Universe Today
With the recent launch of the
Transiting Exoplanet Survey Satellite
(TESS) - which took place on
Wednesday, April 18th, 2018
- a lot of attention has been focused on the next-generation space telescopes that will be taking to space in the coming years. These include not only the
James Webb Space Telescope
, which is currently scheduled for launch in 2020, but some other advanced spacecraft that will be deployed by the 2030s.
Such was the subject of the recent
2020 Decadal Survey for Astrophysics
, which included
four flagship mission concepts
that are currently being studied. When these missions take to space, they will pick up where missions like
and
Chandra
left off, but will have greater sensitivity and capability. As such, they are expected to reveal a great deal more about our Universe and the secrets it holds.
As expected, the mission concepts submitted to the 2020 Decadal Survey cover a wide range of scientific goals - from observing distant black holes and the early Universe to investigating exoplanets around nearby stars and studying the bodies of the Solar System. These ideas were thoroughly vetted by the scientific community, and four have been selected as being worthy of pursuit.
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Artist's concept of the Large Ultraviolet/Optical/Infrared Surveyor (LUVOIR) space telescope. Credits: NASA/GSFC
[/caption]
As Susan Neff, the chief scientist of NASA's
Cosmic Origins Program
, explained in a recent NASA
press release
:
The four selected concepts include the
Large Ultraviolet/Optical/Infrared Surveyor
(LUVOIR), a giant space observatory developed in the tradition of the
Hubble Space Telescope
. As one of two concepts being investigated by NASA's Goddard Space Flight Center, this mission concept calls for a space telescope with a massive segmented primary mirror that measures about 15 meters (49 feet) in diameter.
In comparison, the JWST
'
s (currently the most advanced space telescope) primary mirror measures 6.5 m (21 ft 4 in) in diameter. Much like the JWST, LUVOIR's mirror would be made up of adjustable segments that would unfold once it deployed to space. Actuators and motors would actively adjust and align these segments in order to achieve the perfect focus and capture light from faint and distant objects.
https://asd.gsfc.nasa.gov/luvoir/design/LUVOIR_15m_DeploymentAnimation_hires.mp4
With these advanced tools, LUVOIR would be able to directly image Earth-sized planets and assess their atmospheres. As Study Scientist Aki Roberge
explained
:
There' also the
Origins Space Telescope
(OST), another concept being pursued by the Goddard Space Flight Center. Much like the
Spitzer Space Telescope
and the
Herschel Space Observatory
, this far-infrared observatory would offer 10,000 times more sensitivity than any preceding far-infrared telescope. Its goals include observing the farthest reaches of the universe, tracing the path of water through star and planet formation, and searching for signs of life in the atmospheres of exoplanets.
Its primary mirror, which would measure about 9 m (30 ft) in diameter, would be the first actively cooled telescope, keeping its mirror at a temperature of about 4 K (-269 °C; -452 °F) and its detectors at a temperature of 0.05 K. To achieve this, the OST team will rely on flying layers of sunshields, four cryocoolers, and a multi-stage continuous adiabatic demagnetization refrigerator (CADR).
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Artist's concept of the the Origins Space Telescope (OST). Credits: NASA/GSFC
[/caption]
According to Dave Leisawitz, a Goddard scientist and OST study scientist, the OST is especially reliant on large arrays of superconducting detectors that measure in the millions of pixels. "When people ask about technology gaps in developing the Origins Space Telescope, I tell them the top three challenges are detectors, detectors, detectors," he said. "It's all about the detectors."
Specifically, the OST would rely on two emerging types of detectors: Transition Edge Sensors (TESs) or Kinetic Inductance Detectors (KIDs). While still relatively new, TES detectors are quickly maturing and are currently being used in the HAWC+ instrument aboard NASA's
Stratospheric Observatory for Infrared Astronomy
(SOFIA).
Then there's the
(HabEx) which is being developed by NASA's Jet Propulsion Laboratory. Like LUVOIR, this telescope would also directly image planetary systems to analyze the composition of planets' atmospheres with a large segmented mirror. In addition, it would study the earliest epochs in the history of the Universe and the life cycle of the most massive stars, thus shedding light on how the elements that are necessary for life are formed.
Also like LUVOIR, HabEx would be able to conduct studies in the ultraviolet, optical and near-infrared wavelengths, and be able to block out a parent star's brightness so that it could see light being reflected off of any planets orbiting it. As Neil Zimmerman, a NASA expert in the field of coronagraphy,
explained
:
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Artist's rendition of the Habitable Exoplanet Imager (HabEx) space telescope. Credits: NASA/JPL
[/caption]
To address this challenge, the HabEx team is considering two approaches, which include external petal-shaped star shades that block light and internal coronagraphs that prevent starlight from reaching the detectors. Another possibility being investigated is to apply carbon nanotubes onto the coronagraphic masks to modify the patterns of any diffracted light that still gets through.
Last, but not least, is the
X-ray Surveyor known as Lynx
being developed by the Marshall Space Flight Center. Of the four space telescopes, Lynx is the only concept which will examine the Universe in X-rays. Using an X-ray microcalorimeter imaging spectrometer, this space telescope will detect X-rays coming from
Supermassive Black Holes
(SMBHs) at the center of the earliest galaxies in the Universe.
This technique consists of X-ray photos hitting a detector's absorders and converting their energy to heat, which is measured by a thermometer. In this way, Lynx will help astronomers unlock how the earliest SMBHs formed. As Rob Petre, a Lynx study member at Goddard,
described
the mission:
[caption id="attachment_139116" align="aligncenter" width="580"]
Artist's impression of the X-ray Surveyor (Lynx) space telescope. Credits: NASA/MSFC
[/caption]
Regardless of which mission NASA ultimately selects, the agency and individual centers have begun investing in advanced tools to pursue such concepts in the future. The four teams submitted their interim reports back in March. By next year, they are expected to finish final reports for the National Research Council (NRC), which will be used to inform its recommendations to NASA in the coming years.
As Thai Pham, the technology development manager for NASA's Astrophysics Program Office,
indicated
:
With TESS now deployed and the JWST scheduled to launch by 2020, the lessons learned in the next few years will certainly be incorporated into these missions. At present, it is not clear which of the following concepts will be going to space by the 2030s. However, between their advanced instruments and the lessons learned from past missions, we can expect that they will make some profound discoveries about the Universe.
Further Reading: NASA
,
NASA (2)
