When is Delta IV Heavy rocket launch from Cape Canaveral? What we know about next attempt

Delta IV Heavy rocket, retirement is on hold − for a little longer.

When is United Launch Alliance's massive Delta IV Heavy rocket going to launch?

The much-anticipated Delta IV Heavy rocket will potentially launch from Cape Canaveral − for the very last time − on Tuesday, April 9, with the launch at 12:53 p.m. EDT, pending range approval.

When is United Launch Alliance's massive Delta IV Heavy rocket going to launch? As of Tuesday, April 2, the next attempt for its final liftoff ever is coming up, according to an FAA navigational advisory (see below). Here's what we know.

What happened to Delta IV Heavy rocket launch from Cape Canaveral, Florida? Why did Delta IV Heavy scrub?

With minutes to go until the planned 2:45 p.m. EDT Thursday, March 28, target liftoff for the Delta IV Heavy and weather just at the edge of acceptable, the launch scrubbed. United Launch Alliance CEO Tory Bruno said winds exceeded the acceptable limit, causing a hold, and that was when a gaseous nitrogen pipeline ground pump failed. The pump provides pneumatic pressure to the launch vehicle systems.

ULA said they would do a 24-hour turnaround, and the launch was then planned for 1:37 p.m. EDT Friday, March 29. But Bruno later posted on X, formerly known as Twitter, that the "pump failed again ... Stand by."

Just before 8 p.m. Thursday, ULA said they'd be standing down to continue to work on the pipeline.

"The team continues to troubleshoot the pipeline and more time is needed to instill confidence in the system," the company said in a statement. "We will continue to work with our customer to confirm our next launch attempt and a new date will be provided upon resolution."

The much-anticipated Delta IV Heavy rocket will potentially launch from Cape Canaveral − for the very last time − on Tuesday, April 9, with the launch at 12:53 p.m. EDT, pending range approval. (Stay tuned to FLORIDA TODAY Space Team's coverage of this end-of-an-era flight.)

The Delta IV Heavy, which is bound for retirement, will send a classified payload into orbit for the National Reconnaissance Office on the NROL-70 national security mission.

Tuesday, April 9: ULA Delta IV Heavy final launch

The Delta IV Heavy rocket will lift off from Cape Canaveral, Florida, with a classified payload on the NROL-70 national security mission, conducted in tandem with the National Reconnaissance Office and the Space Force’s Space Systems Command. The massive rocket launches the NRO's heaviest satellites. The missions that Delta IV Heavy carried were not all related to science; many were for navigation and U.S. security. Delta IV transported mostly NRO, US Air Force, and US Space Force payloads, getting them safely to their orbit or destination.

The Delta IV Heavy made its debut during a December 2004 demonstration flight from Launch Complex 37.

• Mission: United Launch Alliance's last Delta IV Heavy triple-core rocket will launch on the NROL-70 national security mission.

• Launch: Tuesday, April 9, with the launch at 12:53 p.m. EDT, pending range approval.

• Location: Launch Complex 37 at Cape Canaveral Space Force Station

• Trajectory: Due east

• Local sonic boom: No

• Booster landing: None

• Live coverage: Starts two hours before liftoff at floridatoday.com/space.

How to watch ULA Delta Heavy rocket launch from Florida online

When there's a new attempt, tune in to floridatoday.com/space for USA TODAY Network's Space Team live coverage and updates on the last Delta IV Heavy launch, starting about two hours before liftoff. You can download the free app for iPhone or Android or type floridatoday.com/space into your browser.

What is Delta Heavy?

Delta Heavy refers to United Launch Alliance's Delta IV Heavy rocket. The ULA rocket made history for its transportation of the NASA Parker Solar Probe in 2018 and the first orbital test flight of the Orion crew capsule in 2014.

It was following the success of this flight that NASA’s Orion crew capsule flew on NASA’s Space Launch System (SLS) rocket, successfully demonstrating an uncrewed mission around the moon in 2022. ULA assisted in this flight as well, as the organization designed the upper stage of the SLS rocket.

The Orion spacecraft is set to take Artemis II astronauts around the Moon in late 2025.

How big is Delta IV Heavy rocket? What’s the size and power of ULA Delta IV Heavy rocket?

The Delta IV Heavy rocket has three Delta IV core stages together. According to the ULA website, each rocket engine produces up to 702,000 lbs. of thrust. With this performance, one can see why ULA dubbed it "the most metal." These engines are not small either. Just one engine weighs around 14,876 pounds and is 204 inches (17 feet) in length.

Powered by liquid hydrogen and liquid oxygen, the Delta IV Heavy appears to "set itself on fire" just before liftoff as buoyant hydrogen gas, which is used to cool down the rocket before launch, ignites and burns off. The fiery start may look frightening, yet it's part of the process.

Where to watch Delta IV Heavy rocket launch live from areas close to the Space Coast of Florida

In Florida, we can best see this historic moment in person if you're anywhere on the Space Coast (Brevard County) or certain spots in the First Coast or Fun Coast (Volusia County) or the Treasure Coast (Indian River County, St. Lucie County and Martin County). Pro tip: If you do watch it in person, get to your viewing destination early and prepare to stay later after the launch because of heavy traffic.

Who can see Delta IV Heavy rocket launch from Cape Canaveral, Florida? Which cities can see Delta IV Heavy liftoff?

ULA provided a helpful graphic (see above) that shows Delta IV Heavy's intended flight path and its launch visibility:

• Launch, Space Coast, Orlando, northern part of the Treasure Coast, Indian River County, Sebastian, Vero Beach, parts of northern part of Daytona Beach, New Smyrna Beach and Oak Hill

• 1: Launch + 30 seconds, Space Coast, Orlando, northern part of the Treasure Coast, Indian River County, Sebastian, Vero Beach, parts of northern part of Daytona Beach, New Smyrna Beach and Oak Hill

• 2: Launch + 60 seconds, Space Coast, northern part of Daytona Beach, New Smyrna Beach, Treasure Coast, possibly Martin County, possibly St. Lucie County, parts of East-Central Florida like Orlando, near University of Central Florida, Bithlo

• 3: Launch + 90 seconds, visibility extends to Orlando, Sanford, Kissimmee, Daytona Beach, other parts of Central Florida

• 4: Launch + 120 seconds, visibility extends to Port St. Lucie, Lakeland, Sebring, Winter Haven, Palatka, St. Augustine

• About 130 seconds (Port/Starboard, booster jettison), visibility extends to include most of central and East Coast of Florida

• 5: Launch + 150 seconds, visibility extends to West Palm Beach, Ocala, the Village, Sebring, most of central and East Coast of Florida, Tampa, parts of West Coast of Florida

• 6: Launch + 180 seconds, Jacksonville, Gainesville, Tampa, Arcadia, North Port, West Palm Beach, Boca Raton, Pompano Beach, Fort Lauderdale, most of central and East Coast of Florida, parts of West Coast of Florida

• 7: Launch + 210 seconds, visibility extends to Hollywood, Florida; the Everglades, Hialeah, Miami, most of central and East Coast of Florida, parts of West Coast of Florida

• 8: Launch + 240 seconds (booster engine cutoff); visibility extends to Hollywood, Florida; the Everglades, Hialeah, Miami, most of central and East Coast of Florida, parts of West Coast of Florida. It could include Homestead and possibly Key Largo

• Beyond 240 seconds, Delta IV Heavy should see center booster separation and main engine start, according to the ULA graphic.

• 9: Launch + 270 seconds, most of central and East Coast of Florida, parts of West Coast of Florida

• 10: Launch + 300 seconds, most of central and East Coast of Florida, parts of West Coast of Florida

• Beyond 300 seconds, the graphic shows Delta Heavy payload fairing jettison.

• 11: Launch + 330 seconds, most of central and East Coast of Florida, parts of West Coast of Florida

• Clearwater and St. Petersburg appear to be out of range. Interestingly, the Bahamas and Freeport are in the launch visibility zones.

The above guidelines are estimates based on the graphic provided by ULA.

Rocket launch calendar for Florida

Below is more info about the Delta IV Heavy rocket launch this week and suggestions on where and how to watch it. FLORIDA TODAY's rocket launch calendar for the month is updated frequently. (Check that link often for rocket launch times and dates because they are routinely subject to change for a variety of reasons.)

FLORIDA TODAY provides interactive launch coverage at floridatoday.com/space with frequent updates on launches at least 90 minutes in advance, sometimes longer, depending on the mission. For questions or comments, email Space Reporter Rick Neale at rneale@floridatoday.com or tweet him @rickneale1 on X, the social platform formerly known as Twitter.

Sangalang is a lead digital producer for USA TODAY Network-Florida. Follow her on Twitter or Instagram at @byjensangalang. Support local journalism. Consider subscribing to a Florida newspaper.

This article originally appeared on Florida Today: Delta IV Heavy launch. When is ULA rocket liftoff from Florida?