The Lynx X-ray Observatory
|Names||Lynx X-ray Surveyor (previous name)|
|Mission type||Space telescope|
|Start of mission|
|Launch date||2036 (proposed)|
|Reference system||Sun–Earth L2 orbit|
|Focal length||10 m|
|Collecting area||2 square meters at 1 keV|
|Resolution||0.5 arcsec across the entire field of view|
|Lynx X-ray Mirror Assembly (LMA)|
High Definition X-ray Imager (HDXI)
Lynx X-ray Microcalorimeter (LXM)
X-ray Grating Spectrometer (XGS)
The Lynx X-ray Observatory Wordmark
The Lynx X-ray Observatory (Lynx) is a NASA-funded Large Mission Concept Study commissioned as part of the National Academy of Sciences 2020 Astronomy and Astrophysics Decadal Survey. The concept study phase is complete as of August 2019, and the Lynx final report has been submitted to the Decadal Survey for prioritization. If launched, Lynx would be the most powerful X-ray astronomy observatory constructed to date, enabling order-of-magnitude advances in capability over the current Chandra X-ray Observatory and XMM-Newton space telescopes.
See also: Large strategic science missions
In 2016, following recommendations laid out in the so-called Astrophysics Roadmap of 2013, NASA established four space telescope concept studies for future Large strategic science missions. In addition to Lynx (originally called X-ray Surveyor in the Roadmap document), they are the Habitable Exoplanet Imaging Mission (HabEx), the Large Ultraviolet Optical Infrared Surveyor (LUVOIR), and the Origins Space Telescope (OST, originally called the Far-Infrared Surveyor). The four teams completed their final reports in August 2019, and turned them over to both NASA and the National Academy of Sciences, whose independent Decadal Survey committee advises NASA on which mission should take top priority. If it receives top prioritization and therefore funding, Lynx would launch in approximately 2036. It would be placed into a halo orbit around the second Sun–Earth Lagrange point (L2), and would carry enough propellant for more than twenty years of operation without servicing.
The Lynx concept study involved more than 200 scientists and engineers across multiple international academic institutions, aerospace, and engineering companies. The Lynx Science and Technology Definition Team (STDT) was co-chaired by Alexey Vikhlinin and Feryal Özel. Jessica Gaskin was the NASA Study Scientist, and the Marshall Space Flight Center managed the Lynx Study Office jointly with the Smithsonian Astrophysical Observatory, which is part of the Harvard–Smithsonian Center for Astrophysics.
According to the concept study's Final Report, the Lynx Design Reference Mission was intentionally optimized to enable major advances in the following three astrophysical discovery areas:
Collectively, these serve as three "science pillars" that set the baseline requirements for the observatory. Those requirements include greatly enhanced sensitivity, a sub-arcsecond point spread function stable across the telescope's field of view, and very high spectral resolution for both imaging and gratings spectroscopy. These requirements, in turn, enable a broad science case with major contributions across the astrophysical landscape (as summarized in Chapter 4 of the Lynx Report), including multi-messenger astronomy, black hole accretion physics, large-scale structure, Solar System science, and even exoplanets. The Lynx team markets the mission's science capabilities as "transformationally powerful, flexible, and long-lived", inspired by the spirit of NASA's Great Observatories program.
As described in Chapters 6-10 of the concept study's Final Report, Lynx is designed as an X-ray observatory with a grazing incidence X-ray telescope and detectors that record the position, energy, and arrival time of individual X-ray photons. Post-facto aspect reconstruction leads to modest requirements on pointing precision and stability, while enabling accurate sky locations for detected photons. The design of the Lynx spacecraft draws heavily on heritage from the Chandra X-ray Observatory, with few moving parts and high technology readiness level elements. Lynx will operate in a halo orbit around Sun-Earth L2, enabling high observing efficiency in a stable environment. Its maneuvers and operational procedures on-orbit are nearly identical to Chandra's, and similar design approaches promote longevity. Without in-space servicing, Lynx will carry enough consumables to enable continuous operation for at least twenty years. The spacecraft and payload elements are, however, designed to be serviceable, potentially enabling an even longer lifetime.
The major advances in sensitivity, spatial, and spectral resolution in the Lynx Design Reference Mission are enabled by the spacecraft's payload, namely the mirror assembly and suite of three science instruments. The Lynx Report notes that each of the payload elements features state-of-the-art technologies while also representing a natural evolution of existing instrumentation technology development over the last two decades. The key technologies are currently at Technology Readiness Levels (TRL) 3 or 4. The Lynx Report notes that, with three years of targeted pre-phase A development in early 2020s, three of four key technologies will be matured to TRL 5 and one will reach TRL 4 by start of Phase A, achieving TRL 5 shortly thereafter. The Lynx payload consists of the following four major elements:
The Chandra X-ray Observatory experience provides the blueprint for developing the systems required to operate Lynx, leading to a significant cost reduction relative to starting from scratch. This starts with a single prime contractor for the science and operations center, staffed by a seamless, integrated team of scientists, engineers, and programmers. Many of the system designs, procedures, processes, and algorithms developed for Chandra will be directly applicable for Lynx, although all will be recast in a software/hardware environment appropriate for the 2030s and beyond.
The science impact of Lynx will be maximized by subjecting all of its proposed observations to peer review, including those related to the three science pillars. Time pre-allocation can be considered only for a small number of multi-purpose key programs, such as surveys in pre-selected regions of the sky. Such an open General Observer (GO) program approach has been successfully employed by large missions such as Hubble Space Telescope, Chandra X-ray Observatory, and Spitzer Space Telescope, and is planned for James Webb Space Telescope and Nancy Grace Roman Space Telescope. The Lynx GO program will have ample exposure time to achieve the objectives of its science pillars, make impacts across the astrophysical landscape, open new directions of inquiry, and produce as yet unimagined discoveries.
The cost of the Lynx X-ray Observatory is estimated to be between US$4.8 billion to US$6.2 billion (in FY20 dollars at 40% and 70% confidence levels, respectively). This estimated cost range includes the launch vehicle, cost reserves, and funding for five years of mission operations, while excluding potential foreign contributions (such as participation by the European Space Agency (ESA)). As described in Section 8.5 of the concept study's Final Report, the Lynx team commissioned five independent cost estimates, all of which arrived at similar estimates for the total mission lifecycle cost.