Requirements and feasibility for the transition from a Ballistic Missile capability to an Anti-Satellite (ASAT) capability

Ballistic missiles and Anti-Satellite (ASAT) weapons operate using similar technological means but not with the same level of technology or engineering maturity. ASATs require a more sophisticated systems engineering and integration requirements to be able to adapt to the challenges posed by an ASAT intercept. The main difficulty arises from the requirements for detection in space and the high closing velocities needed to execute an ASAT intercept [1]. This distinction has been blurred after the recent Chinese ASAT test. There have been contentions that other nations could in the near-future master this technology gap and convert their primitive ballistic missile capabilities into an effective ASAT weapons capability. This report examines whether Iran, a nation with modest missile capability, could use its missile capability to project a viable ASAT threat to US Low-Earth Orbit (LEO) satellites. The study suggests that, even given the chance that Iran has a missile of IRBM capability, it would not be easily able to leap-frog the technology gap from a ballistic missile capability to an ASAT capability. Unless it develops and tests the system vigorously and visibly Iran would not possibly project an ASAT threat. Chapter 1 of the report analyzes the capability of the Iranian Shahab4 missile, including the velocity attained by the missile at an altitude of 1000 kilometers. Chapter 2 provides an analysis of the total thermal energy emitted by a model satellite in the IR band of interest for the given ASAT characteristics. Using the total thermal energy in the IR band, the detection range from which the ASAT can lock on to the satellite is determined. Chapter 3 details the ideal PNG law simulation performed using the parameters obtained in Chapters 1 and 2. The miss distances and acceleration requirements are shown graphically to capture the nuances and limits in the capability of an ASAT based on current Iranian technology level. The conclusion explains the limits and assumptions of this analysis and scope for further work. Chapter 1 Missile Capability In the analysis undertaken for the study, a three stage missile, the Iranian Shahab-4 is taken as the baseline anti-satellite weapon. The capability of the missile and the altitude that it can attain when launched vertically on a path into space as opposed to against a target in Earth are ascertained using the Rocket equations. 1.1 The Rocket Equation for Multiple Stages The rocket equation is given by ∆V1 = −Ve1ln( mfinal1 minitial1 ) = −Ve1ln(r1) (1.1) where ∆V1 is the total change in velocity imparted to the rocket body using the propellant of the first stage after the first stage burnout. Similarly ∆V2 = −Ve2ln(r2) (1.2) Assuming Ve1 = Ve2 = Ve ∆V1 + ∆V2 = −Veln(r1)− Veln(r2) = −Veln(r1r2) (1.3) Now ∆V for multistage rockets is