Hubble is not the only NASA mission that has seen better days. In fact, it’s one of four of the agency’s most recognizable programs currently in safe mode or not communicating with Earth. A NASA spokesperson, Felicia Chou, said she couldn’t say whether these circumstances were unprecedented for the agency; when I reached her Friday afternoon, many of the people who could answer that question were out of the office. “While it does seem like we have aging spacecraft because of safe modes and running out of fuel, we have an entire new generation of spacecraft and landers with the latest technology that are already in space, recently launched, or are coming up,” Chou assured me.
But the number of sidelined mission seems at least unusual in recent memory. Each announcement of a new problem has been met with an outpouring of support from scientists, engineers, and space fans alike, who are rooting for a mission’s recovery.
The wave of mission hiccups began in June, with a massive storm on Mars. The planet’s thin atmosphere swelled with dust and blocked sunlight from reaching the surface. In the darkness, the solar-powered Opportunity rover could no longer charge its batteries, so it went to sleep. The skies cleared in September, and engineers hoped that the return of sunshine would prompt Opportunity to wake up. But they still haven’t heard from the rover, and NASA leadership has already thought about when the team may have to give up on it.
The Kepler Space Telescope was next. Since its launch in 2009, Kepler has discovered thousands of planets beyond the solar system, including 30 Earth-sized planets that orbit in their stars’ habitable zones, where liquid water, a precursor to life, can exist. Kepler was expected to run out of fuel sometime this year and lose the ability to orient itself, but engineers didn’t know exactly when. The spacecraft’s design didn’t call for a gas gauge, which some scientists have privately said would probably have been a good idea, in retrospect.
In July, Kepler started showing signs of running very low on fuel, and the observatory has been in and out of safe mode since. The telescope emerged from slumber in August, observed the skies for about a month, and then went under again in October. On Friday, NASA announced that engineers had awakened Kepler once more. They will now download the telescope’s latest data while trying to use as little fuel as possible.
In mid-September, another Mars rover went to sleep. Engineers discovered a technical problem on Curiosity’s main computer that prevented it from beaming home the science and engineering data stored in its memory. They turned off the robot’s scientific instruments just in case, and last week switched it over to a backup computer. Nearly a month later, they’re still investigating the glitch.