The ability for a satellite to defend itself against an ASAT attack is a reasonable way to increase the survivability of a high-value space system. One method of self-defense would be to design a suite of optical or radar sensors and small, lightweight missiles into the satellite. Analysts estimate that employment of an on-board self-defense system would increase the total system cost by between ten and twenty percent of the total satellite cost. Alternatively, a small escort satellite carrying the same capabilities might be a more capable system, especially if the goal was to detect, track and intercept the ASAT while the primary satellite continued its mission. Analysts currently estimate that employment of an escort defense system would increase the total system cost by between twenty and forty percent of the total satellite cost. However, with continued advances in technologies for capable microsatellites the cost of deploying such a system will decrease. In the more distant future, self-defense missiles might be replaced by a high-energy lasers or high-power microwave systems.

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Wilson, Tom. Threats to United States Space Capabilities. Washington, D.C.: U.S. Space Commission, 2001. [ 8 quotes ]