[amsat-bb] Friendship 7 details?

Jim White jim at coloradosatellite.com
Tue Jan 10 02:54:12 UTC 2017


I worked Apollo comms from late 67 until 71 in Hawaii and on Eniwetok 
Atoll.  As I recall prior to Apollo there were astronauts deployed to 
all the ground stations who were sort of local CAPCOMs.  They talked 
back to the Cape and later Houston by land line, some by 4 wire land 
line.  If there was any HF involved it would have been to places like 
the Seychelles via commercial links or to the tracking ships.

It was with the advent of the ARIA aircraft that we started using HF 
between them and shore stations, and using them, shore stations and 
ships to connect the astronauts back to the single Houston CAPCOM.  The 
ARIA filled in the over-the-ocean gaps between the shore stations.  We 
built an elaborate system of multiple HF links to assure good comm 
through as many as 8 aircraft during the first few orbits and at 
recovery.  One of the innovations we worked out was cross patching the 
AGC from a tone in one sideband of an HF receiver to the other channel 
to suppress the white noise when no one was talking. That let us do very 
effective double HF hops, plus S band. For example from Hawaii to 
Eniwetok on HF, Eniwetok to the ARIA on HF, S band via the dish in the 
nose of the ARIA to the Apollo capsule - with no more white noise than a 
phone line. There are some very good web sites about how all that 
worked.  One is

http://honeysucklecreek.net/other_stations/ARIA/index.html  There are 
also some great stories on flyaria.com

The most challenging part of the HF piece of this was that the launches 
almost all occurred as dawn was happening over the Pacific, and that was 
where they fired the engine to leave earth orbit (TLI) so we had to have 
ARIA comms to them for those first orbits.  Imagine the challenge of 
establishing full duplex quite HF comms with 4 aircraft taking off 
before dawn from a couple of Pacific islands, then leap frogging 
frequencies up the bands until the Apollo capsule came over a couple of 
times in late morning. This was pretty much the height of the cycle so 
we might go from 5 MHz to 22 MHz freqs in a couple of hours with perhaps 
5 or 6 frequency changes.   It was actually much more complicated than 
I'm describing here with 5 ground stations around the Pacific and as 
many as 30 HF frequencies in use at once.  All wonderful fun for us hams 
in the program, building these complex HF networks in changing 
conditions under great pressure not to mess up.  And great fun using 
10KW to 40KW transmitters and huge fields of Rhombics, giant rotatable 
log periodics, vertical logs, 400' tall discones and pretty much every 
other HF antenna you can think of.

Jim


On 1/9/2017 1:24 PM, Robert Bruninga wrote:
> After seeing the great movie “hidden figures” last night, I had lots of
> questions from my faded memory of the time (it was the same year I got my
> ham license and was 14 years old).  This Wiki page has a lot… but the
> questions lingering in my mind were:
>
> https://en.wikipedia.org/wiki/Project_Mercury
>
>
>
> 1)      Was his mission planned at 3 orbits? (I thought it was more and
> then cut to three).
>
> 2)      If #1, then they must have had to have recovery ships at a
> different spot for every potential orbit since he could not maneuver
> anything other than when to fire the retros.  If it was 7 cut to three,
> then I guess they only needed two ship areas…
>
> 3)      What frequency was CAPCOM?  Was it the 108 MHz?   I think the
> tracking stations all relayed the voice via HF?
>
> 4)      Also related to #1, if something happened to the pilot, I assume
> ground control could fire the retros.
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