The AFRL/STP Nanosat-2 Mission on Delta IV Heavy: A Demonstration of Current Responsive Space Capabilities

In mid CY2003, the Air Force Space and Missile Systems Center commander (SMC/CC) tasked the Department of Defense Space Test Program (STP) with finding a payload that could be manifested on the Air Force Delta IV Heavy Launch Vehicle Demonstration (HLVD), which was originally scheduled for a May 2004 Initial Launch Capability (ILC). In late CY2003, the decision was made to pursue the Air Force Research Laboratory (AFRL) Nanosat-2/Three Corner Sat (NS2/3CS) satellite constellation. In January 2004, SMC/CC provided the direction to proceed with the Nanosat-2 integration effort. Fortunately, the new HLVD ILC had moved to 3 July 2004. This situation created the ultimate exercise in "responsive space": notice-to-proceed to space vehicle delivery for integration in less than three months. A subsequent launch delay to September 2004 approximately halfway through the effort did not significantly relieve the schedule pressure, due to increased requirements being levied on the payload. Originally designed for deployment from the Space Shuttle (STS), the NS2/3CS payload consisted of the three university-built satellites comprising the 3CS constellation, and an AFRL-developed Multi-Satellite Deployment System (MSDS) incorporating novel low-shock separation systems developed under contract to AFRL by Planetary Systems Corp. (PSC) and Starsys Research Corp. (SRC). With the transition to Delta IV, new launch vehicle environments and requirements forced a radical and rapid reconfiguration of the Nanosat-2 mission from the ground up. The Delta IV Heavy first flight was a demonstration mission orbiting an inert "Demosat", and the NS2/3CS hardware was modified to piggyback on the Demosat until the MSDS released the 3CS constellation into low earth orbit. The ground rule for manifesting NS2/3CS was zero (minimized) impact on the HLVD mission. All interfaces were optimized for low schedule, performance and budget risk. Due to the transition to HLVD environments and a new target orbit, available mission lifetime fell from months to days, resulting in a limited 3CS mission de-scope. While retaining the core elements of the original NS2/3CS mission architecture, the MSDS deployment topology was reworked to meet Delta IV mechanical and electrical interface requirements, the number of satellites in the 3CS constellation was reduced from three to two, and mission operations were streamlined and accelerated. From start-work, system reconfiguration was accomplished in only 36 days, and qualification tests and analyses were subsequently completed over the ten week period leading up to encapsulation. The entire AFRL/STP effort was performed with a critical mission team numbering only in the low tens. As one of the more responsive missions attempted to date, the NS2/3CS mission provided valuable insight into the viability of highly accelerated and non-traditional assembly, integration & test (AI&T) practices. Using the NS2/3CS experience as a baseline, this paper outlines the engineering and programmatic challenges enjoined in the new industry paradigm of "responsive space," as well as the strengths and weaknesses of doing responsive space using current industry capabilities