Spaceflight Insider

Launch of Worldview-4 slips to October, SBIRS Geo-3 TBD

Atlas V 401 rocket lifts the GPS IIF-11 satellite to orbit. ULA Photo posted on SpaceFlight Insider WorldView-4

The launches of the WorldView-4 and SBIRS Geo-3 satellites have been delayed for a variety of reasons ranging from mechanical issues to wildfires. Photo Credit: United Launch Alliance

Two missions slated to fly on United Launch Alliance (ULA) Atlas V 401 rockets have been delayed for a variety of reasons. Whereas the launch of the commercial WorldView-4 satellite has been pushed back to “early October”, the flight of SBIRS Geo-3 has slipped due to unspecified issues with the spacecraft.

ULA issued the following statement on Sept. 22 regarding the impact of the local wildfires on the launch timeline:

The launch of a United Launch Alliance Atlas V carrying the WorldView-4 satellite for DigitalGlobe previously scheduled for Sept. 26 has been delayed due to the wildfires at Vandenberg Air Force Base. United Launch Alliance is working with the Western Range and DigitalGlobe to identify a new launch date in early October.

The wildfires actually prompted the second delay. The first was caused by a small hydrogen leak that caused ice to build up on a ground side umbilical.

Meanwhile, the launch of the U.S. Air Force’s Space Based Infrared System (SBIRS) Geosynchronous Orbit Flight-3 satellite, more commonly known as SBIRS GEO-3, has also been delayed. Lt. Gen. Samuel Greaves, SMC commander and Air Force Program Executive Officer for Space, provided the following information in a statement issued by the U.S. Air Force:

Fueling of the satellite and the launch, originally scheduled for Oct. 3, was delayed on Sep. 10 to give the SBIRS government/contractor engineering team time to investigate a potential parts issue discovered on two other non-SBIRS satellites. A preliminary review of the data suggested a possible issue with the liquid apogee engines. A Liquid Apogee Engine is used by the SBIRS satellite to provide the thrust required to raise the satellite to the proper orbit after the spacecraft has been released from the launch vehicle. Earlier this month, a non-Lockheed Martin commercial satellite experienced a similar anomaly to the July MUOS-5 event. The Air Force is working to understand the commonality between the two anomalous engines and the SBIRS design. The SBIRS satellite remains safe at the launch base.

“Assured access to space is a prime National Security Space directive,” Greaves said. “A fundamental part of assured access to space is safely getting our satellites to orbit which is extraordinarily challenging and technical. Ensuring the safety of our national security space assets is critical and we will extensively investigate all possible causes before launching the SBIRS GEO-3 satellite.”



Jason Rhian spent several years honing his skills with internships at NASA, the National Space Society and other organizations. He has provided content for outlets such as: Aviation Week & Space Technology,, The Mars Society and Universe Today.

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