NASA Dawn back on course after briefly slipping into Safe Mode

NASA's Dawn spacecraft has resumed normal operations after a high-energy particle event forced the mission to enter safe mode, knocking its ion drive offline.

Although mission managers deduced the source of the problem and restarted its propulsion systems, the unexpected hiccup will likely delay Dawn’s arrival at dwarf planet Ceres.

Safe mode was triggered on Sept. 11 and it is thought the same phenomenon that triggered a safe mode three years agoduring Dawn's approach to giant asteroid Vesta is to blame for this incident.

A high-energy cosmic ray hit the spacecraft's ion drive electronics, disabling it.

In addition to the ion drive glitch, Dawn's main antennae that the spacecraft uses to communicate with Earth was also knocked offline, meaning engineers had to decipher the problem using Dawn’s secondary, lower bandwidth antennae.

"This anomaly presented the team with an intricate and elaborate puzzle to solve," said Robert Mase, Dawn project manager at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif.

"We followed the same strategy that we implemented three years ago to recover from a similar radiation strike, to swap to one of the other ion engines and a different electronic controller so we could resume thrusting quickly," said Dawn Mission Director and Chief Engineer Marc Rayman also of JPL.

“We have a plan in place to revive this disabled component later this year.”

NASA DAWN: Spacecraft operating normally after safe mode triggered

Artist concept of NASA's Dawn spacecraft orbiting Ceres during an upcoming flyby. 

Credit: NASA/JPL-Caltech/UCLA

The Dawn spacecraft has resumed normal ion thrusting after the thrusting unexpectedly stopped and the spacecraft entered safe mode on September 11.

That anomaly occurred shortly before a planned communication with NASA's Deep Space Network that morning.

The spacecraft was not performing any special activities at the time.

Engineers immediately began working to restore the spacecraft to its normal operational state.

The team determined the source of the problems, corrected them, and then resumed normal ion thrusting on Monday night, Sept. 15.

"This anomaly presented the team with an intricate and elaborate puzzle to solve," said Robert Mase, Dawn project manager at NASA's Jet Propulsion Laboratory in Pasadena, California.

After investigating what caused the spacecraft to enter safe mode, the Dawn team determined that it was likely triggered by the same phenomenon that affected Dawn three years ago on approach to the protoplanet Vesta: An electrical component in the ion propulsion system was disabled by a high-energy particle of radiation.

"We followed the same strategy that we implemented three years ago to recover from a similar radiation strike, to swap to one of the other ion engines and a different electronic controller so we could resume thrusting quickly," said Dawn Mission Director and Chief Engineer Marc Rayman of JPL.

"We have a plan in place to revive this disabled component later this year."

Complicating the issue, the team discovered that the spacecraft had experienced not just one anomaly, but also a second one that affected the ability to point the main antenna at Earth to communicate.

Because the spacecraft could not communicate using its main antenna, the team had to utilize the weaker signals of another antenna, slowing their progress.

In addition, Dawn is so far from Earth that radio signals take 53 minutes to make the round trip.

Although they have not yet specifically pinpointed the cause of this issue, it could also be explained by a high-energy particle corrupting the software running in the main computer.

Ultimately the team reset the computer, which restored the pointing performance to normal.

As a result of the change in the thrust plan, Dawn will enter into orbit around dwarf planet Ceres in April 2015, about a month later than previously planned.

Ceres

The plans for exploring Ceres once the spacecraft is in orbit, however, are not affected.

Vesta

Dawn orbited Vesta, the second most massive object in the main asteroid belt, from July 2011 until September 2012.

The spacecraft's ion propulsion system enabled it to spiral away from Vesta and head toward Ceres, the most massive object in that region.

NASA JUNO Mission: Falls into Safe Mode after Earth Fly-by

This 2010 artist's rendering depicts NASA's Juno spacecraft with Jupiter in the background. 

NASA's Jupiter-bound spacecraft will swing by Earth for one last visit Wednesday Oct. 9, 2013 before speeding to the outer solar system. 

Wednesday's flyby allows the Juno spacecraft to gather the momentum it needs to arrive at Jupiter in 2016. (AP Photo/NASA/JPL, File)

NASA's Jupiter-bound spacecraft hit a snag Wednesday soon after it used Earth as a gravity slingshot to hurtle toward the outer solar system, but mission managers said it's on course to arrive at the giant planet in 2016.

Juno emerged from Earth's shadow in safe mode, a state that spacecraft are programmed to go into when there's some trouble.

Despite the problem, "we believe we are on track as planned to Jupiter," said project manager Rick Nybakken of the NASA Jet Propulsion Laboratory, which manages the $1.1 billion mission.

Engineers continued to diagnose the issue, which occurred after Juno whipped around Earth in a momentum-gathering flyby.

Up until Wednesday, Juno had been in excellent health. While in safe mode, it can communicate with ground controllers, but its activities are limited.

Previous missions to the outer solar system have used Earth as a celestial springboard since there's no rocket powerful enough to make a direct flight.

The Galileo spacecraft buzzed by Earth twice in the 1990s en route to Jupiter, the solar system's largest planet located 484 million miles from the sun.

Launched in 2011, Juno flew beyond the orbit of Mars, Earth's closest planetary neighbor, before looping back toward our home planet for a quick visit.

Wednesday's rendezvous boosted Juno's speed from 78,000 mph (125,523 kph) relative to the sun to 87,000 mph—enough momentum to cruise past the asteroid belt to Jupiter, where it should arrive in 2016.

During the swing past Earth, Juno snapped pictures. The solar-powered, windmill-shaped spacecraft slipped into Earth's shadow as planned, but engineers were puzzled by the too little data it sent back afterward.

At closest approach, it hurtled 350 miles above the ocean off the coast of South Africa.

NASA said skywatchers with binoculars or a small telescope might have seen it streak across the sky, weather permitting.

Ham radio operators around the globe were encouraged to say "Hi" in Morse code—a message that might be detected by Juno's radio.

By space mission standards, Juno's Earth rendezvous was low-key compared with the Curiosity rover's nail-biting landing on Mars last year, which drew crowds. Since flybys have been executed before, project managers predicted a smooth flight.

The unexpected problem causes "a moderate level of concern," Nybakken said.

Despite a government shutdown that has prevented NASA from updating its website or tweeting, the space agency's missions continue to operate. Earlier this week, NASA's newest spacecraft, LADEE, slipped into orbit around the moon.

Since the 1970s, spacecraft have circled or flown past Jupiter including the Voyagers, Pioneers, Galileo, Ulysses, Cassini and, most recently, the New Horizons barreling toward Pluto.

Missions have beamed back stunning views of Jupiter's trademark Great Red Spot, a raging hurricane-like storm, and its many moons.

Juno promises to inch closer to Jupiter than previous spacecraft, orbiting the planet for at least a year and studying its cloud-covered atmosphere and mysterious interior to better understand how the giant planet formed.

NASA MARS Opportunity Rover Found in Standby Safe Mode

NASA's twin Mars rovers, Spirit and Opportunity, have now spent nine years on the surface of Mars.

CREDIT: NASA/JPL

NASA's long-lived Opportunity Mars rover has gone into a self-imposed standby mode on the Red Planet, the robot's handlers say.

Mission controllers for Opportunity, which landed on Mars in January 2004, first learned of the issue on Saturday (April 27).

On that day, the rover got back in touch after a nearly three-week communication moratorium caused by a planetary alignment called a Mars solar conjunction, in which Mars and Earth are on opposite sides of the sun.

The Opportunity rover apparently put itself into standby on April 22 after sensing a problem during a routine camera check, mission managers said.

John Callas

"Our current suspicion is that Opportunity rebooted its flight software, possibly while the cameras on the mast were imaging the sun," Opportunity project manager John Callas, of NASA's Jet Propulsion Laboratory in Pasadena, Calif., explained in a statement Monday (April 29).

"We found the rover in a standby state called automode, in which it maintains power balance and communication schedules, but waits for instructions from the ground," Callas added.

"We crafted our solar conjunction plan to be resilient to this kind of rover reset, if it were to occur."



Opportunity's handlers prepared new commands Monday designed to spur the rover into resuming operations, mission team members said.

The golf-cart-size Opportunity landed on Mars more than nine years ago along with its twin, Spirit, on a three-month mission to search for signs of past water activity on the Red Planet.

The two rovers found plenty of such evidence, and then kept trundling across Mars. Spirit was declared dead in 2010, but Opportunity is still going strong.

Mars solar conjunctions occur every 26 months, so Opportunity's team knows how to weather them. This most recent conjunction, in fact, is the fifth that the rover has endured.

Mars solar conjunctions affect NASA's entire fleet of robotic Red Planet explorers. Mission controllers resumed sending commands to the agency's venerable Mars Odyssey orbiter Monday and plan to do the same with the Mars rover Curiosity on Wednesday (May 1), officials said.

NASA's Mars Rover Curiosity in Safe Mode After Computer Glitch

This self-portrait of NASA's Mars rover Curiosity combines dozens of images taken by the rover's Mars Hand Lens Imager on Feb. 3, 2013. 

The portrait was taken at the rock target "John Klein," where the rover collected the first ever bedrock sample of Mars using its drill on Feb. 8. 

CREDIT: ASA/JPL-Caltech/MSSS

A computer glitch on NASA's Mars rover Curiosity has forced the robot to switch to a backup computer while engineers try to resolve the problem.

In the meantime, Curiosity's science work is on hold, and the spacecraft is in a minimal-activity state known as "safe mode" while its backup computer is updated with the command codes and parameters it needs to take over the rover's full operations.

"We're still early on in the process," said Richard Cook, Curiosity project manager at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "We have probably several days, maybe a week of activities to get everything back and reconfigured."

The issue cropped up Wednesday (Feb. 27), when the spacecraft failed to send its recorded data back to Earth and did not switch into its daily sleep mode as planned. After looking into the issue, engineers decided to switch the Curiosity rover from its primary "A-side" computer to its "B-side" backup on Thursday at 5:30 p.m. EST (22:30 GMT).

"Don't flip out: I just flipped over to my B-side computer while the team looks into an A-side memory issue," NASA officials wrote on behalf of the rover via Curiosity's Twitter feed.

The computer problem is related to a glitch in flash memory on the A-side computer caused by corrupted memory files, Cook said. Scientists are still looking into the root cause the corrupted memory, but it's possible the memory files were damaged by high-energy space particles called cosmic rays, which are always a danger beyond the protective atmosphere of Earth.

"The hardware that we fly is radiation tolerant," Cook told SPACE.com, "but there's a limit to how hardened it can be. You can still get high-energy particles that can cause the memory to be corrupted. It certainly is a possibility and that's what we're looking into."

Once Curiosity is up and running again, the rover should have no problem using its B-side computer as its primary computer for a while, officials said. As standard protocol, Curiosity, like many spacecraft, has redundant main computer systems as a safety precaution for just this type of anomaly.

"While we are resuming operations on the B-side, we are also working to determine the best way to restore the A-side as a viable backup," said JPL engineer Magdy Bareh, leader of the mission's anomaly resolution team, said in a statement.

Eventually, the team will want to turn the A-side computer back on and make sure both computers on the rover are healthy.

"We also want to look to see if we can make changes to software to immunize against this kind of problem in the future," Cook said.