Washington: A software glitch that triggered communication loss with NASA’s New Horizon spacecraft has been rectified and the probe is on way for a Pluto fly-by on July 14, the US space agency has said.

The investigation into the anomaly that caused New Horizons to enter “safe mode” last weekend has concluded that no hardware or software fault occurred on the spacecraft.

The underlying cause of the incident was a hard-to-detect timing flaw in the spacecraft command sequence that occurred during an operation to prepare for the close flyby.

“I am 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 are on the verge of returning to normal operations and going for the gold,” he added.

A glitch caused New Horizons to switch to a back-up computer that triggered an 81-minute break in radio communications with mission controllers back on Earth.

Preparations are now on to resume the originally planned science operations on July 7 and to conduct the entire close flyby sequence as planned.

Adding to the challenge of recovery is the spacecraft’s extreme distance from Earth.
New Horizons is almost 3 billion miles away, where radio signals, even travelling at light speed, need 4.5 hours to reach home.

Two-way communication between the spacecraft and its operators requires a nine-hour round trip.

Just hours after its flyby of Pluto on July 14, the spacecraft will observe sunlight passing through the planet’s atmosphere, to help scientists determine the atmosphere’s composition.

“It will be as if Pluto were illuminated from behind by a trillion-watt light bulb,” noted New Horizons scientist Randy Gladstone.

“We are really on the final path. It just gets better and more exciting every day,” said project manager Glen Fountain.