The Naval Research Laboratory's Spacecraft Engineering Division requires contractor support for space system and aerospace engineering services, including research and development for space systems, communication systems, and tracking systems. This is a sources sought/RFI issued for planning purposes only, not a formal RFP, and no awards will result from responses to this notice. The government will not reimburse response costs, and inquiries beyond the stated information will not be answered. Performance of the required services will take place in Washington, DC. This effort is a re-compete of a previously awarded contract, and interested parties are asked to submit a capabilities statement demonstrating relevant experience and past performance.