NEMO science orbit animation 2 minutes, STK 6 Click image to play NEMO Functional Block Diagram (FBD) Visio Click image to enlarge Multilobe high-gain rigid antenna concept

NEMO, the Neptune Exploration Mission of Opportunity, was a team project for ASEN 5148 Spacecraft Design.  This project was carried out in an industry-standard fashion, including answering an Announcement of Opportunity, formulating requirements, performing trade studies, and generating a final phase-A report and presentation.  Ten students were on this team; I served as C&DH lead, with responsibilities including investigating hardware and software options, and performing radiation analysis over the mission lifetime.  I also produced Functional Block Diagrams (FBDs) of the spacecraft systems, and performed STK modeling to visualize and refine the mission’s science imaging plans and concept of operations.  This project was very interesting due to the extreme distance and time scales involved.  It’s nontrivial to design a spacecraft that has to last 20 years before it even reaches its destination.

The Satellite Tool Kit (STK) visualization here was challenging because STK does not include Neptune’s moons by default.  I retrieved the orbital elements from JPL’s database, and entered them manually.  The blue box in the main window (and the blue cone in the small window) is the main science instrument’s field of view.  The red oval in the small window is NEMO’s science orbit; every dot is one day apart.  The primary science goal of the AO was to perform long-term observations of Neptune’s auroral ring, so the hundred-day orbit was not a hindrance.  Neptune’s largest moon Triton is a fascinating object because it is in a retrograde orbit – it orbits in the opposite direction to nearly every other body in the solar system.

Three teams each produced a different design to meet the same AO.  Our team was commended on sticking closely to the requirements and producing a straightforward design, which was both (relatively) inexpensive, and (relatively) low-risk.

Selected project documents:

• Final report (PDF, 2.2MB)
• Spacecraft Functional Block Diagram (PDF, 350KB)
• CDH Functional Block Diagram (PNG, 350KB)
• Spacecraft Electrical Interconnect Diagram (PNG, 650KB)
• STK animation (h264, 8MB)