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Near-Earth-Object Rendezvous SGM

Concept for a Near-Earth-Object Rendezvous Second-Generation Microspacecraft. The spacecraft autonomously provides full-body imaging and imaging spectroscopy of a near-Earth asteroid or comet as well as in situ alpha/proton/x-ray measurement and gamma-ray spectroscopy. After mapping the object, the spacecraft moves closer along a radial toward the most illuminated pole of rotation, releases the surface drop package, backs away, and, after some data reduction, relays the in situ measurement data to Earth. (As with the other example SGM, no uplink is used, but this is more of a challenge in this mission class than in the other examples.) Estimated spacecraft wet mass, launch configuration size, and load power are, respectively, 7 kg, 20 cm x 35 cm x 33 cm, and 6 to 13 W (depending on transmitter state: off or on). Augmentation with a miniature propulsion stage is required (but not shown in the picture), which increases the launch mass and payload volume. Spacecraft separation from the stage is shortly after the final rendezvous burn is complete.

Developed in 1993-1995, a vision, approach, and example system concepts for Second-Generation Microspacecraft (SGM) have the intent of helping enable NASA's paradigm shift to less expensive, better, faster missions. Envisioned is a future in which a significant number of missions can be carried out with SGM that have low life-cycle cost, provide high return on investment, allow frequent flight, and contribute to innovation in technology. Key elements of the approach to realizing this vision include reducing spacecraft resource requirements and complexity, minimizing spacecraft size and mass, using production "core" building blocks and extensive spacecraft autonomy, and eliminating non-cost-effective redundancy.

The first element of the approach also implies targeting appropriate, focused missions and payloads, using on-board analysis and data compression, minimizing spacecraft power needs, and using low-nuclear or, preferably, non-nuclear energy sources. Example spacecraft system concepts that are consistent with the approach include the Outer Solar System Flyby SGM, Near-Earth-Object Flyby SGM, Near- Earth-Object Rendezvous SGM, and Space Physics Fields and Particles SGM.