Month: June 2019

Enlarge / This is one of the 664 uranium cubes from the failed nuclear reactor that German scientists tried to build in Haigerloch during World War II. (credit: John T. Consoli/University of Maryland)

When University of Maryland physicist Timothy Koeth received a mysterious heavy metal cube from a friend as a birthday gift several years ago, he instantly recognized it as one of the uranium cubes used by German scientists during World War II in their unsuccessful attempt to build a working nuclear reactor. Had there been any doubt, there was an accompanying note on a piece of paper wrapped around the cube: "Taken from Germany, from the nuclear reactor Hitler tried to build. Gift of Ninninger."

Thus began Koeth's six-year quest to track down the cube's origins, as well as several other similar cubes that had somehow found their way across the Atlantic. Koeth and his partner in the quest, graduate student Miriam "Mimi" Hiebert, reported on their progress to date in the May issue of Physics Today. It's quite the tale, replete with top-secret scientific intrigue, a secret Allied mission, and even black market dealers keen to hold the US hostage over uranium cubes in their possession. Small wonder Hollywood has expressed interest in adapting the story for the screen.

Until quite recently Koeth ran the nuclear reactor program at UMD, which is how he met his co-author. Hiebert is completing a PhD in materials science and engineering, specializing in the study of historical materials in museum collections (glass in particular) and the methods used to preserve them, using the reactor facility for neutron imaging of a few samples. Koeth told her about his research into his cube's origins, and she started collaborating with him as a side project.

Enlarge / A rendering of what a Super Heavy-Starship launch would look like. (credit: SpaceX)

Earlier this month, the principal Mars "development engineer" for SpaceX, Paul Wooster, provided an update on the company's vision for getting to the red planet. During his presentation at the 2019 Humans to Mars Summit in Washington DC, Wooster said SpaceX remains on track to send humans to Mars in the "mid-2020s." He was likely referring to launch opportunities for Mars in 2024 and 2026, but he also acknowledged that much work remains to reach that point.

SpaceX plans to bring humans to Mars with a two-stage rocket: the Starship upper stage and a Super Heavy booster (the latter formerly known as the Big Falcon Rocket, or BFR). Iterative design versions of the Starship are being built at facilities in both Boca Chica, Tex., and near Cape Canaveral, Fla. SpaceX founder Elon Musk is expected to provide an update on their development in late June.

Wooster said that SpaceX is working to "minimize the number of things that we need to do to in order to get that first mission to Mars." Part of that minimization involves a massive payload capacity. Starship, once refueled in low Earth orbit, is planned to have a capacity of more than 100 tons to Mars.