” said Hans Konigsman, vice president of spaceX at Build and Flight Reliability. “And in doing so, it prevented a potentially difficult start that could damage the engine hardware.”

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Merlin strengthens with the help of an inert fluid called TEA-TEB – or triethylluminium-triethylboraine – which helps in the initial PF. Ignition provides a bright green flash in order.

“And then we have liquid oxygen, and we have kerosene, or RP-1,” Koenigsman told reporters last week. “And you need to present these fluids in the right order. If you do it in the wrong order, if you want to drop liquid oxygen and RP-1 and igniter fluids, then what will happen, we call it hard start. “

Konigsman said a strong start would “knock” the engine in most cases, but could cause damage. “So usually, you don’t want to. You want a good start. ”

SpaceX sent Merlin’s engines back to a test site in central Texas, where inspections revealed a substance that interfered with a line, causing a pressure relief valve in the gas generator on the two engines. Is.

Konigsman said the vent port, which means only one-sixth of an inch wide, was blocked by hard-cut masking wood. He said liquid lacquer – similar to red nail polish – is used by a third-party vendor who anodizes aluminum engine parts for SpaceX.

The locker protects some parts during the anodizing treatment process, but the vendor – who has not been identified by authorities – is expected to remove the material before sending the parts to SpaceX for engine construction.

The gas generator on each Merlin engine delivers a turbopump feeding kerosene and liquid oxygen propellants to the main combustion chamber.

Engineers at SpaceX’s McGregor test site showed that the engines performed normally after removing the obstruction from the vent valve. Koenigsman said the issue was “very subtle, but obviously there could be some adverse effects on engine operation.”

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“The GPS mission-mission mission will still use the same booster as the first launch attempt,” said the GPS 3-4 mission director at the Space Force’s Space and Missile Systems Center. “The two engines that boosted launch abortions have been replaced by inspection and verification reviews, with no surviving masking lacs replaced.”

SpaceX and Space Force officials confirmed all nine Marlin engines on the Falcon 9 rocket were ready to take off after a test-firing on a 40 Saturday pad.

In addition to rockets for GPS missions, engine issues have also affected vehicles for a couple of upcoming NASA openings. So far, the problem has only affected missions using the new Falcon 9 boosters.

The first operational flight of SpaceX’s Crew Dragon spacecraft is scheduled to begin on November 14 for a half-year journey to the International Space Station with three NASA astronauts and a Japanese mission expert for a lift from the Kennedy Space Center.

SpaceX is replacing the two Merlin engines on the Falcon 9 rocket for the Curl Dragon mission, which engineers found disturbed by the same initial tendency displayed by the engines on the rocket for the GPS mission. The problem delayed the launch of Crew Dragon from October 31st to November 14th.

NASA’s commercial crew program manager Steve Stitch said last week that the agency’s engineers wanted to analyze engine data from the GPS launch before clearing the crew dragon for a lift later this month.

The engine problem has also delayed the launch of the US-European Sentinel-6 Michael Freilich Oceanography Satellite from Vandenberg Air Force Base in California. That mission was originally scheduled to explode on November 10, but is now scheduled to launch on November 21.

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