The Origins Space Telescope will trace the history of our origins from the time dust and heavy elements permanently altered the cosmic landscape to present-day life. How did galaxies evolve from the earliest galactic systems to those found in the universe today? How do habitable planets form? How common are life-bearing worlds? To answer these alluring questions, Origins will operate at mid- and far-infrared wavelengths and offer powerful spectroscopic instruments and sensitivity three orders of magnitude better than that of Herschel, the largest telescope flown in space to date. After a 3 ½ year study, the Origins Science and Technology Definition Team will recommend to the Decadal Survey a concept for Origins with a 5.9-m diameter telescope cryocooled to 4.5 K and equipped with three scientific instruments. A mid-infrared instrument (MISC-T) will measure the spectra of transiting exoplanets in the 2.8 – 20 μm wavelength range and offer unprecedented sensitivity, enabling definitive biosignature detections. The Far-IR Imager Polarimeter (FIP) will be able to survey thousands of square degrees with broadband imaging at 50 and 250 μm. The Origins Survey Spectrometer (OSS) will cover wavelengths from 25 – 588 μm, make wide-area and deep spectroscopic surveys with spectral resolving power R ~ 300, and pointed observations at R ~ 40,000 and 300,000 with selectable instrument modes. Origins was designed to minimize complexity. The telescope has a Spitzer-like architecture and requires very few deployments after launch. The cryo-thermal system design leverages JWST technology and experience. A combination of current-state-of-the-art cryocoolers and next-generation detector technology will enable Origins’ natural backgroundlimited sensitivity.
The Origins Space Telescope (OST) will trace the history of our origins from the time dust and heavy elements permanently altered the cosmic landscape to present-day life. How did the universe evolve in response to its changing ingredients? How common are life-bearing planets? To accomplish its scientific objectives, OST will operate at mid- and far-infrared wavelengths and offer superlative sensitivity and new spectroscopic capabilities. The OST study team will present a scientifically compelling, executable mission concept to the 2020 Decadal Survey in Astrophysics. To understand the concept solution space, our team studied two alternative mission concepts. We report on the study approach and describe both of these concepts, give the rationale for major design decisions, and briefly describe the mission-enabling technology.
One of the flagship-class missions under study for the Astro 2020 Decadal review is the Lynx x-ray mission. It has significant design heritage to the highly successful Chandra X-ray Observatory. This report will highlight work done by the CAN Consortium of Northrop Grumman, Ball and Harris supporting the mission concept development led by the Lynx Science and Technology Definition Team (STDT) and MSFC Study Office. By comparing the Lynx requirements against the demonstrated performance of the Chandra Observatory, this paper will highlight the high TRL technologies that can be re-used from Chandra and those that will require new development , which impacts the Lynx architecture and development requirements. This paper will also summarize the top level performance budgets, performance predictions and suggestions on the calibration approach.
Lynx, one of four strategic mission concepts under study for the 2020 Astrophysics Decadal Survey, will provide leaps in capability over previous and planned X-ray missions, and will provide synergistic observations in the 2030s to a multitude of space- and ground-based observatories across all wavelengths. Lynx will have orders of magnitude improvement in sensitivity, on-axis sub-arcsecond imaging with arcsecond angular resolution over a large field of view, and high-resolution spectroscopy for point-like and extended sources. The Lynx architecture enables a broad range of unique and compelling science, to be carried out mainly through a General Observer Program. This Program is envisioned to include detecting the very first supermassive black holes, revealing the high-energy drivers of galaxy and structure formation, characterizing the mechanisms that govern stellar activity - including effects on planet habitability, and exploring the highest redshift galaxy clusters. An overview and status of the Lynx concept are summarized.
Large visible telescopes present challenging requirements for manufactured surface figure and stability. By comparison, far infrared (IR) telescopes relax many of these requirements by ~100x. These relaxed requirements may translate into reduced cost, schedule, mass, and system complexity. This paper explores how different mirror substrate materials might take advantage of these requirements while operating in a cryogenic environment. Primary mirror materials are evaluated for an Origins Space Telescope (OST) concept, using a 9.1 m segmented aperture in a 30 μm diffraction limited system.
For internal coronagraph options on the LUVOIR or HabEx mission concepts, the stated challenge of 10 picometers RMS wavefront stability over 10 minutes will govern the performance of every structure that connects the focal plane assembly to each optical surface. This paper interrogates wavefront stability of a mounted mirror assembly for a primary mirror segment assembly, and stability of the optical surface. Analysis describes stability of each element in a primary mirror segment assembly (PMSA) to understand the impact of each component of the PMSA on surface figure error (SFE) over short time periods.
Ion figuring is an optical fabrication method that provides deterministic surface figure error correction of previously polished surfaces by using a directed, inert, and neutralized ion beam to physically sputter material from the optic surface. Considerable process development has been completed and numerous large optical elements have been successfully final-figured using this process. The process has been demonstrated to be highly deterministic, capable of completing complex-shaped optical element configurations in only a few process iterations, and capable of achieving high- quality surface figure accuracies. A review of the neutral ion beam figuring process will be provided, along with discussion of processing results for several large optics. Most notably, processing of Keck 10 meter telescope primary mirror segments and correction of one other large optic where a convergence ratio greater than 50 was demostrated during the past year will be discussed. Also, the process has been demonstrated on various optical materials, including fused silica, ULE, zerodur, silicon, and chemically vapor deposited (CVD) silicon carbide. Where available, results of surface finish changes caused by the ion bombardment process will be discussed. Most data have shown only limited degradation of the optic surface finish, and that it is generally a function of the quality of mechanical polishing prior to ion figuring. Removals of from 5 to 10 micrometers on some materials are acceptable without adversely altering the surface finish specularity.
The final surface figure error correction of a 1.3 m ULETM frit-bonded, ultra- lightweight, off-axis primary mirror petal was successfully completed using the ion figuring process. The petal was a concave aspheric optical element. Ion figuring is an optical fabrication method that provides highly controlled error correction of previously polished surfaces using a directed, inert and neutralized ion beam to physically sputter material from the optic surface. The surface figure error of the petal following conventional polishing was 5.02 (lambda) p-v, 0.62 (lambda) rms, and was improved to 0.17 (lambda) p-v, 0.015 (lambda) rms in four process (test-ion figure) iterations ((lambda) equals 632.8 nm). A multi-iteration process sequence was selected to address the various surface figure error volume and spatial frequency components and involved applying three different beam removal functions. The benefits of ion figuring a complex shaped optic using multiple figuring-testing iterations were clearly demonstrated.
The ion figuring process has been successfully used to correct the residual surface figure error on a 1.8 m ZerodurTM off-axis segment of the new Keck telescope primary mirror. The segment is one of 36 hexagonal mirror segments composing the full aperture of the 10 m primary mirror. Ion figuring is an optical fabrication method that provides highly deterministic error correction of previously polished optical surfaces using a directed, inert, and neutralized Argon ion beam to physically sputter material from the surface. Figure error correction is accomplished by varying the velocity of the constant-output ion source as it scans across the optic surface. The surface figure error was reduced from 0.726 micrometers rms to 0.090 micrometers rms in two test-figure iterations. The demonstration provided information and requirements for future processing of ZerodurTM and other glass-ceramic materials, and clearly showed the applicability of ion beam figuring to the final correction of large, complex optics.
The Kodak 2 .5m Ion Figuring System (IFS), intended for the final figuring of large optics using a directed
inert neutralized ion beam, has been installed and is operational. Process development and production implementation
efforts are currently underway. Thermal heating effects due to exposure to the ion beam removal function
are discussed. Details of processing and results from an ion figuring correction of a 0.Sm lightweighted optic are