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.

Vision…Courage…Ingenuity

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

http://web.archive.org/web/20100118182008/http://www.boeing.com:80/defense-space/space/bss/factsheets/376/earlybird/ebird.html

$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 http://www.comara.org/legacy/ctr/CTR_V07-1_Spring_1977-Comstar.pdf

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.

http://www.thespacereview.com/article/1787/1

Hughes donated a model of the Comstar satellite to the Smithsonian National Air and Space Museum.  Photographs of the model can be seen at https://airandspace.si.edu/collection-objects/model-communications-satellite-comstar

 

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.

ATS Mobile Terminals—the Pope Paul VI’s Visit to Columbia, the 2500th Anniversary of the Persian Empire and President Nixon’s Visit to China—Roland Boucher

This Hughes mobile satellite ground station was designed and built in 30 days to transmit live color television coverage of Pope Paul VI’s visit to the Eucharistic Congress in Bogota, Columbia in 1968.

The Go-Ahead

In the spring of 1968 Hughes was asked if it were possible to broadcast, through a satellite, the upcoming visit of Pope Paul VI to Bogota, Columbia. The Early Bird satellites operated by Comsat were considered but they required an 85-foot ground antenna.  Time and cost precluded this approach.  We were about to say NO then I suggested to the group that ATS-3 with is high gain receiving antenna could be used allowing a much smaller 15-foot diameter antenna.  The Hughes Ground Systems Group had just completed a prototype 10,000-watt transmitter.  If it could be made available we had a chance.  I also suggested that the terminal contain a VHF communication set in case the telephone service from Bogota to Hughes California prove unsuitable.  NASA agreed to make ATS-3 available, and one month before the expected arrival of the Pope in Columbia we were given the go-ahead.

Time was short; I moved my office into Lou Greenbaum’s shop and began work.  We needed almost immediate shipment of all components needed to build the terminal.  Lou and I drove to Fullerton to inspect the transmitter; it was OK so I asked that it be shipped to Lou’s shop that week.  The first problem came up the next day when the Purchasing department announced that no military terminal structure was available in less than six weeks.  They said a garbage truck tilt up box could be made available in one week. I said buy it, and tell them to put the ribs on the inside, panel it with mahogany plywood, and provide a strong roof and a door on one end. Next, I was told that the only 15-foot antenna available for immediate delivery was from Gabriel’s Horns in New Hampshire. I remember saying, “BUY IT!  God must be on our side”.

Testing Everything

Tom Hudspeth loaned us a prototype ATS spacecraft up and down frequency converter and the FM video modulator used to transmit Spin Scan Camera video. I borrowed a Boonton signal generator from the equipment pool to provide the FM voice subcarrier.  We borrowed the prototype of the VHF terminal installed on the Coast Guard Ice Breaker Glacier and built a 3-element Yaggi antenna to talk to Hughes from Bogota in case the phone lines were not reliable.  When the Fullerton transmitter was installed it would trip off in seconds after turning on.  This went on for about a week then I asked the technician Fullerton sent to install the transmitter, “What did you do different — it was working in Fullerton”.  He told me that nothing was changed except the directional couplers use in Fullerton had been borrowed so he installed new ones. I asked if he was careful to get the directional arrows on the directional couplers pointing in the right direction and he replied “what arrows?”  In ten minutes the transmitter was working again.  We tested the station, tracking the satellite, which was not perfectly stationary.

At first glance, one might think that we were forced to transmit blind since we could not possibly receive video on a 15-foot antenna.  Fortunately, the video signal has a very large amount of energy in the blanking pulse and this is transmitted at the 30-hertz frame rate.  We tracked the ATS-3 using this narrow band signal and plotted optimum antenna pointing angles with two carpenters tape measures mounted to the antenna gimbals.  Later in Bogota we used the VHF link to talk directly with the NASA ground stations to verify signal saturation levels in the spacecraft.  The station was flown to Bogota in a USAF C-130 and set up in less than one week.  Figures 3 and 4 show the terminal in operation in Bogota, Columbia.

The 15-foot antenna was dropped and dented during assembly in Bogota. We found a great body man who “made it all smooth again”.  He was right and it worked.

Operations in Columbia

Comsat insisted that Hughes had no license to transmit television signals through a satellite and that we should lease the terminal to them for the Pope’s visit.  I had adjusted the Boonton signal generator to provide voice signal levels about 1/10 the normal Comsat levels.  Their man on site in Bogota complained, also he also could not understand how we could possibly know when we were pointing our antenna at the spacecraft.  I knew the Comsat voice levels were unnecessary for acceptable quality and refused saying I wanted to make sure we had excellent quality video of the Pope. As to the antenna pointing, we had tracked the spacecraft for weeks, if the carpenter tape measures read correctly we were pointing at the satellite.  I knew NASA tested the VHF link every day so I could pick up the mike on our VHF terminal and ask for the microwave signal saturation level.  For the next 20 years satellite television quality was compared to BEST or “Bogotá Quality”

The Italian cameramen who accompanied the Pope had set up their control trailer next to our terminal. Early test using their video signal showed a troublesome amount of 60-cycle hum.  When this was pointed out, the Italian technical guy suggested that we tie both trailer and terminal together and drive a stake in the ground between them establishing a common ground. He also suggested that we disconnect the ground at the local power distribution transformer establishing the stake between our stations as the only ground. It worked.

After the successful transmission of the visit of the Pope to Bogota the first mobile satellite transmitting station went to Persia to transmit the 2500th anniversary of the Persian Empire in October 1971 to the world, then on February 5, 1972, a C-130 flew it to China for the historic visit by President Nixon .

I would like to thank The Bogota team which included Al Koury, Jim Burns, Jack Clarkson and Bernie Burns as well as those nameless others in Lou Greenbaum’s Satellite Command and Control Department who were vital in completing the terminal in 30 days.

I would also like to thank Howard Ozaki who provided the tunnel diode low noise receiver amplifier, Clovis Bordeaux Hughes Fullerton who provided the 10-kilowatt Transmitter, and especially Tom Hudspeth for his many valuable suggestions and “Loans”.