677 research outputs found
The Genesis Trajectory and Heteroclinic Cycles
Genesis will be NASA's first robotic sample return mission. The purpose
of this mission is to collect solar wind samples for two years in an L_1 halo
orbit and return them to the Utah Test and Training Range (UTTR) for
mid-air retrieval by helicopters. To do this, the Genesis spacecraft makes
an excursion into the region around L_2 . This transfer between L_1 and
L_2 requires no deterministic maneuvers and is provided by the existence
of heteroclinic cycles defined below. The Genesis trajectory was designed
with the knowledge of the conjectured existence of these heteroclinic cycles.
We now have provided the first systematic, semi-analytic construction of
such cycles. The heteroclinic cycle provides several interesting applications
for future missions. First, it provides a rapid low-energy dynamical channel
between L_1 and L_2 such as used by the Genesis Discovery Mission. Second,
it provides a dynamical mechanism for the temporary capture of objects
around a planet without propulsion. Third, interactions with the Moon.
Here we speak of the interactions of the Sun-Earth Lagrange point dynamics
with the Earth-Moon Lagrange point dynamics. We motivate the discussion
using Jupiter comet orbits as examples. By studying the natural dynamics
of the Solar System, we enhance current and future space mission design
Development of an Automatous Ground Robot for Strawberry Yield Monitoring
The objective of this project was to design and build an autonomous agricultural robot platform that is ready to be adapted for strawberry yield predication. The robot was required to have an all-electric drivetrain as a requirement for the project. A key requirement for this robot is to have the flexibility to be used with different crops and with different applications. It is also designed to be able to change width for use in fields with varying row spacing. The end product of these design requirements is a robot platform that has the capability of supporting a payload in excess of 200 pounds, allowing for installation of equipment for many different applications. The robot has four-wheel drive and four wheel steering capability, all with electric motors and actuators
Experimental validation of phase space conduits of transition between potential wells
A phase space boundary between transition and non-transition, similar to
those observed in chemical reaction dynamics, is shown experimentally in a
macroscopic system. We present a validation of the phase space flux across rank
one saddles connecting adjacent potential wells and confirm the underlying
phase space conduits that mediate the transition. Experimental regions of
transition are found to agree with the theory to within 1\%, suggesting the
robustness of phase space conduits of transition in a broad array of two or
more degree of freedom experimental systems, despite the presence of small
dissipation.Comment: 7 pages, 6 figure
Constructing a Low Energy Transfer Between Jovian Moons
There has recently been considerable interest in sending a spacecraft to orbit Europa, the smallest
of the four Galilean moons of Jupiter. The trajectory design involved in effecting a capture by Europa
presents formidable challenges to traditional conic analysis since the regimes of motion involved depend heavily on three-body dynamics. New three-body perspectives are required to design successful
and efficient missions which take full advantage of the natural dynamics. Not only does a three-body
approach provide low-fuel trajectories, but it also increases the flexibility and versatility of missions.
We apply this approach to design a new mission concept wherein a spacecraft "leap-frogs" between
moons, orbiting each for a desired duration in a temporary capture orbit. We call this concept the
"Petit Grand Tour."
For this application, we apply dynamical systems techniques developed in a previous paper to
design a Europa capture orbit. We show how it is possible, using a gravitional boost from Ganymede,
to go from a jovicentric orbit beyond the orbit of Ganymede to a ballistic capture orbit around
Europa. The main new technical result is the employment of dynamical channels in the phase space
- tubes in the energy surface which naturally link the vicinity of Ganymede to the vicinity of Europa.
The transfer V necessary to jump from one moon to another is less than half that required by a
standard Hohmann transfer
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