We propose a method for discerning the gravity fields and sub-surface mass distribution of a solar system small body, without requiring dedicated orbiters or landers. In this concept, a spacecraft releases a swarm of small, low-cost probes during a flyby past an asteroid or comet. By tracking those probes, we can estimate the asteroid's gravity field and infer its underlying composition and porosity. This approach offers a diverse measurement set, equivalent to planning and executing many independent and unique flyby encounters of a single spacecraft. The resulting dataset can yield a global model of the body's mass distribution and reveal unique aspects of the body's interior that are otherwise unobservable. This concept offers the possibility of achieving new scientific measurements that extend our understanding of our solar system, benefit human spaceflight, and support planetary defense. It also represents a practical deep space application of the swarm paradigm that is common in other fields, in that the ensemble of deployed probes enables fundamentally new measurement sets. In Phase I we established a basic feasibility of the concept by simulating a series of asteroid encounters and evaluating the available tracking methods. In Phase II, we intend to address the key remaining risks and concerns by increasing the fidelity of our simulations, evaluating important trades, considering other relevant mission contexts, and prototyping and characterizing the dispenser and probes. These activities will be informed by active engagement with mission science and engineering leadership, with the objective of identifying a path forward for implementation.
More »A variety of engineers and scientists, including NIAC fellows, speculate that tiny chip-scale space- craft will constitute meaningful sensor platforms in the coming decades. The NASA Technology 6 Roadmap supports this possibility in the late 2020's. This gravimetry concept represents a mean- ingful step towards that goal. Specifically, this concept benefits from, but does not explicitly require, extremely small probes. Size is relevant because it dictates the number of probes that can be carried for a given payload mass and volume. This research addresses the nontrivial challenge of storing and deploying dozens of compact probes without interfering with the spacecraft bus or adding a risk of future collision. Even for missions unrelated to gravimetry, this research will result in a well-tested dispenser that could be equipped with alternate tiny payloads. For example, the current instantiation of the dispensed containers (\xd2sabots\xd3) could house the Sprites contained in the recent KickSat experiment. Each Sprite consists of solar cells, a radio, and a gyroscope, all integrated onto a single circuit board. With this in mind, it is not unreasonable to see a path forward for deployed magnetometers, bolometers, dust counters, etc.
More »Organizations Performing Work | Role | Type | Location |
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Johns Hopkins University | Lead Organization | Academia | Baltimore, Maryland |