Possible Challenger To Sputnik, manhole first manmade object in space? Options

[Guest_BruceMoomaw_*]

Where the hell did THAT one get started? It was made clear from the very start of the Mercury program that the first two US manned orbital flights (Glenn and Carpenter) would run 3 orbits each.

[dvandorn]

Bruce, that one got started because of the AZUSA guidance system of the Atlas rocket. The trajectory guys on the first Mercury orbital flight (MA-6, Glenn's flight) were tracking the capsule using the AZUSA system, and their first projection after MECO told them that the capsule's orbit was "safe" (i.e., it wouldn't decay on its own) for at least seven orbits. They called that out and Alan Shepard, at the Cape's CapCom console, passed it along to Glenn.

So, very shortly after orbital insertion, Shepard called up to Glenn, "You have a GO, at least seven orbits."

That call-out had nothing to do with the anticipated length of the mission -- it merely told Glenn that his orbit was high enough that it wouldn't decay naturally before at least the seventh orbit. I believe that this was a planned call-out, and that any value for this call-out greater than three orbits was considered a GO situation.

Since most of the news people covering the flight, and since an even greater percentage of historians who have written about the flight since, didn't have any kind of clue as to how the flight controllers called out their data and how that data was used by all involved, there has been an urban myth that MA-6 was supposed to fly for at least seven orbits. The myth is simply a misunderstanding of the call-out.

-the other Doug

[ljk4-1]

"Chronology of Significant Events and Decisions Relating to the
US Missile and Earth Satellite Development Programs - May 1942
to October 1957"

http://www.blackvault.com/documents/dod/re...room/14/578.pdf