Etienne Marcuz Profile picture
🇫🇷 analyst on strategic systems and technologies 🚀🛰☢️ NOT MoD. My views and my mistakes are my own. Always happy to learn and share 📖

Jan 30, 8 tweets

This launch follows HMS Vanguard overhaul, and therefore is part of a Demonstration And Shake down Operation (DASO). It aims at certifying a SSBN crew and weapon system for future strategic deployments (patrols). The whole system is tested, culminating with missile launch.

Many tracking assets will be involved, on land, in the air and at sea. Among mobile assets, the most important will be USNS Waters acting as the Launch Area Support Ship (LASS), and USNS Pathfinder at reentry area acting fitted with the Navy Mobile Instrumentation System (NMIS).

The SSBN HMS Vanguard is fitted with special systems in order to collect data on and around SSBN environment during launch.
We can see one of the probable probe on a beautiful pic. taken today while HMS Vanguard was leaving Port Cape Canaveral to go to launch area


Two ways communications, incl. data and voice, with USNS Waters/LASS and aircraft such as P-8 are allowed thanks to Buoyant Cable communication System (BCS). At least two P-8 are currently flying over launch area.


6000 km away (for this test) is station TAGS-60 USNS Pathfinder survey ship, equipped with the NMIS. This set consists of several equipment such as two tracking radars (X & C-band), optics, telemetry and weather systems.


For safety reasons, the ship remains ~25 nm from expected reentry zone. In order to evaluate RV (reentry vehicles, or bodies, or warheads) accuracy, a Portable Impact Location System was developed. It consists of 9 to 12 acoustic buoys + 3 communication relay buoys.


The com. relay buoys can collect RV telemetry from 3 RV (MIRV) spaced 12 sec in time from reentry until splashdown in the ocean. Spectrogram below shows such telemetry from a real test. Signal is lost ~35km (altitude) / 9s before impact due to plasma generated ...

... by hypersonic speed when reaching dense atmosphere.

Signal comes back ~2,6km / 2s before impact.

This gives an average speed of 3,8 km/s, explaining why it's REALLY hard (almost impossible) to intercept such a warhead with point defense systems such as Patriot or SAMP/T.

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