The Legendary Observatory Is Going Strong
Hubble teams overcame challenges in 2021, while the telescope continues to produce exciting science.
How fast are the winds in Jupiter's Great Red Spot? Thanks to the long-term Outer Planets Atmospheres Legacy (OPAL) program, the Hubble Space Telescope has taken regular "storm reports" of the planet since 2009 (along with intermittent observations since its launch in 1990). Using more than 10 years of data, researchers found the winds in the outermost "lane" of Jupiter's Great Red Spot are accelerating, increasing up to 8 percent from 2009 to 2020. For decades, Hubble has helped astronomers uncover secrets about our solar system, galaxies, and the universe.
Researchers around the world continue to clamor for its observing time. In 2021, the total number of proposals equated to more than 22,000 orbits, far exceeding the time available. Following a dual-anonymous review process, 2,695 orbits were approved for the regular call, featuring ultraviolet light initiatives that only Hubble can execute, complementary observations that will soon be matched to James Webb Space Telescope observations, and those that probe questions about fundamental physics.
The teams behind Hubble seek to keep the observatory in excellent condition. In December 2020, the institute released a new version of the Guide Star Catalog, updated with data from ESA's Gaia mission and other catalogs. The Guide Star Catalog is an all-sky catalog of positions and magnitudes for almost a billion stars and other objects that help Hubble "lock" onto targets before taking an observation. This meant that all observations performed in 2021 used the improved data and allowed the teams pointing Hubble to mitigate some acquisition performance problems.
Resilient Teams Support Hubble
The Hubble teams have decades of experience managing interruptions to Hubble's observations and have a deep understanding of the telescope. They've also built in redundancies to allow each instrument to operate almost continuously. In March 2021, the team overcame some hiccups. When the Wide Field Camera 3 instrument went into safe mode, it was recovered after a minor software error was identified. And when the Space Telescope Imaging Spectrograph suspended due to a timing issue, it was recovered the next day.
In June, when Hubble's payload computer halted unexpectedly, the Hubble teams worked for more than a month to test every element and configuration. After determining its cause was likely its Power Control Unit, NASA successfully switched to the backup payload computer, returning Hubble to science operations. In late October, all four science instruments entered a safe-mode configuration after detecting a loss of specific data synchronization messages. Teams carefully tested each instrument, and brought them back online safely between November and early December.
The teams that support Hubble are always proactive. In response to these anomalies, they identified and began making changes to how the instruments monitor and respond to missed synchronization messages, and how the payload computer monitors the instruments. They began implementing updates in late 2021 and continued into 2022. After demonstrating feasibility in a lab, the teams are in the early stages of developing a way to reenable payload computer redundancy.
Always Preparing for the Future
Good news was announced for Hubble's Cosmic Origins Spectrograph this year. Teams moved it to its fifth lifetime position in 2021, and are enabling a sixth lifetime position for 2022, ensuring it will operate through 2030, continuing to collect sensitive far-ultraviolet spectroscopy.
The raw data sent by Hubble are normally processed within 48 hours and added to our archive. However, increasingly precise calibrations and improved algorithms make it necessary to reprocess all data from a given instrument from time to time. This reprocessing now happens in the cloud, and the turnaround takes days, when it used to take a few weeks. The outlook for Hubble is unmistakably positive. The telescope is expected to make groundbreaking discoveries for many years to come.