Early Days – Intro



Toda
y, when people remember the Apollo Program, they think of the astronauts and the spacecraft. But none of it would have been possible without accurate tracking and reliable communications with Earth. And there certainly wouldn’t have been any TV from the Moon!

To support the Apollo Program, NASA’s Manned Space Flight Network (MSFN – often pronounced “Misfin”), based at the Goddard Space Flight Center in Maryland, commissioned three 85 foot (26 metre) antennas – equally spaced around the world.

These were –

MSFN locations

Goldstone, California
Honeysuckle Creek, Australia and
Fresnedillas (near Madrid), Spain.


They were near existing Deep Space Network (DSN) stations – Honeysuckle was 20km south of the Tidbinbilla Deep Space Station.

In addition to the new stations, MSFN wings were added to the existing deep space station buildings and the antennas and equipment were modified to operate in the S-Band. This meant that each place would have two stations capable of communicating with Apollo spacecraft at lunar distances.

In addition to that of redundancy, there was another reason for having two Apollo-capable stations at each location. For project Apollo, communications used the higher frequency S-Band (around 2.2GHz), and the beam width of the 85 foot antennas at those frequencies was only 0.43 degree. Ideally, one antenna would track the Command Service Module in Lunar orbit and the other would track the Lunar Module to the surface.

MSFN locations

Three prime Apollo stations were needed to provide continuous coverage at lunar distances, however, at distances out to approximately 16,000km, there would be gaps in antenna coverage. For this reason, a number of smaller (9 metre) USB antennae, as well as tracking ships and ARIA aircraft were also employed for critical periods up to and including TLI and also re-entry.

In addition to each of the three prime 26 metre (85 foot) stations, the nearby Deep Space Network 26 metre stations had additional equipment installed to allow them to track Apollo spacecraft. These Deep Space stations were ‘wing stations’ and acted as second antenna to the MSFN prime stations.

Illustration by Glen Nagle, based on a diagram in NASA publication SP-87.

 

The Unified S-Band Receiver / Exciter / Ranging System had been developed by JPL to provide communications that were much more reliable than those used during the Mercury and Gemini flights.

Collins Radio article on USB

Collins Radio Unified S-Band Project Director George F. Mansur wrote this 1 page article about the USB system in Autumn 1964.

Provided by Alan Gilham (ex-Carnarvon.)

 

At various stages during the Apollo missions, the 64m (210') Mars antenna at Goldstone and the 64m Parkes Radio Telescope were called in to assist – especially during Apollo 11 and the Apollo 13 emergency.

In addition, a number of other stations supported Apollo – notably 9m antennae around the world, including Carnarvon (CRO) – as well as tracking ships and the ARIA (Apollo Range Instrumented Aircraft) fleet.

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This Australian Department of Supply leaflet – distributed in Australia in 1968 – gives a little background to the Australian contribution.

I think this may have been from an exhibit at the Museum of Applied Arts and Sciences in Sydney, in 1968, but I’m not sure now.

The inside pages – which I didn’t scan – had the standard ‘Apollo to the Moon’ diagrams. – Colin Mackellar.