NASA's Parker Solar Probe is performing exceptionally well during its closest approach to the sun this week. On December 24th, at 6:53 a.m. Eastern time, it reached a distance of 6.1 million kilometers from the sun's surface – the closest any spacecraft has ever come. At this point, its velocity reached a staggering 191 kilometers per second.
Launched in 2018, the probe utilized a series of gravity assists from Venus to gradually decrease its perihelion (closest point to the sun). The final Venus flyby, on November 6th, positioned it for this record-breaking perihelion, the closest it will get to the sun during its mission.
“On Christmas Eve of this year, Parker Solar Probe will be the closest human-made object ever to a star,” stated Nour Rawafi, project scientist for the mission at the Johns Hopkins University Applied Physics Lab (APL), during a media briefing on December 10th. “We will be embracing a star.”
While out of contact during the flyby, a beacon signal is expected on December 27th, confirming its successful passage. Telemetry will follow in early January, with science data arriving later in the month.
The spacecraft's thermal protection system is surpassing expectations. Betsy Congdon, lead engineer for the thermal protection system at APL, explained, “We expect lower temperatures that we designed for and that we tested to. We overprepared.” This success is attributed to design margins and the unexpected whitening of the heat shield material at high temperatures, enhancing its performance.
Other systems, including the solar panels, are also exceeding predictions, exhibiting less degradation than anticipated. Rawafi highlighted the spacecraft's overall health, stating, “The system is very healthy and it can go much further than we planned for.”
The mission is providing crucial data on the solar wind and corona, including coronal mass ejections. This information is invaluable for understanding our sun and other stars. Nicholeen Viall, a space scientist at NASA’s Goddard Space Flight Center, emphasized the probe's significance: “Parker is the key because it is so close.”
Two more close approaches are planned for 2025. Funding is being sought to extend the mission beyond 2026, leveraging the spacecraft’s ability to maintain its orbit with minimal fuel consumption. Rawafi confirmed, “The spacecraft can stay there for a long, long time.”