Research

Fundamental geometry of the restricted three-body problem.

My research interests and areas of study in the field of aerospace engineering include:

Proximity Operations in the Restricted Three-Body Problem
Orbital Transfers in the Restricted Three-Body Problem
Trajectory Optimization for Interplanetary Trajectories
Spacecraft Mission Design and Engineering
Low-Thrust Orbital Transfers

1. Proximity Operations in the Restricted Three-Body Problem

Developed an approximation of relative motion in the vicinity of the second primary mass
Utilized suited analytic approximations of Lagrangian orbits
Performed trade-studies between local and global propellant-optimal solutions for planned and contingency maneuvers
Characterized proximity operation maneuvers for future missions, e.g. rendezvous with the lunar gateway and establishment of orbital platforms in cis-Martian space
This research led to the creation of an innovative mission design tool, resulting in porkchop-like plots named prosciutto plots, to be used in evaluating the orbital maneuvering trade-space (ΔV and time-of-flight, including potential risk mitigation maneuvers) as a function of departure and arrival dates for proximity operations taking place near the smaller primary of a three-body system.

Relevant publications on this topic include publications # 1, 2, 8, 13, and 22 (as listed here)

Sensitivity study using Monte Carlo simulations to predict initial conditions of proximity operation maneuvers based on orbit insertion uncertainty.

Example of a prosciutto plot for proximity operations maneuvers in the vicinity of a Lunar Distant Retrograde Orbit (LDRO).

2. Orbital Transfers in the Restricted Three-Body Problem

Worked on new methodologies to compute delta-v-optimal transfers for Earth to cis-lunar orbits, such as lunar halo orbits via the use of an optimization algorithm known as Fireworks Optimization Algorithm in combination with manifolds theory. Sample transfer trajectories are depicted below.
Developed new Concepts of Operations (ConOps), called the Conte-Spencer ConOps (video), for trajectories arriving from interplanetary space that target specific three-body orbit in the Mars-Phobos and Mars-Deimos systems, including Distant Retrograde Orbits (DROs). A video showing a sample Mars-Phobos DRO can be found here.
The aforementioned novel orbital transfers can be utilized for future missions aiming at furthering the presence of robotic and human missions requiring the assembly of multiple vehicles in three-body orbits along with providing suitable locations for resupply/refueling infrastructures located at LDRO and MP DRO. Such locations could also be utilized as base camps for further explorations and safe havens for backup and mitigation plans,

Relevant publications on this topic include publications # 3, 4, 7, 9, 10, 11, 23, and 24 (as listed here).

Example of a Conte-Spencer ConOps for arrival trajectories targeting a Mars-Phobos Distant Retrograde Orbit (MP DRO). Video animation available here.

Direct LEO to lunar halo transfer. Trajectory computed using the Fireworks Optimization Algorithm.

LEO to lunar halo transfer using interior stable manifolds in the vicinity of the Moon. Trajectory computed using the Fireworks Optimization Algorithm.

Sample interior (stable) manifolds (in green) propagating from a halo orbit around the Earth-Moon Lagrange point 2 (L2) and arriving in the vicinity of the Moon.

3. Trajectory Optimization for Interplanetary Transfers

Example of a striped porkchop plot for Lunar DRO to Mars-Phobos DRO transfers, where both constraints on maximum available delta-v and geometrical constraints of the Earth, Moon, Mars, and Phobos cause the departure windows to be limited to 2-3 days every one month.

Developed ConOps for targeting prescribed arrival orbits at Mars launching from an Earth-Moon Lagrangian orbit, such as halo orbits and DROs. This results in the formulation of a mission design tool that can be used to compute delta-v as a function of departure and arrival dates taking into account the geometry of multiple bodies, e.g. Earth, Moon, Mars, and Phobos/Deimos, producing porkchop-like plots, known as striped porkchop plots.
Developed optimized interplanetary trajectories for mission design projects (see next section for more details) in collaboration with colleagues from universities around the world. Such trajectory optimizations include (in parenthesis is the name of the project related to such work):

Relevant publications on this topic include publications # 2, 4, 7, 10, 11, 23, and 24 (as listed here).

Low-thrust zero-velocity rendezvous Earth-Mars (left) and Mars-Earth (right) trajectories.

On the right is depicted a delta-v roadmap, which is a representation the major connections between the various planets and other celestial bodies in the Solar Systems, such as Kuiper Belt Objects (KBOs) and Near Earth Asteroids (NEAs), in terms of delta-v.

Here, a Lunar Distant Retrograde Orbit (DRO) is depicted as an intermediate staging location by showing the amount of delta-v necessary to perform orbital transfers from it to another destination in the Solar System, and vice-versa. In order to construct this delta-v roadmap, only optimal two-burn impulsive maneuvers were considered. Such transfers are not necessarily the most delta-v optimal solutions overall, but they provide an idea of how much delta-v, and thus propellant, is required to explore the Solar System.

In the figure, the aforementioned lunar DRO is placed in the middle of the map and it is shown as a link between various Earth and Moon orbits, e.g. LEO, Low-Lunar Orbit (LLO), Geosynchronous/Geostationary Earth Orbit (GEO), Geosynchronous/Geostationary Transfer Orbit (GTO), Earth-Moon Lagrangian orbits around L1, L2, L4, and L5, and interplanetary trajectories to the Solar System planets along with moons of interest, such as Phobos and Deimos, as well as Kuiper Belt Objects (KBOs), and Near Earth Asteroids (NEA).

4. Spacecraft Mission Design and Engineering

Participated in a variety of competitions including space mission design and engineering challenges. Among these are:

For further details regarding these competitions, including technical papers, videos and animations, please refer to the Design Competitions page.

Relevant publications on this topic include publications # 6, 12, 15, 16, 17, 18, 19, and 21 (as listed here).

Spacecraft diagram of the mothership used in the NASA RASC-AL 2016 mission design. The primary objective of this mission of to deliver four to the moons of Mars.

Spacecraft diagram of the space station HOPE (Human Orbiting Protected Environment) as part of the 2015 ESA Moon Challenge.

Representation of the Phobos Base design presented as part of the AIAA Phobos Base Competition.

5. Low-Thrust Orbital Transfers

Sample low-thrust transfer between SSOs.

Showed the (un)feasibility of low-thrust orbital transfers between Sun-Synchronous Orbits (SSOs) based various design variables, including thrust levels and spacecraft mass. This research was possible thanks to the collaboration with the Astrodynamics Research Group of Penn State (ARGoPS).
Collaborated with colleagues around the world on low-thrust zero-velocity rendezvous Earth-Mars and Mars-Earth trajectories (NASA Revolutionary Aerospace Systems Concepts - Academic Linkage 2016 and AIAA Phobos Base Competition).

Relevant publications on this topic include publications # 14 and 15 (as listed here).

Technical Reports

Have collaborated on the formulation of standards to be adopted in space for various applications and how to improve Project Management processes, methodology and tools for innovative, agile, low cost and high performance space projects.
The Space Divide is defined as the gap between nations mastering space capabilities and the non experienced and space-faring nations. On this matter, the main goal of the Space Generation Advisory Council (SGAC) was to bring together experts and delegates from different regions, including myself, to share the challenges and opportunities faced in bridging the space divide, and nurture collaborations across the different regions. The resulting report was submitted to the United Nations in February 2019.

Relevant publications on this topic include publications # 5 and 20 (as listed here).

Visualization matrix of topics that could be improved to streamline project management in space mission design. Dark shades indicate where major changes are not required while light shades indicate possibilities for improvement.

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