The Navy is in the process of testing the Harpoon Block II+ missile. The main feature of the II+ is the ability to accept in-flight guidance.
Is that really a big deal? Or even a moderately worthwhile capability?
Harpoon has a range of 60 miles and a speed of 540 mph. Doing the math, that translates to 9 miles per minute. Thus, at max range, the Harpoon will cover the distance to the target in 6.6 minutes. Is there really going to be a need to update the targeting in 6.6 minutes? A ship target moving at 30 kts, for example, will move 3.3 nm in 6.6 minutes – presumably still well within the Harpoon seeker range – and that’s the worst case of max range and max target speed.
Presumably, the mid-course guidance (it’s called “mid-course” because it happens part way through the flight, not at the last second) would take place at around the 3 or 4 minute mark of the flight. Seriously? Is there really a need for mid-course flight path changes after 3 or 4 minutes? Even a very fast ship would only have moved a mile or two and most targets less than that. Presumably, we had a pretty good target fix when we launched. It won’t have changed that much! Yes, we can launch on bearing only but if that’s all we had at launch, we’re not going to have any better data 3 or 4 minutes later.
For any case of less than max range or less than max target speed, the need for mid-course guidance just goes from not realistically needed to utterly not needed. There just seems to be little need for mid-course guidance updates. This seems like a capability that sounds nice when you say it but is not worth the cost and added complexity. Remember, not only does the Harpoon have to carry additional equipment (cost and complexity as well as weight) but whatever guiding platform there is has to have a transmitter capable of sending signals in whatever format is required (cost and complexity).
By the way, what platform is going to provide the mid-course guidance data? Any platform that has a good enough fix on the target at the moment of mid-course correction almost certainly had the same good fix at launch with exact knowledge of location, course, and speed thus rendering the need for mid-course guidance moot.
Honestly, I get the feeling that this is just a hyped capability designed to get more developmental funding for the manufacturer. This is a solution looking for problem. There’s a lot of things I’d rather spend the developmental money on than this.