The final launch ever of United Launch Alliance’s Delta IV Heavy, the last of the Delta family of rockets, won’t fly this weekend. In the meantime, SpaceX has a pair of launches on the Space Coast set for Saturday night.

First up from Kennedy Space Center’s Launch Pad 39-A is the Eutelsat-36X mission flying a communications satellite to geosynchronous transfer orbit during a launch window that runs from 5:52-9:50 p.m. The first-stage booster is flying for the 12th time aiming for a landing on the Just Read the Instructions droneship downrange in the Atlantic Ocean.

Next up is a Falcon 9 on the Starlink 6-45 mission carrying 23 Starlink satellites from Cape Canaveral Space Force Station’s Space Launch Complex 40 targeting a 9:02 p.m. liftoff during a one-hour window that runs from 9-10 p.m. The first-stage booster is flying for the 18th time and aiming for a landing on the droneship A Shortfall of Gravitas in the Atlantic.

These would be the 20th and 21st launches from the Space Coast in 2024. SpaceX has another Starlink launch from California slated for late Saturday as well.

For the pair of Florida launches, Space Launch Delta 45’s weather squadron forecasts better than 95% chance for good conditions.

Their flight comes after ULA’s scrub of the Delta IV Heavy flight with just under four minutes on the countdown clock this past Thursday at Canaveral’s Space Launch Complex 37. At issue was a pump on the gaseous nitrogen pipeline from the shared ground systems supplying the Space Force station with the inert gas that is needed for safe launch operations.

“The team continues to troubleshoot the pipeline and more time is needed to instill confidence in the system. We will continue to work with our customer to confirm our next launch attempt and a new launch date will be provided upon resolution,” ULA posted late Thursday, and has not updated its status since.

Now the rocket on the NROL-70 mission carrying a classified satellite for the National Reconnaissance Office awaits confirmation from ULA on a retry, although there are three opportunities booked on the Eastern Range beginning with a four-hour window from 1:25-5:24 p.m. on Monday with backups on Tuesday starting at 1:21 p.m. and Wednesday at 1:17 p.m.

The first launch of a Delta class of rockets came more than 63 years ago and this will be its 389th launch attempt among all its versions.

Delta IV Heavy is making its 16th flight having been introduced in 2004. The medium-lift version of the Delta IV last flew in 2019 while the smaller, older Delta II rocket retired in 2018.

The Delta family of rockets along with Atlas V rockets are being replaced by ULA’s new Vulcan Centaur, which made it maiden launch this past January.