Exercise: The Twin Dilemma

This exercise assessment describes the experience of participants tackling a Tactical Operating Environment (TOE) training simulation using basic EMDAR techniques. The assessement is presented as a series of ‘snapshots’ at key moments in the exercise.

Exercise Overview

This exercise requires EMDAR specialists to discriminate between EM detection patterns from multiple sources. On commencement of the exercise initial low-intensity detections are visible on port and aft arrays which give the appearance of a single TSMO. In fact, each array is displaying EM from a different TSMO.

To reduce the level of difficulty, the TSMOs remain stationary throughout this exercise, although they will output EM consistent with main engine use (participants are informed of this).

This exercise could be undertaken by a single EMDAR specialist or working with a crew including a quartermaster and Officer of the Watch (OOW) commanding.

Exercise Mission Brief

Exercise participants are briefed that multiple vessels may be operating in the star system, believed to be from the same civilisation. These vessels will be operating no further than 10,000 GUs from the system’s NAO (the system’s sole star).

The mission is to obtain a track on one of these vessels at a range of no closer than 1000 GUs for the purpose of making contact.

Exercise Assessment

On commencement, the participants adopt a cruising velocity of 0.1C and a heading of 045.

Snapshot 1

Above: EMDAR snapshot 1The forward and starboard arrays display typical background EM in empty space. Port and aft arrays show increased low-intensity EM which participants conclude is indicative of long-range EM generation, the source of which is most likely a TSMO (the system would automatically filter out EM from an astronomical object).

If this EM is from a single source it would suggest a TSMO at long range off the port quarter.

Participants adjust heading to 135 in an attempt to close range.

Snapshot 2

Above: EMDAR snapshot 2Quickly after this change in heading, aft and port arrays show a sudden increase in EM in the IR (infrared band). Participants conclude that:

  1. the jump in EM intensity is too sudden and large to be consistent solely with a decrease in range
  2. IR is typically emitted by magnetoplasma engines, suggesting an increase in engine output
  3. The spread of detections suggests a range of approximately 3000 GUs

The increase in IR is observed on both port and aft arrays, which would ordinarily suggest a single EM source. However there is a noticeable gap in timing between the jump in IR on the aft array compared to the port array (where the jump is observed later). If this EM was attributable to a single source, the jump would have been observed on both arrays at the same time.

The participants therefore conclude that they are observing multiple EM sources, possibly co-coordinated. To test this, the participants resume the original heading of 045, reasoning that resulting changes in EM intensity should diverge between sources, allowing them to focus on the closest.

Snapshot 3

Above: EMDAR snapshot 3The aft EM detections in the IR band appear to be trending towards increased range and falling intensity, suggesting the vessel is moving away from that EM source.

The port array shows a trend towards decreasing range and increasing intensity, suggesting the vessel is closing on that EM source.

The participants conclude that this confirms they are observing two EM sources. As they now appear to be closing on the port array EM source, the participants elect to maintain heading.

Snapshot 4

Above: EMDAR snapshot 4The aft array is now only showing long-range EM, confirming that the initial port and aft detections were in fact from separate sources.

The detections on the port array have increased in intensity and suggest a range of approximately 1000 GUs. There is now a noticeable increase in long-range EM on the forward array, which may correspond to the port detections. The participants change heading to 000 to maintain required range to port and to close range ahead.


Snapshot 5

Above: EMDAR snapshot 5The course change has stabilised range on the port array at approximately 1000 GU’s. Increased intensity on the forward array suggests the vessel is now reducing range ahead.

The participants aim is to achieve a range of 1000 GU’s (which requires a displayed range of 1000 GU’s on both port and forward arrays).



Snapshot 6

Above: EMDAR snapshot 6Intensity of detections on both port and forward arrays confirms a common EM source. Even though the range on the port array is not changing, the vessel is closing range on the forward array. The fact that intensity on the port array has also increased is highly indicative of a common EM source.

The participants order all stop to avoid overshooting the target range ahead. Initial attempts to achieve a narrowband track are unsuccessful and so the participants decide to wait until the vessel has slowed sufficiently before retrying.


Snapshot 7

Above: EMDAR snapshot 7The reduction in the vessel’s approach speed is reflected in the EM trail drift visible on the forward array. EM intensity on the IR band has increased, with a reduction in spread allowing more accurate estimation of range on both longitudinal and lateral axes (indicated by the blue target lines selected by the EM operator).

The EM intensity and spread makes it easier to target narrowband arrays and a track is acquired. The range of 700 GU’s to port and 1500 GUs forward is slightly outside mission parameters, however.