Formation Flying Tehnologies and Approach for the NASA ST3 Mission
Spaceborne optical interferometry has been identified as a critical technology for many of NASA's 21st century science visions.
formation flying tehnologies NASA ST3 mission inte↗
Engineering topics
Lau, K.
Publications and source records attributed to Lau, K..
Experimental Study of Formation Alignment of Multiple Autonomous Air-levitated Vehicles with Rule-based Controls
An experimental study is made on the alignment of three autonomous air-levitated vehicles with air-jet controls to achieve an equilateral-triangle formation.
equilateral-triangle formation optical sensors↗
Synchronized Formation Rotation and Attitude Control of Multiple Free-flying Spacecraft
In the observation slewing of long base-line interferometers formed by multiple free-flying spacecraft in formation, it is required to rotate the entire formation about a given axis, and to synchronize individual spacecraft rotation with formation rotation.
long↗
Multiple Spacecraft Formations as Collaborating Autonomous Agents
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DS-3 spaceborne optical interferometer↗
The precision segmented reflectors: Moderate mission figure control subsystem
A system concept for a space based segmented reflector telescope figure control subsystem is described. The concept employs a two phase architecture in which figure initialization and figure maintenance are independent functions. Figure initialization is accomplished by image sharpening using natural reference targets. Figure maintenance is performed by monitoring the relative positions and alignments of the telescope components using an optical truss. Actuation is achieved using precision positioners. Computer simulation results of figure initialization by pairwise segment coalignment/cophasing and simulated annealing are presented along with figure maintenance results using a wavefront error regulation algorithm. Both functions are shown to perform at acceptable levels for the class of submillimeter telescopes that are serving as the focus of this technology development effort. Component breadboard work as well as plans for a system testbed are discussed.
Sevaston, G.↗
A Cerenkov - Delta E/Delta X experiment for measuring cosmic-ray isotopes from neon through iron
Cosmic-ray isotope masses are measured in a balloon-borne cosmic-ray experiment. Two Cerenkov counters and an NaI scintillator stack are used to determine changes in energy and in the Lorentz factor for a traversing or stopping particle. The mass is defined at the ratio of the change in energy to the change in the Lorentz factor. For incident elements from neon through iron, mass resolution better than 0.3 a.m.u. is expected, with incident Lorentz gammas ranging from 2.4 to 3.1, depending on the element. The mass resolution is approximately 0.2 a.m.u., measured for Mn-55 ions having an incident Lorentz factor of 2.75.
Buffington, A.↗
Calibration of a stack of NaI scintillators at the Berkeley Bevalac
An analysis of the carbon and argon data reveals that essentially all of the charge-changing fragmentation reactions within the stack can be identified and removed by imposing the simple criteria relating the observed energy deposition profiles to the expected Bragg curve depositions. It is noted that these criteria are even capable of identifying approximately one-third of the expected neutron-stripping interactions, which in these cases have anomalous deposition profiles. The contribution of mass error from uncertainty in delta E has an upper limit of 0.25 percent for Mn; this produces an associated mass error for the experiment of about 0.14 amu. It is believed that this uncertainty will change little with changing gamma. Residual errors in the mapping produce even smaller mass errors for lighter isotopes, whereas photoelectron fluctuations and delta-ray effects are approximately the same independent of the charge and energy deposition.
Schindler, S. M.↗
Position measurements for heavy ion beams using a sodium iodide scintillator
A 50 cm diameter, 1.7 cm thick disc of NaI scintillator has been mounted to permit edge viewing by four photomultipliers. Energetic heavy ions passing through the scintillator at different positions cause a variation in the division of light among the photomultipliers. A performance close to the expected limit for 670 MeV/n neon has been achieved. Calculations of expected response using an optical model agree well with the measurements.
Buffington, A.↗