Live coverage: SpaceX to launch Northrop Grumman Cygnus spacecraft to the International Space Station on Falcon 9 rocket

On Tuesday, July 30, 2024, the Northrop Grumman Cygnus resupply spacecraft is seen being encapsulated inside the SpaceX Falcon 9 payload fairing as it prepares to launch from Space Launch Complex 40 at Cape Canaveral Space Force Station in Florida for the 21st Northrop Grumman commercial resupply services for NASA. The mission will carry 8,200 pounds of science investigations, supplies, and equipment to the International Space Station. Liftoff is scheduled for no earlier than 11:29 a.m. EDT Saturday, Aug. 3. Image: SpaceX

More than 8,200 pounds of science and cargo supplies are preparing to launch to the International Space Station. A Northrop Grumman-built Cygnus spacecraft will begin a roughly two-day journey to the orbiting outpost following its launch atop a SpaceX Falcon 9 rocket.

Liftoff of the NG-21 mission from Space Launch Complex 40 (SLC-40) is set for Saturday, Aug. 3, at 11:29 a.m. EDT (1529 UTC). Spaceflight Now will have live coverage of the launch beginning about 1.5 hours prior to liftoff.

The mission marks the second of three planned launches of a Cygnus on a Falcon 9 rocket while Northrop Grumman and Firefly Aerospace work to build the Antares 330 rocket, which is targeting its first launch in 2025.

NG-21 is set to liftoff from Cape Canaveral Space Force Station as a tropical wave is barreling towards the Sunshine State. Ahead of the launch, the 45th Weather Squadron forecast a 50 percent chance of favorable weather conditions at liftoff on Saturday.

“We are not within the cone of the center. However, tropical cyclone impacts do extend far and away from the center,” said Melody Lovin, a launch weather officer with the 45th Weather Squadron, during a prelaunch teleconference. “So, because of that, Sunday looks like incredibly tricky weather for us, if we do need to utilize that backup launch window.”

As of 5 p.m. EDT (2100 UTC) on Friday, the National Hurricane Center was tracking Tropical Cyclone Four to reach the Florida Keys around 2 p.m. EDT (1800 UTC) on Saturday. By about 10:50 p.m. EDT (0250 UTC) Friday night, the NHC issued its third advisory, stating that the storm was classified as Tropical Depression Four and anticipated it becoming a tropical storm by late Saturday.

If the NG-21 launch were unable to launch on Saturday, conditions at the Cape deteriorate to just a 10 percent chance of weather that would be good enough to launch.

“We’re expecting a steady 25 to 30 miles per hour out of the southeast on Sunday morning,” Lovin said. “Sunday looks pretty tricky, so my team will do their best to find the hole in the clouds tomorrow and get that launch off on time.”

The SpaceX Falcon 9 rocket supporting this mission, B1080 in the SpaceX fleet, will be launching for a 10th time. It previously launched the Ax-2 and Ax-3 private astronaut missions for Axiom Space; the European Space Agency’s Euclid observatory; and a Cargo Dragon spacecraft on SpaceX’s Commercial Resupply Services-30 (CRS-30) mission.

Falcon 9 rolled out to pad 40 in Florida earlier today pic.twitter.com/w4AVFaTwns

— SpaceX (@SpaceX) August 2, 2024

Friday afternoon, the SpaceX and Northrop Grumman teams completed the late loading of some of the more time-sensitive items into the spacecraft.

“This is a complex, integrated operation where we’ve rolled out a mobile cleanroom and attached it to the underside of the fairing and allowed access for cargo to be lifted up into the fairing and loaded directly into the Cygnus spacecraft,” said Jared Metter, the director of Flight Reliability for SpaceX.

“We’re leveraging the same operations that we used on the Cygnus flight conducted by SpaceX earlier this year, so the team is highly confident in conducting these complex, integrated operations.”

Following launch, Cygnus will reach the ISS on Monday, Aug. 5, and will be captured and berthed using the Canadarm around 3:55 a.m. EDT (0755 UTC). Once docked, it will remain at the space station until January, at which point it will burn up in the Earth’s atmosphere.

Fire simulations, 3D-printed liver, CubeSats and more

Onboard the Cygnus spacecraft are more than 800 kg (1,763 lbs.) of science experiments, which feature a variety of studies. Several of those are being sponsored by the ISS National Laboratory and the U.S. National Science Foundation.

One of those is an experiment that will study the spread of flames to better understand the complex workings behind wildfires. That research is being led by James Urban, an assistant professor within the Fire Protection Engineering Department at Worcester Polytechnic Institute’s (WPI).

Urban did his Ph.D. thesis on how wildfires are started by hot metal particles, like those within power lines, as seen in several large fires in California in recent years. He’s also been impacted indirectly by wildfires, like when his classes at WPI in Massachusetts were cancelled due to smoke drifting south from wildfires in Canada.

“I’ve come to appreciate how large of an impact this problem can have both for the people directly involved, but also over wide geographical areas around the fire,” Urban said.

Urban’s experiment will study non-steady flame behaviors, which he describes as “a complex interaction between the hot gases produced from burning all that vegetation that’s rising and the wind that creates these non-steady behaviors that play a very important role for how the flames spread through the fuel.”

Astronauts on board the ISS will be working with the Combustion Integrated Rack to perform the experiment, which involve about 26 burn samples with each burn test lasting between one to two minutes each. The burn samples won’t be sent back to Earth, but Urban and his colleagues will be receiving video from the experiment.

“For a lot of the flammability research, it’s the video footage you get from the tests that is like really like the gold, the treasure trove. You can extract a lot of really useful information from those videos,” Urban said. “There’s also some other sensors too that you can do that too, but the videos themselves are really, really powerful and allow us to do a lot.”

Another experiment launching is the Maturation of Vascularized Liver Tissue Construct in Zero Gravity (MVP Cell-07), which was developed by Redwire Space in partnership with the Wake Forest Institute of Regenerative Medicine. The experiment is designed to improve the processes for bioprinting in microgravity for on-Earth research as well as creating implantable tissue in the future.

“In this investigation, the researchers determine whether bioprinted liver tissue constructs with blood vessels mature and behave the same way in space, where microgravity causes changes in cell shape, size, volume, and adherence properties,” according to NASA’s description of the experiment. “The team aims to determine whether liver cells form proper tissue structures in microgravity and maintain functionality. The team also assesses whether vascular cells correctly form a lining in the blood vessel walls within the liver construct.”

Two CubeSats are also hitching a ride on the NG-21 mission as part of NASA’s CubeSat Launch Initiative: CySat-1 from Iowa State University and DORA (Deployable Optical Receiver Aperture) from Arizona State University. The former will measure soil moisture using a software-defined radiometer, according to NASA.

DORA is a partnership between ASU and NASA’s Jet Propulsion Laboratory (JPL) in Southern California, which will test new CubeSat technology.

“The technology will demonstrate new optical communications without precision pointing and use a solid-state photon detector to gather high data rates using wide-field optical receivers,” NASA wrote in a blog post. “To test the detector’s performance, DORA will measure the background light from reflected sunlight, moonlight, and city lights when deployed from the space station into low Earth orbit.”