The Nancy Roman Telescope has reached another milestone in its development. NASA has announced that the primary mirror of the Space Telescope has now been completed.
The 2.4 m (7.9 ft) mirror took less time to develop than other mirrors because it was not built from scratch. It is a re-shaped and re-surfaced mirror that came from the National Reconstruction Office Fees.
The Nancy Grace Roman Space Telescope was originally named WFIRST (Wide Field Infrared Space Telescope). The telescope project was approved in February 2016, and in May 2020 NASA announced the name change.
In honor of WFIRST, NASA’s first chief astronomer who passed away in 2018, Nancy Grace became the Roman Space Telescope. The telescope is also sometimes called the Roman Space Telescope or RST.
The primary mirror is the heart of the telescope. It is responsible for collecting light which can then be directed towards various devices. The primary mirror of the RST is about the same size as the Hubble, but it is lighter thanks to technological advances.
RST has a much wider field than Hubble, in fact 100 times more. It will use its power and vast field of view to examine near and far cosmic examine objects.
Like the James Web Space Telescope (JWST), the RST is an infrared observatory. The primary goal of JWST is to see as long as possible and see the first light of the universe. But RST is different. His field of vision means that his primary concerns are studying dark energy and exoplanets.
And with its primary mirror now complete, its one step closer to launch, scheduled for sometime in 2025.
“It’s very exciting to have this achievement,” said Scott Smith, Roman telescope manager at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
“Success depends on the team with everyone, and that’s especially true in our current challenging environment. Everyone plays a role in collecting that first image and answering inspiring questions.”
Telescope mirrors are coated with different materials depending on the wavelength of light designed to be understood. Hubble was designed to be viewed in infrared, ultraviolet and optical, so its mirror was coated in layers of aluminum and magnesium fluoride.
The mirror of JWST is coated with gold as it looks at infrared wavelengths for a long time.
The mirror of the Roman Space Telescope is coated with an exceptionally thin layer of silver, used due to its ability to reflect infrared light. It is less than 400 nanometers thick, which is 200 times thinner than human hair.
Like all advanced telescope mirrors, it is also carefully polished. The average bump on the surface of the mirror is only 1.5 nanometers high, which NASA says is twice as easy as the mission needs. If the mirror were the size of the earth, the longest bump would be ump / 4 inches tall.
Because the so-called mirror design is twice as simple, it provides better scientific results than predicted.
“The mirror on the optical prescription for the Roman Space Telescope was definitely finished,” said Bonnie Peters, program manager at L3 Harris Technologies in Rochester, New York.
Nancy Roman. (NASA / ESA)
“It’s much softer than necessary, it will offer more scientific benefits than originally planned,” Patterson said in a press release.
Once the primary mirror collects the infrared light, the light is sent to the telescope’s two instruments: the coronograph instrument and the wide field instrument, which is the primary instrument of the RST.
Coronograph instruments allow RST to study exoplanets by blocking light from their stars. While this may not be the first telescope to use a coronograph, (Hubble has one, but is much weaker) RST should allow telescopes to see planets 1 billion times weaker than their stars. If it works as intended.
The Wide Field Instrument (WFI) is basically a huge 300 megapixel camera. When it has the same angular resolution as Hubble, its field of view is about 100 times wider than Hubble’s. It will give the power to map the distribution and structure of darkness in the universe. It will also help researchers understand how the universe has evolved over time.
“We’re trying to figure out the fate of the universe,” said Jeff Crook of the Nancy Grace Roman Space Telescope project scientist Goddard. “The expansion of the universe is gaining momentum and the Wide Field Instrument is one of the things that will help us if acceleration is increasing or slowing down,” Crook said in a press release.
The rate of expansion of the universe is one of the constant questions of astronomy. It is difficult to reduce the rate of expansion – known as the Hubble constant – and different researchers keep coming up with different values.
In recent years, the measurement of expansion rate has varied between about 67 and 77 (km / s) / mpc. Dark energy is the name given to the driving expansion, and the Roman Space Telescope will investigate the rate using those three techniques: baryon acoustic oscillation, observation of distant supernovae, and weak gravitational lensing.
RST will also complete the calculation of the exoplanet, furthering the work of the Kepler mission. It will be able to investigate distant, giant exoplanets, thanks to its coronograph. RST will also be able to detect rogue planets, planets floating in space without gravitating to any star.
Right now we only count those planets, but RST will help us find more. Some scientists believe that the galaxy may contain 1 trillion of these drifters. Current estimates of the number of rogue planets lack accuracy, but the Roman Space Telescope should estimate them to be 10 times more accurate.
Now that it’s done, the primary mirror will test further. Of particular concern is how the mirror will react to changes in its temperature. The mirror is made of special glass that resists expansion and contraction. Expansion and compression can distort the shape of the mirror, so it makes for very distorted images.
While the mirror has been tested for temperature extremes during development, future testing will test not only the mirror, but also its support structure.
“Roman’s primary mirror is complete, though our work isn’t complete,” Smith said. “We are excited to embark on this mission and look forward to it, and look forward to witnessing the wonders it will reveal.”
RST 2025 is set to launch for a ride on a commercial launch vehicle from Cape Canaveral. It will travel 2 points to the Sun-Earth LG Grazian, where it will take a halo orbit. Its planned mission period is five years.
This article was originally published by Universe Today. Read the original article.
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