NASA Ames UV-LED Poster Overview

UV-LED is a small satellite technology demonstration payload being flown on the Saudisat-4 spacecraft that is demonstrating non-contacting charge control of an isolated or floating mass using new solid-state ultra-violet light emitting diodes (UV-LEDs). Integrated to the rest of the spacecraft and launched on a Dnepr in June 19, 2014, the project is a collaboration between the NASA Ames Research Center (ARC), Stanford University, and King Abdulaziz City for Science and Technology (KACST). Beginning with its commissioning in December, 2015, the data collected by UV-LED have validated a novel method of charge control that will improve the performance of drag-free spacecraft allowing for concurrent science collection during charge management operations as well as reduce the mass, power and volume required while increasing lifetime and reliability of a charge management subsystem. UV-LED continues to operate, exploring new concepts in non-contacting charge control and collecting data crucial to understanding the lifetime of ultra-violet light emitting diodes in space. These improvements are crucial to the success of ground breaking missions such as LISA and BBO, and demonstrates the ability of low cost small satellite missions to provide technological advances that far exceed mission costs

Trajectory Browser Website

The Trajectory Browser is a web-based tool developed at the NASA Ames Research Center to be used for the preliminary assessment of trajectories to small-bodies and planets and for providing relevant launch date, time-of-flight and V requirements. The site hosts a database of transfer trajectories from Earth to asteroids and planets for various types of missions such as rendezvous, sample return or flybys. A search engine allows the user to find trajectories meeting desired constraints on the launch window, mission duration and delta V capability, while a trajectory viewer tool allows the visualization of the heliocentric trajectory and the detailed mission itinerary. The anticipated user base of this tool consists primarily of scientists and engineers designing interplanetary missions in the context of pre-phase A studies, particularly for performing accessibility surveys to large populations of small-bodies. The educational potential of the website is also recognized for academia and the public with regards to trajectory design, a field that has generally been poorly understood by the public. The website is currently hosted on NASA-internal URL http://trajbrowser.arc.nasa.gov/ with plans for a public release as soon as development is complete

UV-LED Project

The performance of certain classes of instruments - ones in which the test article is suspended, or floats, within the instrument - is adversely affected by the buildup of electric charge on the floating object. When spacecraft components are grounded, this charge can be easily controlled. But in the case of a free-floating asset, another method of charge dissipation is needed. One method is to use ultraviolet light to create a flow of electrons to or from the test mass, controlling its charge

Cutting Edge Smartphone Technologies for the Warfighter on the Tactical Edge

No abstract availabl

Mission Concepts and Operations for Asteroid Mitigation Involving Multiple Gravity Tractors

The gravity tractor concept is a proposed method to deflect an imminent asteroid impact through gravitational tugging over a time scale of years. In this study, we present mission scenarios and operational considerations for asteroid mitigation efforts involving multiple gravity tractors. We quantify the deflection performance improvement provided by a multiple gravity tractor campaign and assess its sensitivity to staggered launches. We next explore several proximity operation strategies to accommodate multiple gravity tractors at a single asteroid including formation-flying and mechanically-docked configurations. Finally, we utilize 99942 Apophis as an illustrative example to assess the performance of a multiple gravity tractor campaign

Flyby Anomaly Test Integrating Multiple Approaches (FATIMA)

FATIMA is a mission concept for a small satellite to investigate the flyby anomaly - a possible velocity increase that has been observed in some earlier satellites when they have performed gravitational swingy maneuvers of the earth

mSTAR Requirements and Reference Design

No abstract availabl

UV-LED Project

UV-LED is part of a small satellite technologydemonstration mission that willdemonstrate non-contacting charge controlof an isolated or floating mass usingnew solid-state ultra-violet light emittingdiodes (UV-LEDs). Integrated tothe Saudisat-4 spacecraft and launchedonboard the Dnepr in June 19, 2014,the project is a collaboration betweenthe NASA Ames Research Center (ARC),Stanford University, and King AbdulazizCity for Science and Technology(KACST). This technology demonstrationwill validate a novel method of chargecontrol that will improve the performanceof drag-free spacecraft allowingfor concurrent science collection duringcharge management operations as wellas reduce the mass, power and volumerequired while increasing lifetime and reliabilityof a charge management subsystem.These improvements are crucial tothe success of ground breaking missionssuch as LISA and BBO, and demonstratethe ability of low cost small satellite missionsto provide technological advancesthat far exceed mission cost

Experimental investigation of turbine blade-tip excitation forces

Results of a program to investigate the magnitude and parametric variations of rotordynamic forces which arise in high power turbines due to blade-tip leakage effects are presented. Five different unshrouded turbine configurations and one configuration shrouded with a labyrinth seal were tested with static offsets of the turbine shaft. The forces along and perpendicular to the offset were measured directly with a rotating dynometer. Exploration of casing pressure and flow velocity distributions was used to investigate the force-generating mechanisms. For unshrouded turbines, the cross-forces originate mainly from the classical Alford mechanisms while the direct forces arise mainly from a slightly skewed pressure pattern. The Alford coefficient for cross-force was found to vary between 2.4 and 4.0, while the similar direct force coefficient varied from 1.5 to 3.5. The cross-forces are found to increase substantially when the gap is reduced from 3.0 to 1.9% of blade height, probably due to viscous blade-tip effects. The forces also increase when the hub gap between stator and rotor decreases. The force coefficient decreased with operating flow coefficient. In the case of the shrouded turbine, most of the forces arise from nonuniform seal pressures. This includes about 80% for the transverse forces. The rest appears to come from uneven work extraction. Their level is about 50% higher in the shrouded case

Preliminary Results from the CHOMPTT Laser Time-Transfer Mission

CubeSat Handling of Multisystem Precision Time Transfer (CHOMPTT) is a demonstration of precision ground-to-space time-transfer using a laser link to an orbiting CubeSat. The University of Florida-led mission is a collaboration with the NASA Ames Research Center. The 1U optical time-transfer payload was designed and built by the Precision Space Systems Lab at the University of Florida. The payload was integrated with a NASA Ames NOdeS-derived spacecraft bus to form a 3U spacecraft. The CHOMPTT satellite was successfully launched into low Earth orbit on 16 December 2018 on NASA’s ELaNa XIX mission using the Rocket Lab USA Electron vehicle. Here we describe the mission and report on the status of this unique technology demonstration. We use two satellite laser ranging facilities located at the Kennedy Space Center and Mount Stromlo, Australia to transmit nanosecond, 1064 nm laser pulses to the CHOMPTT CubeSat. These pulses are timed with an atomic clock on the ground and are detected by an avalanche photodetector on CHOMPTT. An event timer records the arrival time with respect to one of the two on-board chip-scale atomic clocks with an accuracy of 200 ps (6cm light-travel time). At the same time, a retroreflector returns the transmitted beam back to the ground. By comparing the transmitted and received times on the ground and the arrival time of the pulses at the CubeSat, the time difference between the ground and space clocks can be measured. This compact, power efficient and secure synchronization technology will enable advanced space navigation, communications, networking, and distributed aperture telescopes in the future