The First Solution to the Lost in Space Problem

In December 2018 and January 2019, weeks after a successful fly-by of Mars and relay of the InSight landing, communication with the MarCO cubsats were lost. The causes of this loss of communications with the MarCO cubesats are unknown, but could be related to a power issue or onboard fault. This leaves the MarCO cubesats effectively, lost in space, having no way to autonomously recover time, position, or velocity, should the spacecraft recover from the anomaly. This research will show a full solution to the lost in space orbit determination problem. This solution is achieved by using self-acquired optical observations via cubesat star tracker, of the planets, moons, and stars, thereby re-initializing the mission operations using low size, weight and power sensors compatible with small spacecraft architecture. Such cases of a lost in space spacecraft have not been systematically investigated until now. This research will show that it is indeed possible to solve this problem, recovering time, position, and velocity, and will show analysis in the context of the high precision requirements of planetary missions. Using the MarCO architecture and hardware as a baseline, this research will present a solution based on the orbital parameters of the MarCO cubesats

Orion Optical Navigation for Loss of Communication Lunar Return Contingencies

The Orion Crew Exploration Vehicle (CEV) will replace the Space Shuttle and serve as the next-generation spaceship to carry humans back to the Moon for the first time since the Apollo program. For nominal lunar mission operations, the Mission Control Navigation team will utilize radiometric measurements to determine the position and velocity of Orion and uplink state information to support Lunar return. However, in the loss of communications contingency return scenario, Orion must safely return the crew to the Earth's surface. The navigation design solution for this loss of communications scenario is optical navigation consisting of lunar landmark tracking in low lunar orbit and star- horizon angular measurements coupled with apparent planetary diameter for Earth return trajectories. This paper describes the optical measurement errors and the navigation filter that will process those measurements to support navigation for safe crew return

A Feedback Quenched Oscillator Produces Turing Patterning with One Diffuser

Efforts to engineer synthetic gene networks that spontaneously produce patterning in multicellular ensembles have focused on Turing's original model and the “activator-inhibitor” models of Meinhardt and Gierer. Systems based on this model are notoriously difficult to engineer. We present the first demonstration that Turing pattern formation can arise in a new family of oscillator-driven gene network topologies, specifically when a second feedback loop is introduced which quenches oscillations and incorporates a diffusible molecule. We provide an analysis of the system that predicts the range of kinetic parameters over which patterning should emerge and demonstrate the system's viability using stochastic simulations of a field of cells using realistic parameters. The primary goal of this paper is to provide a circuit architecture which can be implemented with relative ease by practitioners and which could serve as a model system for pattern generation in synthetic multicellular systems. Given the wide range of oscillatory circuits in natural systems, our system supports the tantalizing possibility that Turing pattern formation in natural multicellular systems can arise from oscillator-driven mechanisms

Impactor Spacecraft Encounter Sequence Design for the Deep Impact Mission

This conference features the work of authors from: Georgia Tech’s Space Systems Design Lab, Aerospace Systems Design Lab, School of Aerospace Engineering, Georgia Tech Research Institute; NASA’s Jet Propulsion Laboratory, Marshall Space Flight Center, Goddard Space Flight Center, Langley Research Center; and other aerospace industry and academic institutionsOn July 4, 2005, another first in space exploration was achieved. NASA’s Deep Impact spacecraft (s/c) released a small, 350 kg Impactor s/c designed to target comet Tempel 1, estimated to be 14 km x 5 km x 5 km in size at the time of release. With a closing speed of approximately 10.3 km/s, the Impactor s/c autonomously guided itself to impact and captured 40 cm resolution images, the highest resolution images ever of the surface of a cometary nucleus, just moments before the collision. The objective of the Impactor s/c was to impact in an illuminated area viewable from the Flyby s/c. This paper describes the Impactor encounter sequence design, execution and contingency planning that contributed to the successful outcome in which all objectives were met.AIAA Space Systems Technical Committee ; AIAA Space Transportation Systems Technical Committee ; Space Technology Advanced Research Cente

Recovering Time and State for Small Satellites in Deep Space

Autonomous navigation in the satellite world is at best, a semi-autonomous solution. All systems currently require an outside presence or prior state to get a navigation. As the small satellite revolution brings about numerous more spacecraft, the need for truly autonomous navigation becomes a greater necessity for deep space travel as communication resources become limited. When spacecraft are in deep space, communication times between a satellite and the Earth can be prohibitive and ride-sharing opportunities as well as on-board faults can leave the spacecraft without time information. The proposed approach uses optical observations of available planets and corresponding celestial satellites (for interplanetary operations) to initially recover the approximate time and state. These observations are then followed by precise, filter-based determination of time, position and velocity from the chosen optical beacons available in interplanetary spaceflight. The innovation of this approach is to use the periodicity of celestial bodies and artificial satellites to initially determine time. This capability is analogous to that of advanced star trackers that can initialize themselves by identifying any star field in the celestial sphere. Being able to quickly and autonomously recover time and position from an environment with no Earth contact will advance mission safety and automation from current methods which require an Earth contact. The impact of this concept crosses both human (full loss of communication scenario) and robotic (autonomous recovery from onboard fault) exploration applications, where some form of spacecraft-to-ground communication is required to establish approximates for time and position. In both cases, the current state-of-the-art navigation systems require some knowledge of time and some approximate position to initialize the estimation process before the mission objectives can be obtained. This presentation will examine the best-known solution for time in different scenarios related to the future of small satellite missions. While the solution is applicable to a wide range of missions, small satellites used for solar system exploration will be the focus as small satellite solutions can then be scaled to larger spacecraft

Radiation Pressure Forces, the Anomalous Acceleration, and Center of Mass Motion for the TOPEX/POSEIDON Spacecraft

Shortly after launch of the TOPEX/POSEIDON (T/P) spacecraft (s/c), the Precision Orbit Determination (POD) Team at NASA's Goddard Space Flight Center (GSFC) and the Center for Space Research at the University of Texas, discovered residual along-track accelerations, which were unexpected. Here, we describe the analysis of radiation pressure forces acting on the T/P s/c for the purpose of understanding and providing an explanation for the anomalous accelerations. The radiation forces acting on the T/P solar army, which experiences warping due to temperature gradients between the front and back surfaces, are analyzed and the resulting along-track accelerations are determined. Characteristics similar to those of the anomalous acceleration are seen. This analysis led to the development of a new radiation form model, which includes solar array warping and a solar array deployment deflection of as large as 2 deg. As a result of this new model estimates of the empirical along-track acceleration are reduced in magnitude when compared to the GSFC tuned macromodel and are less dependent upon beta(prime), the location of the Sun relative to the orbit plane. If these results we believed to reflect the actual orientation of the T/P solar array then motion of the solar array must influence the location of the s/c center of mass. Preliminary estimates indicate that the center of mass can vary by as much as 3 cm in the radial component of the s/c's position due to rotation of the deflected, warped solar array panel .The altimeter measurements rely upon accurate knowledge of the center of mass location relative to the s/c frame of reference. Any radial motion of the center of mass directly affects the altimeter measurements

Deep Impact Comet Encounter: Design, Development and Operation of the Big Event at Tempel 1

This conference features the work of authors from: Georgia Tech’s Space Systems Design Lab, Aerospace Systems Design Lab, School of Aerospace Engineering, Georgia Tech Research Institute; NASA’s Jet Propulsion Laboratory, Marshall Space Flight Center, Goddard Space Flight Center, Langley Research Center; and other aerospace industry and academic institutionsDeep Impact Comet Encounter was a mission to crash the Impactor spacecraft and its Impactor Targeting Sensor (ITS) into Comet Tempel 1 and record the event via a Flyby spacecraft. The Deep Impact spacecrafts, Flyby and Impactor, were launched together aboard a Delta II rocket from Kennedy Space Flight Center on January 12, 2005. Impactor ended its almost six-month mission by successfully transmitting back images of the comet as it plowed into the surface of Tempel 1 on July 4, 2005. Flyby successfully transmitted back the first image of the Impactor’s collision with Tempel 1 via its High Resolution Imager (HRI), the largest telescope ever to be deployed into deep spaceAIAA Space Systems Technical Committee ; AIAA Space Transportation Systems Technical Committee ; Space Technology Advanced Research Cente