Introduction
The primary objective of America’s Maritime Strategy is to demonstrate sea control as a deterrent to wartime escalation. A critical element of the strategy is the carrier battle group providing containment of forward area air and naval forces, and strikes against their bases and support facilities. Unfortunately, transiting battle groups are subject to detection, tracking, and identification by enemy radar and electronic ocean reconnaissance, and infrared-sensing satellites. U.S. fleet operations therefore require an anti-satellite (ASAT) system to control Soviet access to space, and to defeat their spaceborne sensors and command, control, and communications networks. Of the near-term ASAT basing options using kinetic energy weapons, submarines provide the greatest coverage, survivability, and intercept opportunity.
Intercept Opportunities
Regardless of the state of hostilities, satellite deployment allows three intercept opportunities: resident, boost phase, and antipode. Satellites in resident orbit can be precisely intercepted based on track data. Sea-based ASAT platforms provide greater mobility and resident satellite coverage than land-ba.-;ed facilities, which may have to wait days for intercept opportunity. Among the sea-based alternatives, only the submarine provides the necessary covertness for extended, autonomous operations, allowing intercept in areas inaccessible or too threatening to surface ships.
Boost phase intercept at about the 1/4-orbit point during ascent may be necessary as a countermeasure to sub-orbital “quick look” capability in the future. For the three major Soviet launch facilities at Pletsetsk, Kapustin Yar, and Tyuratam, intercept occurs in the Western Pacific (west-to-east launch). These regions coincide with proposed forward operating areas for U.S. naval forces and supporting long range communications; therefore, covert deployment of ASAT -capable submarines into these areas, prior to arrival of U.S. battle groups, requires no change in the Maritime Strategy. Unescorted surface ships carrying ASATs would be wlnerable, requiring air cover and ASW support for protection due to the proximity of coordinated Soviet naval and air force$.
Intercept at the antipode takes advantage of the principle that during launch, a satellite must pass over a point (antipode) on the earth’s surface diametrically opposite to the launch point, minus the earth’s rotation during ascent Intercept from the area in the South Pacific enclosing the antipodes of the three Soviet launch facilities represents a means of blocking access to space.
Oceanographic data for the South Pacific antipodes shows wide variations in the sound velocity profile, bottom contours, and ambient noise. For example, broadband noise levels range from high near the marginal ice zone in the southern latitudes, to low levels, due to the absence of shipping, in the warmer northern area. The diverse acoustic conditions favor the U.S. due to advanced sensor and processing capabilities, and lower radiated platform noise. Sensor and weapon development for under-ice operations should complement existing open ocean ASW tactics and technology. Operational requirements for ASAT basing at the antipode are discussed below.
The Anti-Satellite Weapon
Kinetic energy weapons (KEWs) represent the most mature, reliable, near-term ASAT technology. The kill mechanism is simple: impact the satellite with a few kilogram mass traveling at speeds of several kilometers per second. The primary issues are booster missile size and weight for launcher commonality and reduced cost, versus missile range and KEW impact velocity.
The ASAT interceptor envisioned consists of an autonomous, high-velocity (10 – 12 km/sec), lightweight kinetic kill vehicle (KKV) with visible seeker, mounted on a Standard SM-2 missile with a kick stage. Technical risks are reduced because the boosters and SM-2 Extended Range stage exist, and the KKV and seeker are in the prototype stage. The booster technology, modified for additional mission flexibility, could be used to provide rapid deployment of smaller, low earth orbit and depressed trajectory, single-mission satellites, e.g., for timeurgent intelligence-gathering missions in Third World conflicts.
The advantage of the TOMAHAWK-size envelope is so the missile can be launched from the Mk45 Vertical Launch System, or standard 21- and 30-inch torpedo tubes. Minimal changes would be required in the ship’s fire control, navigation, and communications systems to accommodate the missile’s “fire-andforget” command and control sequence. The missile is enclosed in a transportable canister including a gas generator for ejection and “zeroth-stage” for propulsion to the surface. It would be a relatively safe “wooden round” requiring periodic recertification, but minimal service, access, and environmental control. No additional manpower would be needed to maintain or launch the missile. Finally, full warfighting capability of the host submarine would be retained.
ASAT Submarine Force Level for Antipode Basing
Because the resident and boost phase intercept missions are in accordance with existing operations, no changes in submarine force levels for these missions are anticipated. Force levels for the remaining antipode mission can be made based on the following assumptions and a 688-class model: (1) 5-day transit one-way (2400 nmi to any of several Pacific islands) at a tactical speed of 20 knots, (2) 2 days in-port replenishment, (3) 37 weapon loadout (ASATs and torpedoes), and (4) 3 satellite engagements per day (1 per site per day). The high engagement rate reflects the Soviefs proven ability to “surge” launch for reconstituting satellite networks. Figure 1 shows operating areas at the antipodes for three ASAT ranges based on their projected terminal velocities. The figure illustrates the advantage of larger operating area and lower probability of detection for increased missile range and KKV velocity.
Figure 2 shows the required submarine force level as a function of ASAT load and number of submarines on-station. The figure indicates that ASATs should comprise at least half the weapon mix to reduce the force number and base Joss factor to reasonable levels. The high loss factor is due to the assumed long transit, and relatively high engagement rate and short onstation time. This shows the need for at-sea rearming, particularly in a protracted conflict .
The total force level may be reduced by limiting defensive weapon mix — not a viable wartime option – and reducing the number of submarines on-station. More than two requires significant cost and base support A single submarine must use the higher performance 14 km/sec terminal velocity KKV to cover the antipodes corresponding to the three Soviet launch sites, and allows no redundancy in case of loss. Thus, two submarines on-station are about optimum based on the assumptions and a 50:50 weapon mix. This calls for a total force level of about four 688-class submarines. Should the SSN-21 be available with its larger 50 weapon loadout, it would reduce the level by about 40%. In the future, other ASAT systems, including those using direct-energy for greater range, should be available to complement the sea-based systems in helping to reduce the engagement rate and required force level.
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Soviet Response to Antipode Intercept
There are several possible Soviet responses to a submarinebased ASAT at the antipode. The first is to provide separate, mobile land- and air-launch facilities. The Soviets are currently studying the use of the giant An-225 transport aircraft as an airborne launcher for unmanned space crafl Mobile ICBM boosters are another option. Although these countermeasures defeat the effectiveness of antipode-basing, they provide little defense against boost phase and open ocean intercept. Sovietimposed treaty limits placed on the testing and deployment of sea-based ASATs must also be considered in an era where intentions, but not capabilities, are changing.
The most likely Soviet wartime response to antipode basing would be containment of the ASAT submarines. However, the Soviets are restricted by type and number of ASW assets. Aircraft do not have the necessary size and endurance for transit and loitering, and capacity to deploy sonar in large numbers for wide area search. The location of the antipodes further reduces the effectiveness of airborne communications for off-board processing of aircraft and air-dropped sensor data. For carrier-based aircraft, high value units would require AA W and ASW defenses.
Unassisted Soviet submarine force requirements to provide ASW coverage are based on the assumptions that each submarine is assigned a 250 nmi square area, and a base loss factor of 60% ( 40% on-station). The loss factor is for a 15-knot transit (tactical) speed to and from Cam Rahn Bay, 60 days on-station, and a 15-day replenishment period. Submarine coverage is scaled from open literature U.S. submarine force levels in the GIUK gap: a 1000 nmi barrier with two screens and a total of eight submarines for about 250 nmi per submarine.
The requirements, shown in Table 1 for defending against a single ASAT submarine, indicate excessive Soviet forces necessary to defend their access to space from their three largest launch facilities. Increasing the number of ASAT submarines increases the area and number of ASW forces. Ironically, this is an example of Soviet Admiral Gorshkov’s contention that it has been, and will continue to be, more expensive to mount ASW defenses that to build and man submarines, particularly in out-of-area operations.
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There is an additional issue related to Soviet training and force deployment. Operating submarines in a remote area where long range communications may not be reliable or secure, places greater command and control responsibility on the submarine CO. This is contrary to Soviet training which relies on command from a central authority. As a result, changes in Soviet doctrine would be necessary or effectiveness of command could suffer.
