3 ms·
The sensor stuff is a common but exaggerated discussion point in online discussions about this. There's a ton of previous work. Pershing II used terrain matchin
by jasonwatkinspdx 4y ago
The sensor stuff is a common but exaggerated discussion point in online discussions about this. There's a ton of previous work. Pershing II used terrain matching of SAR images for terminal guidance ages ago. The main technology for making this work is just electrically neutral ablative heat shields, which there are a variety of companies making commercially today. Other historical examples for say visual IR use quartz windows, etc. There's complications due to the heat and related plume, but the sweeping claims about this point are usually off the mark.
- jandrewrogers 4y agoQuartz isn't durable enough for hypersonic IR windows in dense atmosphere. When tested decades ago, actively-cooled sapphire, diamond, and even more durable exotics ablated too quickly for that purpose. I don't know what they are using today but the inability to find an IR transparent material that could survive long enough was a central design problem. This can be seen in the odd compromises made to the seeker design of e.g. THAAD, which doesn't spend much time in the lower atmosphere.