The scientific measurement requirements of future major space astronomy missions are pushing the design limits that can be autonomously deployed JWST-style from even the largest plausible launch vehicles in the 2030s and beyond. In addition, to maximize the scientific return and make missions more cost-effective, they should be capable of being serviced and upgraded. This requirement was even codified by the US Congress in 2010 to ensure the best use of taxpayer investments in science. We need to advance technologies to support this new generation of space telescopes and utilize planned NASA assets to lower costs, reduce risks, and extend mission life of flagship-class science programs for astrophysics and other NASA science. These missions will be capable of searching very large numbers of extrasolar planets for evidence of life and will enable studies, in detail, of the structure of the first star-forming complexes in the earliest galaxies and the central engines in distant galaxies, and will be powerful tools for general astrophysics and solar system science.
We will present and discuss current concepts for using astronauts and robots to service, upgrade, and eventually assemble space observatories and starshades designed to achieve major breakthroughs in our understanding of the cosmos. Notional telescopic missions and instruments (filled apertures, interferometers, evolvable systems, and starshades, among others) will be used to illustrate key characteristics of this approach and demonstrate the broad application such a deep-space facility would provide science missions. The goal of this effort is to understand how to use planned NASA human spaceflight assets and infrastructure, with minimal modification, to assemble, test, and service high-value science facilities. These deep space assets are currently being defined and now is the time to jointly develop requirements and capabilities that meet both science and human exploration objectives.
The technical and engineering merits and challenges of in-space servicing and assembly will be discussed, including issues of launching telescopes and instruments in parts, assembly in space, and repair and replacement of instruments and systems. Possible future space infrastructure that may make on-orbit assembly and servicing feasible will also be discussed. Precursors and demonstration activities will be presented, as well as early candidate missions for in-space upgrade and servicing.
Some concepts for candidate future “flagship” space observatories approach the payload limits of the largest launch vehicles planned for the next few decades, specifically in the available volume in the vehicle fairing. This indicates that an alternative to autonomous self-deployment similar to that of the James Webb Space Telescope will eventually be required. Moreover, even before this size limit is reached, there will be significant motivation to service, repair, and upgrade in-space missions of all sizes, whether to extend the life of expensive facilities or to replace outworn or obsolete onboard systems as was demonstrated so effectively by the Hubble Space Telescope program. In parallel with these challenges to future major space astronomy missions, the capabilities of in-space robotic systems and the goals for human space flight in the 2020s and 2030s offer opportunities for achieving the most exciting science goals of the early 21st Century. In this paper, we summarize the history of concepts for human operations beyond the immediate vicinity of the Earth, the importance of very large apertures for scientific discovery, and current capabilities and future developments in robot- and astronaut-enabled servicing and assembly.
The Large Observatory For x-ray Timing (LOFT) is a mission concept which was proposed to ESA as M3 and M4 candidate in the framework of the Cosmic Vision 2015-2025 program. Thanks to the unprecedented combination of effective area and spectral resolution of its main instrument and the uniquely large field of view of its wide field monitor, LOFT will be able to study the behaviour of matter in extreme conditions such as the strong gravitational field in the innermost regions close to black holes and neutron stars and the supra-nuclear densities in the interiors of neutron stars. The science payload is based on a Large Area Detector (LAD, >8m<sup>2</sup> effective area, 2-30 keV, 240 eV spectral resolution, 1 degree collimated field of view) and a Wide Field Monitor (WFM, 2-50 keV, 4 steradian field of view, 1 arcmin source location accuracy, 300 eV spectral resolution). The WFM is equipped with an on-board system for bright events (e.g., GRB) localization. The trigger time and position of these events are broadcast to the ground within 30 s from discovery. In this paper we present the current technical and programmatic status of the mission.
Dark matter in a universe dominated by a cosmological constant seeds the formation of structure and is the scaffolding
for galaxy formation. The nature of dark matter remains one of the fundamental unsolved problems in astrophysics and
physics even though it represents 85% of the mass in the universe, and nearly one quarter of its total mass-energy
budget. The mass function of dark matter "substructure" on sub-galactic scales may be enormously sensitive to the mass
and properties of the dark matter particle. On astrophysical scales, especially at cosmological distances, dark matter
substructure may only be detected through its gravitational influence on light from distant varying sources. Specifically,
these are largely active galactic nuclei (AGN), which are accreting super-massive black holes in the centers of galaxies,
some of the most extreme objects ever found. With enough measurements of the flux from AGN at different
wavelengths, and their variability over time, the detailed structure around AGN, and even the mass of the super-massive
black hole can be measured. The Observatory for Multi-Epoch Gravitational Lens Astrophysics (OMEGA) is a mission
concept for a 1.5-m near-UV through near-IR space observatory that will be dedicated to frequent imaging and
spectroscopic monitoring of ~100 multiply-imaged active galactic nuclei over the whole sky. Using wavelength-tailored
dichroics with extremely high transmittance, efficient imaging in six channels will be done simultaneously during each
visit to each target. The separate spectroscopic mode, engaged through a flip-in mirror, uses an image slicer
spectrograph. After a period of many visits to all targets, the resulting multidimensional movies can then be analyzed to
a) measure the mass function of dark matter substructure; b) measure precise masses of the accreting black holes as well
as the structure of their accretion disks and their environments over several decades of physical scale; and c) measure a
combination of Hubble's local expansion constant and cosmological distances to unprecedented precision. We present
the novel OMEGA instrumentation suite, and how its integrated design is ideal for opening the time domain of known
cosmologically-distant variable sources, to achieve the stated scientific goals.
<i>Kronos</i> is a multiwavelength observatory proposed as a NASA Medium Explorer. <i>Kronos</i> is designed to make use of the natural variability of accreting sources to create microarcsecond-resolution maps of the environments of supermassive black holes in active galaxies and stellar-size black holes in binary systems and to characterize accretion processes in Galactic compact binaries. <i>Kronos</i> will obtain broad energy range spectroscopic data with co-aligned X-ray, ultraviolet, and optical spectrometers. The high-Earth orbit of <i>Kronos</i> enables well-sampled, high time-resolution observations, critical for the innovative and sophisticated methods that are used to understand the accretion flows, mass outflows, jets, and other phenomena found in accreting sources. By utilizing reverberation mapping analysis techniques, <i>Kronos</i> produces advanced high-resolution maps of unprecedented resolution of the extreme environment in the inner cores of active galaxies. Similarly, Doppler tomography and eclipse mapping techniques characterize and map Galactic binary systems, revealing the details of the physics of accretion processes in black hole, neutron star, and white dwarf binary systems. The <i>Kronos</i> instrument complement, sensitivity, and orbital environment make it suitable to aggressively address time variable phenomena in a wide range of astronomical objects from nearby flare stars to distant galaxies.
Proc. SPIE. 4854, Future EUV/UV and Visible Space Astrophysics Missions and Instrumentation
KEYWORDS: Observatories, Detection and tracking algorithms, Satellites, Data transmission, Data acquisition, Data processing, Software development, Space operations, Data communications, Target acquisition
<i>Kronos</i> is a multiwavelength observatory designed to map the accretion disks and environments of supermassive black holes in various environments using the natural intrinsic variability of the accretion-driven sources. <i>Kronos</i> is envisaged as a Medium Explorer mission to NASA Office of Space Science under the Structure and Evolution of the Universe theme.
We will achieve the <i>Kronos</i> science objectives by developing cost-effective techniques for obtaining and assimilating data from the research spacecraft and its subsequent work on the ground. The science operations assumptions for the mission are:
(1 <i>Need for flexible scheduling due to the variable nature of targets,</i>
(2) <i>Large data volumes but minimal ground station contact,</i>
(3) <i>Very small staff for operations.</i>
Our first assumption implies that we will have to consider an effective strategy to dynamically reprioritize the observing schedule to maximize science data acquisition. The flexibility we seek greatly increases the science return of the mission, because variability events can be properly captured. Our second assumption implies that we will have to develop some basic on-board analysis strategies to determine which data get downloaded. The small size of the operations staff implies that we need to "automate" as many routine processes of science operations as possible.
In this paper we will discuss the various solutions that we are considering to optimize our operations and maximize science returns on the observatory.