I mention that meteoritics, the study of meteorites in hand, often drills much deeper than astronomy (observing dots in the sky), or actual space flights (limited by mass, volume, power, data, etc.). In this paper (in the Dec. issue of Geochimica et Cosmochimica Acta, vol. 386):
Cody, G. D. Alexander, C. M O’D. Foustoukos, D. I. et al. On the origin and evolution of deuterium enrichment in type 1 and 2 chondritic organic solids p. 139 .09.023
Direct observation is the cornerstone of science, of course, but… we don’t live in buildings made of all cornerstones. Cody et al. start by direct observation of meteorites. They then try to synthesize their own meteorite material- in this case, the organics found in carbonaceous-chondrite meteorites. All the while, the synthesis process used labeled raw material: hydrogen that was enriched in deuterium, a second isotope of “plain” hydrogen. What did the synthesis process show? The synthetic, labeled material did resemble the natural deuterium levels found in meteorites- but not all of them. The Tagish Lake meteorite, one of our more unusual specimens, has a lot of differences from other carbonaceous chondrites. We can’t really categorize Tagish Lake; it seems an awful lot like the Type 1 and Type 2 meteorites, but doesn’t fit nicely with the other, previously-established groups (CI1, CM1 and CM2, CR2 and one, lone CR1, etc.).
By running this organics experiment, and comparing the results to different meteorites, we have some comprehension of what happened. At least one explanation- water processes during the early Solar System- can now plausibly (…make of that what you will…) explain Tagish Lake vs. the rest.
And we move a step towards a fuller house. Those who tell you that science can only deduce, never induce, think that they can live by sitting on a cornerstone, and calling it their house. Nor can spaceflights alone ever cover the richness of our meteorite collection- the authors used meteorites sourced from Canada, Australia, and Antarctica. Canada demands much less in the way of rocket fuel, and even Antarctica yields far more meteorites (of all kinds) than spacecraft do.