NASA's Hubble Space Telescope photographed colliding galaxies after recovering from a month-long mystery glitch

• NASA shared the Hubble Space Telescope's first photos since it was fixed this weekend.
• Hubble is back online after a month of mysterious glitching that forced NASA to use backup hardware.
• The photos show colliding galaxies and a long galactic spiral.

The Hubble Space Telescope is back, and NASA has the pictures to prove it.

The Earth-orbiting observatory went offline on June 13 and stayed that way for more than a month while engineers struggled to identify a mysterious glitch. NASA still hasn't announced what exactly caused the problem, but the agency's engineers managed to bring Hubble back online by activating some of its backup hardware on Thursday.

"I was quite worried," NASA Associate Administrator Thomas Zurbuchen said in a Friday video interview with Nzinga Tull, who led the Hubble team through troubleshooting. "We all knew this was riskier than we normally do."

Hubble slowly powered up its science instruments again over the weekend and conducted system check-outs to make sure everything still worked. Then it snapped its first images since the whole debacle started.

The telescope focused its lens on a set of unusual galaxies on Saturday. One of its new images shows a pair of galaxies slowly colliding. The other image shows a spiral galaxy with long, extended arms. Most spiral galaxies have an even number of arms, but this one only has three.

Hubble is also observing Jupiter's northern and southern lights, or auroras, as well as tight clusters of stars. NASA hasn't shared images from those observations yet.

"I'm thrilled to see that Hubble has its eye back on the universe, once again capturing the kind of images that have intrigued and inspired us for decades," NASA Administrator Bill Nelson said in a press release. "This is a moment to celebrate the success of a team truly dedicated to the mission. Through their efforts, Hubble will continue its 32nd year of discovery, and we will continue to learn from the observatory's transformational vision."

A mysterious glitch that took a month to fix

Hubble, the world's most powerful space telescope, launched into orbit in 1990. It has photographed the births and deaths of stars, spotted new moons circling Pluto, and tracked two interstellar objects zipping through our solar system. Its observations have allowed astronomers to calculate the age and expansion of the universe and to peer at galaxies formed shortly after the Big Bang.

But the telescope's payload computer suddenly stopped working on June 13. That computer, built in the 1980s, is like Hubble's brain - it controls and monitors all the science instruments on the spacecraft. Engineers tried and failed to bring it back online several times. Eventually, after running more diagnostic tests, they realized that the computer wasn't the problem at all - some other hardware on the spacecraft was causing the shutdown.

It's still not totally clear which piece of hardware was the culprit. Engineers suspect that a failsafe on the telescope's Power Control Unit (PCU) instructed the payload computer to shut down. The PCU could have been sending the wrong voltage of electricity to the computer, or the failsafe itself could have been malfunctioning.

NASA was prepared for issues like this. Each piece of Hubble's hardware has a twin pre-installed on the telescope in case it fails. So engineers switched all the faulty parts to that backup hardware. Now the telescope is back in full observation mode.

"I feel super excited and relieved," Tull said after making the hardware switch. "Glad to have good news to share."

Though NASA has fixed the glitch, it's a sign that Hubble's age may be starting to interfere with its science. The telescope hasn't been upgraded since 2009, and some of its hardware is more than 30 years old.

"This is an older machine, and it's kind of telling us: Look, I'm getting a little bit old here, right? It's talking to us," Zurbuchen said on Friday. "Despite that, more science is ahead, and we're excited about it."