4 min read<\/p>\n
NASA\u2019s OSIRIS-APEX Unscathed After Searing Pass of Sun<\/h1>\n<\/div>\n<\/div>\n<\/div>\n
Mission engineers were confident NASA\u2019s OSIRIS-APEX (Origins, Spectral Interpretation, Resource Identification \u2013 Apophis Explorer) spacecraft could weather its closest ever pass of the Sun on Jan. 2, 2024. Their models had predicted that, despite traveling 25 million miles closer to the heat of the Sun than it was originally designed to, OSIRIS-APEX and its components would remain safe.<\/p>\n
The mission team confirmed that the spacecraft indeed had come out of the experience unscathed after downloading stored telemetry data in mid-March. The team also tested OSIRIS-APEX\u2019s instruments in early April, once the spacecraft was far enough from the Sun to return to normal operations. Between December 2023 and March, OSIRIS-APEX was inactive, with only limited telemetry data available to the team on Earth.<\/p>\n
![\"Two](\"https:\/\/science.nasa.gov\/wp-content\/uploads\/2024\/05\/edit-26sept2023vs3april2024-stowcam-comparison-copy.jpg\")
<\/a><\/figure>The spacecraft\u2019s clean bill of health was due to creative engineering. Engineers placed OSIRIS-APEX in a fixed orientation with respect to the Sun and repositioned one of its two solar arrays to shade the spacecraft\u2019s most sensitive components during the pass.<\/p>\n
The spacecraft is in an elliptical orbit around the Sun that brings it to a point closest to the Sun, called a perihelion, about every nine months. To get on a path that will allow it to meet up with its new target Apophis in 2029, the spacecraft\u2019s trajectory includes several perihelions that are <\/a>closer<\/a> to the Sun<\/a> than the spacecraft\u2019s components were originally designed to withstand.<\/p>\n \u201cIt\u2019s phenomenal how well our spacecraft configuration protected OSIRIS-APEX, so I\u2019m really encouraged by this first close perihelion pass,\u201d said Ron Mink, mission systems engineer for OSIRIS-APEX, based at NASA\u2019s Goddard Space Flight Center in Greenbelt, Maryland.<\/p>\n Besides confirming that the January perihelion worked out according to predictions, engineers found surprises while testing spacecraft components. A couple of instruments came out better than expected after exposure to higher temperatures.<\/p>\n A camera that helped map asteroid<\/a> Bennu<\/a> and will do the same at Apophis, saw a 70% reduction in \u201chot pixels\u201d since April 13, 2023, the last time it was tested. Hot pixels, which are common in well-used cameras in space, show up as white spots in images when detectors accumulate exposure to high-energy radiation, mostly from our Sun.<\/p>\n \u201cWe think the heat from the Sun reset the pixels through annealing,\u201d said Amy Simon<\/a>, OSIRIS-APEX project scientist, based at NASA Goddard. Annealing is a heat process that can restore function of instruments and is often done intentionally through built-in heaters on some spacecraft.<\/p>\n