Near-universal consensus about anything is rare in ethics. But I think you could get most people to agree on an answer to the question, “Was the invention of the Nazi gas chambers a good invention?” In the Auschwitz concentration camp operated by Nazi Germany during World War II, an estimated 1.1 million people died, most of them Jews, and scientifically-designed gas chambers were used to kill many of them.
Those gas chambers represent a nadir in the history of engineering: designed by a corrupt, malevolent government for industrial-scale executions of people who died in them only because they ran afoul of Hitler’s regime.
Ah, but what if those wanting to try out a gas chamber are not compelled, but have made the decision of their own free will? And have even passed an online test certifying that they are of “sound mind”? And have read a fancy advertising brochure promising “death with style and elegance”? Just climb into the Death Pod—which looks like what you might get if you asked Apple to design a body-length chest-style freezer—lie down, make yourself comfortable, and push the button. The software does all the rest.