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SpaceX launches US military constellation satellites

Mission Tranche 0 will serve as the warfighter immersion tranche and support military exercises.

Falcon 9 rocket takes off from Vandenberg

SpaceX launched on Sunday, April 2, 2023, ten satellites of the Tranche 0 (zero) Transport Layer group, using the Falcon9 v1.2 FT Block 5 rocket n° B1075.2 that took off from the SLC-4E platform at 14:29 UTC (10:29 EDT | 07:29 PDT) from Vandenberg base in California. Falcon 9 headed south in azimuth to achieve a circumpolar orbit inclined 80 degrees to the equator. The first stage 'core' landed in the LZ-4 landing zone near to launch site, and the fairing shells were recovered about 490km from the coast by the vessel NRC Quest. The re-entry of the second stage wreckage occurred over the South Pacific. The mission was sponsored by the Space Development Agency (SDA), an agency of the United States Department of Defense, under its National Defense Space Architecture (NDSA). The second stage placed the satellites in an orbit of 941 x 952 km, with an inclination of 81.00°.

The launch, originally scheduled for March 30, was postponed out of an abundance of caution to investigate technical issues with the rocket. York Space Systems built eight ' transport ' satellites and SpaceX built two ' tracking ' satellites based on its Starshield chassis. To fully populate Tranche 0, York Space Systems and Lockheed Martin will each produce ten transport satellites, for a total of twenty T Zero transport satellites. SpaceX and L3Harris will each deliver four tracking satellites, for a total of eight spacecraft. Ground support for Tranche 0 is provided by the United States Naval Research Laboratory.

Falcon 9 launches the SDA Tranche 0 mission to low-Earth orbit
“This is a major achievement for the SDA and the entire Department of Defense. It shows that our main pillars, proliferation and spiral development, can contribute to national security,” said Derek Tournear, director of the SDA. “Through this release, we have demonstrated that SDA can maintain a schedule to deliver enhanced capabilities every two years. This revolutionary approach is enabled by growth in the commercial market, allowing us to move forward to provide combat capabilities in every future trench.”

It was the second attempt to launch the B1075 with Tranche zero mission. The launch was scheduled for March 30th, but canceled close to T-zero due to unspecified technical problems that caused the automatic system to cancel the takeoff. Later options, in the following days, were postponed “…to allow for additional checks”, a phrase used by SpaceX to cover up breakdowns, logistical problems or procedural abnormalities in launch preparation.

The Space Development Agency plan