The objections River made apply to the thing you linked, too: namely to stay in a low-earth trajectory for any significant fraction of one orbit requires a speed of 28,000 km/h and more importantly all of that speed must be tangential (“horizontal”). It is expensive in energy to get rid of that tangential component of momentum, and most of it must be gotten rid of in order for the warhead to intersect the Earth’s surface with any accuracy.
(Yes, ICBM’s reach that speed, too, or close to it, but only when the direction of travel is close to straight down. I.e., the tangential component of velocity never gets above a few 1000 km/h.)
Yes, it gets a lot cheaper to get rid of speed when the vehicle is designed to interact with the atmosphere like the Space Shuttle was, as opposed to just shooting through it like a bullet or an ICBM warhead is, but that does not support your point (Tsvi) because such vehicles are the subject of intense study by all the advanced militaries (under the name “hypersonic glide vehicle”) and I have seen no signs that any nation is willing to forswear investment in or deployment of this new class of weapons.
In the decades during which hypersonic glide vehicles were infeasible, River is probably correct in asserting that there was no military advantage to be got from either nukes on satellites or fractional orbital bombardment systems.
The objections River made apply to the thing you linked, too: namely to stay in a low-earth trajectory for any significant fraction of one orbit requires a speed of 28,000 km/h and more importantly all of that speed must be tangential (“horizontal”). It is expensive in energy to get rid of that tangential component of momentum, and most of it must be gotten rid of in order for the warhead to intersect the Earth’s surface with any accuracy.
(Yes, ICBM’s reach that speed, too, or close to it, but only when the direction of travel is close to straight down. I.e., the tangential component of velocity never gets above a few 1000 km/h.)
Yes, it gets a lot cheaper to get rid of speed when the vehicle is designed to interact with the atmosphere like the Space Shuttle was, as opposed to just shooting through it like a bullet or an ICBM warhead is, but that does not support your point (Tsvi) because such vehicles are the subject of intense study by all the advanced militaries (under the name “hypersonic glide vehicle”) and I have seen no signs that any nation is willing to forswear investment in or deployment of this new class of weapons.
In the decades during which hypersonic glide vehicles were infeasible, River is probably correct in asserting that there was no military advantage to be got from either nukes on satellites or fractional orbital bombardment systems.