NROL-107 (Silent Barker) | Atlas V 551

Lift Off Time
(Subject to change)

August 29, 2023 – 12:34 UTC | 08:34 EDT

Mission Name

NROL-107 or Silent Barker

Launch Provider
(What rocket company is launching it?)

United Launch Alliance (ULA)

(Who’s paying for this?)

National Reconnaissance Office (NRO) and United States Space Force (USSF)


Atlas V 551

Launch Location

Space Launch Comple-41 (SLC-41)

Payload mass

Not specified, up to 8,900 kg (19,600 lb)

Where is the satellite going?


Will they be attempting to recover the first stage?

No, this is not a capability of the Atlas V rocket

Where will the first stage land?

It will crash into the Atlanic Ocean

Will they be attempting to recover the fairings?

No, this is not a capability of the Atlas V rocket

Are these fairings new?


How’s the weather looking?

The weather is currently 80% GO for launch (as of August 28, 2023 at 12:00 UTC)

This will be the:

– 1st launch of the Atlas V rocket in 2023
– 2nd mission for ULA in 2023
– 98th overall Atlas V mission
– 157th overall ULA mission
– First launch of Atlas V in 10+ months
– 136th orbital launch attempt of 2023

Where to watch

Official livestream

What’s All This Mean?

In its first launch in nearly 11 months, an Atlas V will take to the skies over Florida yet again in the 18th and final launch of a National Reconnaissance Office mission on an Atlas V. Setting up for multiple Atlas V launches for the remaining months of 2023, NROL-107, also called Silent Barker, will be launched on the Atlas V 551 configuration. The Atlas V 551 configuration is often called “The Bruiser” because of its heavy-lift and thrust capabilities.

Launch will take place at Cape Canaveral Space Force Station, Florida, United States from Space Launch Complext 41 (SLC-41).

Atlas V 551 during rollout ahead of the NROL-107/Silent Barker mission (Credit: ULA)


Due to the classified nature of NROL-107, a joint mission for the United States’ National Reconnaissance Office and United States Space Force, there is no readily available public information on the specifics of satellite operation and intended purpose. However, ULA states that the satellite will “improve space domain awareness”, indicating that there is technology on board to be able to detect and track objects around Earth, from a space-based station.

On the contrary, ground based tracking stations can oftentimes be inhibited by weather or other naturally occuring atmospheric and ionosphereic conditions. Data from this satellite, gathered and processed by the NRO, will enhance the United States’ ability to respond to potential threats and other events with greater knowledge than before.

ULA’s Silent Barker mission art work (Credit: ULA)

As with every launch, ULA releases artwork with significance relating to the mission and its partners. For example, in the artwork above, the two shooting stars resemble the close collaboration between the United States Space Force and the National Reconnaissance Office. According to ULA, the fox represents the “cunning nature of the Intelligence Community (IC) and the Department of Defense (DoD) that gives our warfighters the edge against America’s adversaries”.

What Is The Atlas V?

The Atlas V is an expendable medium lift launch system and member of the Atlas rocket family. The rocket has two stages. The first is a Common Core Booster (CCB), which is powered by an RD-180 engine and burns kerosene (RP-1) and liquid oxygen (LOx). This is accompanied by up to five strap-on solid rocket boosters. The second stage is the Centaur upper stage, which is powered by one or two RL10 engines and burns liquid hydrogen (LH2) and liquid oxygen (LOx).

In the 551 configuration, the Atlas V is capable of carrying up to 8,900 kg to Geostationary Transfer Orbit (GTO).

What Does 551 Mean?

Atlas V rockets have a three-number configuration code. The first number represents the fairing diameter size in meters, so in this instance, there is a 5-meter fairing. The second number denotes the number of solid rocket boosters (SRBs), which attach to the base of the rocket. The number of SRBs for a 5-meter fairing can range from 0 – 5. In this case, there will be five SRBs attached to the center core. The third number shows the number of engines on the Centaur Upper Stage, which is one in this configuration. So this means that this rocket will have a 5-meter fairing, five solid rocket boosters, and one engine on the Centaur Upper Stage.

A diagram of the entire Atlas V family with the SRB placement for each number shown. (Credit: NASA)

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