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ULA prepares Atlas V 551 for MUOS-4 mission after Erika delays flight

United Launch Alliance PLF 4 Payload Fairing Cape Canaveral Air Force Station Space Launch Complex 41 Mobile User Objective System MUOS 4 ULA image posted on SpaceFlight Insider - Copy

Colorado-based United Launch Alliance plans to send the fourth MUOS satellite to a geosynchronous orbit atop an Atlas V 551 booster. Photo Credit: ULA

CAPE CANAVERAL, Fla — On Sept. 2, 2015, ULA is planning to launch the fourth of Lockheed Martin’s Mobile User Objective System (MUOS-4) satellites. The payload will be delivered to geosynchronous orbit by an Atlas V 551 booster. The flight was delayed from taking aloft on August 31, thanks to a Tropical Storm by the name of Erika.

The 551 is the most powerful version of the Atlas family of launch vehicles and is capable of creating approximately 2.8 million lbf (12.455 MN) of thrust at liftoff produced by the Russian-made RD-180 rocket engine in its first stage, along with the five Aerojet Rocketdyne AJ-60A solid rocket boosters.

“Many thousands of things need to go right during a launch and we don’t get a second chance once the rocket lifts off, said the MUOS-4 Mission Director, Air Force Space and Missile Systems Center, Dr. Walt Lauderdale. “For the MUOS-4 launch vehicle, the government team  completed 158 hardware pedigree reviews, data package reviews for an additional 323 hardware items, 165 launch vehicle verification tasks and 66 spacecraft to launch vehicle interface verification tasks.”

MUOS-4 is a part of a fleet of U.S. Navy communication satellites developed by Lockheed Martin and the U.S. Air Force Research Laboratory. It is anticipated that the deployment of the MUOS satellites will ensure that U.S. national security has secure and stable communications and connectivity.

According to the primary contractor for the MUOS system, things appear to be moving forward with the deployment of the system according to schedule.

“In January we launched MUOS-3, and in February we delivered the final of four required ground stations. Then, in June, following our successful completion of on-orbit testing, the U.S. Navy accepted MUOS-3 and at the end of that month we shipped MUOS-4 to the Cape,” said Lockheed Martin’s Vice President for Narrowband Communications Iris Bombelyn. “With the launch of MUOS-4 and with all of the ground stations now in place, the MUOS network will now provide global coverage, allowing mobile forces to communicate from almost anywhere in the world.”

This satellite will join the three previous MUOS spacecraft already on orbit in improving ground communications even in remote areas for video, voice, and data transmission. In total, ULA will launch five MUOS satellites (four satellites placed into a geosynchronous orbit with one on-orbit spare) by 2016 using the Atlas V.

Hurricane Erika as seen by NOAA NASA GOES spacecraft NOAA image posted on SpaceFlight Insider

Erika dissipated on August 29-30, clearing the way for United Launch Alliance to start the MUOS_4 mission. Image Credit: NOAA

The MUOS satellite design includes a dual payload which will allow the U.S. Navy to transition from the current Ultra High Frequency (UHF) system to a Wideband Code Division Multiple Access (WCDMA) system. The new WCDMA system provides multiple benefits over the existing UHF SATCOM satellites.

The WCDMA system has 16 times more capacity, the signals are able to reach through vegetation for ground communication, and its prioritization and localized beam power has better control of its signals. These new satellites will also act as cellphone towers approximately 22,200 miles (35,727 km) above the Earth. This means that U.S. forces will have smartphone communication capabilities in even the most remote areas of the world. The MUOS satellites have and will continue to enhance communication for voice, video, and data.

“The quality of the service provided by MUOS is better than your cell phone…,” Bombelyn said.

In many ways, the system is like a cellular service for members of the U.S. military, except that the “tower” is orbiting some 22,000 miles (35,406 km) above the Earth.

“Recently, the AFRL announced that it had used MUOS during an Antarctic resupply mission… these features have attracted the attention of a number of international allies and that is something that is very important for the U.S. government because we do need to have that interoperable capability and communications,” Bombelyn said.

Earlier this month, the Air Force Research Laboratory reported significant improvements for ground communication, specifically in the Antarctic region. Most satellites in geosynchronous orbit rarely provide substantial communication networks in the Antarctic; however, the MUOS satellites provide the region with secure voice communication and high-speed data.

“Think about how you feel when you don’t have cellphone coverage, especially when you need it most,” said Michael Gudaitis, AFRL team lead with the Air Force Research Laboratory’s Information Directorate. “In Antarctica, with the MUOS system we were able to demonstrate calls from places where no other radio or cellphone would work.”

It has been suggested that this secure communication coverage will support the rise of tourism, shipping, resource exploration, and search and rescue missions in the area.

Of greater importance to the fleet’s producers, the deployment of the fourth MUOS-4 satellite should allow the U.S. military to have a more solid and secure communications system.

The MUOS-4 spacecraft was encapsulated into its payload fairing or “PLF” on August 10 in preparation for flight.

ULA plans to launch the final MUOS satellite within the next year to complete the constellation. In terms of Tropical Storm Erika, United Launch Alliance has stated that it is closely monitoring the storm.

United Launch Alliance Atlas V 551 Mobile User Objective System MUOS-4 satellite photo credit Laura Ann Whitlock SpaceFlight Insider

If Wednesday’s launch goes ahead as scheduled, there is still one MUOS spacecraft awaiting launch. That mission is planned for a 2016 flight. Photo Credit: Laurel Ann Whitlock / SpaceFlight Insider



Amoree Hodges Florida Institute of Technology image posted on SpaceFlight InsiderAmoree Hodges is a SpaceFlight Insider Launch Correspondence intern from the Florida Institute of Technology, where she is currently working on obtaining her Bachelors degree in Astronomy & Astrophysics. Amoree loves telescopes and all things that are related to space, and NASA.

Hodges is planning a career in public science communications, and will be using her internship with SpaceFlight Insider to get great science and engineering communications experience while she works on completing her studies. In her capacity as a volunteer, Ms. Hodges has not only produced written content for SpaceFlight Insider – but has also served as the co-host for one of our live webcasts.




Founded at the very dawn of the Space Race in 1958, the Florida Institute of Technology is the only independent, technological university located in the Southeast. Times Higher Education ranks Florida Tech in the Top 200 Universities in the World. The university has been designated a Tier One Best National University in U.S. News & World Report, and is one of just nine schools in Florida lauded by the 2014 Fiske Guide to Colleges. The university offers undergraduate, graduate and doctoral programs. Fields of study include science, engineering, aeronautics, business, humanities, mathematics, psychology, communication and education.

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