After more than three decades of groundbreaking discoveries, the Hubble Space Telescope is facing what could be the twilight phase of its momentous mission. Although NASA claims that the observatory is still in good health, there are many problems. A series of hardware failures, particularly in the gyroscopes that guide its pointing, is forcing the space agency to review operations of Hubble, reducing its scientific activities. And while there are those who call for a new rescue mission, NASA remains silent for now. He prefers to focus on judicious management of the telescope's remaining resources. In fact, I would talk about the only resource to focus on: a gyroscope. Is this the beginning of the end for Hubble?
Series faults and “safe mode”
Hubble's problems began on May 24. That's when the telescope has entered "safe mode", “safe mode,” a state that suspends science operations to protect the observatory. This is not an isolated event. Of late, these “safe modes” have occurred with worrying regularity, often due to erroneous readings from a malfunctioning gyroscope.
Gyroscopes, which use the angular momentum of a rapidly rotating wheel to measure Hubble's speed and motion as it points at its targets, are essential to the telescope's operation. Without reliable gyroscopic guidance, Hubble would be like an observer with blurred vision, unable to focus on most celestial objects.
A contingency plan: single-gyro mode
Faced with this situation, NASA announced a change of course: Hubble will switch to "gyroscope mode", an emergency plan developed more than 20 years ago, after the Space Shuttle Columbia disaster. This transition, expected to be completed by mid-June, will leave Hubble with only one fully functional gyroscope, held in reserve, and will require a reconfiguration of both the telescope and ground control, as well as a review of plans for all science observations.
According to NASA, this mode should allow Hubble to continue producing high-level science, with minimal impact on most observations. However, the efficiency of the telescope will suffer: Hubble will be slower to aim its targets and will have reduced access to the sky at any given time, which could hamper the study of transient phenomena such as supernovae. Simply put: Hubble will see less, it will see worse, it will see slower.
The decline of an icon
These problems come at a delicate time for Hubble. In addition to hardware failures, the telescope is facing a slow but inexorable decay of its orbit, which projections say could lead to an atmospheric reentry in the mid-to-late 30s.
Some experts estimate that switching to “one gyroscope” mode could reduce Hubble's overall scientific productivity up to 25%. A worrying prospect for an observatory that, despite its 33 years of honorable service, remains a scientific instrument of the highest order, with requests for observation time that constantly exceed availability.
Hubble, the rescue that no one wants to do (maybe)
Faced with these challenges, there are those who call for a new service mission for Hubble, similar to those carried out in the past by Space Shuttle astronauts. This time, however, it would be a question of relying on commercial vehicles such as SpaceX's Crew Dragon, with all the risks and unknowns involved. The billionaire Jared isaacman came forward, offering to fund such a mission in collaboration with SpaceX.
But NASA, for now, stays cold: The risks to crew safety and potential impacts on Hubble's science operations appear to outweigh the benefits. In other words, the future is uncertain. NASA says it is confident it can keep the telescope operational and scientifically productive through the remainder of the 20s and perhaps beyond. But with gyroscopes failing and orbit decaying, time is running out.
Now we need to better manage Hubble's residual resources, maximizing the scientific return within the limits imposed by circumstances. Not an easy task, but the future of one of the greatest is at stake space observatories never built: with a little luck and a lot of effort, Hubble will continue to amaze us for a few more years. And then it will be up to the next generation of space telescopes.
