User blog comment:Rozh/Surface-to-Orbit Artillery/@comment--20110322132539

Personally, the concept of a Magnetically Accelerated Surface-to-Orbit Artillery (MASOA, as you so aptly abbreviated the term to) is sound - as per the Contact Harvest repurposed Mass Driver. However, as per previous discussion, there are issues with the idea; especially when we discuss the cost-effectiveness of a MASOA compared to a Orbital Defense Platform.

I do believe MASOA would be more expensive than a ODP, given the amount of time, effort, and expenditure needed to construct one, transport it to a location, and then set it up. As the device is not going to be movable, its going to be an even easier target than an ODP. Furthermore, its going to be less effective at planetary defense, as the projectile will encounter a large amount of atmospheric air resistance when fired, removing kinetic energy from the projectile.