UPDATE 1210 GMT: An EA correspondent offers a vital addition to the analysis:
I think that caution should be applied on the theme of whether Ahmadi Rostan was a nuclear scientist or not. His links with the technical aspects of the nuclear programme are much clearer than, for example, those of Masoud Ali-Mohammadi [the scientist killed in January 2010 in a similar manner to yesterday's bombing]. His scientific curriculum fully fits the crucial gas stage of the uranium conversion and, according to Mehr, he was questioned recently by IAEA inspectors, who in turn are accused of making him known to the US and Israeli intelligence communities.Unless the IAEA just questioned him to understand his procurement activities, there must have been valid technical reasons for them doing so, hence the label "nuclear scientist", which after all is a rather generic one. What Ahmadi was not was professor or even lecturer of any substantial level --- he wouldn't have been able to hold such a position with only a bachelor's degree.<
EA reader "M. Zand" (see Comments) points us in a similar direction, noting an article by Somayeh Soltani at Tehran Emrooz, "What was Engineer Ahmadi’s project?":
It is said that Martyr Ahmadi Roshan through a joint project was in particular working with polymer membranes to separate gases. To enrich Uranium, one uses polymer membranes such that Uranium is turned into Uranium hexafluoride gas, and then this gas is filtered through polymer membrane. With this Uranium 235 is filtered through polymer membrane and therefore enriched to Uranium 238.
Expect a lot more media sound and some fury today over Wednesday's car bomb in Tehran, in which a motorcyclist killed Mostafa Ahmadi Roshan and his driver by attaching an explosive to their automobile.
Even the basic facts are being garbled in the accounts. For example, Ahmadi Roshan, according to all the information we have, was not a "nuclear scientist". He was a chemist, graduating in 2002 from Sharif University in Tehran, who was working in the procurement section of the Natanz uranium enrichment facility.
That may be an important post --- what Ahmadi Roshan was procuring has not come out in the information in the Iranian media --- but it does make the victim a "nuclear scientist". And it does not appear to put him at the heart of any scientific effort by Tehran to turn uranium into a bomb.
Still, that is the narrative that will run in most of the media because it makes for higher drama. And most of that media --- inside and outside Iran --- will also tack on "killed by Israel", possibly adding "and the US". That is speculation. Plausible speculation, but still unestablished, just as the responsibility of West Jerusalem and Washington in the other three attacks on Iranian scientists since January 2010 has not been confirmed.
What will be important in all this is the bomb's contribution to the political manoeuvres of the Islamic Republic and of other protagonists in the conflict. As Ahmadi Roshan is buried today, many statements will be made not only about his martrydom but about the "enemy" and Iran's determination to defeat it. Will any of those statements contribute to a shift in Tehran's position, one that portends the "war" that some in the Western media are anticipating?
Not likely, but then again we will have to watch the follow-up outside Iran. The US Government, through levels as high as Secretary of State Hillary Clinton, condemned the attack and denied responsibility. However, Washington is still super-charged with talk of a showdown with Tehran --- often ignoring what is actually happening inside Iran --- so expect a lot of political chest-thumping, be it about another not-so-covert "victory" or about the imminence of an overt Israeli attack.
The US-led line is still to bring Tehran to its knees, in advance of any negotiations on the nuclear issue, through an escalation of sanctions. Far from the car bomb, Secretary of Treasury Tim Geithner is pursuing that effort in China and Japan this week, and the European Union is nearing its decision to suspend oil imports from Tehran.
That is most distinct from any military effort against Iran; however, bombs and missiles make for more provocative rhetoric stories. So the danger is that the sanctions will get wedged into another narrative --- Will a cornered Tehran strike? Is President Obama finally overcoming a reluctance to support an attack? --- which breeds this conflict.