The original scientific paper has now been published. Thankfully, I can report MIT's scientists did not compare L/D ratios of HGVs & birds. But the paper raises one very interesting claim about the detectability of an HGV from space. http://scienceandglobalsecurity.org/archive/sgs28tracy.pdf
/1 https://twitter.com/TheDEWLine/status/1350185790622605316

The read of the @nytimes story and others is that the authors treated the slower speed of an HGV relative to a ballistic missile on a depressed trajectory as big news. But given the cross-range maneuverability of an HGV, I don't consider it's slower speed as a big deal. /2

But what is a big deal is the detectability of an HGV from space. The MIT paper's authors use open source data to conclude that an HGV can be detected and tracked by SBIRS and DSP over nearly their full glides. IF that's true, it would defeat one of the key advantage of HGVs. /3

We've heard Mike Griffin, former USD/R&E, say many times that HGVs are 10-20 times dimmer during glides as ballistic missiles, rendering them significantly harder for space-based early warning capabilities to detect and track in order to cue interceptor missiles. /4

Indeed, Griffin repeatedly emphasized that it was this vulnerability that drove the Chinese and Russian militaries to field HGVs in the first place, as they sought to find a higher-percentage chance to evade the US military's ballistic-oriented defenses. /5

That apparent vulnerability also is one of the main justifications for establishing a vast new space warning and tracking system by the Space Development Agency, featuring new IR sensors optimized for the cooler thermal profiles of HGVs and HCMs. /6

The big ? then is whether MIT's scientists have judged the capabilities of the existing missile warning systems correctly, or if they have over-estimated how those satellites to can cue terminal defenses to HGVs despite their dimmer signature and cross-range capability. /END.