Engineering topics

Nicholas, Austin

Publications and source records attributed to Nicholas, Austin.

22 records · Page 2

NASA NTRS2017

GTOC9: Methods and Results from the Jet Propulsion Laboratory Team

The removal of 123 pieces of debris from the Sunsynchronous LEO environment is accomplished by a 10-spacecraft campaign wherein the spacecraft, flying in succession over an 8-yr period, rendezvous with a series of the debris objects, delivering a de-orbit package at each one before moving on to the next object by means of impulsive manoeuvres. This was the GTOC9 problem, as posed by the European Space Agency. The methods used by the Jet Propulsion Laboratory team are described, along with the winning solution found by the team. Methods include branch-and-bound searches that exploit the natural nodal drift to compute long chains of rendezvous with debris objects, beam searches for synthesising campaigns, ant colony optimisation, and a genetic algorithm. Databases of transfers between all bodies on a fine time grid are made, containing an easyto- compute yet accurate estimate of the transfer V . Lastly, a final non-linear programming optimisation is performed to ensure the trajectories meet all the constraints and are locally optimal in initial mass.

Sims, Jon↗

NASA NTRS2016

Small Aerostationary Telecommunications Orbiter Concept for Mars in the 2020s

Current Mars science orbiters carry UHF proximity payloads to provide limited access and data services to landers and rovers on Mars surface. In the era of human spaceflight to Mars, very high rate and reliable relay services will be needed to serve a large number of supporting vehicles, habitats, and orbiters, as well as astronaut EVAs. These will likely be provided by a robust network of orbiting assets in very high orbits, such as areostationary orbits. In the decade leading to that era, telecommunications orbits can be operated at areostationary orbit that can support a significant population of robotic precursor missions and build the network capabilities needed for the human spaceflight era. Telecommunications orbiters of modest size and cost, delivered by Solar Electric Propulsion to areostationary orbit, can provide continuous access at very high data rates to users on the surface and in Mars orbit.In the era of human spaceflight to Mars very high rate andreliable relay services will be needed to serve a largenumber of supporting vehicles, habitats, and orbiters, aswell as astronaut EVAs. These could be provided by arobust network of orbiting assets in very high orbits. In thedecade leading to that era, telecommunications orbiterscould be operated at areostationary orbit that could support asignificant population of robotic precursor missions andbuild the network capabilities needed for the humanspaceflight era. These orbiters could demonstrate thecapabilities and services needed for the future but withoutthe high bandwidth and high reliability requirements neededfor human spaceflight.Telecommunications orbiters of modest size and cost,delivered by Solar Electric Propulsion to areostationaryorbit, could provide continuous access at very high datarates to users on the surface and in Mars orbit. Twoexamples highlighting the wide variety of orbiter deliveryand configuration options were shown that could providehigh-performance service to users.

Lock, Robert E.↗

NASA NTRS2016

Additional Mission Applications for NASA's 13.3-kW Ion Propulsion System

NASA's Space Technology Mission Directorate has been recently developing critical technologies for high-power solar electric propulsion (SEP), including large deployable solar array structures and high-power electric propulsion components. An ion propulsion system based on these developments has been considered for many SEP technology demonstration missions, including the Asteroid Redirect Robotic Mission (ARRM) concept. These studies and the highpower SEP technology developments have generated excitement within NASA about the use of the ARRM ion propulsion system design for other types of potential missions. One application of interest is for Mars missions, especially with the types of orbiters now under consideration for flights in the early 2020's to replace the aging Mars Reconnaissance Orbiter. High-power SEP can deliver large payloads to Mars with many additional capabilities, including large orbital plane changes and roundtrip missions, compared to chemically-propelled spacecraft. Another application for high-power SEP is for exo-planet observation missions, where a large starshade spacecraft would need to be repositioned with respect to its companion telescope relatively frequently and rapidly. SEP is an enabling technology for the ambitious science goals of these types of missions. This paper will discuss the benefits of high-power SEP for these concepts based on the STMD technologies now under development.

Space Technology Mission Directorate↗

NASA NTRS2015

SMART: A Propositional Logic-Based Trade Analysis and Risk Assessment Tool for a Complex Mission

This paper introduces a new trade analysis software called the Space Mission Architecture and Risk Analysis Tool (SMART). This tool supports a high-level system trade study on a complex mission, such as a potential Mars Sample Return (MSR) mission, in an intuitive and quantitative manner. In a complex mission, a common approach to increase the probability of success is to have redundancy and prepare backups. Quantitatively evaluating the utility of adding redundancy to a system is important but not straightforward, particularly when the failure of parallel subsystems are correlated.

Ono, Masahiro↗