This html article is produced from an uncorrected text file through optical character recognition. Prior to 1940 articles all text has been corrected, but from 1940 to the present most still remain uncorrected. Artifacts of the scans are misspellings, out-of-context footnotes and sidebars, and other inconsistencies. Adjacent to each text file is a PDF of the article, which accurately and fully conveys the content as it appeared in the issue. The uncorrected text files have been included to enhance the searchability of our content, on our site and in search engines, for our membership, the research community and media organizations. We are working now to provide clean text files for the entire collection.
Ironically, what the world did not see during the spectacular intercepts of Iraqi Scud missiles by U.S. Army Patriot missiles during Operation Desert Storm has had an even bigger impact on the future of ballistic-missile defense. Aegis ships—the cruiser Mobile Bay (CG-53) and others—tracked Scuds from hundreds of miles away with the precision required to support missile intercepts. But none of those ships was equipped with a missile capable of intercepting the high-flying ballistic threat.
As a result, the U.S. Navy convened an antiair warfare working group to study the possibilities of modifying existing at-sea combat systems for theater ballistic-missile defense (TBMD). At the same time, several Department of Defense study groups, including the Defense Science Board, met to discuss the future capability of the nation in general to counter ballistic missiles. Each study reached the same conclusion: our existing Aegis ships, with vertical launching systems, SPY-1 radar, and the SM-2 Block IV variant of the Standard Missile, provided excellent integrated combat systems that—with some modifications— could provide a significant counter against the ballistic missile threat in a relatively short time.
Such a Navy effort is now underway. It includes nearly 50 cruisers and destroyers and takes advantage of ships already equipped with SPY radar, vertical launch system, and the command, control, and communication system necessary for TBMD. Repair parts, technical agencies, formal classroom training, and Navy personnel themselves are already in place and operating. The plan relies on an existing investment of more than $40 billion and accelerates development efforts to achieve real combat capability in just a few years.
Aegis/SM-2 Block IV A
Initial efforts focus on modifying the Aegis SPY radar and weapon-control system software to enhance tactical ballistic-missile detection, provide continuous tracking, and calculate engagements. Without changes to the transmitter or other hardware, SPY radar software changes can schedule the correct wave forms at higher altitudes in order to enhance detection opportunities and track ballistic threats. Weapon- control software modifications will calculate the fire-control solution, predict intercept points, appoint target priorities, launch missiles, and coordinate missile uplink commands with the SPY radar.
The Aegis display and command- and-decision systems will be modified to display these target tracks together with the engagement envelopes calculated in the weapon- control system.
After extensive land-based testing, the new software will be ready for the final phase of computer program development—at- sea testing, which includes missile firings. This process will ensure that the tactical programs are debugged and mature upon delivery to the fleet. A planned user operational evaluation system in 1997 will enhance the capability to respond to a crisis situation. Full initial operating capability is planned for a few years later. All 22 vertical-launch-equipped Aegis cruisers and all Arleigh Burke (DDG-51)-class Aegis destroyers (26 authorized through fiscal year 1993) could receive the Aegis/SPY radar modifications.
In order to provide an interceptor capable of killing ballistic missiles, the Standard Missile Block IV is slated to undergo modification. Currently in full-scale development, the SM-2 Block IV provides a missile with the range and kinematic performance required fof the TBMD mission. Warhead, seeker, and fuse changes will be required. Warhead changes will capitalize on the ongoing Patriot missile design efforts intended to improve upon its Desert Storm performance. An adjunct infrared seeker is planned for the Standard to minimize miss distance during the terminal phase of the engage-
bility, and the approval of necessary requirements documentation to formalize the acquisition process.
During May 1992, the House Armed Services Committee was the first of the four key defense committees to endorse spending “not less than $90 million for exploration of promising concepts for naval TMD, including modification to the Aegis weapon system and enhancements to the Standard Missile interceptor.” The committee also directed the organization to assess the near-term contribution and cost effectiveness of exoatmospheric capabilities, including Standard missiles with kick-stage rocket motors and a light exoatmospheric projectiR (LEAP) hit-to-kill vehicle.
The House Appropriations Committee agreed, and stated in its report that “Navy TMD programs should be accelerated and provided with increased budget support within SDI.” It also noted that it “strongly supports an increased role for the Navy in providing TMD. . and recognizes sea-based “advantages in mobility, flexibility, sustainability, and coverage.” The appropriations committee re-
ment. Fuse improvements will account for faster closing velocities between the ballistic target and the interceptor. Navy officials anticipate that the SM-2 Block IV Standard, modified as a TBMD interCeptor (now designated SM-2
Slock IV A) will retain its full capability against aircraft and cruise missiles in order to provide the fleet with a multimission missile. The Aegis weapon-control system "'ill select the modes of missile op- emtion appropriate for the specified larget and transmit a command to launch system.
The SM-2 Block IV A and the Aegis system software modifications will provide an antiballistic- missile capability similar to that provided by the most advanced upgrades planned for the Patriot system. Like Patriot, SM-2 Block IV A and Aegis will provide the lower tier of a two tiered sea-based defensive system capable of defending debarkation ports, airfields, and troops ashore.
To provide a higher-altitude, longer-range interceptor, the Navy plans to build upon the ongoing Strategic Defense Initiative Organization (SDIO) technology effort to develop a lightweight exoatmospheric projectile (LEAP). Like other ongoing interceptor efforts, this projectile emphasizes a kinetic kill vehicle. As ballistic missiles fired from longer ranges reenter the atmosphere, their increased speed makes existing fragmentation warhead technology less effective. The hit-to-kill concept strives to smash the mass of the kinetic kill vehicle into the target at high speed, while the inbound ballistic missile is still in the upper atmosphere. Homing accuracy comes from an infrared seeker and miniaturized rocket motors to divert or adjust the position of the kill vehicle before intercept. The SDIO technology effort has focused on reducing the size and weight of these vehicles and improving their performance to make them suitable for use on board Standard Missile-sized launch vehicles. Some of the nation's key defense contractors are involved with the LEAP work, including three of the biggest aerospace defense firms: Rockwell International, Hughes, and Boeing. All three contractors have built and tested LEAP vehicles. Upper atmosphere flight tests are ongoing.
The Navy Standard missile is an attractive LEAP launch vehicle.
The SDIO has started a Navy LEAP flight-test program in order to gain a better understanding of it. The Phase I flight test program will use SM-2 Block II (Terrier) launch vehicles to propel the LEAP and a “kick stage” rocket motor into the exoatmosphere. In September 1992, the USS Richmond K. Turner (CG-20) validated the concept of the Standard Missile launch vehicle by sending up a Terrier round with a payload built to the dimensions and weight of a real LEAP.
Phase II of the Navy LEAP flight-test program, currently scheduled to begin in 1995, will use the SM-2 Block IV Standard as the launch vehicle.
While LEAP is a potential upper-tier sea-based interceptor with great promise, the SDIO is working with the Army and Navy
Port “strongly supports aggressive exploration of promising concepts for Naval TMD” because of relative cost effectiveness of naval systems and upgrades that can be fielded more quickly.” _
Subsequently, all four congressional defense committees formally approved initiation of Navy TMD at not less than $90 million in fiscal year 1993. The appropriations hill provided full funding.
Support for Navy TBMD has been embraced quickly by industry teams, who see this new initiative as capitalizing on existing production-line investments by modifying existing weapon systems and missiles. It keeps engineering teams together and goes a long way toward preserving defense-related jobs. Navy TBMD enjoys strong, wide-based support throughout the Department of Defense, Congress, and within the defense community at large. Allied navies in Europe and the Western Pacific already are expressing interest in coming involved.
Saddam Hussein’s use of Scud missiles in the Gulf War woke up national political and military planners. Future
SM-2 Block IVA for TBMD Common Missile for ATBM / ASCM Defense
to ensure that ultimately the best interceptor becomes incorporated into the Aegis weapon system. Another sea-based upper- tier candidate is the Army’s theater high-altitude area defense (THAAD) missile. Like LEAP,
THAAD uses hit to kill technology to destroy ballistic missiles.
Cost and operational analyses are evaluating all the sea-based, upper-tier options.
Long-Range Ballistic-Missile Targeting
We could target long-range exoatmospheric interceptors in a variety of ways. Sensor netting, which employs computers to compare, correlate, and fuse the data from different sensors with different angles on the target, has great promise. The Navy already has developed one such system called cooperative engagement. Through a high-speed data network, it shares radar measurement data between different units, a capability more important than sharing track positional data, like Link 11. Cooperative engagement, or systems like it, could enhance theater ballistic-missile defense by giving all shooters (Aegis ships, Patriot units, and
THAAD) the benefit of a composite, multisensor detection and tracking system. For example, during Desert Storm, ships tracked Scuds from a side aspect, detecting a large target. Meanwhile, the Patriot radars worked hard to acquire a much smaller head-on aspect target. Should a sensor netting system such as cooperative engagement become a part of the TBMD architecture, all shooters would reap the benefits of an apparently much larger target through sensor netting and cueing. Cueing is one sensor “telling” another sensor where to “look” through the data network. The SDIO and the Navy plan to conduct Aegis-to-Patriot cuing experiments in the near term. Alternatives to sensor netting, including a plan to double the range of the SPY radar on board
Aegis ships, are still viable options.
Other assets that may assist in long-range targeting include national space- based sensors, such as the defense support program satellites and aircraft- mounted sensors. Although they are still in early stages, infrared seekers installed on board AWACS, E-2, or P-3 type aircraft, will enhance the theater commander’s'ability to make early TBM detections—and turn early warning into targeting.
These complementary efforts, an area-defense capability built upon the SM-2 Block IV A, a greater theater capability built upon THAAD, LEAP, or some other variant, and continued work to develop sensor netting and improve satellite and airborne targeting support, can provide a layered defense of land targets from Aegis ships at sea. Such a multitiered system could give the nation much greater flexibility in deploying a theater ballistic-missile defense capability during the current decade and beyond.
Commander Carey is currently the Navy program integration officer in the Strategic Defense Initiative Organization.
1
t
1
t
t
(
t
l
(
I
1
r
c
I
t
f
1
I ] 1 I
regional contingencies will see potential enemies threaten to use or actually fire ballistic missiles. The proliferation of these missiles, possibly armed with weapons of mass destruction, and their increasing accuracy highlight a growing requirement for capable, flexible, and sustainable defensive systems. Naval forces can play a crucial and unique role in littoral areas by providing ballistic-missile protection from the sea, while follow-on forces are deploying ashore. This ability provides an on-scene rapid response that is highly mobile and can remain on station indefinitely. Such a capability could extend to a wide- ranging defense—up to and including the sea-based corn' ponent of a global protection system.
The nation has made a broad-based commitment, and the Navy’s Aegis fleet provides the means to achieve a forward-deployed defense fairly quickly. This new and significant sea-based theater ballistic-missile defense promises to provide the nation an extremely effective capability for a relatively modest cost.
Captain Rempt is assigned to the Theater Defense Directorate within th6 Strategic Defense Initiative Organization.