Hubble’s aging hardware was last serviced directly in 2009 by Space Shuttle astronauts, and engineers at the time estimated it would last until about 2016. push everything much further, ”says Tom Brown, head of the Hubble Space Telescope mission office at the Space Telescope Science Institute in Baltimore. “The most recent estimates indicate that there is a good chance that we will be doing science the way we do today until at least 2026, and maybe the whole decade. It looks pretty good right now.
Hubble has been used in virtually all types of astronomical investigation: studying the planets and moons of our own solar system; observing distant stars, galaxies, supernovae, nebulae and other astrophysical phenomena; study the origins and expansion of the universe.
His work in the science of exoplanets over the past decade has been particularly surprising, given that when the telescope was launched in 1990, we were still five years away from detecting the first exoplanet to orbit a sun-like star. Hubble is not useful for finding exoplanets, but rather for follow-up observations that can characterize planets and their atmospheres once they have been found. When the James Webb Space Telescope launches later this year, the two combined observatories could finally help scientists identify an Earth-like world that is truly hospitable to life.
The JWST is often touted as the successor to Hubble, but that’s not entirely true. Hubble can observe the universe in visible and ultraviolet wavelengths, while JWST’s focus is on infrared observationns, which help us study objects from early universes and characterize chemistry on other worlds. Being located in space, Hubble doesn’t have to worry about inference caused by Earth’s atmosphere, which is particularly detrimental to ultraviolet observations (the ozone layer blocks most UV rays).
This is also critical when we need eyes to study poorly understood phenomena. Take the 2017 detection of gravitational waves produced by the collision of two neutron stars. Hubble was able to observe the consequences of the event, providing data outside of the infrared spectrum that was used to define the shape and course of the fusion in sharper detail.
Four major science instruments are currently active aboard Hubble, so even if a thing or two stop working, there’s still a ton of major science the rest of the observatory can do. The telescope is also built with a lot of redundancy, so unique hardware and software failures don’t necessarily prevent individual instruments from functioning.
That being said, there are no plans for a new mission of service. If there’s a catastrophic outage that takes Hubble entirely offline, it’s hard to see NASA giving the green light to a repair mission for an observatory more than three decades old.
So what replaces Hubble when it’s finally ready to retire? Brown says other countries have nascent plans to orbit other missions that could take over the visible and UV investigations currently being conducted by Hubble. India’s Astrosat space telescope currently performs UV observations from space, but with a much smaller aperture. China plans to launch a space telescope called the Xuntian in 2024, and state media say it will observe an area of space 300 times larger than Hubble can.
The true successor to Hubble could be the Large Ultraviolet Optical Infrared Surveyor space telescope proposed by NASA, or LUVOIR, a versatile observatory capable of observing in multiple wavelengths (including infrared, optical and ultraviolet). But if it is funded, LUVOIR will not be launched before 2039 at the earliest.
It is possible that Hubble will remain active until it can be truly replaced, but most astronomers are bracing for a great lack of knowledge when it finally stops working. “Hubble is truly the first game for doing ultraviolet and optical astronomy,” says Brown. “A lot of astronomy, especially when it comes to understanding temperature and chemistry in space, depends on what information you can really get from it. I’m afraid the space community will really feel the loss when Hubble stops functioning. “