61 research outputs found
Adaptive Multi-Functional Space Systems for Micro-Climate Control
This report summarizes the work done during the Adaptive Multifunctional Systems for Microclimate
Control Study held at the Caltech Keck Institute for Space Studies (KISS) in 2014-2015.
Dr. Marco Quadrelli (JPL), Dr. James Lyke (AFRL), and Prof. Sergio Pellegrino (Caltech) led
the Study, which included two workshops: the first in May of 2014, and another in February
of 2015. The Final Report of the Study presented here describes the potential relevance of
adaptive multifunctional systems for microclimate control to the missions outlined in the 2010
NRC Decadal Survey.
The objective of the Study was to adapt the most recent advances in multifunctional reconfigurable
and adaptive structures to enable a microenvironment control to support space exploration in
extreme environments (EE). The technical goal was to identify the most efficient materials,
architectures, structures and means of deployment/reconfiguration, system autonomy and energy
management solutions needed to optimally project/generate a micro-environment around space
assets. For example, compact packed thin-layer reflective structures unfolding to large areas
can reflect solar energy, warming and illuminating assets such as exploration rovers on Mars or
human habitats on the Moon. This novel solution is called an energy-projecting multifunctional
system (EPMFS), which are composed of Multifunctional Systems (MFS) and Energy-Projecting
Systems (EPS)
The Wide Brown Dwarf Binary Oph 1622-2405 and Discovery of A Wide, Low Mass Binary in Ophiuchus (Oph 1623-2402): A New Class of Young Evaporating Wide Binaries?
We imaged five objects near the star forming clouds of Ophiuchus with the
Keck Laser Guide Star AO system. We resolved Allers et al. (2006)'s #11 (Oph
16222-2405) and #16 (Oph 16233-2402) into binary systems. The #11 object is
resolved into a 243 AU binary, the widest known for a very low mass (VLM)
binary. The binary nature of #11 was discovered first by Allers (2005) and
independently here during which we obtained the first spatially resolved R~2000
near-infrared (J & K) spectra, mid-IR photometry, and orbital motion estimates.
We estimate for 11A and 11B gravities (log(g)>3.75), ages (5+/-2 Myr),
luminosities (log(L/Lsun)=-2.77+/-0.10 and -2.96+/-0.10), and temperatures
(Teff=2375+/-175 and 2175+/-175 K). We find self-consistent DUSTY evolutionary
model (Chabrier et al. 2000) masses of 17+4-5 MJup and 14+6-5 MJup, for 11A and
11B respectively. Our masses are higher than those previously reported (13-15
MJup and 7-8 MJup) by Jayawardhana & Ivanov (2006b). Hence, we find the system
is unlikely a ``planetary mass binary'', (in agreement with Luhman et al. 2007)
but it has the second lowest mass and lowest binding energy of any known
binary. Oph #11 and Oph #16 belong to a newly recognized population of wide
(>100 AU), young (<10 Myr), roughly equal mass, VLM stellar and brown dwarf
binaries. We deduce that ~6+/-3% of young (<10 Myr) VLM objects are in such
wide systems. However, only 0.3+/-0.1% of old field VLM objects are found in
such wide systems. Thus, young, wide, VLM binary populations may be
evaporating, due to stellar encounters in their natal clusters, leading to a
field population depleted in wide VLM systems.Comment: Accepted version V2. Now 13 pages longer (45 total) due to a new
discussion of the stability of the wide brown dwarf binary population, new
summary Figure 17 now included, Astrophysical Journal 2007 in pres
Modeling the transmission and thermal emission in a pupil image behind the Keck II adaptive optics system
The design and performance of astronomical instruments depend critically on the total system throughput as well as the background emission from the sky and instrumental sources. In designing a pupil stop for background- limited imaging, one seeks to balance throughput and background rejection to optimize measurement signal-to-noise ratios. Many sources affect transmission and emission in infrared imaging behind the Keck Observatory’s adaptive optics systems, such as telescope segments, segment gaps, secondary support structure, and AO bench optics. Here we describe an experiment, using the pupil-viewing mode of NIRC2, to image the pupil plane as a function of wavelength. We are developing an empirical model of throughput and background emission as a function of position in the pupil plane. This model will be used in part to inform the optimal design of cold pupils in future instruments, such as the new imaging camera for OSIRIS
Liger for Next Generation Keck Adaptive Optics: Opto-Mechanical Dewar for Imaging Camera and Slicer
Liger is a next generation adaptive optics (AO) fed integral field
spectrograph (IFS) and imager for the W. M. Keck Observatory. This new
instrument is being designed to take advantage of the upgraded AO system
provided by Keck All-Sky Precision Adaptive-optics (KAPA). Liger will provide
higher spectral resolving power (R4,000-10,000), wider wavelength
coverage (0.8-2.4 m), and larger fields of view than any current
IFS. We present the design and analysis for a custom-made dewar chamber for
characterizing the Liger opto-mechanical system. This dewar chamber is designed
to test and assemble the Liger imaging camera and slicer IFS components while
being adaptable for future experiments. The vacuum chamber will operate below
Torr with a cold shield that will be kept below 90 K. The dewar test
chamber will be mounted to an optical vibration isolation platform and further
isolated from the cryogenic and vacuum systems with bellows. The cold head and
vacuums will be mounted to a custom cart that will also house the electronics
and computer that interface with the experiment. This test chamber will provide
an efficient means of calibrating and characterizing the Liger instrument and
performing future experiments.Comment: 8 pages, 6 figure
Modeling the transmission and thermal emission in a pupil image behind the Keck II adaptive optics system
The design and performance of astronomical instruments depend critically on the total system throughput as well as the background emission from the sky and instrumental sources. In designing a pupil stop for background- limited imaging, one seeks to balance throughput and background rejection to optimize measurement signal-to-noise ratios. Many sources affect transmission and emission in infrared imaging behind the Keck Observatory’s adaptive optics systems, such as telescope segments, segment gaps, secondary support structure, and AO bench optics. Here we describe an experiment, using the pupil-viewing mode of NIRC2, to image the pupil plane as a function of wavelength. We are developing an empirical model of throughput and background emission as a function of position in the pupil plane. This model will be used in part to inform the optimal design of cold pupils in future instruments, such as the new imaging camera for OSIRIS
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