Issue link: https://iconnect007.uberflip.com/i/1253723
76 SMT007 MAGAZINE I JUNE 2020 a snowball that causes a lot of issues all the way downstream. When you have to reject an assembly and send it to scrap, the issues can be just as great. There is an added financial consideration since most or all of the components have already been installed, and it reduces the number of parts ready to be shipped. It is very important to perform root-cause analysis on any assem- blies that have been rejected to determine if this is a one-off issue, or if it is something much more systemic. Systemic may be the easier of those two options since the failure would be more repeatable and most likely easier to cor- rect, but the cost of getting to that point might be considerable. It seems I ran out of steam on the corona- virus/reliability comparisons, and I can only assume we are both thankful for that. The point remains that keeping suspect material away from normal production until deemed fit for use will have a gigantic impact on reliabil- ity. Now go wash your hands. SMT007 Eric Camden is a lead investigator at Foresite Inc. To read past columns or contact Camden, click here. Coalesced from dust exploded outward by the solar nebula, planetesimal blobs aggregated due to gravity to form the rocky planets in the innermost part of the solar system. Their identity is complicated by the fact that Mer- cury, Venus, Earth, and Mars are different in chemical composition. Two MIT scientists in the Department of Earth, Atmo- spheric, and Planetary Sciences (EAPS) recreated in a lab the first magmas these objects might have produced. There's also physical evidence of these magmas in meteor- ites. Tiny pieces of planetary building blocks exist to this day in meteorites, fitting into two major categories. Chon- drites are made of original material and are the most com- mon type. Achondrites come from parent bodies that have experienced some sort of modification. Ureilites, the sec- ond most abundant group of achondrites, were the origi- nal subject of this investigation. The scientists carried out the experiments using a device at MIT that kept the system "closed" and retained all alkalis. They loaded a tiny metal capsule with the same chemical elements that might be present in a planetes- imal and subjected it to conditions of low oxygen, rock- melting temperatures, and pressures expected in the relatively small bodies' interiors. Once those conditions were met, the sample's magma was frozen by dropping to room temperature quickly. Analyzing the magma, cooled into a glass, was tricky. Once they measured the samples, the pair was shocked at the implications. Previously, it was assumed dissimilarities between the terrestrial planets came about during the initial scat- tering of elements in the solar nebula and related to how those elements condensed from gases into solids. Now, with the melts hosting a lot of the alkalis, it would only take some method of melt removal to leave the residual planetesimals depleted in potassium and sodium. (Source: MIT News) When Baby Planets Melt