"Never again" is the phrase echoed among NASA leaders recalling the last major tragedy in the space program that occurred 20 years ago this week, when Space Shuttle Columbia broke apart over Texas on Feb. 1, 2003, never making its way back home to Florida.

But with more spacecraft, more players and farther-flung destinations like the moon and Mars, the potential for another disaster has grown.

NASA Administrator Bill Nelson, who as a member of Congress flew on the space shuttle on the mission immediately before the Space Shuttle Challenger disaster in 1986, recalled this week how engineers at one of the shuttle's contractors told their managers to call off the launch because of the weather. The cold was ultimately blamed for shrinking an O-ring that led to the explosion.

"The management would not listen to the engineers begging them to stop the count, and that went up all the way to the top," Nelson said.

The warning signs for Columbia on STS-107 were out there as well. Nelson's mission's shuttle commander, Robert "Hoot" Gibson, told Nelson how he would always inspect the orbiter in space during missions he flew in the time between the two shuttle disasters.

Mars is a dusty planet. From tiny dust devils to vast storms that shroud the planet, dust is a constant challenge for research missions. That was especially true for Ingenuity, the rotorcraft that since February 2021 has been exploring Mars alongside NASA's Perseverance rover. Now, researchers at Stevens Institute of Technology, the Space Science Institute, and the Jet Propulsion Laboratory have completed the first real-world study of Martian dust dynamics based on Ingenuity's historic first flights on the Red Planet, paving the way for future extraterrestrial rotorcraft missions.

The work, reported in the Journal of Geophysical Research: Planets, could support NASA's Mars Sample Return Program, which will retrieve samples collected by Perseverance, or the Dragonfly mission that will set course for Titan, Saturn's largest moon, in 2027.

Electric space propulsion systems use energized atoms to generate thrust. The high-speed beams of ions bump against the graphite surfaces of the thruster, eroding them a little more with each hit, and are the systems' primary lifetime-limiting factor. When ion thrusters are ground tested in an enclosed chamber, the ricocheting particles of carbon from the graphite chamber walls can also redeposit back onto the thruster surfaces. This changes the measured performance characteristics of the thruster.

Researchers at the University of Illinois Urbana-Champaign used data from low-pressure chamber experiments and large-scale computations to develop a model to better understand the effects of ion erosion on carbon surfaces —the first step in predicting its failure.

"We need an accurate assessment of the ion erosion rate on graphite to predict thruster life, but testing facilities have reported varying sputtering rates, leading to large uncertainties in predictions," said Huy Tran, a Ph.D.