A week after a milestone mission from the East Coast, United Launch Alliance will mark its 101st blastoff when an Atlas V rocket roars to life Thursday morning at Vandenberg Air Force Base.

Liftoff from Space Launch Complex-3 on South Base is planned for 5:49 a.m. The actual launch window, typically a much shorter time frame to get the spacecraft to the proper place in space, is top secret, but does not extend beyond 6:30 a.m.

“We are excited and ready to take on our first Atlas launch of 2015,” said Col. J. Christopher Moss, 30th Space Wing commander who also will be the launch decision authority.

“Our team and mission partners have put a lot of hard work into preparing for this important mission for our nation.”

The 19-story-tall Atlas rocket will carry a National Reconnaissance Office spacecraft for a mission labeled NROL-55 into orbit as its primary cargo. Officials remain mum about details of the spy satellite, only saying it is for national security purposes.

More is known about the 13 small satellites, known as CubeSats, scheduled to hitch a ride as secondary cargo on the rocket aboard what the NRO calls the Government Rideshare Advanced Concepts Experiment, or GRACE.

The miniature spacecraft, sponsored by the NRO and NASA, will test assorted technology, officials said.

For instance, a CubeSat developed with NASA funding will evaluate the ability to point a small satellite accurately as it demonstrates data transfer by laser at rates of up to 200 megabytes per second — a factor of 100 increase over current high-end CubeSat communications systems.

The NASA-sponsored CubeSats will test new small satellite control and communications systems, Earth observations, amateur radio communications and an X-Band radio science transponder.

The CubeSats represent the first to be designed, built and operated by students in Alaska and the first from Native American tribal college students, NASA officials said.

United Launch Alliance, formed in 2006 as a joint venture of The Boeing Company and Lockheed Martin Corp. Atlas and Delta rocket manufacturing and launching operations, on Friday celebrated its 100th launch with the successful Atlas V departure from Cape Canaveral Air Force Station, Florida.

The rocket carried a communications satellite for Mexico.

Of the first 100 launches since ULA formed, 29 occurred from Vandenberg with the remainder flying from Florida.

Weather-willing, Atlas V launches from Vandenberg are visible from around the Central Coast.

SLC-3, which can be seen from several vantage points around the Lompoc Valley, is the most eastern launch facility visible looking toward South Base, south of Ocean Avenue.

Key off-base viewing sites include the peak of Harris Grade Road plus several spots around Vandenberg Village to watch as the rocket travels south away from the base.

Typically, beaches around South Base are closed for safety reasons related to rocket launches.

“A launch like this takes teamwork and dedication,” said Lt. Col. Eric Zarybnisky, 4th SLS commander.

The 4th Space Launch Squadron is in charge of mission assurance and safety for the launch.

“Our mission assurance technicians and engineers have worked hand-in-hand with United Launch Alliance going over critical procedures and tasks to ensure this launch is a safe and successful one,” Zarybnisky said.

— Noozhawk North County editor Janene Scully can be reached at .(JavaScript must be enabled to view this email address) . Follow Noozhawk on Twitter: @noozhawk, @NoozhawkNews and @NoozhawkBiz. Connect with Noozhawk on Facebook.