factor on the fly-out envelope is the KV battery, which is sized for 1,100 sec of operation. As noted to the right of the figure, there is ample payload margin for an even heavier KV if more divert capability is desired.

GMD-E Midcourse Kill Vehicle

As set forth above, the KV for the GMD-E interceptor is more capable and heavier than the exoatmospheric kill vehicle (EKV) and therefore supports the resilient CONOPS underpinning a multiple-SLS firing doctrine. It has all the recommended features described in Chapter 3, including an X- and S-band communication transponder of sufficient transmit power and antenna configuration for two-way link closure with either X- or S-band radars, radiation-hardened electronics, and battery capacity for 1,100 sec.

The KV’s long-wavelength infrared (LWIR) sensor can see threat objects at room temperature at a range of 2,000 km and small, colder objects shortly thereafter as range-to-go decreases. This longer acquisition range and acuity is achieved with a 30-cm-diameter aperture and a 256 × 256 two-IR-band focal plane array. A visible band array is also recommended. The focal plane and adjacent optics are cooled down to about 100 K in flight before sensor uncap using a gas blow-down system. This provides as much as 200 sec of observation by the onboard sensor in most first-shot engagements, thus maximizing opportunity for concurrent viewing of the spatial and temporal dynamics of target objects by both the onboard optical sensor and radars in view while the interceptor is closing on the target complex. The analysis used to size the sensor is provided in classified Appendix J.

The KV Divert and Attitude Control System (DACS) is sized for a divert capability of 600 m/sec, which, with the almost-1-degree sensor field of view, can handle handover uncertainties of ±30 km or more. The large payload margin of the interceptor would allow additional divert and step staring by the sensor, which in turn would permit even larger handover uncertainties if desired.

The KV has an encrypted, dual-channel communications transponder with both X- and S-band two-way encrypted links compatible with either type of radar as the ground transmitter and receiver. This provides two-way communication with interceptors after end-of-first-stage-burnout for radar TOM updates or override commands from the battle manager. The encrypted downlink has enough bandwidth to display what the onboard sensor sees and designates from sensor uncap to intercept.

A notional inboard profile of the recommended GMD-E KV is shown in Figure 5-5, and a weight statement is shown in Table 5-2.

Figure 5-6 displays the sensor and KV fully fueled (“wet”) mass as a function of cooled sensor aperture, given the performance and characteristics shown in Table 5-2. Note that the GMD-E kill vehicle fits nicely on that curve, albeit with less functionality included. A feature known as a “kill enhancement device”



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