Thread by @SimonHoejbjerg

In Ballistic Missile Defense (BMD) Launch on Remote (LOR) and Engage on Remote (EOR) are concepts that are often talked about and discussed.

But why do we need LOR and EOR and what do the concepts bring to the BMD systems on the battle field?

This will be a LONG thread!

In this thread, I will try to visualize and explain when LOR and EOR make sense over organic engagements and why.

Often, I see and hear people talk about LOR and EOR, but struggling to really understand the underlying concepts and requirements to the various elements.

First of all: All visuals in this thread are notional and not representative of any live systems - this thread is to highlight and discuss principles, not actual system performance of real systems. The visuals are all generated using an unclassified BMD planner and simulator.

Second of all: The examples in this thread are simplified for the sake of discussion. Obviously there are a bunch of (really deep) rabbit holes that one could go down into as well as several very complicated technical details - they might be the basis for another thread one day.

Third: See this MDA chart for a basic explanation of Organic Engagement, LOR and EOR.

As discussed above, this thread will try to explain what this really means and why we need it.

Here we go....

Bottom Line Up Front:

LOR and EOR are needed, when there is a mismatch between the effective range of an interceptor and the organic sensor, i.e. the organic sensor has to short detection range.

If the organic sensor's detection range is sufficient, LOR and EOR are not needed.

In the scenario I have generated, "Blueland" is going to defend itself against an IRBM threat from "Redland" - both countries are outlined by colored polygons.
In Redland the expected launch area is marked by a red circle.
In Blueland the defended area is marked by a blue circle.

For another thread on basic BMD planning and deployment of systems, see this thread.

https://twitter.com/SimonHoejbjerg/status/1139631877554409473?s=20

The deployed system, that is assigned to the defended area in Blueland has a radar field of view shown here.

And a kinematic volume of the interceptor shown here.

By kinematic volume, I mean the effective range of the interceptor. It might be able to fly longer, but this volume is where it can effectively generate a kill. The maximum effective range of the interceptor.

If we overlay the to volumes, we can see that they are almost identical.

While that may seem good to some, it will actually cause problems with the coverage, as we will see later on when we attempt to intercept a ballistic missile.

In the following visuals, I will show a bunch of defended area analyses with different color coding.

This is the legend need to understand that.

To clarify: Threat Out of Range means that the threat has insufficient range to reach that area.

The defended area analysis show that the system does have a very big footprint and not a lot of shoot-look-shoot opportunities.

As I will illustrate in the following, this is because the sensor isn't matched optimally to the interceptor.

The big issue, is that the system cannot launch an interceptor until the sensor has detected that threat, which happens when at the point where the blue line (sensor track line) meets the red ballistic trajectory.
While the interceptor is flying out, the threat is moving too...

This means that even though the inteceptor is launched almost immediately (yellow dotted line), the actual intercept doesn't happen until the solid yellow line.
Notice that it is nowhere near the max range of the interceptor.

In other words: We are not using the full range of the interceptor, which is why we are not getting the maximum defended area that this particular interceptor can actually offer.

So lets deploy a forward sensor that allows our system to perform an LOR mission and see what happens.

What you see, compared to the organic footprint are these points:
- The footprint is increased
- More shoot-look-shoot options
- No non-detects

This is the reason:
Although the organic sensor detects the threat at (3), the interceptor is launched at (1) based on the remote data. Therefore the interceptor has flown to (2) by the time the organic sensor detects the threat.

This means that time to first launch is (1), time to first intercept is (2), which is at the maximum range of the interceptor and there's another launch opportunity at (3) with an intercept opportunity at (4)

So not only does LOR enable the interceptor to intercept at maximum range, it also allows a shoot-look-shoot opportunity that we didn't have before. If the first intercept is a miss, we have time to launch again.

Now, because LOR allows us to intercept at the maximum range of the interceptor, we would not benefit from EOR in this scenario - the interceptor cannot fly further, anyway.
This is also shown in the defended area analysis for EOR.

If the organic sensor had a longer range, that was better matched to the interceptor, we would see different results in organic mode. In fact we see similar analysis results compare to LOR and EOR.

This is obviously because the longer range of the organic sensor allows us to launch the interceptor sooner (1), intercept at maximum interceptor range (2), re-launch if required (3) and re-intercept at (4).
This would make a requirement for LOR void.

But what happens if we have a missile with a (significant) longer range than the organic sensor (the original organic sensor)? How would that look?

(Thread not complete, but twitter won't let me thread more, so this is still work in progress)

First of all, we get almost the same coverage as with the original missile we shorter range. Again, this is because the organic sensor is poorly matched to this range.
This small differences in size of the defended area is due to a slightly faster velocity of this interceptor

Of course the detailed reason is that we cannot launch the interceptor until the organic sensor has detected the threat (1), which obviously prevents the intercept (2) to happen at the maximum range of the missile.

With LOR enabled with the longer range missile, we see that we get a bigger footprint, but still not as big as it could probably be.

This is why, that even though LOR allows the intercept further out (2) it is still not at the maximum range of the interceptor because it must take place inside the organic sensor's field of view.

This is a scenario where we will benefit from EOR, as can be seen in this defended area analysis.

Now we get the full coverage from the interceptor.

And this is why:
Notice how early the interceptor is launched (1) to allow it to intercept at maximum range (2).
In this scenario, EOR would not only allow shoot-look-shoot, but also another round of kill assessment and re-engagement due to the long range between (2) and (3).

Now obviously, if the organic sensor had longer range, the requirement for LOR and EOR would change. It may not go away, depending on the sensor range, but it would change, as seen here.
I feel like detailed explanations might not be needed at this stage 😉

As can seen, this enhanced organic sensor still doesn't give enough coverage, so let's try one that's even more enhanced, with an even longer range.
As can be seen, the intercept (2) happens closer to maximum range, but still not entirely there.

Obviously it is possible, to give the organic sensor even further range, which would ultimately mean that LOR and EOR would not be required. This might be practically impossible for various reasons, so LOR and EOR can be the only solution to long range interceptors.

To summarize:
LOR and EOR are needed when the missile range and organic sensor range are not well matched. In those cases, LOR and/or EOR and allow maximum leverage of an interceptor's full range and provide the maximum defended area instead of modifying the organic sensor.

Now, in this thread and scenario I have only used surface based sensors to provide remote data.
But as @tomkarako, @ketodorov and @RLHeinrichs et al frequently argue, the remote sensor can just as well be space based, which will not be limited by earth's curvature etc.

@tomkarako @ketodorov @RLHeinrichs As I said initially, there are several rabbit holes etc., to go into, but in the interest of keeping it simple this is the end of the thread.
I hope it was interesting...
Thanks for reading, if you stayed until the end 🙏