The whole article is based on an invalid premise: despite what the (Air Force) author says, there are not “independent services for land, sea and air.” Every service but the Coast Guard has ground combat units, three of the five have ships, and all five services operate aircraft. If that is domain-focused organization, we are doing an idiotic job of it.
Ideally, we would have multi-domain services dedicated to independent operations in different realms: the Army fighting operational land warfare, the Navy/Marine Corps/Coast Guard doing the same at sea, and the Air Force conducting independent strike operations directly against the enemy homeland. The US Air Force is strongest when it focuses on independent strike operations and it is weakest when it tries to control operational aviation functions like CAS.
Therefore, space should not be handed off to a single service, because it is useful to all three operational constructs. A joint-service combatant command is probably in order, (we’ve had one for three decades), but a new service would be confused. Also, as space currently only supports land/sea maneuver and strike operations, a US Space Corps would be a distinct second-class citizen in the armed forces.