The Mid-Infrared Instrument (MIRI) on NASA's James Webb Space Telescope is now cooled by a gaseous helium cryocooler to under 7 Kelvin. With the cooler in its final state, the Webb team is operating the MIRI instrument this week as part of seventh and final stage of the telescope alignment. When the instrument is operating, the detectors and electronics produce heat, which is balanced by the cryocooler to keep MIRI at a stable, and very cold, operating temperature. The near-infrared instruments also warm up during operations and have to dissipate heat, although for these instruments this is done with passive cooling; the heat from the detectors and electronics is radiated into deep space.

Now that the instruments are at their operating temperatures, the telescope mirrors will also continue cooling down to their final temperatures, but they are not quite there yet. The primary mirror segments and the secondary mirror are made of beryllium (coated with gold). At cryogenic temperatures, beryllium has a long thermal time constant, which means that it takes a long time to cool or to heat up.

On April 18, NASA decided to move forward with plans to complete the deployment of the Lucy spacecraft's stalled, unlatched solar array. The spacecraft is powered by two large arrays of solar cells that were designed to unfold and latch into place after launch. One of the fan-like arrays opened as planned, but the other stopped just short of completing this operation.

Through a combination of rigorous in-flight solar array characterization and ground testing, Lucy engineers determined the unlatched solar array is nearly fully open, positioned at approximately 345 out of the full 360 degrees, and is producing ample energy for the spacecraft. Nonetheless, the team is concerned about potential damage to the array if the spacecraft conducts a main engine burn in its present configuration.

After launch, the arrays were opened by a small motor that reels in a lanyard attached to both ends of the folded solar array. The team estimates that 20 to 40 inches of this lanyard (out of approximately 290 inches total) remains to be retracted for the open array to latch.

The solar array was designed with both a primary and a backup motor winding to give an added layer of reliability for the mission-critical solar array deployment.

Charlie Duke is part of a tiny fraternity that's getting even smaller: People who walked on the moon.

Duke, 86, visited his Apollo 16 spaceship on Wednesday at the U.S. Space and Rocket Center to mark the 50th anniversary of his one and only trip to the lunar surface.

Even during times of conflict on the ground, space has historically been an arena of collaboration among nations. But trends in the past decade suggest that the nature of cooperation in space is shifting, and fallout from Russia's invasion of Ukraine has highlighted these changes.

I'm an international relations scholar who studies power distributions in space—who the main players are, what capabilities they possess and whom they decide to cooperate with. Some scholars predict a future in which single states pursue various levels of dominance, while others foresee a scenario in which commercial entities bring nations together.