Tropical Storm Erika Delayed Blastoff for US Navy set for Sept. 2 on Most Powerful Atlas V Rocket: Watch Live

CAPE CANAVERAL AIR FORCE STATION, FL – Blastoff of an advanced communications satellite for the US Navy is set for early Wednesday morning, Sept. 2, using the most powerful variant of the United Launch Alliance (ULA) Atlas V rocket – following a 48 hour postponement due to terrible weather expected from Tropical Storm Erika, which pounded islands in the Caribbean causing destruction and over 20 deaths.

The threat of strong winds and heavy rains forced Florida Gov. Rick Scott to declare a state of emergency in every county in Florida last Friday that was still in effect as rains doused central Florida on Monday.

ULA decided against rolling the Atlas V rocket out to the seaside pad on Saturday in support of the then planned launch of the Multi-User Objective System satellite on Aug. 31.

Liftoff of the Multi-User Objective System-4 (MUOS-4) satellite for the US Navy is now slated for 5:59 a.m. EDT from Space Launch Complex-41 at Cape Canaveral Air Force Station in Florida, and will be broadcast live.

The launch window extends for 44 minutes from 5:59-6:43 a.m. EDT and the weather outlook is now promising.

US Air Force weather forecasters currently predict a 70% chance of favorable weather conditions for “GO” at launch time on Wednesday morning.

The primary concern is for cumulus clouds.

The unmanned Atlas V expendable rocket will launch in its mightiest configuration known as the Atlas V 551 with five solid rocket boosters augmenting the first stage.
Therefore the predawn liftoff is expected to be absolutely spectacular, resonating with a thunderous roar rising on a huge smoke trail that will light up the darkened skies all around the Florida Space Coast for spectators here and far beyond.

You can watch the launch on your laptop or smart phone since it will be carried live on a ULA webcast:

The ULA webcast starts about 20 minutes before launch.

The launch time moves up 4 minutes in the event of a 24 hour delay. The weather prognosis stands at 70 percent “GO”.

MUOS-4 US Navy communications satellite stowed inside huge 5 meter diameter payload fairing atop Atlas V rocket at pad 41 at Cape Canaveral Air Force Station, FL set for launch on Sept. 2, 2015. EDT. Credit: Ken Kremer/

MUOS is a next-generation narrowband tactical satellite communications system designed to significantly improve ground communications for U.S. forces on the move.

This is the fourth and last satellite in the MUOS series and will provide military users 10 times more communications capability over existing systems, including simultaneous voice, video and data, leveraging 3G mobile communications technology.

MUOS-4 satellite artwork. Credit: US Navy/ULA

MUOS-3 launched earlier this year.

The launch countdown will begin at 11:09 p.m. EDT on Tuesday night, Sept. 1, followed by fueling of the Atlas V rocket.

Ken is onsite for launch coverage from Cape Canaveral Air Force Station and the Kennedy Space Center.

Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.

Ken Kremer

United Launch Alliance Atlas V rocket with MUOS-4 US Navy communications satellite poised at pad 41 at Cape Canaveral Air Force Station, FL, set for launch on Sept. 2, 2015. EDT. View from atop NASA’s SLS mobile launcher at the Kenned Space Center. Credit: Ken Kremer/


Learn more about MUOS-4 US Navy launch, Orion, SLS, SpaceX, Boeing, ULA, Space Taxis, Mars rovers, Orbital ATK, Antares, NASA missions and more at Ken’s upcoming outreach events:

Sep 1 – Sep 2: “MUOS-4 launch, Orion, Commercial crew, Curiosity explores Mars, Antares and more,” Kennedy Space Center Quality Inn, Titusville, FL, evenings

Ken Kremer

Dr. Ken Kremer is a speaker, research scientist, freelance science journalist (KSC area,FL) and photographer whose articles, space exploration images and Mars mosaics have appeared in magazines, books, websites and calendars including Astronomy Picture of the Day, NBC, FOX, BBC,, Spaceflight Now, Science and the covers of Aviation Week & Space Technology, Spaceflight and the Explorers Club magazines. Ken has presented at numerous educational institutions, civic & religious organizations, museums and astronomy clubs. Ken has reported first hand from the Kennedy Space Center, Cape Canaveral, NASA Wallops, NASA Michoud/Stennis/Langley and on over 80 launches including 8 shuttle launches. He lectures on both Human and Robotic spaceflight - Follow Ken on Facebook and Twitter

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