Recent talk about hypersonic missiles got me wondering whether SpaceX’s reusable rockets would lend themselves to this role. Austin Vernon suggests that SpaceX’s Starship is America’s Secret Weapon:
B-52s flying from Barksdale AFB to complete a mission in East Asia incur a marginal cost of $50/kg to deliver bombs. Starship’s cost is cheaper and can put weapons on target in less than thirty minutes. Each Starship launch has the same payload as three B-52s.
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The supply line would be a natural gas pipeline and a rail line providing fuel and projectiles to a domestic launchpad instead of ships crossing oceans.
I hadn’t considered this though:
Orbital weapons still need intelligence to tell them where to go. Starship’s sister system, StarLink, provides an answer. StarLink is a constellation of thousands of small Low Earth Orbit satellites that gives customers low latency broadband internet. It uses sophisticated phased-array radios that allow ground terminals to track satellites traveling thousands of miles per hour.
As Casey Handmer points out, StarLink can use its radios to do high fidelity synthetic aperture radar (SAR). SAR is already one of the primary ways militaries find enemy ships, and researchers have used it to track planes. It could also see ground vehicles.
While the US already has satellites capable of doing this, they are expensive and limited in number. Individual StarLink satellites cost a few hundred thousand apiece to build and launch on Starship. One of the first things China would do in war is shoot down our military satellites with anti-satellite missiles. That is a problem with bespoke satellites but not with Starlink. Anti-Satellite missiles cost tens of millions of dollars. Each Starship launch could drop off hundred of StarLink satellites. The Chinese would have to expend incredible resources to keep StarLink offline.
A satellite constellation provides other bonuses. Our GPS satellites are both hard to replace and sensitive to jamming. StarLink can provide GPS coordinates (with a few meters less accuracy), and its phased array radios make it difficult to jam.
The upshot is StarLink gives the US survivable sensing, communication, and navigation capabilities.