Mission type | Space observatory |
---|---|
Operator | NASA |
Website | www |
Mission duration | 5 to 10 years (proposed) [1] |
Spacecraft properties | |
Launch mass | 18,550 kilograms (40,900 lb) (maximum) [1] |
Dry mass | ≈10,160 kg (22,400 lb) |
Payload mass | ≈6,080 kg (13,400 lb) (telescope + instruments) |
Power | 6.9 kW (maximum) [1] |
Start of mission | |
Launch date | 2035 (proposed) |
Rocket | Observatory: Space Launch System (SLS) Block 1B [1] Starshade: Falcon Heavy |
Orbital parameters | |
Regime | Lagrange point (Sun-Earth L2) |
Main | |
Diameter | 4 m (13 ft) |
Wavelengths | Visible; possibly UV, NIR, IR (91 – 1000 nm) |
Resolution | R ≥ 60,000; SNR ≥ 5 per resolution element on targets of AB ≥ 20 mag (GALEX FUV) in exposure times of ≤12 h [1] |
Instruments | |
VIS camera, UV spectrograph, coronagraph, starshade [1] [2] | |
The Habitable Exoplanet Observatory (HabEx) is a space telescope concept that would be optimized to search for and image Earth-size habitable exoplanets in the habitable zones of their stars, where liquid water can exist. HabEx would aim to understand how common terrestrial worlds beyond the Solar System may be and determine the range of their characteristics. It would be an optical, UV and infrared telescope that would also use spectrographs to study planetary atmospheres and eclipse starlight with either an internal coronagraph or an external starshade. [3]
The proposal, first made in 2016, is for a large strategic science missions NASA mission. It would operate at the Lagrange point L2.
In January 2023, a new space telescope concept was proposed called the Habitable Worlds Observatory (HWO), which draws upon HabEx and the Large Ultraviolet Optical Infrared Surveyor (LUVOIR). [4]
In 2016, NASA began considering four different space telescopes as the next Flagship (Large strategic science missions) following the James Webb Space Telescope and Nancy Grace Roman Space Telescope. [3] They are the Habitable Exoplanet Observatory (HabEx), Large Ultraviolet Optical Infrared Surveyor (LUVOIR), Origins Space Telescope, and Lynx X-ray Surveyor. In 2019, the four teams turned their final reports over to the National Academy of Sciences, whose independent Decadal Survey committee advises NASA on which mission should take top priority. [3]
The Habitable Exoplanet Imaging Mission (HabEx) is a concept for a mission to directly image planetary systems around Sun-like stars. [5] [6] HabEx will be sensitive to all types of planets; however its main goal is to directly image Earth-size rocky exoplanets, and characterize their atmospheric content. By measuring the spectra of these planets, HabEx will search for signatures of habitability such as water, and be sensitive to gases in the atmosphere potentially indicative of biological activity, such as oxygen or ozone. [6]
In 2021, the National Academy of Sciences released its final recommendations in the Decadal Survey. It recommended that NASA consider a new 6-meter (20-foot) aperture telescope combining design elements of LUVOIR and HabEx. The new telescope would be called the Habitable Worlds Observatory (HWO). A preliminary launch date was set for 2040, and the budget was estimated to be $11 billion. [7] [8] [9]
HabEx's prime science goal is the discovery and characterization of Earth-sized planets in the habitable zones of nearby main sequence stars, it will also study the full range of exoplanets within the systems and also enable a wide range of general astrophysics science.
In particular, the mission will be designed to search for signs of habitability and biosignatures in the atmospheres of Earth-sized rocky planets located in the habitable zone of nearby solar type stars. [10] Absorption features from CH
4, H
2O, NH
3, and CO, and emission features from Na and K, are all within the wavelength range of anticipated HabEx observations.
With a contrast that is 1000 times better than that achievable with the Hubble Space Telescope, [10] HabEx could resolve large dust structures, tracing the gravitational effect of planets. By imaging several faint protoplanetary disks for the first time, HabEx will enable comparative studies of dust inventory and properties across a broad range of stellar classifications. [5] This will put the Solar System in perspective not only in terms of exoplanet populations, but also in terms of dust belt morphologies. [10]
General astrometry and astrophysics observations may be performed if justified by a high science return while still being compatible with top exoplanet science goals and preferred architecture. A wide variety of investigations are currently being considered for HabEx general astrophysics program. They range from studies of galaxy leakiness and inter-galactic medium reionization through measurements of the escape fraction of ionizing photons, to studies of the life cycle of baryons as they flow in and out of galaxies, to resolved stellar population studies, including the impact of massive stars and other local environment conditions on star formation rate and history. [10] More exotic applications include astrometric observations of local dwarf galaxies to help constrain the nature of dark matter, and precision measurement of the local value of the Hubble Constant. [10]
The following table summarizes the possible investigations currently suggested for HabEx general astrophysics: [10]
Science driver | Observation | Wavelength |
---|---|---|
Local Hubble Constant | Image Cepheid in type Ia supernova host galaxies | Optical-NIS |
Galaxy leakiness and reionization | UV imaging of galaxies (LyC photons escape fraction) | UV, preferably down to LyC at 91 nm |
Cosmic baryon cycle | UV imaging and spectroscopy of absorption lines in background quasars | Imaging: down to 115 nm Spectroscopy: down to 91 nm |
Massive stars/feedback | UV imaging and spectroscopy in the Milky Way and nearby galaxies | Imaging: 110–1000 nm Spectroscopy: 120–160 nm |
Stellar archaeology | Resolved photometry of individual stars in nearby galaxies | Optical: 500–1000 nm |
Dark matter | Photometry and astrometric proper motion of stars in local group dwarf galaxies | Optical: 500–1000 nm |
Based on the science drivers and purpose, the researchers are considering direct imaging and spectroscopy of reflected starlight in the visible spectrum, with potential extensions to the UV and the near infrared parts of the spectrum. The telescope has a primary monolithic mirror that is 4 metres (13 ft) in diameter.
An absolute minimum continuous wavelength range is 0.4 to 1 μm, with possible short wavelength extensions down below 0.3 μm and near infrared extensions to 1.7 μm or even 2.5 μm, depending on the cost and complexity. [10]
For characterization of extraterrestrial atmospheres, going to longer wavelengths would require a 52 m (171 ft) starshade that would launch separately on a Falcon Heavy, [1] or a larger telescope in order to reduce the amount of background light. An alternative would be to keep the coronagraph small. Characterizing exoplanets at wavelengths shorter than ~350 nm would require a fully UV-sensitive high contrast optical train to preserve throughput, and will make all wavefront requirements more stringent, whether for a starshade or a coronagraph architecture. [10] Such high spatial resolution, high contrast observations would also open up unique capabilities for studying the formation and evolution of stars and galaxies.
HabEx would search for potential biosignature gases in exoplanets' atmospheres, such as O
2 (0.69 and 0.76 μm) and its photolytic product ozone (O
3). On the long wavelength side, extending the observations to 1.7 μm would make it possible to search for strong additional water signatures (at 1.13 and 1.41 μm), and would also allow to search for evidence that the detected O
2 and O
3 gases were created by abiotic processes (e.g., by looking for features from CO
2, CO, O
4). A further infrared capability to ~2.5 μm would allow to search for secondary features such as methane (CH
4) that may be consistent with biological processes. Pushing even further in the UV may also allow distinction between a biotic, high-O2 atmosphere from an abiotic, CO
2-rich atmosphere based on the ozone absorption of 0.3 μm. [10]
Molecular oxygen (O
2) can be produced by geophysical processes, as well as a byproduct of photosynthesis by life forms, so although encouraging, O
2 is not a definite biosignature, unless it is considered in its environmental context. I.e., while O2 production to ~20% of atmospheric content seems to be part of life on Earth, too much oxygen is actually poisonous to life as humans know it and could easily be created by planetary situations like a incredibly deep world spanning ocean. [11] [12] [13] [14] [15]
The Spitzer Space Telescope, formerly the Space Infrared Telescope Facility (SIRTF), is an infrared space telescope launched in 2003, that was deactivated when operations ended on 30 January 2020. Spitzer was the third space telescope dedicated to infrared astronomy, following IRAS (1983) and ISO (1995–1998). It was the first spacecraft to use an Earth-trailing orbit, later used by the Kepler planet-finder.
NASA's series of Great Observatories satellites are four large, powerful space-based astronomical telescopes launched between 1990 and 2003. They were built with different technology to examine specific wavelength/energy regions of the electromagnetic spectrum: gamma rays, X-rays, visible and ultraviolet light, and infrared light.
A coronagraph is a telescopic attachment designed to block out the direct light from a star or other bright object so that nearby objects – which otherwise would be hidden in the object's bright glare – can be resolved. Most coronagraphs are intended to view the corona of the Sun, but a new class of conceptually similar instruments are being used to find extrasolar planets and circumstellar disks around nearby stars as well as host galaxies in quasars and other similar objects with active galactic nuclei (AGN).
Darwin was a suggested ESA Cornerstone mission which would have involved a constellation of four to nine spacecraft designed to directly detect Earth-like planets orbiting nearby stars and search for evidence of life on these planets. The most recent design envisaged three free-flying space telescopes, each three to four metres in diameter, flying in formation as an astronomical interferometer. These telescopes were to redirect light from distant stars and planets to a fourth spacecraft, which would have contained the beam combiner, spectrometers, and cameras for the interferometer array, and which would have also acted as a communications hub. There was also an earlier design, called the "Robin Laurance configuration," which included six 1.5 metre telescopes, a beam combiner spacecraft, and a separate power and communications spacecraft.
A biosignature is any substance – such as an element, isotope, molecule, or phenomenon – that provides scientific evidence of past or present life on a planet. Measurable attributes of life include its complex physical or chemical structures, its use of free energy, and the production of biomass and wastes.
The New Worlds Mission is a proposed project comprising a large occulter flying in formation with a space telescope designed to block the light of nearby stars in order to observe their orbiting exoplanets. The observations could be taken with an existing space telescope or a dedicated visible light optical telescope optimally designed for the task of finding exoplanets. A preliminary research project was funded from 2005 through 2008 by NASA Institute for Advanced Concepts (NIAC) and headed by Webster Cash of the University of Colorado at Boulder in conjunction with Ball Aerospace & Technologies Corp., Northrop Grumman, Southwest Research Institute and others. Since 2010 the project has been looking for additional financing from NASA and other sources in the amount of roughly US$3 billion including its own four-meter telescope. If financed and launched, it would operate for five years.
Margaret Carol "Maggie" Turnbull is an American astronomer and astrobiologist. She received her PhD in Astronomy from the University of Arizona in 2004. Turnbull is an authority on star systems which may have habitable planets, solar twins and planetary habitability. She is also an expert on the use of the coronagraph in the direct detection of exoplanets.
Daniel Apai is a professor and astrophysicist at The University of Arizona in Tucson, Arizona. He is known for his studies of astrobiology, extrasolar planets, and the formation of planetary systems. He is the principal investigator of the Earths in Other Solar Systems team of NASA's Nexus for Exoplanet System Studies and the Hubble Space Telescope Cloud Atlas Treasury program, and Project EDEN, a large survey for habitable planets in the immediate solar neighborhood. He is leading the Nautilus Space Observatory space telescope concept and co-leading the technology development underpinning it.
The Nancy Grace Roman Space Telescope (shortened as Roman or the Roman Space Telescope, and formerly the Wide-Field Infrared Survey Telescope or WFIRST) is a NASA infrared space telescope in development and scheduled to launch to a Sun–Earth L2 orbit by May 2027.
Astrophysics Strategic Mission Concept Studies [AMSCS] is a program within the National Aeronautics and Space Administration agency of the United States government for possible projects leading to probable prospective missions.
Enduring Quests and Daring Visions is a vision for astrophysics programs chartered by then-Director of NASA's Astrophysics Division, Paul Hertz, and released in late 2013. It lays out plans over 30 years as long-term goals and missions. Goals include mapping the Cosmic Microwave Background and finding Earth like exoplanets, to go deeper into space-time studying the Large Scale Structure of the Universe, extreme physics, and looking back farther in time. The panel that produced the vision included many notable American astrophysicists, including: Chryssa Kouveliotou, Eric Agol, Natalie Batalha, Misty Bentz, Alan Dressler, Scott Gaudi, Olivier Guyon, Enectali Figueroa-Feliciano, Feryal Ozel, Aki Roberge, Amber Straughn, and Joan Centrella.
The Carl Sagan Institute: Pale Blue Dot and Beyond was founded in 2014 at Cornell University in Ithaca, New York to further the search for habitable planets and moons in and outside the Solar System. It is focused on the characterization of exoplanets and the instruments to search for signs of life in the universe. The founder and current director of the institute is astronomer Lisa Kaltenegger.
The Large Ultraviolet Optical Infrared Surveyor, commonly known as LUVOIR, is a multi-wavelength space telescope concept being developed by NASA under the leadership of a Science and Technology Definition Team. It is one of four large astrophysics space mission concepts studied in preparation for the National Academy of Sciences 2020 Astronomy and Astrophysics Decadal Survey.
NIRCam is an instrument aboard the James Webb Space Telescope. It has two major tasks, as an imager from 0.6 to 5 μm wavelength, and as a wavefront sensor to keep the 18-section mirrors functioning as one. In other words, it is a camera and is also used to provide information to align the 18 segments of the primary mirror. It is an infrared camera with ten mercury-cadmium-telluride (HgCdTe) detector arrays, and each array has an array of 2048×2048 pixels. The camera has a field of view of 2.2×2.2 arcminutes with an angular resolution of 0.07 arcseconds at 2 μm. NIRCam is also equipped with coronagraphs, which helps to collect data on exoplanets near stars. It helps with imaging anything next to a much brighter object, because the coronagraph blocks that light.
Origins Space Telescope (Origins) is a concept study for a far-infrared survey space telescope mission. A preliminary concept in pre-formulation, it was presented to the United States Decadal Survey in 2019 for a possible selection to NASA's large strategic science missions. Origins would provide an array of new tools for studying star formation and the energetics and physical state of the interstellar medium within the Milky Way using infrared radiation and new spectroscopic capabilities.
Contribution to ARIEL Spectroscopy of Exoplanets (CASE) is a detector subsystem contribution to an infrared spectrometer instrument for the planned European ARIEL space telescope. It is being developed by NASA as a contribution to the European Space Agency (ESA) project to add scientific capabilities to the space telescope to observe the chemical composition of the atmospheres of exoplanets, as well exoplanetary metallicities. The ARIEL spacecraft with CASE on board is planned to launch in 2029.
Large Interferometer For Exoplanets (LIFE) is a project started in 2017 to develop the science, technology and a roadmap for a space mission to detect and characterize the atmospheres of dozens of warm, terrestrial extrasolar planets. The current plan is for a nulling interferometer operating in the mid-infrared.
Dr Aki Roberge is a research astrophysicist at NASA’s Goddard Space Flight Center, where she is currently the Associate Director for Technology and Strategy. Her research focuses on observational studies of debris disks and planet formation around nearby young stars, with an aim to be able to characterize planets around other stars, perhaps even to find signs of life on them. She is particularly known for her research on the debris disk around Beta Pictoris.
The Habitable Worlds Observatory (HWO) is a large infrared, optical, and ultraviolet space telescope recommended by the National Academies’ Decadal Survey on Astronomy and Astrophysics 2020. It will be optimized to search for and image Earth-size habitable exoplanets in the habitable zones of their stars, where liquid water can exist, by using a coronagraph to block out the light of their stars, as well as provide broad astrophysics observations. HWO builds upon studies conducted for two earlier mission concepts called the Large Ultraviolet Optical Infrared Surveyor (LUVOIR) and Habitable Exoplanets Observatory (HabEx).