New Horizons team planning on resuming science on July 7
Following an hour and twenty-minute glitch during which contact between NASA’s New Horizons spacecraft and Earth was lost, members of the mission team are working around the clock to restore normal function. The issues with the spacecraft that is rapidly approaching its primary target occurred in the late hours of July 4. By the next day, the New Horizons team had “worked the problem ” – and appear to have gotten a handle on the situation.
Just ten days before the July 14 Pluto flyby, at 1:54 p.m. EDT (17:54 GMT) on July 4, communication from the spacecraft was lost when its autopilot system detected a still unidentified problem and successfully switched to New Horizons’ backup computer – exactly as it is programmed to do under such circumstances.
Contact with Earth was restored at 3:15 p.m. EDT (19:15 GMT) the same day by the autopilot system after it placed the spacecraft in “safe mode”. Despite early concerns about the mission being at risk, everything ran as programmed in the event of such an anomaly.
At 4 p.m. EDT (20:00 GMT) on Saturday, the New Horizons team held an Anomaly Review Board (ARB) meeting to review the data returned by the spacecraft and put a recovery plan into motion.
Once the spacecraft was in “safe mode”, the autopilot told the backup computer to contact Earth and send back telemetry to help the mission team at Johns Hopkins University Applied Physics Laboratory identify and correct the problem.
New Horizons is still on course for its encounter with the Pluto system and does not require any corrective maneuvers. Even if it never comes out of “safe mode”, which is unlikely, it would still fly by the Pluto system at the designated time and speed.
No images were scheduled to be taken by the spacecraft on July 4. Those that were planned for July 5 will likely not have been taken. It is unclear whether the single image scheduled for July 6 will be captured as planned. By Sunday, July 5, the situation had become sufficiently clear that the team was confident enough to announce that they will attempt to instruct the New Horizons spacecraft to resume scientific operations – as soon as Tuesday, July 7.
“I’m pleased that our mission team quickly identified the problem and assured the health of the spacecraft,” said Jim Green, NASA’s Director of Planetary Science. “Now – with Pluto in our sights – we’re on the verge of returning to normal operations and going for the gold.”
The mission team already has enough optical navigation images taken over the last few weeks and months, so these losses will not affect its flight plan through the Pluto system.
Given the rapid pace of events, it is likely the only data lost was that incurred during the period the spacecraft was in safe mode. This is limited to additional approach animations of Pluto and Charon and some light-curve data for Pluto’s small moons Nix and Hydra.
Carrying out any plan is complicated by the nine-hour time for round trip communication with the spacecraft, which is now close to three billion miles (4.9 billion km) from Earth. Traveling at the universal speed of light, radio signals take four-and-a-half hours to reach New Horizons and another four-and-a-half hours from the spacecraft back to Earth.
While waiting for more information from the spacecraft, mission team members are compiling a list of possible causes for the glitch.
New Horizons is currently less than 7.5 million miles from Pluto after a three-billion-mile cruise across the Solar System since its January 2006 launch from Cape Canaveral Air Force Station’s Space Launch Complex 41 in Florida. The spacecraft was sent barreling out of the inner Solar System toward the Kuiper Belt on a United Launch Alliance Atlas V 551 rocket.
Principal investigator Alan Stern told Spaceflight Insider that this event served to add extra stress – to an already intense time!
“Everyone here is working, it’s been a 20-hour day for me. Buckley is, I am sure, home asleep. I can’t go beyond except to say expect an update on Sunday,” Stern said.
Laurel Kornfeld is an amateur astronomer and freelance writer from Highland Park, NJ, who enjoys writing about astronomy and planetary science. She studied journalism at Douglass College, Rutgers University, and earned a Graduate Certificate of Science from Swinburne University’s Astronomy Online program. Her writings have been published online in The Atlantic, Astronomy magazine’s guest blog section, the UK Space Conference, the 2009 IAU General Assembly newspaper, The Space Reporter, and newsletters of various astronomy clubs. She is a member of the Cranford, NJ-based Amateur Astronomers, Inc. Especially interested in the outer solar system, Laurel gave a brief presentation at the 2008 Great Planet Debate held at the Johns Hopkins University Applied Physics Lab in Laurel, MD.