Scrub recap: Scroll down to review live updates from the Wednesday, April 9, weather-postponed liftoff attempt of a United Launch Alliance Atlas V rocket from Cape Canaveral on the inaugural Amazon Project Kuiper production satellite mission.
Original story: It’s launch day for Amazon’s first-ever payload of 27 production satellites for the ecommerce giant’s future Project Kuiper internet constellation!
Welcome to FLORIDA TODAY Space Team live coverage of tonight’s United Launch Alliance KA-01 mission from Cape Canaveral Space Force Station.
ULA crews are now targeting 8:59 p.m. EDT to launch a 205-foot Atlas V rocket — powered by five side rocket boosters — from Launch Complex 41.
“Project Kuiper is Amazon’s low Earth orbit satellite broadband network. Its mission is to provide fast, reliable internet to customers around the world, including those in unserved and underserved communities, using a constellation of more than 3,200 LEO satellites,” the ULA mission page said.
The Atlas V will soar skyward along a northeasterly trajectory, and no Central Florida sonic booms should occur. However, odds of “go for launch” weather were now only expected to reach 40% by the end of the launch window at 9 p.m.
Update 8:59 p.m.: After inclement weather triggered tonight’s scrub, ULA officials have announced a new launch date will be announced when approved by Eastern Range leaders.
“We will work with our partners at the U.S. Space Force Space Launch Delta 45 for the timing of our next launch opportunity,” webcast commentator Caleb Weiss said.
Update 8:45 p.m.: ULA crews just scrubbed tonight’s Atlas V launch attempt.
“Weather is observed and forecast NO GO for liftoff within the remaining launch window this evening, according to Launch Weather Officer Brian Belson,” a ULA tweet said.
Update 8:37 p.m.: As tonight’s unexpired launch window continues ticking away, ULA officials provided insight as to why cumulus clouds pose a threat to ascending rockets.
“The cumulus cloud rule is violated when the rocket would fly through or too close to a cumulus cloud. The exact standoff limits are determined by cloud top temperature, with colder clouds requiring the rocket to stay a further distance away to guard against rocket-triggered lightning,” a blog update said.
Tonight’s Project Kuiper mission is utilizing a 10-mile zone.
Update 8:24 p.m.: Now, ULA’s latest launch liftoff time is 8:59 p.m., just one minute before tonight’s launch window concludes.
“That is near the very end of the available launch window today. We continue to hope the weather situation will clear,” a ULA blog update said.
Update 8:15 p.m.: Should ULA try to launch during Thursday night’s backup launch window, the Space Force’s 45th Weather Squadron predicted meteorological conditions will be 90% favorable for liftoff — a far-different scenario compared with tonight’s blustery weather.
“On Thursday, weather looks considerably more favorable. High pressure and a loosening pressure gradient are expected to strengthen the inversion and reduce wind speed over central Florida, limiting the vertical development of any showers that come ashore,” the squadron’s forecast said.
“The Cumulus Cloud Rule is the primary weather concerns for the backup day,” the forecast said.
Update 8:03 p.m.: ULA is now targeting 8:39 p.m. for liftoff.
As a reminder, tonight’s launch window closes at 9 p.m.
Update 7:58 p.m.: As the 9 p.m. closure of tonight’s launch window looms, ULA reports cumulus clouds continue violating the eastern, offshore portion of the 10-mile safety ring surrounding Launch Complex 41.
“Winds also remain elevated above the safe liftoff limit,” a ULA tweet said.
Update 7:47 p.m.: ULA crews have pushed back tonight’s launch attempt yet again — to 8:22 p.m. — because of cumulus clouds and winds.
Update 7:44 p.m.: In a blog post, ULA officials reported “weather conditions in the local Cape Canaveral area remain unfavorable for a launch at this time.”
The launch team remains postured to resume the countdown as soon as 8:03 p.m., if the weather improves.
Update 7:38 p.m.: This Atlas V graphic depicts potential visibility for launch spectators across much of the eastern United States, ranging from 30 seconds to 6½ minutes after liftoff along the rocket’s flight path.
Update 7:26 p.m.: ULA is now targeting 8:03 p.m. for liftoff as weather conditions improve at Cape Canaveral.
“Weather update: Cloud cover is now acceptable. Just continuing to wait on the winds,” a ULA tweet said.
Update 7:18 p.m.: In a weather-delay blog update, ULA officials highlighted the history of the Centaur upper stage.
“Today’s launch marks the 275th flight of Centaur. This venerable U.S. upper stage is the high-energy, hydrogen-fueled rocket that unlocked access to the moon and every planet in our solar system for robotic explorer spacecraft,” the update said.
“Since successfully debuting in November 1963, Centaur makes it possible for the U.S. to launch spacecraft of greater size and weight over other upper stage designs. Hydrogen serves as the difference maker, offering more pounds of thrust per pound of propellant consumed per second than any other fuel possible in chemical rockets,” the update said.
Update 7:08 p.m.: In a blog update, ULA officials said Cape Canaveral’s clouds and winds are clocking in beyond the mission’s safety limits.
“We are hoping the conditions improve to allow liftoff by 7:40 p.m. EDT,” the update said.
Update 6:52 p.m.: ULA is now targeting 7:40 p.m. for liftoff.
Update 6:45 p.m.: ULA crews have paused the countdown at a T-minus-4-minutes planned hold point, awaiting improved weather.
Tonight’s two-hour launch window lasts until 9 p.m., and a new target liftoff time has not been announced.
“We can stay in this hold indefinitely while we monitor the winds and cloud cover,” a ULA blog post said.
Update 6:41 p.m.: ULA’s webcast just noted that cumulus clouds are creating “no go” launch weather conditions now.
The odds of “go for launch” weather are expected to only reach 20% at the 7 p.m. target liftoff time, with chances increasing to 40% by the end of the two-hour launch window.
Update 6:32 p.m.: ULA’s launch webcast is now posted above, right below our countdown clock.
Liftoff is scheduled in 28 minutes from Cape Canaveral Space Force Station.
Update 6:24 p.m.: FLORIDA TODAY Photographer/Videographer Craig Bailey shot this video of blustery pre-launch conditions near Launch Complex 41.
“The latest weather forecast update now calls for broken low clouds, isolated showers in the area, northerly winds 20-28 knots and a temperature near 64 degrees. There is an 80 percent chance of weather rule violation for the launch window tonight,” a ULA blog update said.
Update 6:12 p.m.: Brevard County Emergency Management officials have activated the agency’s launch operations support team ahead of ULA’s upcoming Atlas V launch.
Update 6:02 p.m.: ULA crews have completed filling the first-stage liquid-oxygen tank, and “topping mode” is underway.
However, National Weather Service radar from the Melbourne Orlando International Airport station shows significant stormy weather offshore and just south of the Cape — and ULA reports the weather remains “red” for liftoff because of winds and clouds.
Update 5:45 p.m.: Check out ULA’s video below detailing tonight’s upcoming mission.
Update 5:32 p.m.: As rocket fueling continues, it’s worth noting that the Space Force assigned two national security launches during the 2025 fiscal year to ULA for a total price of $427.6 million, military officials announced Monday.
SpaceX was assigned seven missions totaling $845.8 million, while Blue Origin will have its first opportunity for a mission in the 2026 fiscal year.
“These missions will provide our nation with its most critical space-based effects needed to ensure national security,” Brig. Gen. Kristin Panzenhagen said in a press release. “With these missions, our acquisition team and the launch service providers are putting new space capabilities on orbit to outpace our competitors.”
Update 5:15 p.m.: Fueling remains ongoing for both the rocket’s first stage and Centaur upper stage.
“Now 20 percent of the Centaur LOX tank has been filled. The liquid oxygen — chilled to Minus-298 degrees F — will be consumed during the launch by the Centaur’s single RL10A-4-2 engine along with liquid hydrogen to be pumped into the stage a little later in the countdown,” a 5:10 p.m. blog update said.
Update 4:57 p.m.: The Atlas V is “go” for fueling, according to a readiness poll of ULA’s launch team.
However, the forecast still only shows 20% odds of favorable weather for the 7 p.m. launch target time. As a reminder, tonight’s two-hour launch window extends until 9 p.m.
Crews previously chilled the rocket’s first-stage liquid oxygen system and pressurized the pad’s liquid-oxygen tank for the Centaur upper stage.
Update 4:44 p.m.: The upcoming Atlas V launch will become the 29th orbital rocket launch of 2025 thus far from NASA’s Kennedy Space Center and Cape Canaveral Space Force Station.
Click here for the FLORIDA TODAY Space Team’s updating log of these missions, complete with photo galleries and story links.
Update 4:30 p.m.: ULA reports its launch-time forecast now only shows a 20% chance of favorable weather conditions, with scattered clouds, isolated showers and northerly winds of 20 to 28 knots.
“In the pre-fueling weather briefing to mission management, Launch Weather Officer Brian Belson reports that winds and cumulus clouds are violating the weather criteria at the present time,” a blog update said.
For the latest news and launch schedule from Cape Canaveral Space Force Station and NASA’s Kennedy Space Center, visit floridatoday.com/space.
Rick Neale is a Space Reporter at FLORIDA TODAY. Contact Neale at Rneale@floridatoday.com. Twitter/X: @RickNeale1
