I do not think an interstellar spacecraft crashed at Roswell.
Generally speaking, I could accept the Mogul explanation.
My lack of confidence in a pure Mogul explanation has to do with Blanchard's order for media publicity.
For the record, Blanchard's order for publicity is, IMHO, even more ridiculous if he really thought they had recovered some sort of interplanetary vehicle.
The 1952 film,
Above and Beyond, dramatizes Col. Tibbets and the lead up to, and accomplishment of, the Hiroshima strike. The film is a dramatization, but it clearly presents a
stifling secrecy culture for the 509th. IMHO, every Roswell researcher or buff should be required to see this film. From what I've read, including at
Wiki, Blanchard was backup for Tibbets and would have flown the Hiroshima strike if Tibbets had been grounded for any reason.
In the climaxing phase of World War II, then Colonel Blanchard was directed to prepare and supervise the detailed operations order for the delivery of the first atomic bomb on Hiroshima. He was the backup pilot for the Hiroshima A-bomb drop, which was ultimately delivered by Colonel Paul W. Tibbets, Commanding Officer of the 509th Atomic Bombardment Group or Wing.
So I seriously question a "Gomer Pyle" type SNAFU by West Point graduate, and highly competent commander, Wm. Blanchard, of taking personal initiative to publicize the recovery of any strange debris. Blanchard was committed to a culture of secrecy, and there does not seem to be any reason to be in such a damned hurry to publicize the recovery trash that, based on the photos in Ramey's office, looked pretty much like any ordinary kind of humanly manufactured material available in those days. It would certainly seem to me that Blanchard would have considered the possibility that the debris was from a classified US device of some sort. So why publicize it?
However, US intel was certainly interested in what the Soviets were up to. The link above that George gives to the Dave Thomas
The Roswell Incident and Project Mogul article says the whole point of Mogul was to monitor Soviet atomic testing:
The Mogul project was so classified and compartmentalized that even Moore didn’t know the project’s name until Robert Todd informed him of it a couple of years ago. The unclassified purpose of the project was to develop constant-level balloons for meteorological purposes.
Its classified purpose was to try to develop a way to monitor possible Soviet nuclear detonations with the use of low-frequency acoustic microphones placed at high altitudes. No other means of monitoring the nuclear activities of a closed country like the USSR was yet available, and the project was given a high priority. One of the NYU tasks was the development of constant-level balloons for placing the acoustic microphones aloft. After some preliminary flights in Bethlehem, Pennsylvania, in April 1947, which failed due to high winds, the project moved to New Mexico.
In June and early July 1947, numerous NYU balloon flights were launched from Alamogordo Army Air Field in New Mexico.
So according to this article, by 1947 the US was concerned that the Soviets were developing, or possibly had developed an a-bomb.
In addition, the Soviets had been "given" three B-29s during WWII when the aircrews were unable to return to US bases, but landed instead at their "ally's" bases in the USSR. The B-29 was among the most advanced aircraft of the day and provided the Soviets their own long-range atomic bomber (though the three that they had acquired were conventional, not Silverplate B-29's). The Soviets flew their first TU-4 clone of the B-29 in the spring or early summer of 1947. It seems certain to me that Blanchard and higher ups in the USAF would have been deeply concerned that Soviet agents would monitor operations of the 509th at Roswell to collect any info they could on B-29 operations, as well as any atomic information they could acquire.
As I understand the timeline of events, it seems likely that Marcel's B-29 had just taken off from Roswell heading for Fort Worth with samples of the debris when Blanchard ordered media publicity of the debris. One might note that flying a paltry box of debris in a freaking Silverplate B-29 is not the most effective use of tax-payer money, as transport planes are more economical. But such a flight would make a splash on any Soviet agents monitoring Roswell.
Furthermore, IMHO it would be highly unlikely for Blanchard to have sent Marcel in a B-29 to Fort Worth without first coordinating with the superior officer that Marcel was going to report to, General Ramey. In other words, Blanchard and Ramey would have been in phone contact prior to Marcel ever getting off the ground. If for nothing else, just to make sure that Ramey would be in his office when Marcel arrived.
So, all this background leads me to speculate that the Roswell "event" may have been some sort of counter intel operation, with humanly manufactured mundane debris planted in an isolated field, in order to shake up Soviet agents in the US, and then to try to track their communications by looking for "flying disc" or something similar. Perhaps only Ramey and Blanchard knew about it, and perhaps all other 509th personnel were in the dark about it. Maybe. Or maybe not.
While I did arrive at this possible explanation before I'd become aware of James Carrion, or that he'd also proposed a similar view, I'll mention him for first making this idea public, as far as I know. On the other hand, I am not convinced by Carrion's Ghost Rocket "Rosetta" theory. There were too many Ghost Rocket reports and were too widespread, IMHO.