Foreign Relations of the United States, 1977–1980, Volume IV, National Security Policy

51. Memorandum From Secretary of Defense Brown to President Carter¹

Washington, February 25, 1978

You will recall that at the session in the NMCC last month² you asked for more information on what U.S. and Soviet laser capabilities are today and what they will be in the future.

The attached is a response to that request.

Harold Brown

Attachment

Paper Prepared in the Department of Defense³

Washington, undated

US AND SOVIET LASER WEAPONS CAPABILITIES

(S) The potential of laser weapons is embodied in three fundamental characteristics: delivery of energy at the speed of light, a potentially large magazine, and a wide field of fire within which the laser can switch rapidly from target to target. The US High Energy Laser (HEL) program is intended to develop the technology base for laser devices, and to demonstrate the feasibility and potential of the HEL as a weapon. We plan to assess, by the early 1980s, the viability of lasers in comparison to other weapons. Principal applications defined today include defense of aircraft, ships and ground targets against aircraft and tactical missiles. A decision to develop prototype weapons for these applications would produce laser weapons by the late 1980s. We are also examining concepts for space-based laser ASAT devices. The feasibility of such devices could be demonstrated by the late 1980s.

(TS) The Soviet laser weapons program enjoys a high priority. Several HEL ranges and test sites have been identified in the USSR, and the size and nature of these facilities indicate an annual HEL investment which is considerably higher than our own. We feel that the current Soviet laser technology level is comparable to ours. While we may tend to lead in pointing and tracking capability, the Soviets have probably achieved higher power levels. We believe the Soviets have underway a number of prototype development projects designed to assess the viability of laser weapons. Table 1 summarizes our assessment of US and Soviet laser weapon capabilities in an anti-satellite (ASAT) role. In this context, “capability” implies operational deployment in sufficient numbers to provide a meaningful effect. The US capabilities are potential capabilities—they are not capabilities which exist or are planned for implementation, but reflect what could be achieved in an orderly program without fiscal constraints. Similarly, the estimated Soviet capabilities reflect what could be achieved.

(S) Three types of capabilities are listed: “jam sensor”, “kill sensor”, and “kill structure”. “Jam sensor”, implies introducing false targets or obliterating some portion of the image. “Kill sensor”, implies permanent damage to the sensor or sensing medium. These capabilities generally require the laser to be in or near the optical field of view. Finally, “kill structure” involves damage to softer structural elements such as solar arrays. The power required to kill structure is about seven orders of magnitude higher than the power required to jam sensors.

(TS) Within one year, both the US and the Soviets could jam satellite sensors (film or detector arrays) at essentially all altitudes and kill sensors in satellites at low altitudes. The US airborne laser provides a near term advantage in reducing the reaction time from command to kill. But the Soviets may have a near term advantage in the ability to effect structural damage.

(TS) By the early 1990s, the US and the Soviet Union could have the capability to jam and kill sensors on high altitude satellites. Structural kills would be limited to medium altitude unless space-borne laser weapons were deployed. While a space deployment is possible by the early 1990s, it would be a substantial technological undertaking with considerable development risk.

(S) The entries in Table 1 indicating effective altitudes were developed using simple assumptions about spectral sensitivity and damage levels. A case by case analysis could easily result in an order of magnitude variation in effective range.

(TS) US and Soviet laser weapon capabilities in missions other than ASAT are summarized in Table 2. Both US and Soviet HEL programs will be demonstrating lethality and capability from now through the mid-1980s. We estimate that prototype air defense systems will be available in the Soviet Union by the early 1980s. Prototype US systems will be demonstrated in the mid-1980s. By the early 1990s, both the US and the Soviet Union could develop a capability for the short range point defense of ships, ground targets and aircraft. This capability could include structural as well as sensor kill devices. A US or Soviet space-based laser defense capability could defend friendly satellites against ASAT attack by the early 1990s. But development and deployment of such a capability in this time frame will involve significant risk. It is not likely that either the US or the Soviet Union will develop an effective laser ABM capability by the early 1990s.

Table 1

Table Prepared in the Department of Defense⁴

Washington, undated

U.S. AND SOVIET LASER WEAPONS CAPABILITIES IN ANTI-SATELLITE MISSIONS

		POTENTIAL5 U.S. CAPABILITY			ESTIMATED SOVIET CAPABILITY
Time Frame	Laser Basing Mode	JAM SENSORS (film, detector arrays)	KILL SENSORS (film, detector arrays)	KILL STRUCTURE OF SATELLITES	JAM SENSORS (film, detector arrays)	KILL SENSORS (film, detector arrays)	KILL STRUCTURE OF SATELLITES
Now (within one year)	Ground	To geosynchronous altitudes.	Low-altitude (800 km) (Photo recon)6	None	To geosynchronous altitudes. (Photo & launch warning)	Low-altitude (800 km) (Photo recon)7	Uncertain—possible subsystem damage or degradation at low-altitude8
	Aircraft	To geosynchronous altitudes.	Low-altitude (500 km) (Photo recon)	None	None	None	None
	Space	None	None	None	None	None	None
		POTENTIAL U.S. CAPABILITY			ESTIMATED SOVIET CAPABILITY
Time Frame	Laser Basing Mode	JAM SENSORS (film, detector arrays)	KILL SENSORS (film, detector arrays)	KILL STRUCTURE OF SATELLITES	JAM SENSORS (film, detector arrays)	KILL SENSORS (film, detector arrays)	KILL STRUCTURE OF SATELLITES
Early 1990s	Ground	All altitudes.	High-altitude (17,000 km)9	Mid-altitude (1000 km) (Photo, some ELINT, Ocean Recon, Weather)10	All altitudes.	High-altitude (17,000 km)11	Mid-altitude (1000 km)
	Aircraft	All altitudes	High-altitude (17,000 km)	Same as above without reaction time limits.	All altitudes.	High-altitude (17,000 km)	Same as ground based.
	Space	Not Applicable	Not Applicable	Possible capability against all satellites.	Not Applicable	Not Applicable	Possible Capability—Capability comparable to US, but may not mirror US approaches.

Table 2

Table Prepared in the Department of Defense¹²

Washington, undated

(Number of weapons for a “meaningful effect”)

U.S. AND SOVIET CAPABILITIES LASER WEAPONS—OTHER THAN ASAT

	POTENTIAL13 U.S. CAPABILITY		ESTIMATED SOVIET CAPABILITY
Mission	Now	Early 1990s	Now	Early 1990s
Point defense—Ship (enough to equip 6 aircraft carriers)	None—technology and lethality demonstrations underway.	Sensor kill devices widely deployed—initial capability for other devices.	None14	Ship defense system against anti-ship missiles, cruise missiles.
Point defense—Ground target (approx. 30)	None—technology and lethality demonstrations underway.	Sensor kill devices widely deployed—initial capability for other devices.	None15	Short range (3–8 km) air defense and mobile lasers against personnel & light armored vehicles.
	POTENTIAL U.S. CAPABILITY		ESTIMATED SOVIET CAPABILITY
Mission	Now	Early 1990s	Now	Early 1990s
Defense of Aircraft (several 10’s if on strategic bombers)	None—technology and lethality demonstrations underway.	Short range (3–8 km) capability in large aircraft. Possible limited capability in fighter aircraft.	None16	Short range (3–8 km) capability. Potential means of improving present aircraft deficiencies.
Space Defense (Anti-ASAT) (1 or 2)	None	Possible capability to defend all U.S. satellites from space attack.	None	Possible capability—Capability comparable to U.S., but may not mirror US approaches.
ABM—terminal intercept of RVs (perhaps 50–100)	None	None	None	None

1. Source: Carter Library, National Security Affairs, Brzezinski Material, Brzezinski Office File, Subject Chron File, Box 124, Weapons Systems: 1–3/78. Top Secret.
2. See footnote 2, Document 50.
3. Top Secret.
4. Top Secret.
5. Implementation of these capabilities is not included in current US programs. [Footnote is in the original.]
6. Reaction time limited. [Footnote is in the original.]
7. Reaction time limited. [Footnote is in the original.]
8. Reaction time limited. [Footnote is in the original.]
9. Reaction time limited by number and distribution of sites. [Footnote is in the original.]
10. Reaction time limited by number and distribution of sites. [Footnote is in the original.]
11. Reaction time limited by number and distribution of sites. [Footnote is in the original.]
12. Top Secret.
13. Implementation of these capabilities depends upon assessments relative to competing weapons. Assumed no fiscal constraints but conservative development approach. [Footnote is in the original.]
14. Believed prototype projects underway. [Footnote is in the original.]
15. Believed prototype projects underway. [Footnote is in the original.]
16. Believed prototype projects underway. [Footnote is in the original.]