The 20th Anniversary of the First Commercial Lunar Flyby Rescue Mission—Jerry Salvatore

This year marks the 20th anniversary of the remarkable efforts that recovered the Hughes HGS-1 after a failed launch.  This satellite launched as AsiaSat was placed in an unusable 51-degree inclined orbit after the fourth stage of the Proton launch vehicle failed.  A recovery plan that involved two lunar flybys was developed and implemented.  I documented this historic journey a year later and presented it at the 50th International Astronautical Congress in Amsterdam on October 4, 1999. This definitive paper describes the complex rescue limitations in detail, discusses the numerous mission considerations that had to be addressed, defines the nominal rescue maneuvers plan, and documents all (planned and ad hoc) maneuvers during the 68-day journey. This document will be posted on the Hughes heritage website for all to read the facts of the rescue.

May 13, 2018 marks 20 years since HGS-1 flew around the moon for the first time in a risky, epic rescue mission that attempted to transfer a Hughes HS601 HP spacecraft stranded in a highly inclined (51.6 degrees) geosynchronous transfer orbit (GTO, via a Proton upper stage failure ) into a useful geosynchronous orbit (GSO, similar to Syncom 2).

This mission was actually initiated on April 10, 1998, had an ad hoc second flyby of the moon on June 6, 1998 and achieved the best possible GSO orbit on June 16, 1998 with an inclination of about 7.5 degrees relative to the equator and a longitude south of Hawaii.

During this historic rescue, I wrote two US patents for Hughes that used single and multiple lunar flybys to assist transfer from any GTO to a GEO (geostationary orbit). Both patents were awarded in late 2000.

In the interim, a small company Innovative Orbital Design (IOD) filed suit against Hughes claiming we had infringed on their intellectual property. This is the same company that claimed to be responsible for giving Hughes the idea to use the moon for rescue with Belbruno’s “Fuzzy Boundary” theory. The court found that IOD’s claims were without merit and dismissed the suit by summary judgement. The court did not allow the case to proceed to trial and fined IOD for certain Hughes costs of defense. The initial legal and political attacks on this innovative Hughes accomplishment were successfully refuted.

Ironically, on the 10th anniversary (2008) of the HGS-1 flyby, a Lockheed Martin spacecraft, AMC-14, owned by SES, experienced a similar failure of the Proton upper stage resulting in a similar stranded orbit to HGS-1.  I was employed by SES for one month to study a possible lunar flyby rescue.  The lunar geometry in this case was near perfect and a double lunar flyby would restore roughly eight years of the nominal 15 – year GEO mission.  The only requirement was for Boeing (who now owned my original patents) to allow the rescue to occur.  Unfortunately, SES had a $50 million law suit against Boeing to replace a satellite, lost during a sea launch explosion, at the original cost. Boeing required dismissal of the law suit, SES refused and the rescue mission was aborted.  Amen to any previous or future commentary of whether the patents were valid or unenforceable. In hindsight, though, I regret writing the patents that precluded a “near perfect” rescue of HGS-1’s stranded younger sister a decade later.

On the 15th anniversary (2013) a bombshell article, “Beyond GEO”, was published on the Space Review website (and republished on the Hughes heritage website). The story told by Rex Ridenoure reveals that an alternate rescue plan to the practical one that I devised was supported by Hughes personnel (Chris Cutroneo, Loren Slafer, and Cesar Ocampo). Rex acknowledges that Slafer told him on January 28 (a couple of weeks after his initial proposal) that the plan was impractical. I learned of this impossible plan from Ocampo a month later and instructed him not to reveal the official Hughes approach. Unfortunately, Rex reveals that Ocampo told Belbruno of the Hughes approach a month after he was instructed not to be a “leaker”. This occurred two weeks before our first maneuver Rex reveals there were subsequent leaks during the entire mission.

After several months in the blind with no contribution to this mission, Rex admits that he and Belbruno initiated their own PR campaign to sell their story about how the core enabling idea of using the Moon to salvage AsiaSat 3 entered into the option trade space at Hughes; and to insure this story was not buried by the personal or corporate motivations that apparently wanted to squelch the facts. Rex concluded in the article that “the story got out and stuck”. The rebuttal to “Beyond GEO” was published two months later on both the Space Review and Hughes heritage websites as 2 essays: “The Real Story”, part 1-Jerry Salvatore, mission director, and part 2-Mark Skidmore, project manager.

Remarkably after 20 years there still is controversy surrounding the facts of this recovery effort.  On March 10, 2018, Chris Cutroneo wrote a blog for the Hughes heritage website entitled “HGS-1 Mission–Setting the Facts Straight.” This blog resurrects the Ridenoure and Belbruno PR campaign described above and purports to be factual. While Chris is entitled to his personal opinions, he is not allowed to distort the facts in his blog.

Chris Cutroneo, Loren Slafer and Cesar Ocampo worked with Ridenoure and Belbruno in January 1998 on an untenable rescue plan. Chris confirms that these Hughes personnel were told by the HGS project office in February to terminate all conversations with these outsiders. Subsequently, Cutroneo and Slafer voluntarily chose not to contribute or consult during any phase of the rescue mission. Chris’ statement “I relayed Cesar’s calculations and Rex’s information to Jerry via email, mentioning Rex’s company as well as the fuzzy boundary theory and that it was a novel theory but impractical” is absolutely “fake news”. As stated above I learned of this absurd plan from Ocampo in late February, well into the planning phase of the actual mission. This invented fact would apparently support his opinion in the blog, “But I believe we did have their idea in hand that helped us come up with the idea to do a lunar flyby and mimic the Apollo missions”.

Chris’ description of Cesar Ocampo’s position is correct. Cesar is a brilliant trajectory analyst who verified my original thesis and performed all trajectory studies during the entire mission. I named him a co-author on the definitive paper as well as the two patents issued because of his analytical contributions to the rescue mission. I was his principal sponsor when he was named  “Hispanic Engineer of the Year” in 1998. However, I learned from Rex’s paper 15 years later that: He divulged our approach to Belbruno in late March; He continued his leaks to Belbruno during the mission; He refused to obey the HGS program office in April about public discussions of the mission; He wrote a paper seven years after the mission that lifted key paragraphs from the definitive paper (which has never been posted on the internet), embraced the Ridenoure PR propaganda and accused Hughes of unethical behavior.

Five years ago, Cesar shared a quote by me during the mission on the heritage website: “There are those who make things happen, others who watch it happen, and the rest who ask what happened. And Jerry falls in the first category.” In his response to my article on the HGS-1 mission Cesar adds, ‘I will be forever grateful to Hughes and individuals there, for having given me the opportunity to spend four wonderful years at Hughes, and the opportunity to work on HGS-1 and other missions. This has been a major highlight in my career.’

Chris further states in a final note, “HGS-1 achieved only a short period of time in GEO orbit post recovery.  There was a more optimum time (better Earth, Moon, Sun geometry) to pull off the recovery plan, 6 months later than when we started it. It would have achieved a much longer life span (years), orbitally, for the satellite.  It was unclear to me as to why this option was not selected.”

This is the second incorrect statement in his blog.  I refer him to the trajectory design section of the definitive paper to help him understand the real options available.  The fact is that given the lunar/spacecraft orbit geometry and spacecraft propulsion capability, no GEO orbit was achievable with the lunar flyby until 2029.  Only GSO inclined orbits were achievable at about 2-year intervals.  The first opportunity in April 1998 was selected.  The resulting GSO orbit with an initial inclination of about 7.5 degrees was designed to become GEO (zero inclination) in 2007 using solar/lunar perturbations.  The spacecraft was operated by Hughes Global Services for several years. The US Navy leased several transponders and it provided service to the Atlantic Fleet up to its deorbit.  It was operational on 9/11 when an urgent call came for more capacity.  Unfortunately, HGS-1 ran out of fuel and was placed in a multiyear pendulous GSO disposal orbit in late 2002 that positioned it over the dateline in 2007.  This would minimize any possible collision hazard as the spacecraft traveled in the equator with no neighbors.  It worked!

I recorded my views about this mission in an article in the July 15, 2013 Space Review entitledThe Chief Technologist’s View of the HGS-1 Mission.”  Mark Skidmore, Hughes program manager for the recovery mission, also presented his views in the July 8, 2013 Space Review in an article entitled “An alternative view of the HGS-1 salvage mission.”  I believe that two articles provide the most complete and correct description of the events surrounding the recovery mission design and implementation.

Shadow Dancing: The Satellite Data System By Dwayne A. Day


In the late 1960s the CIA was researching technology as part of the ZAMAN program to develop a satellite with the capability to directly image the ground below and send that imagery electronically to a ground station. One issue facing ZAMAN’s designers was how to store the imagery on the satellite and to then transmit it. If the satellite could only transmit the images while in view of a ground station this would dramatically limit how many images could be sent each day because the satellite would only be over a ground station for a limited amount of time. But there was a solution: instead of transmitting signals directly down to the ground, the imagery satellite could send them upward, to a communications relay satellite in a much higher orbit, and that satellite could relay the images to the ground. This approach added complexity, but provided numerous advantages, including increasing available transmission time.

This relay satellite, soon given the obscure name of Satellite Data System, could send the data down to a distant ground station, even one on the other side of the Earth from the reconnaissance satellite taking the pictures. The Satellite Data System, or SDS for short, was eventually developed under a unique management arrangement. Although it carried a highly classified mission payload—“black” in the jargon of the intelligence community, the satellite itself was developed and procured by the unclassified—“white”—Air Force Space and Missile Systems Office, thus straddling the edge of the shadowy world of satellite reconnaissance. A declassified history by Vance O. Mitchell, “The NRO, the Air Force, and the First Reconnaissance Relay Satellite System, 1969-1983,” describes how this unusual management relationship was developed—and almost fell apart—during its early years.

The CIA and NRO Approve Data Relay

In 1968, CIA official Leslie Dirks, who was then the program manager for ZAMAN, which had been underway for several years evaluating technology for a real-time imaging satellite, decided to rely on relay satellites rather than onboard data storage and transmission to a ground station for the ZAMAN satellite. By October 1969 Dirks named his assistant division chief as the manager for the relay satellites. The manager’s name is deleted in the declassified history, but he is described as conservative, detail oriented, and very methodical.

The National Reconnaissance Office (NRO) was the organization that was responsible for overseeing the development of intelligence satellites. The NRO included an Air Force component known as Program A and publicly acknowledged as the Secretary of the Air Force Office of Special Projects, or SAFSP. The NRO also included a CIA component housed in the CIA Deputy Directorate of Science and Technology’s Office of Development and Engineering and known as Program B, which was then leading the ZAMAN effort. Program A and Program B had often battled each other for primacy within the NRO. In 1969 NRO officials began planning for relay satellites, and by June they became a separate line item in the NRO’s budget. The relay satellite program formally began in spring 1970 when a preliminary evaluation selected a small number of civilian firms for a year-long system definition phase to begin in July of that year. The plan was to down-select to a single company in October 1971.

Using an additional satellite system in high orbit to relay images from ZAMAN satellites in low Earth orbit would be both expensive and complicated. But it also offered advantages over the direct transmission to ground approach, including longer transmission times. An added advantage of the relay system was that it enabled multiple satellite constellations, not just a single satellite at a time. Another advantage was that the imaging and relay satellites would be very far from each other and the ground station and it would be difficult for the Soviets to determine that the satellites were working together, thus increasing operational security.

Some of the details of both programs remain classified, but while these early decisions about the data relay satellite were being made, ZAMAN was still primarily a technology development program, not an approved satellite development program. Nevertheless, it was clear to those running the National Reconnaissance Program—the formal term for the collection of top secret intelligence satellites managed by the NRO along with their budgets—that these new systems were going to be very expensive. That created a dilemma for the National Reconnaissance Office leadership, who sought to be low-key even among those who had security clearance to know about the NRO.

Spreading the Responsibility and the Costs

On August 15, 1969, the NRO’s Executive Committee decided to give relay satellite development to the Space and Missile Systems Office (SAMSO). SAMSO was part of the Air Force Systems Command and not affiliated with the Secretary of the Air Force Special Projects office—the classified NRO Program A office—in Los Angeles. Unlike Program A, SAMSO was both overt and completely outside of the NRO, and giving a non-intelligence organization responsibility for a new satellite vital to national reconnaissance was extremely unusual. The NRO’s ExCom also gave the program an overt designation: the “Satellite Data System,” or SDS.

According to Vance Mitchell’s history of the relay satellite program, there were three reasons to give development responsibility for the Satellite Data System to SAMSO:

  • Funding it through Air Force channels would hold down the National Reconnaissance Program budget. The ExCom members were concerned about the NRO budget exceeding a billion dollars, believing that this was a threshold above which their program would receive added political scrutiny from the few elected officials who were cleared to know about the NRO. Other NRO programs had already shifted money into the Air Force side to keep the total NRO budget down. It was not until the early 1970s that the National Reconnaissance Program budget finally crossed the billion-dollar mark.
  • Having SDS as an Air Force program would imply to the Soviets that it was not connected to reconnaissance and therefore enhance mission security.
  • The Air Force Satellite Control Facility was responsible for communicating with satellites and had acquired considerable experience. In addition, the Aerospace Corporation had been evaluating data relay satellites in 1968 into 1969 and had become knowledgeable about the subject. Aerospace worked closely with the Space and Missile Systems Office.

SAMSO designated the SDS program as secret with a “special access required” annex. There were only two other SAR programs at the time. One was the Defense Support Program (DSP) missile warning satellite, and the other may have been what became the Global Positioning System. SAR allowed the release of selected information about the NRO’s communications relay payload without divulging critical items that might compromise its mission. The CIA’s connection to SDS and details of the NRO communications payload were confined to a special compartment within the NRO’s own BYEMAN security system. Anybody requiring access to this information had to be cleared by the NRO.

Once SAMSO was designated in charge of SDS, it immediately led to questions within SAMSO and the Air Force. Air Force personnel involved in SDS development believed that since the Air Force was providing the personnel, expertise and offices to run the SDS development, SAMSO was now more than a junior partner in somebody else’s program and should be treated as a full partner. Brigadier General Walter R. Hedrick Jr., Director of Space and Deputy Chief of Research and Development, wanted changes in SDS to make it more responsive to Air Force missions. Hedrick wanted the satellites to serve both Air Force and NRO requirements. He wanted to add secondary payloads to the spacecraft in addition to the communications relay payload.

CIA officials connected to the SDS development believed that the SDS satellites were supposed to have a single NRO communications relay payload and no other missions. They were concerned that the NRO might become a “customer” on its own relay satellite and have the satellite’s covert intelligence mission compromised in the process.

By November 1969 there was pressure to create a management agreement that both sides would accept. CIA officials agreed to allow Air Force secondary payloads on SDS, but demanded a guarantee that the intelligence relay mission still had priority. In March 1970, the NRO accepted the management changes demanded by the Air Force while the Air Force guaranteed the NRO communications mission top priority.

Selecting Satellites and Payloads for SDS

The contract definition phase for SDS began in August 1970, a few months later than planned. Two contractors were involved: Hughes, and one other aerospace firm whose identity was deleted from the official history but was either TRW or Ford Aerospace. Both companies, like Hughes, were involved in developing communications satellites.

One of the secondary missions initially proposed for SDS was relaying data collected by Air Force DSP missile warning satellites then in development. But in summer 1970 members of the DSP program office—then operating under the deliberately obscure designation of Project 647—began to have reservations about using SDS relays for DSP satellites. Later in the year the Project 647 office withdrew from participation in the SDS in favor of relaying DSP data directly to the ground. That decision required DSP to develop its own ground stations, including a politically sensitive ground station in Australia. It also meant that SDS again became a single payload satellite.

This change annoyed Grant Hansen, the Assistant Secretary of the Air Force for Research and Development. Hansen wanted dual or multiple users on SDS. In a January 1971 meeting with several reconnaissance officials he discussed the options. Hansen had justified SDS in front of Congress on the basis of it having more than one payload and did not want to go back to members of Congress and explain why that was no longer the case. In an effort to force both SAMSO and the NRO to develop other payloads for SDS, Hansen suspended funding to SDS and placed the program on temporary hold.

In August 1970 three orbital configurations for SDS were being evaluated. The favorite option for several intelligence officials involved putting the relay satellites in geosynchronous orbit. But this was soon rejected. Although it provided good global coverage, it had a high price tag and an unacceptable level of technical risk. The other two options offered less coverage. One of these involved placing satellites in highly-inclined, highly-elliptical orbits so that they would swing low and fast over the South Pole and then head high up over the northern hemisphere, putting them in line of sight with both a low-orbiting reconnaissance satellite over the Soviet Union and a ground station in the United States.

Hansen’s ploy to force SAMSO and NRO to develop other options for the SDS satellites finally started to bear fruit. By early March 1971 Air Force and intelligence officials had identified at least six possible secondary payloads and two were considered most feasible. One of these was relatively minor: a small S-band transponder on each satellite could relay communications between the headquarters of the Air Force Satellite Control and a remote tracking station at Thule, Greenland, ending reliance upon balky land lines.

Another communications payload would support the Single Integrated Operational Plan, the Air Force’s nuclear war-fighting strategy. SIOP required communications with Strategic Air Command B-52 Stratofortress bombers and KC-135 Stratotankers. The SIOP at the time depended on ground-based high frequency broadcasts, which were vulnerable to jamming and nuclear disruption. An SDS payload in Earth orbit would be less vulnerable and could provide coverage in northern regions that were hard to cover. But according to Mitchell’s SDS history, the SIOP payload was regarded as a “heavy mother” requiring a helix antenna, transmitters, receivers, additional solar cells and cabling and structures weighing over 136 kilograms (300 pounds). In late May 1971, the two contractor teams determined that the SIOP payload was not a good candidate and the Air Force ruled it out for SDS.

Grant Hansen was apparently displeased that once again SDS was being reduced to a satellite system with a very limited mission. A review board including representatives from Hansen’s office slashed SDS funding for Fiscal Year 1972 in an effort to force program managers to go back and find another payload for the satellites.

General Sam Phillips, who was then in charge of SAMSO but had previously played a major role in running NASA’s Apollo program, protested the funding cut. The relay program was reduced to minimum effort until they could reach an acceptable agreement, or the relay program was taken away from SAMSO and transferred back to the NRO.

Although the specific details are deleted from Mitchell’s history, Mitchell indicates that the SIOP communications payload was eventually incorporated into the SDS satellite design despite its substantial mass and power requirements.

Secrecy and its paperwork

According to Mitchell, by spring 1971 there was increasing USAF opposition to the special access requirements (SAR) in place for SDS and the two other space programs because of the difficulties they created for management and operations. Although at least one of the SARs was eliminated around this time, Deputy Director of the NRO Robert Naka wanted to keep the Satellite Data System’s SAR in place. Finally, in January 1972 Director of the NRO John McLucas removed the SAR from the SDS program and withdrew all relevant material into the NRO’s own BYEMAN security compartment.

General Phillips and one other officer did not think that an entirely covert SDS program was necessary, but they believed that SDS security should be tightened. They and NRO officials agreed that the NRO’s BYEMAN security compartment would be used to protect details on the satellite’s bandwidth, near-real-time operations, transmission, specific frequencies, and the NRO relationship. Documents about the program would be classified at the secret level and would only refer to the secondary payloads. They would also state that SDS satellites were deliberately “over-engineered” in case the Air Force wanted to add more payloads, thus explaining why such a large satellite had a relatively limited communications payload. Previously the NRO payload had been referred to as “User A” but documents would now indicate that User A had been deleted.

The birth of KENNEN

In September 1971 President Richard Nixon formally approved development of the ZAMAN electro-optical imaging system. By November its name was changed to KENNEN, although it would become better known to the public by the designation of its camera system, KH-11. With the imaging satellite development now underway, the Satellite Data System finally had a confirmed primary mission and a deadline requiring that it become operational before the first KENNEN satellite was launched. KENNEN was initially scheduled for an early 1976 launch, although this eventually slipped to late in the year.

The communications relay payload that was developed for the KENNEN used a 60 GHz frequency that did not penetrate the Earth’s atmosphere. This meant that if the Soviets listened in on the KENNEN they would detect no emissions coming from it, creating the impression that it was passive even while it was sending signals up to the SDS.

At an April 20, 1972, meeting of the NRO’s Executive Committee (ExCom), NRO Director John McLucas was satisfied with existing management arrangements for SDS. SAMSO would continue management, the NRO’s Program B—led by the CIA—would exercise technical oversight, and the Air Force would fund and publicly defend the program to Congress. The NRO officials also established a more streamlined chain of command from SAMSO to the Secretary of Defense level.

The NRO director also moved SDS’s BYEMAN security responsibilities from the CIA-led Program B to the Air Force-led Program A (SAFSP), which strengthened the appearance of a strictly Air Force project and enhanced Air Force authority over the program. He also ordered that there be no further mention at all of a third payload outside the classified BYEMAN security channel, which meant that only people with BYEMAN clearances could speak or know about SDS’s communications relay payload. Information prohibited from public release included the number of satellites, orbits, technical descriptions, launch dates, finances, and mention of ground facilities.

On June 5, 1972, SAMSO selected Hughes to build the satellites. According to a 2011 interview with former CIA and Hughes official Albert “Bud” Wheelon, the winning Hughes design was based upon the company’s proven Intelsat IV spin-stabilized satellite, which weighed over 700 kilograms. The first Intelsat IV had been successfully launched into geosynchronous orbit in January 1971. Although both Intelsat IV and SDS were spinning drums covered with solar cells, SDS had a different set of antennas mounted to a de-spun platform at its top.

Anthony Tortillo, a Hughes engineer, was assigned to the SDS program. Hughes had a problem getting sufficient numbers of its own personnel security clearances, so a number of Air Force officers at the captain and major level with the required security clearances were detailed to work at Hughes.

Changes in Payloads and Operations

The SDS’s primary payload was always the communications relay for the KENNEN reconnaissance satellites. The two secondary payloads were just that—secondary. In August 1974 the Secretary of the Air Force approved adding a third secondary payload to the satellites, the Atomic Energy Detection System. This was introduced starting with the third satellite. Similar nuclear detection payloads—also known as “bhangmeters”—were already carried on Defense Support Program satellites. They could detect nuclear detonations in the atmosphere and space.

According to declassified Air Force documents, the Air Force started procurement with a structural test model designated X-1, followed by a qualification model designated Y-1 and equipped with most of the electronic systems to demonstrate that the satellite could perform the functions it was designed for. The initial plan was to procure four flight spacecraft (designated F-1 to F-4) and refurbish Y-1 to be a flight spare.

By the first half of 1975, testing of X-1 was completed, assembly of Y-1 was completed and it was undergoing initial testing, and fabrication of F-1 was well underway. By November 1975, the Air Force approved procurement of two additional satellites, F-5 and F-6, which were supposed to be compatible with the space shuttle.

The first two SDS satellites were launched into orbit atop Titan III-34B rockets in June and August 1976. The first KENNEN was launched in December that same year. Although the satellites all worked, according to several sources there were early operational problems with getting them to smoothly work together.

In 1977, a CIA employee sold a copy of the KH-11 user’s manual to the Soviet Union, giving away many of the secrets of the KENNEN satellite. However, Mitchell’s history hints that the Soviet Union did not understand the connection between the KENNEN and SDS satellites until the summer of 1978, confirming a claim that program planners had made about SDS early on, that it would be difficult for the Soviets to figure out that the satellites in highly different orbits were part of the same mission, especially since the KENNEN did not appear to be transmitting while over Soviet territory.

The fourth and fifth SDS satellites were delivered in May and October 1980, and Y-1 was refurbished, redesignated F-5A, and delivered in May 1980. In 1981 the Air Force proposed purchasing satellite F-7. It is unclear how many of these satellites were eventually launched, and one or more may have been retired to a classified storage facility at the end of the program.

Eventually, the first series of satellites were replaced by an updated version designed to be compatible with the shuttle from the start and apparently based upon the large Hughes Intelsat VI communications satellite. The National Reconnaissance Office surprisingly released photos and video of these later block 2 satellites in the late 1990s. Equally surprisingly, in early 2017, NASA revealed that it had been offered a spare satellite from an unnamed government agency. That satellite was clearly one of these block 2 vehicles. (See “Spinning out of the shadows,” The Space Review, March 13, 2017.) At some point, possibly even early during the 1970s, the SDS program received the classified code name QUASAR. That name was reportedly still being used into the twenty-first century.

The More Things Change…

In October 1976, the Air Force announced long-range plans that did not include SIOP payloads on future SDS satellites. Instead, the SIOP payloads would be mounted on the planned Air Force Milstar communications satellites. Milstar was a highly ambitious and complex communications satellite system that would support multiple Air Force requirements. When first conceived, the Air Force planned to have Milstar satellites in geosynchronous orbit as well as a constellation of satellites in medium-altitude polar orbits. The satellites in their different orbits would be able to communicate with each other, creating a complex interlocking communications network around the Earth. They were also supposed to be protected against enemy jamming and hardened to survive the effects of nuclear weapons. If it worked as planned, Milstar would provide a tremendous leap in communications capability for multiple Air Force and other users.

The CIA’s Leslie Dirks asked members of his staff to evaluate including the SDS relay capability on the Air Force’s Milstar. The initial concept was for three Milstar satellites in polar orbits to perform the relay capability for future KENNEN satellites. But CIA officials quickly grew skeptical about this proposal. Milstar was going to be very complex and face technical risks and problems in development resulting in delays which could affect the KENNEN relay mission. In addition, the NRO’s communications relay payloads would then become secondary payloads for satellites that had many other Air Force missions. CIA officials questioned what would happen if one of the NRO’s payloads failed on a Milstar satellite—would the Air Force launch an expensive replacement satellite simply to fulfill the NRO’s requirement? Two of Dirks’ aides recommended against putting the KENNEN communications relay payload on Milstar and Dirks agreed.

Dirks’ decision proved to be a good one. The early Air Force plan was for Milstar to begin operations in 1982, but Milstar soon ran into major development problems. Ultimately, the first Milstar did not launch into space until 1994. The Air Force had to postpone plans to transfer the SIOP communications payload from SDS to Milstar, and SDS continued carrying SIOP payloads into the 1990s.

Shuffling Responsibilities

Dirks’ decision to not transfer the KENNEN communications relay payload to Milstar meant that the SDS program would have to continue, and since the Air Force no longer had a requirement for SDS, the program would have to be transferred to the National Reconnaissance Office, with NRO funding and BYEMAN security measures. In November 1981, NRO Director Pete Aldridge approved the transfer of responsibility for SDS.

Aldridge’s decision created controversy. Brigadier General Jack Kulpa, who headed SAFSP and was therefore the NRO’s Program A director, lobbied to transfer the SDS from SAMSO into Program A, arguing that this would provide continuity and Program A had sufficient experience to run the program, although KENNEN was run by the CIA’s Program B and there was still an ongoing rivalry between personnel in Programs A and B. Yet another suggestion was to create an NRO Program D office solely to manage the relay satellite program.

SDS Director Colonel Clyde McGill and his supervisor, SAMSO commander Lieutenant General Richard Henry, lobbied to leave SAMSO responsible for SDS. They argued that withdrawing SDS into the National Reconnaissance Program benefitted nobody. Both the NRO and the Air Force needed SDS to serve as a “bridge organization” that could work in both the white and black worlds and provide access to evolving technologies for both sides. Although Mitchell’s history of SDS is unclear on this point, apparently Henry and McGill were successful at convincing Aldridge to maintain SDS as a SAMSO-led program, at least for a few more years.

The NRO will apparently declassify information about the early years of the KENNEN program sometime in 2018. If it does, we may learn more about SDS and its mysterious dance between the black and the white space communities.

Dwayne Day is interested in hearing from anybody with stories about the SDS. He can be reached at

HSGEM – The Hughes GeoMobile Satellite System Story—Andy Ott

In the early 1990’s, Hughes Space and Communications Group (HSCG) teamed with Hughes Network Systems (HNS) to develop a satellite based cellular communications system.  This was to be a total end-to-end system. HSCG was responsible for the Space Segment (spacecraft, spacecraft on-orbit as well as launch operations, including the facilities, software for both spacecraft bus and payload, and launch vehicle procurement). HNS was responsible for the user and ground segments (ground hardware infrastructure, network management, gateway stations, as well as cell phones and the billing system). Project management, including overall “Big-S” Systems Engineering, was the responsibility of HSCG as the prime, requiring formation of a GeoMobile Business Unit within HSCG.

The spacecraft did not fit into either the existing HS601 product line nor the under development at the time HS701 product line, necessitating a unique spacecraft, labeled HSGEM. There were many new, unique requirements for HSGEM space segment, the following is a list of a few of the major challenges:

  1. 13 KW Spacecraft Bus with dry weight 5,500 – 7,000 lbs. A modular Xenon Ion Propulsion System (XIPS) addition, if required due to launch vehicle selection. Payload weight 3500 – 4000 lbs.
  2. A single L-Band 12.25-meter aperture antenna to provide both transmit and receive communications. The Astromesh reflector is 18 ft in length by 44 inches in diameter stowed for launch and when fully deployed is a 52.5 ft by 40 ft ellipse with a 12 ft depth. A 128-element feed array provides in excess of 200 individually controllable spot beams.
  3. Elimination of potential Passive Intermodulation Products (PIM) sources for the spacecraft bus and payload. The diplexer was a special challenge due to the single antenna and the significant difference between receive and transmit power at L-band.
  4. Digital Signal Processor (DSP) to provide channelization, routing and beamforming; all functions previously performed by analog and passive hardware. The DSP included a mobile-to-mobile switch to allow for direct routing of mobile terminal to mobile terminal calls, thereby reducing round trip delay to a single hop. The DSP utilized state of the art at the time ASICs jointly designed and qualified by Hughes and IBM and manufactured by IBM. Flexible digital beamforming was a special challenge.
  5. Common software for payload, spacecraft system test and launch plus on-orbit operations integrated from Commercial, off the shelf (COTS) products and HSCG developed DSP command and control.
  6. Unique approach to North-South station keeping using the power of the payload to perform electronic beam steering vs chemical station keeping while operating in inclined orbit.

A development vehicle and the first two spacecraft were manufactured by HSCG, the Satellite Control Center by Raytheon and the Network Control Center and ground infrastructure by HNS.  The first launch of a HSGEM spacecraft, however, occurred in the year 2000 after HSCG was bought by Boeing. Although Boeing activities are not discussed on this website, it is public information that the first HSGEM was successfully launched by Sea Launch and met or exceeded all requirements (space and ground), resulting in a very successful and happy customer. The satellite and ground systems are still operational today (2018) and revenue creating, exceeding the 12-year life requirement of the contract.

Fig I: HSGEM spacecraft in launch configuration at HSCG High BayFig 2: HSGEM On-orbit

Key to the commercial success of this project was its efficient use of very valuable and much in-demand L-Band frequency spectrum. Ability to control more than 200 individual spot beams allowed for reuse of the same frequency spectrum more than 40 times and tailoring the coverage area to meet needs of specific customers. A comprehensive article, “The Hughes Geo-Mobile Satellite System”, was co-authored by HSCG (John Alexovich and Larry Watson) and HNS (Anthony Noerpel and Dave Roos) with major support from the rest of the “Big S” Systems Team and presented at the 1997 International Mobile Satellite Conference held in Pasadena California. The article is an excellent description of the end-to end system. Some of the key points are as follows (full article appears immediately following key points).:

  1. HSGEM is sized to provide 16,000 voice circuits for 2 million subscribers, including presence of up to 10 dB of shadowing.
  2. The maximum coverage area with over 200 beams, each approximately 0.7 degrees in diameter or 450 km across, is 12 degrees as viewed from geosynchronous altitude.
  3. Dual mode terminals provide the ability to communicate with either the HSGEM or with local terrestrial cellular systems (GSM) for voice, data, facsimile, and supplementary services.
  4. The HSGEM accommodates many features that support flexibility and reconfigurability as technology further advances, which has been demonstrated over 17 years (so far).


Early Bird…..Remarkable 5-Year Record in Space Hughes News April 17, 1970

Early Bird, the world’s first commercial communications satellite and the granddaddy of the Intelsat IV now in production, celebrated its fifth birthday April 6 after logging 3 billion miles in space and a faultless performance.

The birthday coincided with the opening of the American Institute of Aeronautics and Astronautics third Communications Satellite Systems conference at the International Hotel, where a giant cake replica of the remarkable bird was cut and served to NASA, Comsat and Hughes people who collaborated to bring into the world the tiny satellite with this record.

The Significance of It All

Dick Bentley, now assistant manager of the Communications Satellite Labs in Space Systems Division who was the Early Bird Program manager, cut the cake and reminisced about the satellite’s significance.

“Early Bird has been a model in every sense of the word,” Mr. Bentlley said.  “Essentially, there have been no failures, even in the control system.”  This is testimony to the ability of the people at Hughes to build highly reliable systems.  Early Bird proved what can be done!

“Several years ago when we were forecasting this kind of reliability the promise sounded incredible.  Not today.  Most people in industry now speak of satellite lifetimes of 5 years.  Some even go as high as 7 or 10 years. Early Bird is the basis for this confidence,” he added.

Early Bird’s success as the first commercial communications satellite has led to subsequent planning and implementation of commercial satellite programs.

Things Would Be Different

 If Hughes had not won out and proved the feasibility of the synchronous altitude concept and station keeping techniques, and if Early Bird did not have the reliability exceeding that of the trans-Atlantic cables, the whole approach to communications satellites would well be drastically different today.

Probably the greatest spinoff of the Early Bird experiment, and it was just that, will be its great impact on and benefit to people everywhere.  Every place on earth can be linked to every other place by a worldwide communications network featuring satellites and low-cost ground stations.

When historians record the genesis of this network, valued at billions of dollars, Early Bird must certainly will be listed as the father of it all.


This, again, is a tribute to the contributions of the people at Hughes who had the vision, the courage of their convictions, and technical ingenuity to design and build a spacecraft that not only has met all objectives but has exceeded the contractual requirements in every way.

Operational for nearly four years, Early Bird was retired from active service by Comsat a year ago but was called into service for the Apollo 11 mission.  Two months later it again was placed on reserve status.  But it still can chirp, anytime its needed.


See “World’s First Commercial Communications Satellite at

$66 Million Contract For Satellites Placed by Comsat General– Hughes News October 12, 1972


Comsat General Corporation has awarded Hughes a $65.9 million contract for four advanced high-capacity satellites which will be operated by Comsat under a lease arrangement for the American Telephone and Telegraph Company.

Comsat General’s contract followed the Federal Communications Commission’s Sept. 12 approval of five U. S. domestic satellite systems, four of which will use satellites built by HAC’s Space and Communications Group

Immediately after the FCC action Comsat President Joseph V. Charyk executed the agreements calling for the first delivery in late 1975.  Vice President Albert D. Wheelon, S&CG executive on behalf of Allen E. Puckett, executive vice president and assistant general manager.

Anik-Type Family

A whole family of Anik-I type satellites is being built in S&CG with Western Union’s Westar for telecommunications and TV slated for service by next summer.  (Hughesnews Aug. 18, 1972).  The WU system was approved earlier by the FCC.

The General Telephone and Electronics Corporation and the American Satellite Corporation also had systems approved by the FCC in the Sept. 12 action.

ASC has ordered three Anik-type satellites (Hughesnews March 30), and expects them to be operational by the third quarter of 1974.

GTE has contracted with the Hughes subsidiary National Satellite Services for 10 leased channels on a 12-transponder satellite.  GTE plans a September operational dated on its domestic system to provide either 12,000 one-way voice-grade circuits, 10 TV channels or various combinations.

Comsat’s order for four spacecraft, each having twice the capacity of the Intelsat IVs, will result in these Hughes-built satellites covering the U. S. territorial limits for the decade following launch in 1976.

Although design life is seven years, S&CG engineers are eyeing the possibility of 10 years service for these advanced spacecraft.  With 24 channels compared to the Intelsat IV’s 12 and Intelsat IVA’s 20, the Comsat domestic birds will be bigger, standing about 18 feet high and weighing about 3200 pounds in orbit.

Three Antennas

To provide coverage over a third of the earth’s circumference the spacecraft will have three antennas.  Each satellite will be placed in geostationary orbit at 22,300 miles altitude and have a capacity for approximately 14,000 two-way high quality voice circuits.

Frequencies will be used in the presently allocated 4 and 6 Gigahertz bands.  Horizontally and vertically polarized transmit and receive antennas will be mounted atop the spin-stabilized body of each spacecraft.

Through the first-time application of the cross-polarization technique on a commercial satellite, the entire frequency band will be utilized twice by each satellite, thus doubling capacity and conserving limited spectrum space.

In addition, each satellite will carry amillimeter wave experimental package permitting tests and development of higher frequencies near 19 and 28 Gigahertz for possible future commercial satellite applications.

The contact signing was preceded by final negotiations between Comsat officers and S&CG’s Contracts Director Chuck LeFever, Program Manager Al Owens, Assistant Program Manager Dick Hemmerling, and Steve Parker senior contract negotiator.

Clell McKinney of HAC’s Corporate Marketing office in Washington DC provided assistance.

Further Notes—Jack Fisher

Comstar, with the Hughes designation HS-351, was based upon the Hughes Intelsat IV and IVA designs with a number of improvements.  Four satellites were built and launched by the Atlas Centaur—the first two in 1976 and the other two in 1978 and 1981—providing telephone service for ATT and GTE.  The Comstar program and spacecraft design are described in the Spring 1977 issue of the COMSAT Technical Review—see

The fourth Comstar launched in 1981 has a very interesting history having been sold to the island nation of Tonga, a Pacific archipelago.  For an account of that history see Dwayne Day’s article in the Space Review.

Hughes donated a model of the Comstar satellite to the Smithsonian National Air and Space Museum.  Photographs of the model can be seen at


HGS-1 Mission – Setting the Facts Straight Chris Cutroneo

For years I struggled with talking about this story and what I knew. I was an employee of Boeing (and Dept Manager of the Mission Group) up until 2016 and I didn’t feel it was my place to discuss this on-line. Now that I am 2 years into retirement and have I seen the blog posting from Steve Dorfman regarding HGS-1 mission, I think, finally, it needs some clarification – and the full truth. I was both the lead Astrodynamacist Team leader of the Asiasat-3 mission (on console when the Proton 3rd stage failed to ignite) as well as the function manager of the Mission Analysis and Operations group (30+ engineers). Cesar Ocampo was a direct report to me.

For weeks after the launch, we struggled with Asiasat-3. We knew it did not have enough fuel to get to GEO and at the time we were baby sitting it. Not long after the failure (Dec launch) in January, I got a call from Rex Ridenour. In our discussion he described that there was an idea floating around his company that we could send Asiasat-3 using the “fuzzy boundary theory” from Bel Bruno. I took down some notes after a brief discussion and I approached Cesar Ocampo with the data that Rex had provided. Cesar (he had some “issues” but was undoubtedly super smart) found the paper, read it and did some calculations which I reviewed. He said yes, in theory sending the s/c 1,000,000 miles out (we had fuel to do this) could recover the s/c but we both felt it was highly impractical especially given the impossible comm link for controlling/monitoring the s/c once it was out that far and we needed to maneuver it. I relayed Cesar’s calculations and Rex’s information to Jerry via email, mentioning Rex’s company as well as the fuzzy boundary theory and that it was a novel theory but impractical.

Please note that Cesar was NOT part of the Asiasat-3 mission team. He had no access to what was going on there until I (and the Astro Functional Manager) brought him this info. Cesar was at that time working on the 702 XIPS orbit ascent and the difficulties of constant thrust maneuver planning.

Soon after the idea of going around the moon came up and back to the MAO group. I fully believe this was 100% Jerry Salvatore’s idea. Jerry brought Cesar into the solution process to do a lot of analysis using STK. Jerry fed him the big picture and Cesar did basically all orbital calculations and mission planning using STK and the mission planning was off and running. Please note that we did not use Bel Bruno’s idea – it was impractical but inspirational. We were directed after the Lunar Fly By idea came out to stop talking to Ridenour and Bel Bruno. But I believe we did have their idea in hand that helped us come up with the idea to do a Lunar Fly By and mimic the Apollo missions – I am nearly 100% sure of this since I was the primary relayer between them in the early days before stepping away once the HGS project took off. Ridenour and Bel Bruno claimed, at one point we “stole” their idea but we didn’t. But, I think that all Hughes path we got on would not have happened without Ridenour and Bel Bruno to get us out of or standard orbit planning thinking to come up with a solution that worked.

Final note: HGS-1 achieved only a short period of time in GEO orbit post recovery. There was a more optimum time (better Earth, Moon, Sun geometry) to pull off the recovery plan, 6 months later than when we started it. It would have achieved a much longer life span (years), orbitally, for the satellite. It was unclear to me as to why this option was not selected. There was both amazing technical accomplishments as well as incredible in-fighting going on during the HGS-1 mission – a real dichotomy. Nothing in my career (36 years at Hughes/Boeing with 34 years in mission operations) even came close. Cesar felt slighted (and in a few ways he was but not in others), Jerry felt under siege (by the Bel Bruno comments and I think lawsuit) and Bel Bruno and Ridenour felt slighted in terms of even the most limited recognition in the end. It worked but it could have been so – so much – better.



In early 1963 as a young 31-year-old engineer I was assigned the task of developing a method for mobile users to communicate through a synchronous satellite.  A brief study of the problem indicated that for truly mobile communications the user should be able to use a simple dipole antenna. This led to a company funded effort to demonstrate the reception of the one-half watt Syncom 2 VHF telemetry signal on a simple dipole antenna. On 21 February, the one-half watt Syncom2 VHF telemetry signal was successfully received on a dipole antenna. Three months later, on 8 May 1964, a teletype message was repeated through Syncom 2 telemetry and command system to a ground transmitter with a power of 19 watts using 12 and 14 db. gain Yagi antennas.

When news of these tests reached Frank White of the Air Transport Association he set in motion a series of events that led NASA to fund the ATS VHF Experiment.  His plan was to demonstrate two-way communication between a Pan-Am jet leaving Hong Kong with the NASA ground station at Camp Roberts California via the Syncom telemetry and command system.  On Jan 27 1964, these tests were successful and within weeks NASA funded the ATS VHF experiment.

The ATS-1 is the first of a series of five spacecraft built for NASA Goddard Space Flight Center by the Hughes Aircraft Company. The objectives of the VHF repeater are as follows:

• Demonstrate feasibility of providing continuous voice communications link between a ground control station and aircraft anywhere within the area covered by the satellite

• Demonstrate feasibility of providing a network in which data from small- unmanned stations or buoys are collected via satellite and disseminated

• Evaluate feasibility of VHF navigational systems

• Evaluate airborne and ground stations required in the above ­ mentioned networks

A fifth objective area was later added to demonstrate two-way voice and teletype communications from ships at sea anywhere in the satellite coverage area.

The VHF communications experiment is a frequency ­translation limiting (Class C) repeater receiving at a frequency of 149 Mhz and transmitting at 135 Mhz. The repeater both receives and transmits through an eight-element, phased-array antenna; Table 1 presents the repeater characteristics.

Operation of the repeater is as follows: incoming-signals at 149 mHz arereceived on each dipole element, routed through diplexers, amplified by a low-noise receiver, and shifted in phase to compensate for the relative position of each dipole antenna. The electronically controlled phase shifter in the receiver unit, driven by the waveform generators, causes the output s of each receiver to be in phase only for those signals originating from the earth. Reference sinusoids used to drive the waveform generator s are obtained from the same phased-array control electronics used to position the microwave beam toward the earth. The eight receiver outputs are summed together, filtered, down­ converted to an intermediate frequency (IF) of 29 megacycles, amplified, and passed through a crystal filter to limit the receiver bandwidth.

The IF is then amplified, up converted to 135 mHz, further amplified, and divided into eight equal parts. Each of the eight signals is routed to a transmitter where it is amplified, phase-shifted, and further amplified to a power level of 5 watts. Each transmitter output is routed through its respective diplexer to one of the antenna elements.

The transmitter phase shift is controlled by the waveform generator, which causes the signals from each antenna to reinforce in the direction of the earth. Provision is made to operate only odd or even sets of four transmitters, if desired, to reduce the DC power required.

It is also possible to drive the waveform generator from either the redundant Phased Array Control Electronics or to shut down this unit entirely creating a pancake antenna pattern, approximately 60 x 360 degrees that will encompass the earth during most parts of the launch trajectory and at all times after satellite reorientation.

The ATS spacecraft power supply and thermal design allow for continuous operation of the VHF experiment except during periods of eclipse. The repeater elements are supplied with -24volt and 23.4-volt regulated power. Switches are provided that allow operation of the equipment according to commands from the ground stations. Telemetered outputs are also provided which can be transmitted to earth either by the VHF or microwave telemetry systems.

The repeater is made up of nine subassemblies: eight units containing one transmitter, receiver, and diplexer; and one unit containing an up converter, down converter, waveform generator, and two voltage regulators. These units are shown in Figures 3 and 4.


1) The first VHF phased array in orbit

2) The first phased array to operate on both transmit and receive frequencies

3) The first deployable antenna on a spinning spacecraft

4) The first spacecraft repeater to use separate receivers and transmitters for each antenna element

The VHF antenna consists of eight full-wave dipoles arranged in a circle of one wavelength diameter (86 inches). Volume limitations in the Atlas-Agene shroud dictated the use of a deployable antenna. The eight-dipole elements were mounted on a radial arm attached to the forward solar panel and pivoted to place the antennas in a three-foot circle directly over the apogee motor nozzle during launch.

At separation from the Agena, the spacecraft is spun up; centrifugal force causes the antennas to deploy to the 86-inch diameter at 50 rpm. Deployment takes place during the normal spin up of the spacecraft without the use of ground commands.  When the spacecraft apogee motor is fired, the antennas are subjected to high Mach numbers and high heat fluxes. The rocket motor in the center of the array contains 750 pounds of propellant and burns for 40 seconds increasing the spacecraft’s apogee velocity by 6000 fps.

To withstand the severe thermal environment, the antenna elements were constructed of beryllium, flame-sprayed with aluminum oxide, and further covered with a Teflon ablative material. The high heat capacity of the ablative material and of the beryllium itself maintains the antenna temperatures below the unprotected equilibrium temperature of 3000° F.


The following report is taken from a presentation given in May 1967 at a meeting of the RTCM in Las Vegas Nevada by Roland Boucher.

ATS-1 was launched into orbit on 6 December 1966.  The VHF repeater was first operated 3 days later. Since then, it has been used to successfully communicate voice and data between NASA ground stations at Rosman, North Carolina; Mojave, California; and Kooby Creek Australia. It has sent weather facsimile pictures and has been used to determine propagation properties of the ionosphere.

Simplex air to ground communication tests have been conducted with aircraft operated by Pan American, Eastern, TWA, United, American, and Qantas airlines as well as those operated by the FAA and the U.S. Air Force. Both simplex and duplex communications were successful with a shipboard terminal   constructed by Hughes. This terminal was leased to the U. S. Coast Guard and has operated successfully on the Coast Guard Cutter, Klamath at Ocean Station November in the Pacific Ocean which was described by a member of the U.S. Coast Guard.  In May 1967, the VHF repeater experiment had operated successfully for over 5 months with no signs of degradation.

Prior to the launch of ATS-1, there was considerable skepticism as to the feasibility of VHF satellite communications in mobile service despite the fact that nearly every satellite to date had used the VHF band for its primary mode of telemetry and weather photo video transmission.


The uneven diffractive properties of a disturbed ionosphere can cause deep fades at VHF frequencies. These fades are normally of a very brief nature lasting typically from 8 to 30 seconds. Examination of this phenomenon by Hughes Aircraft Company under NASA contract NAS-510 174 indicated that fades of greater than 6 db. depth could be expected 0.002 percent of the time in the mid-Pacific area, Tests with ATS – 1 during the first 5 months in orbit have failed to yield any statistically significant data on scintillation fades. The rarity of their occurrence makes it almost impossible to detect them in a normal push-to-talk circuit. They do not present a serious problem to this type of communications.


Mobile terminal noise was also cited by some as a nearly insurmountable problem as late as a few months before the ATS-1 launch. Tests on aircraft and on the cutter Klamath have shown this problem can be cleared up by normal RFI practices.


Multi-path fades were held up as an obstacle to VHF mobile communications with fades up to 30 db predicted. Tests with the ATS-1 to date have shown multi-path propagation not to be a serious threat. In examining the records of many hours of shipboard and aircraft communication, no clear evidence of multi-path propagation fades could be found. This despite the fact that Hughes intended to use the evidence of such fades as a requirement for the development of a new type antenna for the NASA/Hughes ATS C. The fades were not found. The antenna was not funded.


Earth-noise temperature was cited as a possible deterrent to VHF satellite communications. The proponents of this concept reasoned that many spurious emissions from the large number of earth transmitters would form a noise blanket which would jam the satellites receivers.

Measurements taken in late 1966 by Boeing Aircraft to determine receiver noise temperatures in flight from a commercial aircraft indicated that cities could be found quite easily by the noise they created. This noise was seldom evident more than 10 or 20 miles from the city centers. Noise temperatures even at relatively low altitudes seldom were in excess of 20 db. with a 10-db-background level being more nearly an average figure.

A simple calculation involving the area of the world covered by cities indicated that this noise would not be a serious problem at synchronous altitude. Corroborating evidence was the fact that most satellite command systems operate in the VHF band. Any serious problems in the uplink would certainly have been discovered before 1966.

The launch of ATS-1 proved this point. Up-link receiver sensitivity of the ATS-1 spacecraft is essentially that measured in the laboratories.


The ATS uplink is in the land mobile band. In the early phases of the in-orbit test program, strong signals were heard in the satellite s passband. Many of these were conversations in English from what appeared to be military personnel. The conversations contained description of maintenance operations on jet aircraft indicating that a ground terminal used to communicate with mobile airport vehicles was transmitting to the spacecraft. Other signals in the spacecraft ‘s pass band that have been annoying at times have contained considerable 60 cycle modulation, indicating they originate from an earth borne transmitter.

None of these emissions proved detrimental to the test program after December 12. On that day, the severity of the jamming indicated that up link ERPs in excess of 2 kilowatts were present

A number of interested parties, through the cooperation of NASA and Aeronautical Radio listened for a one-week period in an effort to determine the origin of these strong signals. They were not present during this one-week period and have not returned. In the first 5 months as equipment and operating procedures have improved both in the aircraft and shipborne tests, this problem, which seemed so serious on 12 December, has been nearly forgotten.  Today VHF communications via satellite have been shown to be feasible for aircraft and maritime mobile application.


Spacecraft operating at microwave frequencies operate their transmitters well below peak power (transmitter Back-Off).  The VHF Experiment on ATS-3 Replaced the Class C RF amplifiers used on ATS-1 with linear RF amplifiers. This was important because it greatly reduced the inter-modulation distortion inherent in multi-channel transmitters. These transmitters were solid state and used a class A/B final stage; The DC power required was reduced 1/2 db. for every 1 db. of back off. This was a very important discovery since power is a very expensive commodity on any Spacecraft.

At low elevation angles multipath can cause a significant loss in signal for short periods of time as the reflected signal alternately cancels and adds to the direct signal. Circular polarization can eliminate this problem when used by receiver and transmitter that was later verified in field tests with TACSAT in 1969.

Hughes designed and tested circular polarized replacements for the dipole antenna elements on ATS-3.  Unfortunately, NASA did not approve their use.  Meanwhile Boeing designed a circular polarized flush mounted VHF antenna for the 747 aircraft.  C.A. Petry at ARINC worked with the airlines and FAA to produce a spacecraft compatible aircraft radio set in ARINC Specification 546.

When the first Boeing 747 was delivered to Pan Am, it was equipped with and ARINC 546 communication transceiver and a circular polarized antenna. This aircraft was equipped for satellite to aircraft communications.

ATS-3 was launched successfully on November 5, 1967, and positioned over the Pacific Ocean. Together with ATS-1 nearly global communications were possible at VHF frequencies.

Hughes designed a small inexpensive VHF terminal for the US Coast Guard that was installed on the USS Glacier, the ship used to resupply the Antarctic Base.  Sun spot activity was heavy during the 1967-68 winter, and HF radio was unusable for long periods of time.  The $4000 Hughes satellite terminal got through every time.

In the fall of 1969 I was selected as a representative of the State Department to the CCIR Conference on satellite communications.  Captain Charles Dorian and I were able to persuade the Russian delegate to support the US position to authorize VHF aircraft communications by satellite.  France led the opposition. The Russians brought along the eastern bloc, even Havana supported us. The French opposition was defeated – WE WON

Unfortunately, France played politics better than we did. As I understand it, they got NASA to oppose Aerosat in exchange for France support of the Space Shuttle. In any case, I received a phone call in Geneva from Hughes saying NASA pulled the plug – ITS ALL OVER.  I had spent nearly almost 10 years in the pursuit of a VHF Aeronautical Satellite to no avail.

At least the military did not have to play these politics.  Both Russia and the US adopted VHF communications (TACSAT).  The Syncom and ATS experiments produced at least two winners.

Completely independent of my employment with Hughes, I had developed the concept of an electrical powered battlefield surveillance drone and a Solar Powered high altitude spy plane. Dr. Bob Roney told me Hughes was not interested.

I left Hughes Aircraft in January 1973 and successfully proposed both aircraft to DARPA. The prototype electric powered battlefield drone flew that year and was shown on Los Angeles television. The 32-foot span proof of concept model of the spy plane flew on solar power alone in 1974.  A patent for the electric powered aircraft was granted on May 18, 1976.


On September 29, 1995, Ben McLeod and Bob Bohanon (Both from Pan American) organized a 30th anniversary celebration in Washington DC. Personnel from ATA, ARINC, Bendix, Comsat, FAA, FCC, Hughes, NASA and or course Pan-AM were in attendance. We all were all thrilled that the aging Frank White was able to attend and were sad that other important contributors from Comsat, Collins Radio, and the US Coast Guard were unavailable or deceased.

INTELSAT VI and the COMSAT Technical Review—Jack Fisher

Comsat was created by the Communications Satellite Act of 1962 and led an interesting and tortuous life until 2000 when it merged with Lockheed Martin Global Telecommunications (LMGT).  LMGT shut down operations in December 2001. COMSAT’s story is well told in David J. Whalen’s book “The Rise and Fall of COMSAT” published in 2014.

From 1971 through 1992 COMSAT published semiannually a technical journal that contains a number of articles concerning various Hughes satellites.  These journals are available online and can be accessed at  From 1990 to 1992 COMSAT devoted five journals to a description of the Hughes INTELSAT VI satellite and it operations.  These are summarized below and can be found at the link indicated above.

COMSAT TECHNICAL REVIEW Volume 20 Number 2 Fall 1990

INTELSAT VI:  The Communications System (This issue is particularly interesting as it describes the INTELSAT procurement process and the evaluation of the Hughes and Lockheed INTELSAT VI proposals.


INTELSAT VI Spacecraft Bus Design

COMSAT TECHNICAL REVIEW Volume 21 Number 2, Fall 1991

INTELSAT VI: From Spacecraft to Satellite Operation

COMSAT TECHNICAL REVIEW Volume 22 Number 1, Spring 1992

INTELSAT VI: System and Applications

INTELSAT 603 Reboost

COMSAT TECHNICAL REVIEW Volume 22 Number 2, Fall 1992



Improved Syncom C Set for May Launch—Hughes News April 10, 1964

Syncom C, an improved version of Syncom 2 that has performed so spectactularly since last July 26, will be shipped from the El Segudno plant next week to the John F. Kennedy Space Center in preparation for launching into a synchronous orbit early in May.

Syncom C has been undergoing extensive tests for several weeks and at presstime all systems aboard the tine spacecraft were “go.”

Leaning heavily on experience gained from the success of the Syncom 2 spacecraft, personnel in Space Systems Division have incorporated several improvements into Syncom C, which will become Syncom 3 the moment it lifts off the pad at Cape Kennedy in May.

Probably the most significant improvement will be in the solar cells which help provide power for the spacecraft’s systems. On Syncom 2 the soar cells were the P on N type with a 6 mill glass cover, providing minimal protection against radiation.

In Syncom C, N on P type solar cells with a 12-mil fused silica quartz cover will be used, providing 10 times the resistance to radiation.

“This will assure in excess of three years of oribital operation before any restriction will be placed on full 24-hour day use of the satellite’s communication systems,” said R. M. “Dick Bentley, Syncom manager, Communications Satellite Laboratory.

The major threat to the solar cells , Mr. Bentley said is the Van Allen radiation belt, which extends on past the 22,300 mile orbit on the synchronous Syncoms. Solar cells on Syncom 2, for example have shown 24 per cent degradation from radiation. It now appears that it will continue to operate effectively until March 1965, though becoming somewhat marginal after September 1964.

A second major improvement involving solar cells in the new fabrication technique which provides a better solar panel structurally from the adhesive standpoint. Preston DuPont of Space Systems developed the technique, which with the support of Components and Materials Lab, which saved 1 pound of weight on the spacecraft, a significant reduction.

With Mr. DuPont’s technique all solar cells are applied to the panel simultaneously through a vacuum differential method, with only a thin layer of epoxy provided the adhesive. The technique has proved extremely successful in ground tests in the Space Environmental Laboratory, with no structural defects or loss of cells due to failure in the bonding.

Syncom is the first spacecraft in history to make use of a hydrogen peroxide control system for a period longer than two weeks.  Syncom 2 uses a combination of hydrogen and nitrogen systems and both have operated effectively, but the dual hydrogen peroxide in the Syncom C system will give increased satellite control capability.

Hydrogen peroxide, with a higher specific impulse, gives more energy per pound of fuel, resulting in 600 feet per second of control capability in the continual pulse mode of Syncom C. The nitrogen-hydrogen combination systems on Syncom 2 gave 350 feet per second capability.

“We’re completely confident, from our experience with the hydrogen peroxide system on Syncom 2, which has performed all types of space maneuvering, that we have a perfectly clean system not subject to corrosion associated with hydrogen peroxide and its containers,” Mr. Bentley said. “Though even a speck of contamination can adversely effect a hydrogen peroxide system, we feel that our procedures are adequate so that no corrosion will exist.”

The other major improvement to Syncom C involves changing one of the transponders from two 500 kc channels for two-way voice communication to dual mode capability.  By command from the ground, the transponder bandwidth can be switched from 10 megacycles for transmitting television to 50 kc for optimum relaying of messages from small terminals.

Syncom C, built in 1962, served as the backup spacecraft for the earlier Syncom launches and has been under the direction of Spacecraft Engineer Bill Penprase from the start of assembly.

“Bill has virtually lived with this spacecraft for two years being totally in charge,” Mr. Bentley said. “He deserves a great deal of credit for getting Syncom C rebuilt, including a new wiring harness, and supervising all the subsequent tests to keep us right on the launch schedule established by NASA.”

Mr. Penprase will continue his vigil over Syncom C right up until it is launched, being one of the last men on the pad before it is boosted into its orbit.

HAC Gets $31 Million Canada Satellite Pact—Hughes News October 2, 1970

For Domestic System

A $31 million contract between TELESAT, Canada and Hughes Aircraft Company was signed Wednesday morning in Ottawa. The System will be one of the first if not the world’s first domestic satellite communications system using satellites in synchronous orbit.

Under the terms of the contract, HAC will supply three spacecraft to implement the space component of TELESAT’s domestic satellite communications system.

First delivery is scheduled for October 1972, with the second and third to be delivered at four-month intervals. Present plans call for launching the first in late 1972 from Cape Kennedy, using a thrust-augmented Thor Delta as the launch vehicle. The start of the commercial operations is planned for early 1973.

Included in the agreement are provisions for performance incentive payments over the full life expectancy of the spacecraft and penalty clauses for late delivery.

Full scale commercial operations are slated to begin with the orbiting of the second satellite by mid-1973. An earth station network, initially of 30 to 40 stations, will range from the main heavy route stations near Victoria, B.C., and Toronto, Ont., to the much smaller stations for communities in Canada’s far north.

Allen Puckett, executive vice president and assistant general manager, signed the contract for Hughes Aircraft, while TELESAT’s President D. A. Golden and Jean Claude Delorme, vice president fo Administration and general counsel, signed for TELESAT.

With Dr. Puckett were HAC’s Albert D. Wheelon, vice president and Group executive of Space and Communications Group; Paul Visher, assistant Group executive; Harold A. Rosen, Satellite Systems Laboratory manager; and Lloyd Harrison, program manager for the Canadian satellites.

With TELESAT officials were representatives of the Northern Electric Company, Ltd., of Montreal, Quebec, and SPAR Aerospace Products, Ltd., of Malton, Ont. Agreements with these two major subcontractors were executed prior to the contract signing between TELESAT and Hughes.

Northern Electric will provide the complete electronics system and SPAR will provide the spacecraft structures and engineering support services.