SpaceX Hopes To Launch Northrup Grumman’s NG-21 Mission Saturday (Update: Scrubbed)

An ill-timed line of thunderstorms forces a scrub Saturday

Update: 12 PM EDT Saturday

A wave of thunderstorms passed through the Cape Canaveral area around 90 minutes before liftoff Saturday, forcing SpaceX to stand down from its launch attempt today.

The company said in a latter post on X.com that they would try again tomorrow, but with a 90% Probability of Violation and an approaching tropical system off of Florida’s west coast, the chances of that don’t seem very high. Monday’s forecast is equally squirrelly as the system is forecast to arc through northern Florida, creating storm squalls and windy conditions across the state.

On the other hand, it’s Florida and the weather here can be unpredictable. So, we’ll see when SpaceX can get this launch off of the pad.

SpaceX is planning to launch Falcon 9 carrying the NG-21 ISS Resupply mission for Northrup Grumman.

SpaceX plans for the booster to return and land at Landing Zone 1 in Cape Canaveral. The Space Coast will hear a sonic boom from the booster as it herald’s its return, which should happen approximately 7.5 minutes after liftoff.

Weather is a major concern for this launch, as a tropical disturbance’s passing to the west in the Gulf of Mexico is expected to bring heavy rains to the Space Coast over the weekend. Current forecasts are calling for weather to arrive sometime Saturday, so the timing of the storm coupled with the normal storm activity of Florida in summer leaves forecasters calling the chances of acceptable weather a coin flip with a 50% chance of a Probability of Violation at launch time.

At A Glance

• Mission: Northrup Grumman NG-21
• Date: NET August 3, 2024
• Launch Window: 11:28AM EDT (1528 Zulu)
• Weather: 50% GO at launch time
• Organization: SpaceX
• Rocket: Falcon 9
• Trajectory: Northeastward
• Launch Site: SLC-40, Cape Canaveral Space Force Station
• Booster Landing: Landing Zone 1, CCSFS
• Payload: Cygnus CRS-2 NG-21 (S.S. Francis R. “Dick” Scobee)
• Destination: International Space Station

Payload

Northrup Grumman’s Cygnus (S.S. Francis R. “Dick” Scobee) cargo spacecraft, loaded with scientific investigations, supplies, and equipment.

According to NASA, the payload includes:

• Test articles to evaluate liquid and gas flow through porous media found in space station life support systems.
• A balloon, penny, and hexnut for a new STEMonstration on centripetal force.
• Microorganisms known as Rotifers to examine the effects of spaceflight on DNA repair mechanisms.
• A bioreactor to demonstrate the production of many high-quality blood and immune stem cells.
• Vascularized liver tissue to analyze the development of blood vessels in engineered tissue flown to the space station.

Weather

General Forecast

The forecast at launch time looks relatively benign:

Official Launch Forecast

The 45th Weather Squadron’s discussion in their launch forecast mentions the tropical system noted above. “All eyes will remain on Potential Tropical Cyclone Four (PTC 4) as it lifts out of the Greater Antilles and into the Gulf of Mexico. The official forecast from the National Hurricane Center has the system becoming a named storm Saturday and skirting the western Florida Peninsula Sunday, potentially making landfall as a Tropical Storm anywhere from the Florida Big Bend to southwest Florida.

Regardless of where the center of the storm makes landfall, the Space Coast will be on the eastern side of the system, and weather is likely to deteriorate with time from Saturday afternoon into Sunday. For the initial launch window, scattered showers are expected to approach the coastline out of the southeast and potentially move onshore.”

Their primary concerns that could necessitate a delay are: the Cumulus Cloud Rule, Surface Electric Fields Rule, and Thick Cloud Layers Rule.

Trajectory

Northeastwards.

Landing

The booster used for this mission, B1080, will land at Landing Zone 1 at Cape Canaveral Space Force Station.

Online Viewing

SpaceX will have a livestream of the launch on their website: NG-21 Mission. This will also be available on the X platform. Coverage starts about five minutes before liftoff.

NASA’s launch coverage begins at 11:00 AM EDT on NASA+, NASA Television, the NASA app, YouTube, and the agency’s website.

Spaceflight Now will have coverage of the launch starting about one hour before liftoff on Youtube: link

For official updates regarding launch times, SpaceX.com is the best source of information. Starlink launch times change from time to time, and the company generally updates their website within minutes of the decision to change the launch time. This is very handy if none of the streaming options on YouTube have started their broadcasts.

Remember that there is a delay between a launch stream and the actual countdown clock. That is simply because of physics: it takes time for the signal to travel from the launch site, through the Internet, and back down to your phone, resulting in a five to fifteen-second delay.

Next Space Flight an app for iOS and Android phones, has a real-time countdown clock that is accurate to a second, give or take. The app is free. Search the App Store or Google Play. They are also on the web: nextspaceflight.com.

_{Note: article originally published by Talk of Titusville by the author}