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Double trouble for NASA with two spacecraft on the fritz

Interstellar Boundary Explorer isn't listening and Surface Water Ocean Topography mission off to unlucky start

NASA is scrambling to fix glitches affecting its Interstellar Boundary Explorer (IBEX) and Surface Water Ocean Topography (SWOT) missions.

Launched in 2008, the IBEX spacecraft orbits Earth looking outward to detect energetic neutral atoms and study how solar wind interacts with matter and radiation at the farthest reaches of the Solar System.

NASA has reset its flight computer many times over its 15-year life, but mission control has failed to regain communications after its latest attempt. The system entered contingency mode on February 18, and although the spacecraft's flight software seems to be operational, additional software commands sent by mission control have been ignored.

Officials believe signals are reaching the satellite but it isn't responding. "If the mission team's efforts to find and remedy the loss of command capability remain unsuccessful, IBEX will perform an autonomous reset and power cycle on March 4," NASA said.

The satellite carries a hexagonal array of solar panels, and carries two large aperture imagers to capture energetic neutral atoms created when the interstellar medium interacts with solar wind. These particles can take anywhere from a month to 11 years to travel to Earth.

In 2009, IBEX discovered a giant ribbon stretching across the Sun's heliosphere – a protective bubble formed by the solar wind encasing all the planets and other astronomical bodies within the Solar System, where energetic neutral atoms are particularly concentrated.

"This is a shocking new result," principal investigator Dave McComas said at the time. "We had no idea this ribbon existed – or what has created it. Our previous ideas about the outer heliosphere are going to have to be revised."

Meanwhile, NASA engineers are also trying to figure out what's wrong with the SWOT satellite. Jointly developed with the Centre National D'Etudes Spatiales in France, the Canadian Space Agency (CSA) and UK Space Agency, the surface water mapping spacecraft was launched in December 2022.

One of its instruments was knocked offline before the satellite had officially begun collecting scientific data. The Ka-band Radar Interferometer (KaRIn) – used to measure water surface heights – was turned on in mid-January before one of its high-powered amplifier subsystems randomly shut down.

Space agencies are working together to figure out how to get it back up and running. NASA said it is testing components simulating the KaRIn instrument. "The mission will continue with its commissioning and calibration activities – planned March through June – to ensure data accuracy in preparation for the beginning of science operations in July 2023," it confirmed in a statement. ®

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