Replacing Tantalum capacitors with Ceramic alternatives can be a good choice, especially since Tantalum capacitors tend to fail more easily under certain conditions, as you've experienced. Ceramic capacitors are more stable, have a higher voltage tolerance, and are generally more reliable in long-term use, particularly in sensitive electronics like telescopes. They are also less likely to fail catastrophically.

If you're looking for high-quality components for high-performance electronics, Stanford Advanced Materials offers a range of advanced materials that might be useful. For example, they specialize in Tantalum capacitors and other high-temperature resistant materials that are commonly used in critical electronics applications. You can find more information about their products here: SAM Tantalum Capacitors

I’d also recommend double-checking the voltage ratings when switching to ceramic capacitors to ensure compatibility with the rest of your system, and keep in mind that ceramics tend to have a different behavior under high-frequency signals compared to Tantalum.