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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 235 records · Page 13
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NASA NTRS2017

NIAC Swarm Flyby Gravimetry Phase II Report

This NASA Innovative Advanced Concept (NIAC) grant has enabled the research and development of a method for conducting small body gravimetry from a spacecraft, using relative measurements to a set of deployed test-masses. The test-masses are tracked from a host spacecraft, which dispenses them near to the small body's surface. Thanks to this close proximity, the probes' orbits can be highly perturbed, which yields useful gravimetric measurements. The most readily achievable approach for tracking the probes is to use an optical instrument on- board the spacecraft. The probes then need only be reflective to sunlight. This implementation, called optical gravimetry (OpGrav), has the fewest requirements for the host spacecraft and probes.The results of this study indicate that OpGrav is feasible and offers meaningful improvement over existing methods. Parametric studies suggest roughly an order of magnitude improvement in accuracy or asteroid accessibility (how small an asteroid one can measure) over Earth-based Doppler-only mass estimation. This exponentially expands the number of potential near-Earth objects that one could study, which has implications for planetary defense.As a sample mission, we evaluated OpGrav as an added instrument on a main- belt asteroid tour mission. In this case, simulations show that OpGrav would increase the number of asteroid mass estimates from 3 of 9 to 7 of 9. That is, OpGrav has sufficient sensitivity to offer utility in missions for which it is not explicitly designed for.We designed and fabricated a prototype hardware implementation for this concept called the Small-body In-situ Multi-probe Mass Estimation Experiment (SIMMEE). This hardware provides a basis for many inputs into the simulations and grounds the models with physical values. The primary design driver for the hardware is a long life, on the order of five years prior to operation, and a need for high pointing accuracy to enable flybys of the smallest objects.The next steps include further hardware testing and extension of the concept to rendezvous cases. We believe that this concept offers planetary scientists a new and relevant means of better understanding small-bodies.

Atchison, Justin A.↗
NASA NTRS2016

Independent Navigation Team Contribution to New Horizons' Pluto System Flyby

The New Horizons spacecraft made it closest approach to Pluto on 14 July 2015. The most significant challenge of this mission was that the Pluto system ephemeris was initially known with a precision of ~1000 km. This needed to be improved significantly on approach in order to meet the science requirements. During the final six months leading to the flyby, a JPL Independent Navigation (INAV) Team was included in the ephemeris knowledge update process as a cross-check on the Project Navigation (PNAV) Team's results. This paper discusses the INAV team's experiences and challenges navigating New Horizons through the Pluto planetary system encounter.

orbit determination↗
NASA NTRS2018

New Results from Galileo's First Flyby of Ganymede: Reconnection-Driven Flows at the Low-Latitude Magnetopause Boundary, Crossing the Cusp, and Icy Ionospheric Escape

On 27 June 1996, the NASA Galileo spacecraft made humanity’s first flyby of Jupiter’s largest moon, Ganymede, discovering that it is the only moon known to possess an internally generated magnetic field. Resurrecting the original Galileo Plasma Subsystem (PLS) data analysis software, we processed the raw PLS data from G01 and for the first time present the properties of plasmas encountered. Entry into the magnetosphere of Ganymede occurred near the confluence of the magnetopause and plasma sheet. Reconnection-driven plasma flows were observed (consistent with an Earth-like Dungey cycle), which may be a result of reconnection in the plasma sheet, magnetopause, or might be Ganymede’s equivalent of a Low-Latitude Boundary Layer. Dropouts in plasma density combined with velocity perturbations afterward suggest that Galileo briefly crossed the cusps into closed magnetic field lines. Galileo then crossed the cusps, where field-aligned precipitating ions were observed flowing down into the surface, at a location consistent with observations by the Hubble Space Telescope. The density of plasma outflowing from Ganymede jumped an order of magnitude around closest approach over the north polar cap. The abrupt increase may be a result of crossing the cusp or may represent an altitude-dependent boundary such as an ionopause. More diffuse, warmer field-aligned outflows were observed in the lobes. Fluxes of particles near the moon on the nightside were significantly lower than on the dayside, possibly resulting from a diurnal cycle of the ionosphere and/or neutral atmosphere.

Collinson, Glyn↗
NASA NTRS2016

Trajectories for Europa Flyby Sample Return

Ballistic trajectories are computed which would enable a sample return mission to Europa without capturing, descending, or landing. The low-cost mission concept utilizes a free return trajectory that also involves a close flyby of Europa. Near Europa, a small impactor would kinetically impact the icy moon and generate a plume, subsequently sampled by the spacecraft. A broad search algorithm is developed to construct feasible itineraries, which considers Venus and Earth gravity assist sequences. High-quality solutions are then differentially corrected to be continuous using high-fidelity dynamics. The complete methodology is applicable to other outer-planet moons, notably Enceladus. The outbound VEEGA option is found to signifcantly reduce launch C3 compared to alternate options. The characteristics and quality of the solutions exhibit substantial variation over the 12-year period of Jupiter. Nevertheless, a variety of optimized results are computed with C3 as low as 16.0 sq.km/sq.sec, re-entry speed well below that of the Stardust capsule, and flight times of 9 to 15 years.

Jones, Drew Ryan↗
NASA NTRS2016

Trajectories for Flyby Sample Return at Saturn's Moons

Ballistic trajectories are computed which would enable a sample return mission to Titan or Enceladus without capturing, descending, or landing. The low-cost mission concept utilizes a free return trajectory that also involves a close flyby of the moon. This work extends the concept, and related trajectory analysis methodology, previously applied to a Europa mission. Specifically, a broad search algorithm is employed to systematically locate potentially feasible itineraries over an entire Saturn period. High-quality approximate solutions are then optimized to be continuous using high-fidelity dynamics. Techniques and software from the Europa analysis, were readily adapted and able to find numerous mission enabling trajectories. A direct mission to Titan is possible with flight time under 16 years and Earth-relative speeds below 11.0 km/sec. The VEEGA option is shown to substantially reduce launch C3, but flight times exceed 21 years. Unfortunately, an Enceladus mission requires a flight time of 25 years or more, and incurs fairly high relative speeds. Nevertheless, an optimized reference mission is computed.

Jones, Drew Ryan↗
NASA NTRS2019

High-Fidelity Multiple-Flyby Trajectory Optimization Using Multiple-Shooting

Rendering a complex spacecraft trajectory in high fidelity can be an expensive endeavor, both computationally and from a human time/cost standpoint. However, in many cases, a low-fidelity trajectory that reasonably approximates a high-fidelity counterpart is much easier to obtain. Thus, it is important to have an efficient process for converting a trajectory from lower-fidelity model to high fidelity. We present a method for converting low-fidelity trajectories into high fidelity that relies on multiple shooting, nonlinear programming, and numerical integration. The procedure converts any zero-radius sphere-of-influence gravity-assist events to fully integrated flyby events. Several numerical examples are presented that showcase the flexibility of the high-fidelity rendering process across multiple mission types and flight regimes.

high-fidelity↗
NASA NTRS2019

Power Systems for Miniature Interstellar Flyby Probe

In the last few years, the concept that an ultra-lightweight probe could be sent to one of the nearby stars pushed by a laser beam reflecting from a lightweight sail has moved from science fiction into conceptual design. A candidate interstellar sail envisions a two- to three-gram "starchip" micro probe, flying past a planet of Proxima Centauri after a 20 year voyage. With the probe moving at 60,000 km/sec, the flyby encounter at the target planet is within 1 AU of the target planet at most a few hours, and in the case of an encounter with a planet of Proxima Centauri, is close to the star for only a few minutes. With current technology, no power system exists that can produce the required power with a mass of less than one gram.

Landis, Geoffrey A.↗
NASA NTRS2019

Power System for Miniature Interstellar Flyby Probe

In the last few years, the concept that an ultra-lightweight probe could be sent to one of the nearby stars pushed by a laser beam reflecting from a lightweight sail has moved from science fiction into conceptual design. The Breakthrough Starshot project envisions a two- to three-gram "starchip" micro probe, flying past a planet of Proxima Centauri after a 20 year voyage. With the probe moving at 60,000 km/sec, the flyby encounter at the target planet lasts at most a few hours. With current technology, no power system exists that can produce the required power with a mass of less than one gram.

Landis, Geoffrey A.↗
NASA NTRS1993

Small Spacecraft Conceptual Design For a Fast Pluto Flyby Mission

The Pluto Fas Flyby mission is a pre-Phase A mission development activity being pursued at the Jet Propulsion Laboratory and funded by NASA's Code SL. Its objective is to conduct first reconnaissace level science at Pluto before its atmospheric collapse in the next two to three decades.

Pluto↗
NASA NTRS1993

The Pluto Fast Flyby Mission: Completing the Reconnaissance of the Solar System

The concept of a fast flyby mission to Pluto has been advanced as a means to complete the reconnaissance of the known solar system. In order to acquire data on the Pluto system at the earliest possible time, and within the professional lifetime of investigators now active in the field, concepts are being developed for relatively small spacecraft in the mass range of 70 Kg to 350 Kg with flight times to Pluto of 7 to 13 years. Necessarily, the science complement on such a mission will be very mass and power limited. The challenge will be to define a spacecraft and an instrument package that will maximize the scientific return within these limitations. Cost, of course, will be a major consideration, and funds for new technology development specific to this mission will not be extensive...

Henry, Paul K.↗
NASA NTRS2017

Cassini Maneuver Experience Through the Final Targeted Titan Flyby and the Grand Finale

Amassing valuable scientific information about the Saturnian system for 13 years, the Cassini spacecraft is now in the last phase of its mission. The Grand Finale, a series of 22 orbits with Cassini passing through a gap between Saturn’s innermost ring and its upper atmosphere, began after the last targeted Titan flyby on April 22, 2017 and ends with the spacecraft plunging into Saturn on September 15, 2017. This paper reports on the maneuvers performed to achieve the final targeted Titan encounter and the maneuvers used to maintain the Grand Finale orbits.

Wong, Mau C.↗
NASA NTRS2019

Architecture of a faul-tolerant and verifiable outer planet flyby

Flyby missions to outer solar system objects require a very high confidence of since there are no second chances. The quantity, quality, and diversity of science measurements to be made in a matter of hours or days must justify the mission cost. Accordingly, the mission architecture must include a high degree of redundancy, large design margins, and an ability to correct or operate through anomalies while at the same time being deterministic enough for confidence in system verification and validation. In this paper we present a system architecture as part of a proposed mission to Triton, called “Trident”.

Mitchell, Karl L.↗
NASA NTRS2022

Concept for 2033 Crewed Mars Orbital Mission with Venus Flyby

The 2033 Mars launch period provides a unique opportunity for a round trip mission with a total flight time of only 1.6 years. A concept is presented to perform a crewed Mars orbital mission in 2033 that would minimize development and mission risk by using conventional hypergolic in-space propulsion stages with a common design. The Mars mission vehicle would include a Mars transit habitat, an Orion spacecraft, and chemical propulsion stages. It would be launched by a combination of SLS and commercial rockets to be aggregated in high Earth orbit or at the Lunar Gateway. The crew would launch to the mission vehicle in Orion as the final element in the assembly. After transit to Mars, the crew would spend about 30 days in a high Mars orbit and then return to Earth via a Venus flyby and gravity assist. A sunshade would be deployed for thermal control of the mission vehicle inside 1 AU. The crew would return directly to Earth in the Orion crew module, with the transit habitat being expended. The 2033 mission would not be a “one-off”, but could be a pathfinder for crew transport for landing missions to follow, perhaps starting as early as 2037.

Woolley, Ryan↗
NASA NTRSDate not supplied

Enabling Multiple Small Satellite Near-Earth Asteroid Flyby Missions Using Small Solid Rocket Kick Stages with Rideshare Opportunities

The large number of Near-Earth Asteroids (NEA’s) provide almost daily launch opportunities to send small rideshare spacecraft to explore our nearest neighbors. Most asteroid missions require large spacecraft with a dedicated launch service. The large delta-V required for an interplanetary trajectory would typically preclude a NEA flyby rideshare unless it was going to the same target body as the primary mission. In this paper, a low-cost, compact, high energy kick stage with 3-axissteeringis proposed that would enable this mission type. This kick stage is compatible with an ESPA ring so that multiple NEA missions can be deployed as rideshares on a single launch.

William W Benson↗