AIROscope: Ames infrared balloon-borne telescope

A balloon-borne telescope system designed for astronomical observations at infrared wavelengths is discussed. The telescope is gyro-stabilized with updated pointing information derived from television, star tracker, or ground commands. The television system furnishes both course and fine acquisition after initial orientation using a pair of fluxgate servo compasses. Command and control is by a UHF link with 256 commands available. Scientific and engineering data are telemetered to the ground station via narrow band F.M. in the L band. The ground station displays all scientific, engineering and status information during the flights and records the command and telemetry digital bit stream for detailed analysis. The AIROscope telescope has a 28-inch diameter primary mirror and Dall-Kirkham optics. The beam is modulated by oscillating a secondary mirror at 11 or 25 Hz with provision for left or right beam fixed positions by command

Autonomous Navigation for Mars Exploration

The autonomous navigation technology uses the multiple sensors to percept and estimate the spatial locations of the aerospace prober or the Mars rover and to guide their motions in the orbit or the Mars surface. In this chapter, the autonomous navigation methods for the Mars exploration are reviewed. First, the current development status of the autonomous navigation technology is summarized. The popular autonomous navigation methods, such as the inertial navigation, the celestial navigation, the visual navigation, and the integrated navigation, are introduced. Second, the application of the autonomous navigation technology for the Mars exploration is presented. The corresponding issues in the Entry Descent and Landing (EDL) phase and the Mars surface roving phase are mainly discussed. Third, some challenges and development trends of the autonomous navigation technology are also addressed

Advancing Tests of Relativistic Gravity via Laser Ranging to Phobos

Phobos Laser Ranging (PLR) is a concept for a space mission designed to advance tests of relativistic gravity in the solar system. PLR's primary objective is to measure the curvature of space around the Sun, represented by the Eddington parameter $\gamma$, with an accuracy of two parts in $10^7$, thereby improving today's best result by two orders of magnitude. Other mission goals include measurements of the time-rate-of-change of the gravitational constant, $G$ and of the gravitational inverse square law at 1.5 AU distances--with up to two orders-of-magnitude improvement for each. The science parameters will be estimated using laser ranging measurements of the distance between an Earth station and an active laser transponder on Phobos capable of reaching mm-level range resolution. A transponder on Phobos sending 0.25 mJ, 10 ps pulses at 1 kHz, and receiving asynchronous 1 kHz pulses from earth via a 12 cm aperture will permit links that even at maximum range will exceed a photon per second. A total measurement precision of 50 ps demands a few hundred photons to average to 1 mm (3.3 ps) range precision. Existing satellite laser ranging (SLR) facilities--with appropriate augmentation--may be able to participate in PLR. Since Phobos' orbital period is about 8 hours, each observatory is guaranteed visibility of the Phobos instrument every Earth day. Given the current technology readiness level, PLR could be started in 2011 for launch in 2016 for 3 years of science operations. We discuss the PLR's science objectives, instrument, and mission design. We also present the details of science simulations performed to support the mission's primary objectives.Comment: 25 pages, 10 figures, 9 table

Natural motion around the Martian moon Phobos : The dynamical substitutes of the libration point orbits in an elliptical three-body problem with gravity harmonics

The Martian moon Phobos is becoming an appealing destination for future scientific missions. The orbital dynamics around this planetary satellite is particularly complex due to the unique combination of both small mass-ratio and length-scale of the Mars-Phobos couple: the resulting sphere of influence of the moon is very close to its surface, therefore both the classical two-body problem and circular restricted three-body problem (CR3BP) do not provide an accurate approximation to describe the spacecraft’s dynamics in the vicinity of Phobos. The aim of this paper is to extend the model of the CR3BP to consider the orbital eccentricity and the highly-inhomogeneous gravity field of Phobos, by incorporating the gravity harmonics series expansion into an elliptic R3BP, named ER3BP-GH. Following this, the dynamical substitutes of the Libration Point Orbits (LPOs) are computed in this more realistic model of the relative dynamics around Phobos, combining methodologies from dynamical systems theory and numerical continuation techniques. Results obtained show that the structure of the periodic and quasi-periodic LPOs differs substantially from the classical case without harmonics. Several potential applications of these natural orbits are presented to enable unique low-cost operations in the proximity of Phobos, such as close-range observation, communication, and passive radiation shielding for human spaceflight. Furthermore, their invariant manifolds are demonstrated to provide high-performance natural landing and take-off pathways to and from Phobos’ surface, and transfers from and to Martian orbits. These orbits could be exploited in upcoming and future space missions targeting the exploration of this Martian moon

Virtual image out-the-window display system study. Volume 2 - Appendix

Virtual image out-the-window display system imaging techniques and simulation devices - appendices containing background materia

Space craft reliable trajectory tracking and landing using model predictive control with chance constraints

This work considers the study of chance constrained Model Predictive Control (MPC) for reliable spacecraft trajectory tracking and landing. Objectives of the master thesis: • To identify and study mathematical dynamic models of a spacecraft. • To study the trajectory design and landing schemes for a given mission. • To study the source of uncertainty in the model parameters and external disturbances. • To study the chance constrained MPC scheme for the reliable and optimal trajectory tracking and landing. • To testing the new analytic approximation approaches, Inner and Outer, for chance constraints. • To study appropriate MPC algorithms and implement on case-studies. In the first part of the thesis considers deterministic dynamical models of spacecraft are discussed. The first example is about the tracking of trajectory and soft landing on the surface of an asteroid EROS433, this model uses Cartesian coordinates. In the second example, in a similar way to the first example, the trajectory and soft landing is performed on the surface of a celestial body. It is assumed that the celestial body is a perfect sphere, something that does not happen in the first example. Thus, the second example uses a Spherical coordinate system. The third example is about a Lander that enters the Martian atmosphere. This Lander follows a designed trajectory until reaching a certain altitude over the Martian surface. At this altitude the Lander deploys a parachute to make the landing. To solve the deterministic examples described above, the following sequence of steps are: • pose the deterministic Nonlinear Optimal Control Problem (NOCP), • convert the infinite Optimal Control Problem (OCP) to a finite Nonlinear Programming Problem (NLP), applying the Runge-Kutta 4th order discretization method, • apply the Quasi-sequential method to the deterministic NLP obtained from the previous step, • solution of the reduced NLP obtained from the previous step using IpOpt software. The steps outlined above are also part of the Nonlinear Model Predictive Control (NMPC) approach. In the second part of the thesis, the same examples of the first part are used but now with stochastic variables. To find the control law in each model, the stochastic NMPC was used. The above mentioned approach begins with a chance constrained OCP. The latter is discretized obtaining an NLP. The problem with this NLP, with chance constraints, is that is very difficult to solve in analytic form. So these chance constraints are approached by a different method that exist in the state of the art. This thesis work is focused on approaching the chance constraints through Analytic Approximation Strategies, specifically by the recent: Inner and Outer Approximation methods. The chance constrained MPC is expensive from a computational point of view, but it allows to find a control law for a more reliable trajectory-tracking and soft landing . That is suitable for applications with random disturbances, model inaccuracies, and measurement errors.Tesi

Viking '75 spacecraft design and test summary. Volume 1: Lander design

The Viking Mars program is summarized. The design of the Viking lander spacecraft is described

Navigation of a manned satellite supply vehicle back to earth

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1959.Includes bibliographical references (leaves 128-132).by James E. McCormick, John H. Axley, Forrest R. Hanvey.M.S

Lunar navigation study, sections 1 through 7 Final report, Jun. 1964 - May 1965

Lunar navigation analysis using passive nongyro, inertial navigation, and radio frequency technolog