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The Hubble Space Telescope is suspended in space following the deployment of part of its solar panels and antennas in April 1990. The Hubble Space Telescope was set aside this month by failure of the pointing system. (NASA via AP)
The great American observatories – the Hubble, Chandra, Compton and Spitzer space telescopes – have scrutinized the unknown and made decisive discoveries on the newborn stars, the dark matter and the age of the universe itself.
But these telescopes, whose era began in 1990, are aging, if not already dead, and there is no budget or political will to replace them. This sobering reality was highlighted this month as two technical issues, including the Hubble Space Telescope, temporarily interrupted their science.
Reduced budgets and delayed projects mean that astronomers will lose some of their eyes in the sky before NASA can launch new telescopes. This will make some searches impossible.
"The reluctance to invest in a substantial science has begun to worry us," said astrophysicist Matt Mountain, president of the Association of Universities for Research in Astronomy, which operates the Hubble Telescope on behalf of The NASA. We are facing a very intimidating prospect as a community, "said Mountain." Some fields simply will not have a telescope. And science can not be realized otherwise. "
Some of the biggest questions in science – what is black energy? Does life exist beyond the solar system? – only large observatories working in certain parts of the light spectrum can answer them.
Investing in these issues "is a choice for the nation," said Paul Hertz, director of astrophysics at NASA. "The missions we carry out will be influenced by the priorities of the community as well as the funding choices made by the political authorities." system."
The system gave priority to the large observatory program when it was designed in the 1970s and 1980s – four telescope missions covering the entire spectrum of light in space. They were launched between 1990 and 2003. There was the Compton Gamma Ray Observatory to capture the most energetic explosions of the universe. The Spitzer Space Telescope can search for infrared radiation from exoplanets and newborn stars. Chandra's X-ray observatory could probe the depths of black holes and uncover evidence of dark matter and dark energy.
The Hubble Space Telescope was the jewel of the program. Its huge platinum light collection in ultraviolet and visible wavelengths helped determine the age of the universe, revealed black holes in the center of galaxies and photographed the most distant objects ever seen.
Space telescopes are difficult to design and expensive to build. But they are necessary to have a clear overview of the cosmos. Even at night, the Earth's atmosphere distorts the light of space, making images blurry and other signals, especially gamma rays, impossible to see.
The concerted use of the fleet further increases the power of these telescopes. Last year, observations of Hubble, Chandra, Fermi and dozens of other telescopes allowed astronomers to confirm theories on fundamental physics when they observed the collision of two dead stars.
They can not always have this ability.
The Compton telescope was lost in 2001, when a problem with its gyroscope – which allows a telescope to turn and point something – forced the space agency to intentionally split it to the ground or risk that the spacecraft would Crumbles without control of the sky.
Spitzer, who is slowly moving away from Earth, will end his mission when he loses contact with next year. This loss was expected, but the difficulties with Hubble and Chandra this month were unimaginable.
An image of the lagoon nebula, a stellar nursery located 4,000 light-years from Earth, taken by the Hubble Space Telescope. (NASA, ESA and STScI)
None of the spacecraft's problems are fatal, NASA said. Chandra returned online just days after a small problem with one of his gyroscopes that forced the telescope to go into secure mode. Hubble, who was also embarrassed by another gyroscope-related problem, is expected to return to normal operations no later than a few weeks from now. NASA expects both telescopes to continue operating in the 2020s.
Despite everything, the brief touch of forgetfulness has left astronomers scared.
"People have suddenly realized that Hubble is not going to live forever," he said. Tom Brown, Hubble Mission Leader, Space Telescope Science Institute. Chandra is 19 years old; Hubble is 28 years old.
Brown said his frenzied fellow astronomers had kept his phone ringing "nonstop" over the past two weeks. "They think about what will happen next."
The astrophysics program, valued at $ 1 billion a year, NASA currently uses eight large telescopes to study the space beyond the solar system. Among them, all but one are in their "extended missions" – the bonus years beyond the period for which the spacecraft was originally designed.
The only NASA flagship space observatory under construction is the James Webb Space Telescope, whose golden cup is designed to capture the infrared radiation of the oldest objects in the universe.
NASA wanted Webb's mission to coincide with Hubble's. But the launch of this giant $ 10 billion has been delayed several times because the space agency deals with design problems and costly human errors. This year, NASA announced that Webb would not be launched until 2021 at the earliest, thus reducing the time for concerted observation.
Technicians raise the mirror of the James Webb Space Telescope during testing and integration in 2017. (Laura Betz / NASA via AP)
NASA's next big project would be the The wide-field infrared surveyor telescope, which also targets infrared wavelengths, was considered in 2010 as the top priority in astrophysics at the National Academy of Sciences. But funding from the observatory has been suspended since President Trump failed to use the telescope for his last two budget requests.
Research perspectives on other parts of the light spectrum are, at best, unclear. In case of Hubble's failure, Brown pointed out, there would be no visible or ultraviolet telescopes on this scale. Similarly, NASA has no big X-ray observatories ready to replace Chandra. Compton has been replaced by the smaller Fermi telescope, which has two out of four instruments. Fermi is already 10 years old and five years older than her initial mission.
Julie McInery, a gamma-ray astrophysicist at Fermi, is concerned that even a temporary breach in the telescope's coverage could have lasting repercussions in her field.
"You need to have a minimum level of activity in any telescope area to keep your expertise in the community and to be able to continue building instruments," she said.
To avoid such shortcomings, NASA should start developing new missions now; most space telescopes require several decades between design and launch.
The Hubble Ultra Deep Field, a famous image of some of the most distant galaxies observed taken by the Hubble Space Telescope. (NASA)
Space agencies in other countries are already working on such programs. The European Space Agency is developing the ATHENA X-ray Observatory for its launch in the 2030s. China announced in 2016 that it would build its own optical telescope with a field of view 300 times greater than Hubble's.
"Their budgets are going up," said Mountain.
In the United States, NASA's budget has not kept pace with inflation and the fraction of federal spending allocated to the agency has been cut in half since 1980. The agency was the subject of a close examination of the considerable delays and cost overruns of the Webb telescope. "The telescope that ate astronomy," he was nicknamed bitterly.
This spring, NASA announced that it would "restrict" (reduce the budget) four proposals that it was planning to launch in the 2030s.
"We need to make sure we can achieve scientific breakthroughs while maintaining a realistic, achievable budget and scope for the next decade," said Hertz, director of the astrophysics division, earlier this year.
But it takes big budgets to "rewrite the science textbooks," said Mountain. It will be difficult to replicate the capabilities of large observatories without spending the same kind of resources. "The cumulative cost of Hubble has been about $ 10 billion But look what he bought: a Nobel Prize-winning research on accelerating the expansion of the universe, among other innovative work .
A radiographic image taken by the Chandra Observatory revealing the evidence of thousands of black holes at the center of our galaxy. (NASA / CXC / Columbia University / C. Hailey et al.)
Hertz acknowledged that creating successors at the four major observatories would require a much larger investment from the federal government. "Some scientific issues require extremely ambitious observatories and can not be achieved at a lower cost," he said.
Detecting life outside our solar system requires a telescope like Webb. To explain dark energy and to explain the acceleration of the expansion of the universe, one must have a large and sensitive instrument, such as the Wide Field Infrared Survey.
Hertz said NASA was trying to make the most of limited resources. During the last Hubble maintenance mission in 2009, astronauts provided the satellite with several backups of critical equipment, adding decades to its life. At age 19, Chandra exceeded the term of his original mission by more than a decade; This month's gyroscope problem was the first problem of this type he encountered.
Small and medium-sized explorers – costing less than $ 120 million and $ 200 million respectively – are constantly developing. Transiting Exoplanet Survey Satellite, a MidEx project designed to search for unknown worlds around nearby stars, began its scientific operations this summer.
Even without a gamma telescope on the horizon, McInery is said to be optimistic.
"Yes, we are moving away from the golden age because this series of large observatories has disappeared," she said. "But there are new things that will take its place. We are on the threshold of a new era. "
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