NASA limits Hubble Space Telescope to a single gyro, hopefully extending its life

NASA held a conference today at 4:00 pm EST to report on the status of the Hubble Space Telescope (HST). It recently went into Safe Mode due to an ongoing issue with the Telescope’s gyros. The telescope uses these gyros to maintain its orientation in space.

Initial report

Present at today’s conference was Mark Clampin, director of astrophysics at the Science Mission Directorate. Alongside him was Patrick Crouse, Project Manager of the Hubble Space Telescope. In today’s press update, NASA reported that one of the gyro’s has been repeatedly returning faulty readings. These readings are causing it to enter Safe Mode. Most recently the Telescope entered Safe Mode on May 24^th due to the same issue.

Mark reported they will continue to operate using only 1 gyro so it can continue through to the mid-2030s. Patrick noted this was an ongoing issue for the last few months. He also stated this has been occurring more and more frequently. Patrick noted that this procedure was developed over 20 years ago, so this isn’t a new plan. A NASA document from 2008 detailed single gyro operations in light of gyro failures at that time.

The reduction in the number of usable gyros will reduce the telescope’s efficiency by about 12%. Patrick also noted that it will not be able to track objects closer than the orbit of Mars. The HST will not be able to slew fast enough to track these objects. He later stated that less than 1% of Hubble’s past targets have been targets that would fall into this limitation.

Patrick reported that NASA hopes to continue science observations from HST by about mid-June.

Questions from the press

In response to a question from CBS, Patrick reported that one of the failures by the gyros is caused by corrosion caused by fluid. The use of the fluid helps Hubble to determine its orientation in space.

Florida Media Now asked a question about Hubble’s operating costs. Mark was unable to provide a specific breakdown of costs. He estimated the Hubble Space Telescope to cost about $95 million. Which is approximately 4.32% of the cost to build a SLS rocket. That number does, however, also include grants given to the science community.

The Associate Press had asked if the HST is “on its last leg”. Patrick responded that Hubble is expected to operate through to 2035, even if only on one gyro. Giving the HST at least another decade of operations. Patrick further emphasized in response to this question, “So we do not see Hubble being on its last legs and we do think it’s a very capable observatory”.

Mark addressed the Associate Press’ question regarding recent commercial offers, such as from Jared Isaacman and the upcoming Polaris mission. He thanked the program but is not seeking immediate help for it due to the risk of premature loss of science. Mark also added that reboost is a consideration for the future, but not at this time.

In response to a question from The Atlantic, Mark explained some of the considerations for a servicing mission. One concern is contaminating the space mirror. Another concern is that the team would have to gather the data and information on the new spacecraft that would visit the telescope, updating procedures to do so. Many of those involved in the past servicing missions have since retired.

NPR asked why NASA isn’t actively pursuing a solution to help reboost the HST. Mark noted that a reboost mission must be considered against the limitations of their budget.

Space.com asked about the amount of time each gyro has in years. Patrick responded that each has 16 years or approximately 140,000 hours. So far gyro 6 has 90,000 hours clocked in, or about 11 years. Probability analysis says they have a 70% to have at least 1 gyro available in 2035.