NASA’s Voyager workforce focuses on software program patch, thrusters

Engineers for NASA’s Voyager mission are taking steps to assist make sure that each spacecraft, launched in 1977, proceed to discover interstellar area for years to come back.

One effort addresses gas residue that appears to be accumulating inside slim tubes in a number of the thrusters on the spacecraft. The thrusters are used to maintain every spacecraft’s antenna pointed at Earth. Any such buildup has been noticed in a handful of different spacecraft.

The workforce can also be importing a software program patch to forestall the recurrence of a glitch that arose on Voyager 1 final yr. Engineers resolved the glitch, and the patch is meant to forestall the difficulty from occurring once more in Voyager 1 or arising in its twin, Voyager 2.

Thruster buildup

The thrusters on Voyager 1 and Voyager 2 are primarily used to maintain the spacecraft antennas pointed at Earth in an effort to talk. Spacecraft can rotate in three instructions—up and down, to the left and proper, and across the central axis, like a wheel. As they do that, the thrusters robotically hearth and reorient the spacecraft to maintain their antennas pointed at Earth.

Propellant flows to the thrusters by way of gas traces after which passes via smaller traces contained in the thrusters referred to as propellant inlet tubes which can be 25 instances narrower than the exterior gas traces. Every thruster firing provides tiny quantities of propellant residue, resulting in gradual buildup of fabric over a long time. In a number of the propellant inlet tubes, the buildup is changing into important. To gradual that buildup, the mission has begun letting the 2 spacecraft rotate barely farther in every course earlier than firing the thrusters. This can scale back the frequency of thruster firings.

The changes to the thruster rotation vary had been made by instructions despatched in September and October, they usually enable the spacecraft to maneuver nearly 1 diploma farther in every course than up to now. The mission can also be performing fewer, longer firings, which can additional scale back the full variety of firings accomplished on every spacecraft.

The changes have been rigorously devised to make sure minimal impression on the mission. Whereas extra rotating by the spacecraft might imply bits of science knowledge are often misplaced—akin to being on a telephone name the place the particular person on the opposite finish cuts out often—the workforce concluded the plan will allow the Voyagers to return extra knowledge over time.

Engineers cannot know for certain when the thruster propellant inlet tubes will grow to be fully clogged, however they anticipate that with these precautions, that will not occur for not less than 5 extra years, presumably for much longer. The workforce can take extra steps within the coming years to increase the lifetime of the thrusters much more.

“This far into the mission, the engineering workforce is being confronted with plenty of challenges for which we simply haven’t got a playbook,” mentioned Linda Spilker, undertaking scientist for the mission as NASA’s Jet Propulsion Laboratory in Southern California. “However they proceed to give you inventive options.”

Patching issues up

In 2022, the onboard laptop that orients the Voyager 1 spacecraft with Earth started to ship again garbled standing reviews, regardless of in any other case persevering with to function usually. It took mission engineers months to pinpoint the difficulty. The angle articulation and management system (AACS) was misdirecting instructions, writing them into the pc reminiscence as a substitute of carrying them out. A type of missed instructions wound up garbling the AACS standing report earlier than it might attain engineers on the bottom.

The workforce decided the AACS had entered into an incorrect mode; nevertheless, they could not decide the trigger and thus aren’t certain if the difficulty might come up once more. The software program patch ought to forestall that.

“This patch is like an insurance coverage coverage that may defend us sooner or later and assist us preserve these probes going so long as potential,” mentioned JPL’s Suzanne Dodd, Voyager undertaking supervisor. “These are the one spacecraft to ever function in interstellar area, so the info they’re sending again is uniquely helpful to our understanding of our native universe.”

Voyager 1 and Voyager 2 have traveled greater than 15 billion and 12 billion miles from Earth, respectively. At these distances, the patch directions will take over 18 hours to journey to the spacecraft. Due to the spacecraft’s age and the communication lag time, there’s some danger the patch might overwrite important code or produce other unintended results on the spacecraft.

To scale back these dangers, the workforce has spent months writing, reviewing, and checking the code. As an added security precaution, Voyager 2 will obtain the patch first and function a testbed for its twin. Voyager 1 is farther from Earth than some other spacecraft, making its knowledge extra helpful.

The workforce will add the patch and do a readout of the AACS reminiscence to ensure it is in the fitting place on Friday, Oct. 20. If no rapid points come up, the workforce will situation a command on Saturday, Oct. 28, to see if the patch is working because it ought to.