A race to the stars
Competition between the four projects will be fierce.
Click on a telescope to learn more.
Lynx X-ray Observatory
Primary mirror size: 3 meters
Instruments: Three
Orbit location: Sun-Earth L2
Launcher: Unspecified heavy launcher
Launch mass: 7.9 metric tons
Primary science targets: First supermassive black holes
At a glance
X-rays penetrate conventional mirrors and so must be deflected at grazing angles. Lynx will use hundreds of concentric silicon mirrors, just 1 millimeter thick, to focus photons on detectors 10 meters away.
Between the lines
Gratings that swing into the light path from behind the mirror can tease apart spectral absorption lines from gas clouds in galactic halos and in the cosmic web.
Counting photons
Lynx’s microcalorimeter takes both high- definition images and spectra. It logs every photon’s location and energy by recording temperature rises in an array of silicon sensors.
Habitable Exoplanet Observatory
Primary mirror size: 4 meters
Instruments: Three
Orbit location: Sun-Earth L2
Launcher: Space Launch System block 1B
Launch mass: 35 metric tons
Primary science targets: Earth-like exoplanets
Formation flying
The starshade must fly far from HabEx to block the glare of a distant star so that orbiting planets—one ten-billionth as bright—can be seen.
Deployment
Starshade petal
The petal shape softens the edge of the starshade, reducing the amount of scattered starlight.
Unobstructed view
The off-axis design avoids the need for secondary mirror support struts that could scatter light and swamp precious exoplanet photons.
The ultimate shades
A coronagraph does the job of a starshade, but internally. Deformable mirrors smooth incoming light. A mask less than a millimeter across removes the star’s glare, while a Lyot stop catches stray light.
The Origins Space Telescope
Primary mirror size: 5.9 meters
Instruments: Five
Orbit location: Sun-Earth L2
Launcher: Space Launch System block 2
Launch mass: 30 metric tons
Primary science targets: Gas clouds and planet-forming disks
Stay cool
Origins must be chilled to reduce its own infrared glow. Sunshields drop temperatures to 35 K. Solar-powered, mechanical cryocoolers take the telescope to 4 K without the need to rely on a limited supply of liquid helium.
Approaching absolute zero
Detectors must be cooled even further, to 0.05 K. A magnetic field aligns salt molecules in a "salt pill." As they drift out of alignment they absorb heat. Realignment pumps heat out of the capsule.
Sensing the far infrared
Far-infrared photons are feeble. The detectors would rely on superconducting circuits with zero resistance. In one type, the detector is kept right at its superconducting transition temperature. Slight heating from an absorbed photon would create a sharp, detectable rise in resistance.
Large UV Optical Infrared Surveyor
Primary mirror size: 15 meters
Instruments: Four
Orbit location: Sun-Earth L2
Launcher: Space Launch System block 2
Launch mass: 25 metric tons
Primary science targets: Earth-like exoplanets and first galaxies
Folded for liftoff
LUVOIR’s mirror will fold to fit inside the 8.4-meter-wide fairing of NASA’s Space Launch System (SLS) block 2. The troubled heavy-lift rocket isn’t expected until the 2030s, however, and it may never fly.
Movable mirrors
Tiny pistons will tip and tilt LUVOIR’s 120 mirror segments into a perfect shape with the help of 622 edge sensors.
Built to last
Robotic servicing missions could extend LUVOIR’s life to several decades. Standardized valves, latches, and rails ease the replacement of batteries, solar panels, computers, reaction wheels, and propellant. Rotating the mirror away from the sunshield eases instrument replacement.
