ARIA Introduction

It was not possible for the MSFN’s ground-based tracking stations to provide continuous communications coverage for a spacecraft in low Earth orbit.

This map below – taken from an Apollo 14 groundtrack map – illustrates the problem. The tracking limits for a vehicle in a 100 nautical mile orbit are here shown for Carnarvon, Honeysuckle Creek, Guam and Hawaii (the effects of local topography, as well as the antenna ‘keyholes’ – directions where mechanical constraints meant they could not point – may be readily seen).

This detail from the Apollo 14 Groundtrack Map shows the need for ARIA. For the full map, see the MSFN section.

The MSFN’s tracking ships were deployed to give coverage for key events (launch, TLI and re-entry), but these could not be quickly moved if, for example, launch holds or TLI burns on later revolutions were necessary. Something more mobile was needed.

A 1965 paper by L C Shelton in NASA publication SP-87 (Proceedings of the Apollo Unified S-Band Conference, page 283ff.) points out that 20 to 30 extra ground and ship-based tracking stations would be required to maintain near-continuous coverage.

For this reason, eight Apollo Range Instrumented Aircraft – specially modified and instrumented EC-135N jet aircraft (a military version of the Boeing 707) – were developed to provide airborne voice relay and telemetry with the Apollo spacecraft during critical portions of the TLI and reentry phases of the lunar missions. Their job was to supplement the existing stations and to be able to rapidly move (within the constraints of airspeed and fuel usage) where they were needed.

The ARIA were operated for NASA by the US Air Force Eastern Test Range out of Patrick Air Force Base, just south of the Kennedy Space Center in Florida.

They were designed by the Goddard Space Flight Center – the nose section was modified to house a 7-foot diameter S-band tracking dish, and the interior was configured to contain all the necessary electronic support equipment.

A 7 foot ARIA steerable USB antenna. Photo courtesy Stan Anderson.

ARIA at Patrick AFB, Florida, 1969. Photo: Bob Burns.

Douglas Aircraft, at Tulsa, Oklahoma performed the airframe modifications, and Bendix Field Engineering Corporation performed the electronic design and installation.

Four aircraft were also modified to use an ALOTS pod (Airborne Lightweight Optical Tracking System). The pod was mounted on a C-135 cargo door and could be fitted to the aircraft when needed.

Goddard paid for the overall modification of the first eight aircraft at an approximate cost of $60 million.

The ARIA fleet was co-ordinated from the Aircraft Operations Control Center (AOCC – otherwise known as ARIA Control), in the NW corner of Patrick Air Force Base.

ARIA Control – otherwise known as the Aircraft Operations Control Center (AOCC) – Building 629 at Patrick Air Force Base, Florida, 1969. Note the NASA C-121 Super Constellation parked on the ramp behind the building. Photo: Bob Burns.

Here’s the former ARIA Control as it looked in April 2011. The building has been extended on the right hand side. Photo: Colin Mackellar.

Stan Anderson, ARIA Control, writes:

“To put things in perspective as to ARIA Control’s part in the puzzle:

For Project Apollo NASA had only 23 ground stations in the Manned Space Flight Network (MSFN) to track the spacecraft in earth orbit: 12 ground stations (such as Carnarvon), 8 ARIA aircraft, and 3 ships, the Redstone, Vanguard and the Mercury. I think the Mercury was based in Sydney, the Vanguard at Honolulu and the Redstone at Port Canaveral next to Cape Kennedy. The ships would leave weeks ahead of a launch to get into position and once there could not be moved quickly. That is the reason the ARIA were developed – to provide a rapid redeployment capability if needed.

The fact is that with all 8 ARIA flying (which rarely happened) ARIA Control effectively controlled 30% of NASA’s near-earth tracking capability. For that reason ARIA Control was listed in NASA’s own documentation as their #3 control center behind #1 Houston, and #2 Goddard Space Flight Center.”

A very early photo of the ARIA AOCC. Right now Front Left to Right: Major Irv Schubert, Major Ed Knox, Captain Pete Kendrick, Unknown, Unknown, Sgt Tillman. Back Row, Far Right, is Sgt. Stan Anderson. Scan and names: Doc Weaver. Large, Larger.

In Australia, ARIAs were stationed at Townsville, Darwin and Perth for various Apollo missions.

The Network communicated with the ARIA fleet via HF radio. The aircraft used a trailing wire HF antenna – as seen in the diagram below. Australia’s Overseas Telecommunications Commission provided extensive support for ARIA through its HF antenna farms at Doonside (transmitters) and Bringelly (receivers) on the western fringe of Sydney – and OTC’s terminal in the inner eastern Sydney suburb of Paddington. (This is also where Sydney Video was located.)

A similar communications centre at Guam also supported ARIA, however, all the switching of various circuits to the Cape was done in Hawaii. (More details coming soon.)

Stan Anderson adds: “I believe the OTC station at Perth was our primary link to Cocos Island, which the ARIA used as a refueling stop transiting the Indian Ocean.”

The ARIA console at the OTC Paddington terminal in Sydney. Top: J.N. Hodgson, foreground: A.H. Griffiths, right: B.W. Collett. From on OTC publication.

Stan also adds, “we had more than one ARIA that was tracking the spacecraft in the splashdown area. On a different circuit, you would have heard each ARIA (three or four of them) reporting AOS. I guess it was up to Dom [Mancini, ARIA Communications Controller at the Cape] to choose the one with the best signal to pass through to Goddard and on to Houston.”

Dom Mancini writes,

“The [signals] came to my console in the XY building on the Cape. I would select the best signal to forward to the Goddard Space Flight Center and they forwarded the signal to Houston. I sat with split headsets (one on each ear) so that I wouldn’t miss a call. I even remember the calling frequencies – 10780 and 20390kHz upper sideband. There is not a single individual with the ARIA crews that I did not admire. To me, they were the best of the best.”

To hear some comms through ARIA, click here to hear Apollo 11 Capcom Bruce McCandless speaking with Buzz Aldrin through ARIA 3 on Apollo 11’s first revolution after launch.

Illustration from NASA publication SP-87.

This cutaway diagram shows the 7 foot dish in the nose of the ARIA. NASA image 67-H-1237, September 15, 1967. Caption: ”The A/RIA (Apollo/Range Instrumentation Aircraft), one of eight KC-135N jet aircraft specially modified and instrumented to provide highly mobile voice relay with the Apollo astronauts and telemetry support of the Apollo spacecraft during the critical portions of the lunar trajectory and earth atmosphere reentry phases of NASA Apollo lunar missions. The fleet of eight aircraft will be operational early in 1968 and will be operated for NASA by the Air Force Eastern Test Range in support of NASA manned space flight missions and other general Range support purposes.” – via Hamish Lindsay.

The ARIA’s home base was Patrick Air Force Base, Florida, until November 1975, when the Air Force moved this operation to Wright-Patterson Air Force Base at Dayton, Ohio.

After Apollo, the Air Force renamed them Advance Range Instrumentation Aircraft.

If you worked on ARIA during Apollo and would like to contribute photos, information or stories, I would be delighted to add them to this section. (Send me an e-mail.)

For a dedicated tribute to ARIA, see also Randy Losey’s www.flyaria.com