The NASCOM Communications Network


The NASCOM Communications Network was a very extensive, state of the art, communications network spanning the globe and linking all the tracking stations, the tracking ships, the ARIA aircraft, NASA centres to Goddard Space Flight Center and then on to Houston.

Satellite, undersea cable, leased telephone company broadband circuits and High Frequency radio circuits were all employed to connect the far flung MSFN facilties. In practice, the network performed amazingly well.

The Deakin Switch in Canberra was the main Australian communications hub.

This first map shows the extent of the network in early 1968. (As the note on these maps states, these only show facilities dedicated for the mission in question, and not the entire MSFN.)

MSFN NASCOM map for Apollo 5

The NASCOM Network for Apollo 5 (AS-204 LM).

Bryan Sullivan writes that this diagram is from a NASCOM manual dated 22 January 1968, showing the world wide NASCOM communications network configuration for the AS-204 LM [Apollo-5] mission. “It shows the all the circuits back to the GSFC hub via all the trans Atlantic and Pacific trunks through the various switching centres from each tracking station and even the HF links to the ARIA aircraft and to the tracking ships.”

Circuit designations include –

GDA = Government Data Alternate, meaning the circuit could also support data. (Thanks to Ed Fendell and Kevyn Westbrook.)

NCV = NASA Canberra Voice
NCT = NASA Canberra Teletype (Thanks to Kevyn Westbrook.)

Large, Larger (1.2MB).

Preserved and scanned by Bryan Sullivan,
assembled by Colin Mackellar.


These two maps show the extent of the network for Apollo 11.

MSFN NASCOM map for Apollo 11

The NASCOM Network for Apollo 11 (AS-506).

Map dated 25 June 1969.

Preserved and scanned by Bryan Sullivan.

MSFN NASCOM map for Apollo 11

The NASCOM Network for Apollo 11.

Preserved and scanned by Bryan Sullivan.

NASCOM between Apollos 15 and 16.

NASCOM Dec 1971

NASCOM, December 1971.

This December 1971 schematic of NASCOM shows the amazing global spread of the network.

Large, Larger (5MB).

Preserved by Joe Gormly (Deakin NASCOM Switch),
Scanned and assembled by Colin Mackellar.

NASCOM Dec 1971

NASCOM Australian segment, December 1971.

This excerpt from the December 1971 schematic above shows just the Australian segment. Red explanatory labels added.

Click the image for a 3.2MB PDF file.

Anotated by Colin Mackellar.

Bill Woods, who was with OTC-A (the Australian Overseas Telecommunications Commission), writes:

“There are many untold stories about NASA comms, one of the interesting ones being the 1200 b/s diversity radio link set up for them from Gnangara [near Perth in Western Australia] to Tananarive. This used duplicate 30 KW pep transmitters, operating in both space and frequency diversity, just to achieve a 1200 b/s link…”

It wasn’t always easy to get the right audio to and from the tracking stations – Goddard Voice was an incredibly complex switching centre. Here’s a snippet of audio from Apollo 11 revolution 1. After Capcom Bruce McCandless gets no reply, Houston COMM TECH Chester ‘Chet’ Brantley calls Tananarive. (Richard Stachurski writes that “Chet Brantley was one of the Philco-Ford guys who worked with us on the Green Team”.)