Exhibit 21 SUBSIDIARIES OF THE COMPANY Name Doing Business As State of Incorporation - ----------------- ---------------------- 1. Hygienetics Environmental Services, Inc. Delaware Hygienetics Environmental Services 2. L-3 Communications ILEX Systems, Inc. Delaware ILEX Systems 3. Southern California Microwave, Inc. California Southern California Microwave 4. L-3 Communications SPD Technologies, Inc. Delaware SPD Technologies 5. L-3 Communications ESSCO, Inc. Delaware ESSCO 6. Electronic Space Systems International Corp. U.S. Virgin Islands Electronic Space Systems 7. Electronic Space Systems (UK) Limited United Kingdom Electronic Space Systems (UK) 8. ESSCO Collins Limited Republic of Ireland ESSCO Collins 9. ESSCO Satellite Systems Corp. Delaware ESSCO Satellite 10. L-3 Communications Storm Control Systems, Inc. California Storm Control Systems 11. L-3 Communications DBS Microwave, Inc. California DBS Microwave 12. SPD Electrical Systems, Inc. Delaware SPD Electrical Systems 13. SPD Switchgear Inc. Delaware SPD Switchgear 14. Pac Ord Inc. Delaware Pac Ord 15. Henschel Inc. Delaware Henschel 16. Power Paragon, Inc. Delaware Power Paragon 17. SPD Holdings, Inc. Delaware SPD Holdings 18. Cardiovascular Computer Systems, Ltd. Wisconsin Cardiovascular Computer Systems 19. Digital Technics, L.L.C. Delaware Digital Technics 20. Digital Technics, L.P. Delaware Digital Technics 21. Electrodynamics, Inc. Arizona Electrodynamics 22. L-3 Communications Secure Information Technology, Inc. Delaware L-3 Secure Information Technology 23. L-3 Communications Network Security Systems, LLC Delaware L-3 Network Security Systems 24. L-3 Communications Network Security Systems (Europe) PLC United Kingdom L-3 Network Security Systems (Europe) 25. L-3 Communications U.K. Ltd. United Kingdom L-3 Communications U.K. 26. Storm Control Systems Limited United Kingdom Storm Control Systems 27. L-3 Management Corp. Delaware L-3 Management 28. L-M Acquisition Corporation Maryland L-M Acquisition 29. Microdyne Corporation Maryland Microdyne 30. Microdyne Communications Technologies, Inc. Maryland Microdyne Communications 31. MCTI Acquisition Corp. Maryland MCTI Acquisition 32. Apcom Inc. Maryland Apcom 33. Celerity Systems Inc. California Celerity Systems 34. Microdyne Ltd. U.S. Virgin Islands Microdyne Ltd. 35. Microdyne Outsourcing Incorporated Maryland Microdyne Outsourcing 36. Microdyne U.K., Inc. Delaware Microdyne U.K. 37. Medical Education Technologies, Inc Delaware Medical Education Technologies 38. L-3 Communications Holding GmbH Federal Republic of Germany L-3 Communications Holding 39. L-3 Communications ELAC Nautik GmbH Federal Republic of Germany L-3 Communications ELAC Nautik 40. Power Paragon (Deutschland) Holding GmbH Federal Republic of Germany Power Paragon (Deutschland) 41. EuroAtlas Gesellschaft fur Leistungselektronik mbH Federal Republic of Germany EuroAtlas 42. JovyAtlas Elektrische Umformtechnik GmbH Federal Republic of Germany JovyAtlas