Cygnus Mission Control Fire Alarm Clears NG-18 Launch for 24 Hours

Northrop Grumman was preparing to launch the penultimate Antares 230+ rocket from Wallops Island, Va., for the NG-18 mission to the International Space Station (ISS) at 5:50 a.m. EST (10:50 a.m. UTC). Sunday, November 1. 6; however, a fire alarm in the Cygnus Mission Control Center initially pushed the launch to 5:55 a.m. EST, the end of the window, before finally scrubbing the launch for the day.

Teams have prepared for a 24-hour refresher and will attempt to launch NG-18 again in a 5-minute window that opens at 5:27 a.m. EST (10:27 UTC) on Monday, November 7.

Antares will carry an Enhanced Cygnus spacecraft, named the SS Sally Ridein orbit for an Expedition 68 crew resupply mission. Cygnus will bring crew supplies, new science experiments and other payloads, including a new Nanoracks module, to the station before serving disposal device at the end of its mission for soiled clothing, used experiments, general work and living waste.

Overall, according to Northrop Grumman in an interview with NASASpaceflight, “It’s going to be a pretty standard mission. There’s a full science complement,” said Steve Krein, vice president of civil and commercial space for Northrop Grumman.

Behind that, however, is an increase in the payload that Northrop Grumman was able to carry on this mission.

“So we were able to refine our propulsion modeling, both on the first and second stage, and remove some of the conservatism from our models,” said Kurt Eberly, director of space launch programs at Northrop Grumman. “We offered an additional 70 kilograms, so we launched 8,050 kilograms on NG-12 through 17. And so for NG-18 and 19, we increased that to 8,120 kilograms.”

This total mass includes the wet mass of Cygnus after it is loaded with its thrusters necessary for maneuvering in orbit.

NG-18 will be the first of eight additional cargo flights that have been ordered by NASA from Northrop Grumman to extend Cygnus’ pre-existing Commercial Resupply Services 2 (CRS2) contract. In total, NASA ordered two more flights in 2020, including NG-18 and NG-19, followed by six more in March 2022.

The Cygnus spacecraft for this mission is named after astronaut Sally Ride, who was the first American woman in space. Ride flew on two Space Shuttle missions aboard the Challenger: STS-7 and STS-41G. Ride was also a member of the Rogers commission after the Challenger disaster in 1986.

Ride died in 2012 from pancreatic cancer.

“There’s actually a flag that we fly, an American flag signed by the students and staff of Sally Ride Elementary School in Los Angeles, California. So we’re extremely proud to be able to do this, to honor his legacy,” Krein said.

Launch the campaign

The first stage of the Antares rocket was designed and built in Ukraine. The stage was designed by KB Yuzhnoye and is derived from the now retired Zenit rocket. The stage was later built by Yuzhmash in Dnipro, Ukraine.

The NG-18 mission patch. (Credit: Northrop Grumman)

The launcher uses two Energomash RD-181 engines which were built in Russia. The engines each run on RP-1 kerosene and liquid oxygen (LOX) and have independent thrust vectoring.

The RD-181 engines replaced the Aerojet Rocketdyne AJ-26 engines, which were retrofitted versions of the Soviet NK-33 engines built by Kuznetsov’s design bureau. AJ-26 engines were used on the first four Antares flights.

The RD-181 engines and the Antares first stage were delivered to Northrop Grumman in Wallops in the fourth quarter of 2021. The NG-18 and -19 mission hardware was unaffected by the Russian invasion of Ukraine .

The Cygnus spacecraft itself is made up of two segments: the service module, which includes the propulsion and the two solar panels, and the pressurized cargo module. The pressurized cargo module was built by Thales Alenia Space in Italy, while the service module was built by Northrop Grumman.

After Cygnus arrived at Wallops, the two segments were mated together, creating the spacecraft as a whole. After that, the spacecraft was transported to another facility on Wallops Island where it was loaded with hydrazine and nitrogen tetroxide propellants. It was then reverted to the Horizontal Integration Facility (HIF).

The spacecraft was then brought into a horizontal position, allowing personnel to carry out an initial load of cargo. Cygnus was later incorporated into the Castor 30XL second stage. This was followed by another cargo before the fairing encapsulation.

The Antares 230+ rocket exits HIF for the 1.7 km journey to Pad-0A on November 2. (Credit: NASA)

On November 2, the Antares 230+ rocket deployed from HIF and was flown 1.7 km (1.1 miles) south to Pad-0A. Once on the launch pad, the vehicle rolled down the ramp and was integrated into the launch pad.

“We take that [Antares] up the ramp to the launch pad, we connect the tail to hydraulic pistons that are buried in a pit on the ramp, and then we push vertically,” Eberly said.

The following day, the teams conducted a combined systems test, which verifies the interfaces between the vehicle, the launch pad and the NASA range.

Later in the day, Antares was lowered to a horizontal position and a mobile clean room was then moved above the nose of the rocket, allowing teams to perform late loading operations 24 hours before launch. .

“We have this unique feature that we’ve developed, which we call the ‘pop-top’ fairing, where we can remove the nose cone from the fairing. And that exposes the Cygnus hatch through the fairing opening. And then we set up work platforms on the surface of the fairing and then we can crawl the Cygnus cargo operators,” Eberly said.

Once the late loading is complete, the “pop-top” fairing is reinstalled and the vehicle is brought upright for launch.

The countdown to the Nov. 6 launch began at 05:50 UTC or 1:50 a.m. EDT – 10 minutes before the local time change in Wallops to Eastern Standard Time (EST), which reset the local clock at 1:00 a.m. EST and therefore gave the launch team the full five hours needed for the Antares countdown.

The countdown to the November 7 launch will begin at 00:27 EST (05:27 UTC).

Journey to the ISS

At T0, the Antares rocket will take off from Pad-0A. The first stage RD-181 engines will burn for about two and a half minutes.

Cygnus is captured by Canadarm2 during the NG-17 mission in February 2022. (Credit: NASA)

Following this, the single Castor 30XL will ignite and burn for several minutes. The second stage is a solid rocket motor developed by Northrop Grumman. After burnout, the Cygnus spacecraft will separate into low Earth orbit, which will occur approximately nine minutes after launch.

“After separation, we do a few maneuvers with the upper stage just to make sure there’s no recontact between us and Cygnus using our attitude control system,” Eberly said. “So we’re kind of doing a crab-walking maneuver to back up to make sure there’s a good separation between us and Cygnus.”

After separation, Cygnus will begin to perform periodic burns to enable it to make a timely rendezvous with the ISS. The two solar panels will begin to deploy approximately two hours after launch.

Cygnus is expected to arrive at the ISS two days after launch. NASA astronaut Nicole Mann will capture the spacecraft with Canadarm2 and then dock it at one of the Station’s US segment ports.

The spacecraft is expected to remain at the ISS until January 2023.

Development Antares 330

After the launch of NG-18, the final launch of the Antares 230+ will take place in the spring of 2023 with the NG-19 mission. This comes as Northrop Grumman responds to the Russian invasion of Ukraine by developing a new version of Antares with Firefly Aerospace.

After NG-19, three Cygnus missions, NG-20, -21 and -22, will launch on SpaceX’s Falcon 9 rocket during the interim period when Firefly and Northrop Grumman continue to develop the Antares 330.

“We want to resume these CRS missions as soon as possible. So the first increment is only the first stage which is just hard enough of course, but the Antares 330 is going to have the first stage supplied by Firefly, mated to the existing top stack. And so we think that just minimizes the range of Firefly, and it minimizes the development to allow us to resume CRS missions out of Virginia,” Eberly said.

A render of the Antares 330. (Credit: Northrop Grumman)

The Antares 330 will consist of the same Castor 30XL upper stage that is currently used on Antares, but the first stage will be developed by Firefly Aerospace and will be similar to their Medium Launch Vehicle (MLV) rocket that is also in development. The first stage will be powered by seven Miranda engines.

“We are working very hard with Firefly on the development of this first stage which will form the basis of the Antares 330. And the employees we have here at Wallops, we intend to keep all of them. So we’re putting them to work helping us grow this next stage and our employees in Dulles, VA, and Chandler, Arizona,” Eberly said.

In addition, modifications will have to be made to the existing infrastructure on Wallops Island.

“We need to adjust the ground support equipment inside the HIF, we need to expand the carrier mount launcher, and then we’re also working with Virginia Space to figure out what pad modifications we’re going to need. for this new rocket configuration,” Eberly said.

“It’s going to have a lot more thrust, maybe have a little bit larger diameter, it’s going to be longer. So all of those things are going to conspire to require us to add launchpad capability. And so that’s also in preparation for.

The Antares 330 will also facilitate new modifications to upgrade the Cygnus spacecraft.

“On the Cygnus side, we have won the contract for the next six missions. And one of those add-ons is what we call a mission configuration B, which actually has an extra ring if you will, at the pressure containment module. Mission B configuration in the future will allow us to fly 5,000 kilograms of [cargo] mass,” Krein said.

Along with the Antares 330, Northrop Grumman and Firefly Aerospace are developing a new launch vehicle that will be built entirely in the country and will be available for NASA, commercial and national security markets.

“We will then take that same first stage for the Antares 330, and then we will develop with Firefly a new liquid second stage with a larger fairing,” Eberly said.

“We’re calling it the mid-launch, and we’re going to go through an internal naming contest with our people here…both us and Firefly. We’ll see who wins. But this capability that we’re targeting to debut at the end of 2025. We think it will be a really strong contender.

(Main image: The Antares 230+ spacecraft arrives at Pad-0A on November 2. Credit: NASA)

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