For decades, the U.S. military—and its adversaries—have coveted missiles that travel at hypersonic speed, generally defined as Mach 5 or greater. Intercontinental ballistic missiles (ICBMs) meet that definition when they re-enter the atmosphere from space. But because they arc along a predictable ballistic path, like a bullet, they lack the element of surprise. In contrast, hypersonic weapons such as China's waverider maneuver aerodynamically, enabling them to dodge defenses and keep an adversary guessing about the target.
The worry being these hypersonic demons are unstoppable. But for a great majority of the time even the predictable ballistic path missile have been unstoppable. There have been gains in anti-missile technology to worry missileers, but certainly much cheaper alternatives to hypersonic flight exist, and one has to assume there are larger reasons to pursue it. Again from the article:
Now, DOD is leading a new charge, pouring more than $1 billion annually into hypersonic research. Competition from ambitious programs in China and Russia is a key motivator. Although hype and secrecy muddy the picture, all three nations appear to have made substantial progress in overcoming key obstacles, such as protecting hypersonic craft from savage frictional heating. Russia recently unveiled a weapon called the Kinzhal, said to reach Mach 10 under its own power, and another that is boosted by a rocket to an astonishing Mach 27. China showed off a rocket-boosted hypersonic glide vehicle (HGV) of its own, the Dongfeng-17, in a recent military parade. The United States, meanwhile, is testing several hypersonic weapons. "It's a race to the Moon sort of thing," says Iain Boyd, an aerospace engineer at the University of Colorado, Boulder. "National pride is at stake."
So, simple answer, space war butthead stuff. Not to be dismissive. The tech is fascinating. The tech is finally melding and all the niches for spaceflight are starting to mature. But just to hurl nukes? No dearie dear. Why build a cathedral and use it as a battering ram? My guess is there's a lot more to the Air Force X47-B space plane program than meets the eye. Lots and lots of stuff, not to mention all the Shuttle flights. The USA plays Aw Shucks almost as often as the game of Catch Up.
And guess what? It is still rocket science. One hundred years on from the Wright brothers and it is still hard stuff to do.
Everybody is worried about Russia and China when they shouldn't count out Iran. Or India or Pakistan for that matter. We may be looking at Space War One (or Two? I don't know).
It's just more monkey hive honey spent on space monkey hives that will never happen and instead we get a sky full of warbots.
If so, I want a swarm of warbots working for me.