Molniya COMSATS Applications 1976-1980
EARLY RECOGNITION OF POTENTIAL USES OF
APPLICATIONS SATELLITES
Although Soviet writers early recognized the potential applications of satellites to a wide variety of practical uses, including communications relay, (1) direct broadcast, weather observation, (2) navigation (3) and traffic control, study of Earth resources, and development of permanent manned stations in orbit which would perform many tasks, (4) the Russians were initially slow to exploit space. Whereas the first civil applications satellites appeared in the U.S. program in 1958, the year of the first successful American flight, equivalent Soviet flights were delayed until 1965. Thus, despite seemingly advanced space exploitation technology, the Russians did not move as rapidly from first flights to operational systems as did the Americans.
COMMUNICATIONS SATELLITES
With its vast underdeveloped areas, the Soviet Union benefits greatly from communications satellites. Regions which are remote and difficult to reach are interconnected by satellite without the expense of laying cable through difficult terrain to operate under harsh weather conditions. Through the use of satellites, reliable telephone and television service can be brought inexpensively to all parts of the Soviet Union. In view of such geographic and economic advantages, it is not surprising that the first satellite domestic distribution system in the world was the Soviet Orbita system.
EARLY EXPERIMENTS
At the International Astronautics Federation annual meeting in Stockholm, in August 1961, Arnold W. Frutkin, Director of NASA's International Programs, suggested to Academician Anatoliy A. Blagonravov, of the Soviet Academy of Sciences, that the two nations communicate with each other by means of the balloon satellite, Echo 1, as a gesture of friendliness and a step toward cooperation.
On discovering that the height of the orbit did not provide the mutual visibility necessary for a direct link, it was agreed that the Nuffield Radio Astronomical Observatory of the University of Manchester at Jodrell Bank, England, would be used as the U.S. terminal through the conventional transatlantic submarine cable.
Although such an aim was never achieved, an agreement reached on June 8, 1962, between Dr. Hugh L. Dryden, Deputy Administrator of NASA, and Academician Blagonravov to conduct experimental passive communications transmissions using Echo 2, was fulfilled in part during February and March 1962. The plan called for unmodulated and modulated carrier, teletype, slowed speech, facsimile, and telegraph (Morse code) two-way transmissions to be beamed via the satellite between Jodrell Bank and the radioastronomical facility of the Gorkiy State University at Zemenski. Only transmissions from Jodrell Bank were made. (5)
Although space communications in the form of command controls had been tested in many previous Soviet flights, and voice and television circuits were tested as early as 1960 in the Korabi Sputnik series, Kosmos 41 which was launched August 22, 1964, was the first clear precursor of the present Soviet operational communications satellite system.
At the time, Kosmos 41 was given no special description or publicity. It could not be judged from published sources whether this flight was designed only to test the mechanics of achieving a 12-hour semi-synchronous orbit, and to gather geophysical data and information on the durability of solar cells in exposure to the space environment at those altitudes, or whether the mission was intended as the first of the Molniya 1 flights, and the communications part of the payload suffered a catastrophic failure. However, as soon as the orbital elements were published, Western observers were able to identify its most likely mission as being associated with plans for a communications satellite. This was confirmed in 1969. (6)
THE MOLNIYA AND ORBITA SYSTEMS
The first Molniya 1 (Lighting) satellite was launched on April 23, 1965, in a flight nearly parallel to that performed by Kosmos 41 the previous year. Molniya 1 was described as having the main task of relaying television programs, long distance bilateral, multi-channel telephone, radiophoto, and telegraph communications. Two days after the launch, the first television broadcast was relayed from Moscow to Vladivostok through Molniya 1. On the 27th of April, a return program was carried from Vladivostok to Moscow for further distribution by land line to all the Soviet bloc country members of the Intervision system.
Since the initial orbit attained was not precisely 12 hours, the satellite would not repeat the same ground trace. Hence, on May 4, 1965, it was announced that correction engines had been fired to perfect the orbit to that originally hoped for, so that it would not gradually drift to a less desirable position in relation to Soviet ground stations.
Molniya 2 and Molniya 3 series satellites appeared as time went by and, at one time, all three types were operational simultaneously. The Molniya 2 satellites were phased out and currently eight Molniya 1 and four Molniya 3 satellites are operational at any one time. Molniya provided the first routine color relays and forms the basis of a Washington-Moscow "hotline".
From time to time there are reports of results obtained from scientific instruments carried onboard Molniya satellites. As described later in this chapter, the third and fourth Molniya-ls transmitted TV cloud-cover pictures back to Earth. (7, 8) Molniya satellites have also been used to study particle flows within the radiation belts surrounding the Earth. Two simultaneously operating Molniya 1 satellites were used in January and July, 1971, during magnetic storms of different intensities to investigate the dynamics or relativistic electrons in the outer belt inside and outside the plasmasphere, (9) and a Molniya-2 satellite gathered data on protons and alpha-particles on October 25, 1975. (10)
DESCRIPTION OF MOLNIYA 1
The Molniya 1 is a complex craft somewhat similar to the early lunar and planetary craft. The main body is a pressurized cylinder with conical ends and external cooling/heating coils, related to the temperature regulating system, which are wrapped around the main cylinder. There are also small correcting rockets to maintain the attitude of the spacecraft in the required position. Atop the main cylindrical body are the special correction motor system and Sun-seeking optical sensors. This subsystem is conical in shape and is surrounded by a ring of gas bottles containing fuel for the correction system.
At the opposite end of the main body are Earth-seeking optical sensors. Extending from either side of the main body are the structures for two high-gain antenna systems, steerable parabolic dishes used for the main communications tasks. Also, at the bottom of the main body are six fairly long panels which fold outward to radiate from the main body like petals on a daisy. These are covered with solar cells to power the craft. They generate 500-700 watts over a long period of time. Figure 33 shows this configuration.
Inside the craft are the main communications receivers and transmitters, the buffer batteries, various sensors and telemetry systems, an on-board computer, and other necessary equipment for housekeeping and control.
The directional parabolic antennas have a gain of approximately 18 db. According to a Soviet account, the Molniya 1 Sun sensor locks onto the Sun to maximize the power for the solar cell system, and there is a gyrostabilizer to maintain this attitude. The Earth seekers then lock onto Earth and are used to point the parabolic antennas to maximize signal strength. The ground stations on Earth also track the satellite and point their own antennas directly at the satellite. The two antennas are not used simultaneously. The second antenna is supplied for redundancy to extend useful life. (11)
In 1976, Maarten Houtman of the Netherlands noticed that the Molniya 1 displayed in the State Tsiolkovskiy Museum of the History of Kosmonautics at Kaluga had a four-helix array surrounding the horn. A photograph of this was published in The Royal Air Forces Quarterly. (12)
The communications equipment of the satellite includes three complete transceiver systems, one active, and two as standby in the interest of redundancy to extend operational life Most of the equipment is solid state except for metal-ceramic triodes, klystrons, magnetrons and traveling wave tubes. The useful life of the tubes is 40-50 thousand hours. Although in the first models the input noise level was 2,000-3,000 "K, tunnel diodes were soon to reduce this by a factor of 2 to 3. There are four traveling wave tubes, used, three active, and one as a spare. Television service is provided in a frequency range from 3,400 to 4,100 MHz, and other telecommunications in a frequency range from 800 to 1,000 MHz. Television is transmitted at a power level of 40 watts, and data and telephony at 20 watts.
The capability of the payload includes a complete television channel with additional capability for television audio, multichannel telephony, VHF telegraphy (by multiplexing some of the telephone channels), and photofacsimile. (13)
DESCRIPTION OF MOLNIYA 2
On November 24, 1971, the U.S.S.R. launched its first Molniya 2 communications satellite. The same launch vehicle was used for the Molniya 1 launch so it may be presumed that there was no great increase in the size and weight of the satellite and that the main improvement lay in the electronics. Solar panels were increased, adding about 50 percent to the power. With the change to the higher four and six gigahertz (GHz) frequencies, the earlier umbrella-like antennas with their clusters of three horns were replaced by arrays of five horns each. This configuration is shown in figure 34.
The Molniya 2 announcements mentioned "international cooperation a phrase absent from standard Molniya 1 announcements. t had been suggested that this, along with the use of higher frequencies, may have suggested a move toward compatibility with the Intelsat system, (14) but this now looks less probable.
DESCRIPTION OF MOLNIYA 3
The first Molniya 3 was launched on November 2, 1974 To date no model of the spacecraft has been put on public display The principal difference between Molniya 3 and Molniya 2 satellites seems to be its color television relay and higher communications frequencies. Earlier Molniyas broadcast mainly black and white television and numerous experimental color programs.
THE ORBITA SYSTEM
Orbita is the name used to describe the total complex of ground stations used in conjunction with dedicated communications satellites. Each can receive television transmissions relayed through geosynchronous and Molniya satellites, with further relay to the surrounding area. Additionally, the Orbita stations can receive and transmit telephone, telegraph, facsimile, and weather data via the Molniya satellites.
The first year of operations was limited to tests between Moscow and Vladivostok of the several types of service possible through the system. By 1966, the first phase of installation of Orbita stations was completed to make service more widespread. Each later year has brought an additional increment of ground stations. A special effort was made to have the Orbita system operational over much of the country by the fall of 1967 the celebrations of the 50th anniversary of the U.S.S.R. On November 2, 1967, operations opened to 23 points for regular service to 100 million persons. (15) Another concentrated effort to add stations in more remote regions of the Arctic and eastern Siberia was made before the celebration of the centenary of Lenin's birth in 1970.
The number of ground stations increased as time went by and, by the end of 1981 some 90 stations were installed in many political-administrative centers and large cities of the Soviet Union. The introduction of the Moskva system see p. 933) and the addition of satellites in geosynchronous orbits has not diminished the importance of the Orbita network. (16)
Television signals are transmitted from television studios in Moscow through ground communications channels to one of the ground transmitting stations for communicating with a satellite. They are then emitted through the ground station's antenna to the satellite where, after reception, they are relayed immediately to all receiving stations of the Orbita network located at the time in question in the zone of mutual radio contact from satellites and set aside for working with each specific type of satellite.
Television signals received by the Orbita ground station from the satellite are sent to the local television center through wideband cable lines and over considerable distances by a radio relay link. Finally, the local television center by means of its transmitter and television antenna transmits and relays the television program received through the Orbita network to ordinary collective- or individual-use station antennas.
Selection of the positions of Orbita ground stations, in addition to consideration of the convenience of placement of a direct connection by cable or microwave link to the local television center, takes into account the influence of industrial interference and avoidance, whenever possible, of intersection of the ground-satellite-ground lines of sight with air routes. (17)
Many of the ground stations are "transceiver" stations. This means that they can be used not only to receive television programs from Moscow, but also to transmit locally produced programs to the capital. (18)
A great number of telephone conversations or relays of radio broadcasts can also be carried via the Orbita transceiver stations using a frequency-division-multiplex system. Each telephone channel of 3 kHz bandwidth can accommodate up to 20 telegraph teleprinter signals, each of which requires only a 50-60 Hz bandwidth. The Orbita system is also used to send pages of the central newspapers, such as Pravda and Izvestiya, to remote regions so that local printers can make up the printing matrices at virtually the same time as in Moscow, whereas previously they had to be delivered by aircraft.
The space segment currently consists of one Molniya 3 satellite in its highly elliptical orbit with Raduga satellites at Statsionar 2 (35 °E) and Statsionar 3 (85 °E). (19)
Description of a typical Orbita ground station
Orbita stations are circular and constructed of reinforced concrete. The roof of each station serves as a foundation for the installation of a high-efficiency, fully rotatable, parabolic antenna 12 m in diameter. The antenna design allows for operation of a temperature range from -50 to +50 °C and at wind speeds up to 36 m/s. A shaped feed horn contributes to the utilization factor for the surface of the antenna of approximately 0.7 in the 4/6 GHz band. The gain/temperature specification for stations with these antennas is 31 dB/K. For several links 25-meter antennas are employed.
Antenna pointing is effected by the use of electric motor drives. The tracking system controlling these drives can operate in either the programmable or auto tracking mode.
The antenna-pointing apparatus, receiving equipment, and the switchboard which transfers the signal to and from local land lines together with the associated conversion equipment is housed in a central hall beneath the antenna.
Separate compartments and rooms located around the outside of the central hall contain the air conditioning and cooling for the entire apparatus and the control system for the antenna-pointing equipment. An additional block is necessary for equipment to separate the audio and video signal components. (20)
The operation of each of the Orbita stations is similar. The signals from the antenna are fed through the wave-guide to the band pass filter, through two low-noise parametric amplifiers, which increase signal strength 100 million times, and then on to the rest of the receiving terminal equipment. The first parametric amplifier is cooled by liquid nitrogen and operates without frequency conversion. The second parametric amplifier is not cooled and operates with a double frequency conversion. For operating convenience, even at the cost of some noise, all the receiving equipment is located in the same chamber. The equipment is mounted on a standard bay with an IF filter and preamplifier, as well as quartz crystal heterodyne oscillator with a frequency multiplier and an additional IF filter which prevents overload of the amplifiers by locally generated noise. A tunable beat frequency oscillator is included to provide for manual tuning of the signal in addition to automatic tuning provided by the quartz crystal heterodyne oscillator with a frequency multiplier. (21)
The quality of the television picture output from the ground stations is, in most respects, fully adequate by international standards. The scanning standard is 625 lines/frame, 25 frames/second with audio integral to the video band on a PCM basis. The signal is transmitted from the Orbita ground station to the local broadcast television station by a single hop, point-to-point microwave or coaxial cable link. Further improvements in the Orbita stations have been adding the capability of sending and receiving radio telephone and facsimile signals between the station and six Molniya satellites. Still other equipment being added to Orbita stations will greatly expand theft- capacity to provide the complete range of telecommunications activity, including computer data relay. (22)
Location of ground stations
When the first phase of Orbita station location was complete in November 1967, there were two-way transmission stations at Moscow and Vladivostok as well as receiving stations at Murmansk, Arkhangelsk, Skytyvkar, Ashkabad, Frunze, Alma-Ata, No-vosibirsk, Surgut, Vorkuta, Kemerovo, Norilsk, Krasnoyarsk, Bratsk, Irkutsk, Ulan-Ude, Chita, Yakutsk, Magadan, Komsomolsk, Yuzhno-Sakhalinsk, Khabarovsk, and Petropavlovsk-Kamchatka. By 1975 stations which were either completed or under construction included those at Gur'yev, Abakan, Kyzyl, Dzhezkazgan, Bilibino, Nikolayevsk-na-Amure, Aldan, Pevek, Sangar, Tazovskiy, Anadyr, Nar'yan-Mar, Skovorodino, Kadym, Ust'llimsk, Dushanbe, Khorog, Yuzhno-Kuril'sk, and the television center located in Tadzhikistan in the Pamir mountains. Plans for new stations included Aleksandrovsk and Poronaysk. The general target was to add six to eight stations a year so that by 1980, virtually all of the Soviet Union would have television service. 2S
The Soviet plan called for 60 operating stations by the end of 1975. (24) At the end of 1981 this total had risen to approximately 90 and by the beginning of 1983 the number was stated variously to be 100 or so, just 100, or nearly 100. (25)
Table 26 is a listing of ground stations served by Soviet communications satellites derived from a recent publication of the International Frequency Registration Board of the International Telecommunications Union. It will be noted that not all of the stations mentioned above are included in the listing. Neither is the Orbita station which has been reported at Ulan Bator in the Mongolian People's Republic.
* Uplink frequencies only are provided for these stations.
Notes:
1. Information derived from "List of Space Badiocommunication Stations and Radio Astronomy Stations," I.F.B.B., I.T.U., Geneva, Apr. 1, 1980.
2. Murmansk is listed in sec. 2 as a ground station served by Molniya 2 but does not appear in sec. 1 in its own right.
THE MOLNIYA ORBIT
The Molniya communications satellites are placed in highly elliptical orbits with an eccentricity of approximately 0.74. The orbital period of around 717.75 minutes is chosen so that, despite the very small precession of the orbital plane about the Earth's axis (approximately —0.148 degrees/day) and the motion of the Earth around the Sun, the ground-track repeats itself, albeit some 4.5 minutes earlier each day. Such an orbit, with repetitive ground tracks, may be said to be stabilized.
This combination of eccentricity and orbital period produces apogee and perigee heights (maximum and minimum heights above the Earth's surface) of 39,743 km and 609 km respectively. The apogee is placed to give maximum communications coverage in the Northern Hemisphere across the vast expanse of the Soviet Union with perigee near 60°, northbound (argument of perigee close to 280°). The orbit also processes in its own plane at a rate of 4.98a-3.5(l-e2)-2(5cos2 i-1) degrees/day, where a is the semi-major
axis of the ellipse measured in Earth-radii, e is the eccentricity and i is the inclination of the orbit. When i=63.4°, the final term in the expression becomes zero. All Molniya inclinations have had inclinations lying between 62.8° and 65.4° which have kept precession rates to between 0.007 and —0.022 degrees/day. This has the effect of keeping perigee deep in the Southern Hemisphere throughout the active life of the satellite.
Dr. R.R. Allan, of the R.A.E., showed that these stabilized ground-tracks could only occur in certain positions due to perturbations caused by the departure of the Earth's surface from a true sphere. (26) Fortunately for the Russians, one of these positions takes
the ground-track right across the centre of the Soviet Union. Figure 36 shows the stabilized ground-track of a Molniya satellite, with ticks placed at hourly intervals from apogee.
The major reason for the choice of the highly elliptical orbit is the long dwell-time over the Northern Hemisphere parts of the ground-track due to the extremely low velocity near apogee (approx. 1.5 km/s). The combination of low velocity and an apogee height exceeding six Earth-radii gives periods of up to 8 hours mutual visibility between Vladivostok in the east and Moscow in the west while on the Asian loop. Moreover, during this time, the satellite is visible from most parts of the U.S.S.R.
A considerable part of the North American loop, near apogee, is also visible from the U.S.S.R. across the North Pole and this is by no means a "wasted opportunity." In the first annex to this chapter it is reported that this loop is the one employed for internal TV distribution from Moscow.
METHODS OF ESTABLISHING THE STABILIZED GROUND TRACK
Initially, all Molniya satellites were launched from Tyuratam into orbits inclined at 65° to the Equator. Allan 28 has shown that the fourth Molniya 1 was the first to use a stabilized ground-track. The fifth Molniya 1 was not stabilized and the sixth and seventh only partly stabilized. Thereafter, the correction engine has been used to achieve some degree of stabilization of all Molniya ground track.
The initial method of achieving a stabilized ground-track was to place the satellite into an intermediate orbit with period of the order of 700 to 710 minutes. This resulted in an eastward drift of ground-track of between 3° and 8" per day. When the ground-track had drifted to the desired position, a firing of the correction engine at perigee raised apogee to produce the stabilized orbit. The times elapsing between launch and stabilization ranged from 8 to 20 days.
The launch of the 13th Molniya 1 signaled a move to the Plesetsk launch site and
orbital inclinations of 65.4°. A similar stabilization technique was employed. The change of site was a transfer of routine launches from Tyuratam rather than to reduce the time delay between launch and stabilization of the ground-track. The 15th Molniya 1 was not ground-track-stabilized until the 60 th revolution, 30 days after launch.
All Molniya 2 and Molniya 3 satellites have been launched from Plesetsk, and only eight Molniya 1's have been launched from Tyuratam since the shift to Plesetsk with the 13th Molniya 1 early in 1970 The first four of these flew at the old inclination of 65 degrees but the remainder have had inclinations of 62.9°. Most of these eight launches have been made in mid-winter but the last two were launched in mid-summer during 1976 and 1977.
The seventh Molniya 2 satellite and all subsequent Plesetsk-launched Molniyas have flown at the 62.9° inclination. The change in inclination resulted in a new stabilization pattern. The satellite is placed into an intermediate orbit with a period of between 730 and 740 minutes producing a westerly drift of ground-track of around 10 degrees/day. This has permitted stabilization by lowering apogee within 4 or 5 days of the launch.
RECORD OF MOLNIYA LAUNCHES
Tthe Molniya launches, together with a few Kosmos launches with the same characteristics, which represented either test flights, Molniya failures, or military communications satellites outside the Molniya program but using essentially the same hardware.
MOLNIYA AND RELATED KOSMOS COMMUNICATIONS
SATELLITES
DEVELOPMENT OF THE MOLNIYA SYSTEM
The early history of the Molniya satellites has been described by Allan (29) who pointed out that the 8th, 9th and 10th Molniya 1's constituted a three-satellite system with orbital planes spaced at approximately 120° intervals providing a complete 24-hour coverage of the U.S.S.R. Each satellite repeated the ground-track of its predecessor some 8 hours later in time. He also speculated that the llth and 12th Molniya 1's might be the pioneers of a four-satellite system with orbital planes space 90° apart and satellites following each other at 6-hour intervals.
In 1974, Philip Perkins and Geoffrey Perry, of Kettering Grammar School, developed a simple graphical method for monitoring the operational status of Molniya satellites in the Orbita system. Using data supplied by the Goddard Space Flight Center, they plotted the values of right ascension of the ascending nodes against date and obtained a series of four straight lines spaced at 90° intervals, confirming Allan's hypothesis. (30) Later, Perry developed this technique to produce a simple calculator, consisting of three cardboard discs, to reveal the operational status at a glance. (31) This was first demonstrated in public at the meeting of the National Space Club in Washington, DC, on July 28, 1976. By these techniques they were able to trace the history of replacement of Molniya satellites as they reached the ends of their active lives. Labelling the four groups of satellites from A through D, the replacement history of the Molniya 1's is seen to be as shown in table 28.
It will be seen that the comfortable state of affairs which existed at the end of 1975 following the launch of the 31st Molniya 1 was rudely disturbed early in 1976 by the launch of the 32d Molniya 1 into an orbital plane midway between groups D and A. Three more launches in March and July of that year completed a set of four satellites with planes spaced midway between each of the four original groups. It was suggested that Molniya 1's had been transferred to a wholly military role with a subsequent relocation of positions.32 No sooner had this been published than four more Molniya 1's were placed into the original groups. Currently it would appear that eight Molniya 1's are operational in planes spaced at 45° intervals. Birkill's observations from Sheffield, England, indicate that the Molniya 1's in the main groups still carry domestic traffic on both loops but that the four active inter-group spacecraft operate only on the Asian loop in what may be presumed to be a military mode.
The first Molniya 2 was positioned approximately midway between groups A and D of the Molniya 1's and, when the second Molniya 2 was positioned midway between groups A and B, the possibility arose that the Molniya 2's were a supplementary system to fill gaps in the existing system. However, the third Molniya 2, between groups B and C, was spaced 120 away from the second, i.e., nearer to group C. Although these first three Molniya 2's did not join the Molniya 1 groups, the fourth Molniya 2 was placed in group D and, thereafter, all Molniya 2 launches added their payloads to the Molniya 1 groups. The last Molniya 2 launch was the 17th of the series, in February 1977. It must now be concluded that the Molniya 2's have been phased out. Table 29 shows the replacement sequence of the Molniya 2 satellites.
When the Molniya 3 satellites were introduced they joined groups C, D, A, and B in turn over a 13-month period between November 1974 and the end of 1975. At that time the system comprised four groups, each of three satellites, following each other at approximately 6-hour intervals, with a maximum time difference of 40 minutes between any member of each group.33 Table 30 shows the replacement sequence of the Molniya 3 satellites.
Table 31, due to Andrew Ward, shows the operational status of Molniya satellites as of December 31, 1980. During January 1981, the 10th Molniya 3 and the 41st Molniya 1 were replaced by the next satellites in each series. Andrew Sims has shown that the Molniya 1 replacement was not ground-track stabilized until the third opportunity, 42 days after it was launched.
REPLACEMENT PHILOSOPHY
Flying different types of Molniya in groups and the introduction of the four midgroup Molniya 1's are both forms of built-in system-redundancy similar to the West's in-orbit spares. Nevertheless, it is not unreasonable to suppose that replacement satellites are launched as soon as operational satellites fail or begin to fail. It is to be expected that this would also tend to occur when the particular group was carrying "peak-hour" traffic. Analysis reveals 39.3 percent of the first 35 Molniya 1's to be placed in the current groupings; the last 14 Molniya 2's and the first 12 Molniya 3 s have been launched when their group's apogee-time occurred within +3 hours of 1030 Moscow time. The remainder have been reasonably equally shared between the other 6-hour periods of the day; 21.3 percent in each of the periods from 1930 to 0130 and from 0130 to 0730, with the rest in the period between 1330 and 1930 M.T.
This being the case, one might expect a linear relationship between launch-date and group-designation with a gradient of the order of 320 days. The 717.75 minute orbital period implies that satellites are 4.5 minutes earlier each day and that in 320 days the whole cycle will have been completed. This hypothesis was tested for the aforementioned 61 satellites but no direct linear relationship could be discovered. However, by considering groups A and C together and groups B and D together and similarly pairing the midgroup satellites, Perry and Philip Hill found such a relation-ship with a gradient of 152 days, approximately one-half of that expected if groups are to be considered singly but within 5 percent of the half-cycle duration of approximately 160 days. This was taken
as support for the hypothesis of across-the-pole usage on the North American pass, now confirmed by Birkill's observations.
An attempt to predict Molniya launches in the latter half of 1980 using this relationship met with moderate success, the 13th Molniya 3 and 48th Molniya 1 being launched 40 and 22 days "early" respectively. However, it must be realized that some of the predicted optimum dates might possibly coincide with prohibitive dates due to conditions that would lead to very short lifetimes. Specialists at the Royal Aircraft Establishment, Farnborough, England, have shown that the lifetime of a satellite in a highly eccentric orbit, which is strongly affected by luni-solar gravitational perturbations, is determined by the initial values of the orbital parameters and hence on the timing of the launch. (34, 35)
Tyuratam launches are made with initial ascending nodes some 3 hours after the group's ascending node with Plesetsk launches some 5 hours later still, due to the more westerly location of the launch site.
Reference to table 25 will enable the reader to form his own judgment of the active life spans of these satellites. An explanation of the replacement of the 13th Molniya 2 by the 14th after only 2 months is that the orbit was never properly ground-track-stabilized. Presumably launched to ensure optimum communications during the Apollo-Soyuz mission in the following week, the orbit was lowered to a period of 718.6 minutes. One might speculate that the correction engine failed to make a sufficiently long burn. What-ever the reason, no further correction was made and although it remained in the same orbital plane as the other members of group A, it fell further and further behind in time and consequently drifted off station in a westerly direction.
TABLE 31.-OPERATIONAL STATUS OF MOLNIYA SATELLITES AS OF DEC. 31, 1980
Mean time=N hr 13.61 min, and all satellites are within ±30 minutes o! this.
Mean longitude=115.17" W, and all satellites are within ±5.7' of this.
Molniya =3/10 was replaced by the 14th Molniya=3 on Jan. 9, 1981.
Molniya=l/41 was replaced by the 49th Molniya=l on Jan. 30, 1981.
MOLNIYA FAILURES WITHIN THE KOSMOS PROGRAM
As has already been mentioned elsewhere in this report, certain satellites in the Kosmos series have flown in orbits similar to those of the Molniya satellites. With the exception of Kosmos 41, which was, most probably, an engineering test as part of the R&D leading to the establishment of the Orbita system, it was at one time tempting to regard such satellites as Molniya failures. While it would appear that, from orbital plane spacing considerations, the 6th Molniya 1 replaced Kosmos 174 within 33 days of its launch (36) and that Kosmos 260 could have been a replacement for the 8 th Molniya 1, such an assumption is not valid in the cases of all Kosmos satellites with Molniya-type orbits. Perry pointed out that the orbital plane of Kosmos 706 does not coincide with any of the four groups. (37) In 1977, Perry pointed out that this satellite, and others which did not fit into the groups, had arguments of perigee close to 315° rather than close to the 280" of the successful Molniyas and Kosmos 837 and 853.(38) These two satellites, launched on July 11 and September 1, 1976, were really intended to replace one of the satellites in group D. (39) In the first instance the final stage of the launch vehicle did not fire long enough to achieve the desired highly elliptical orbit and on the second occasion did not fire at all to move from the intermediate parking orbit. The speculation that it was the llth Molniya 2 that was to be replaced, since it had already been in orbit for 18 months, was strengthened when the next successful launch into group D was indeed a Molniya 2.
One can form the opinion that it takes 2 months to ready a replacement payload if there should be a launch failure. When a further attempt was not made around November 1, 1976, it seemed reasonable to assume that group D was not then placed in a "peak-hour" traffic position and that the next attempt would be delayed until the other loop of the ground-track reached this position. The 17th Molniya 2 was placed into group D on February 11, 1977, some 7 months after the launch of Kosmos 837.
Two more failures occurred in 1980. Kosmos 1164 and 1175, launched on February 12 and April 18, were in quite different orbital planes. Kosmos 1164 most probably falls into the early warning category. Four objects from the Kosmos 1175 launch were cataloged in low parking orbits.
As with Kosmos 1164, the TASS announcement of the launch omitted the usual closing statement to the effect that the onboard instrumentation of the satellite was functioning normally. Although in the same orbital plane as the group A satellites it was not clear until the 13th Molniya 3 launch that it was intended to replace the 9th Molniya 3 rather than the 45th Molniya 1.
References:
A. SOVIET SPACE PROGRAMS: 1976-80 (WITH SUPPLEMENTARY DATA THROUGH 1983), UNMANNED SPACE ACTIVITIES, PREPARED AT THE REQUEST OF Hon. JOHN C. DANFORTH, Chairman, COMMITTEE ON COMMERCE, SCIENCE, AND TRANSPORTATION, UNITED STATES SENATE, Part 3, MAY 1985, Printed for the use of the Committee on Commerce, Science, and Transportation, 99th Congress, 1 st. session, COMMITTEE PRINT, S. Prt. 98-235, U.S. GOVERNMENT PRINTING OFFICE WASHINGTON: 1985
1. Shmakov, P.V. Tekhnika Kino i Televideniya No. 4, 1960, pp. 3-7.
2. Kondrat'yev, K. Ya. Uspekhi Fizicheskikh Nauk, vol. 74, No. 2, 1961, pp. 193-222.
3. Siforov, V.I. Priroda No. 6, 1966, pp. 2-3.
4. Bubnov, I.N., and L.N. Kaminin. "Manned Space Stations," Voyennoye Izdatel'stvo Mmisteretva Oborony SSSR, Moscow 1964.
5. Kalashnikov, N.V., L. Ya. Kantor and V.L. Bykov. Elektrosvyaz, vol. 19, No. 7, 1965, pp. 25-30.
6. Pravda, Moscow, Sept. 24, 1969, p. 3.
7. Isvestiya, Moscow, May 20, 1966, p. 6.
8. Krasnaya Zvezda, Moscow, Oct. 22, 1966, p. 1.
9. Senchuro, I.N. and P.I. Sharin, Kosmicheskiye Issledovaniya, vol. 19, No. 5, 1981, pp. 712-717.
10. Panasyuk, M.I. and N.A. Vlasova, Kosmicheskiye Issledovaniya, vol. 19, No. 1, 1981, pp.76-81.
11. Aviatsiya i Kosmonavtika, No. 7, 1968, pp. 17-20.
12. Perry, G.E. R.A.F. Qy., London, vol. 17, No. 2, summer 1977, p. 157.
13. Aviatsiya i Kosmonavtika, No. 7, 1968, pp. 17-20
14. Flight International. Feb. 8, 1973, p. 206a.
15. Moscow Radio, Oct. 26, 1967, 1900 G.M.T.
16. Agadzhanov, P.A., A.A. Bol'shoy and V.I. Galkin. Communications Satellites. Izdatel'stvo Znaniye, 1981, p. 64.
17. Idem.
18. Svoren, R. Nauka i Zhizn, December 1981.
19. Idem.
20. Pravda Moscow, Oct. 29, 1967, p. 3; Second United Nations Conference on the Exploration and Peaceful Uses of Outer Space, National Paper: U.S.S.R., A/CONF. 101/NP/30 Sept 2 1981-Agadzhanov, P.A., et al., idem.
21. Pravda, Moscow, Oct. 29, 1967, p. 3; Radio Moscow, No. 10, Oct. 1967, pp. 16-17; Elektrosvyaz', No. 11, 1967.
22. Radio Moscow, No. 10, Oct. 1967, pp. 15-16. This source discusses more technical aspects of the circuits than are presented here. See also Elektrosvyaz', No. 11, 1967, pp. 4-8.
23. Aviatsiya i Kosmonavtika, No. 5, 1970, pp. 12-13; Vestnik Suyzai, No. 4, April 1970, p. 29.
24. Moscow Radio, May 7, 1975, 0100 GMT; An Audience of Millions, Izvestiya, Moscow, May 7, 1974, p. 6.
25. Soviet Weekly, Feb. 12, 1983, pp. 8-9.
26. Allan, R.R. "The Operation of Molniya Communications Satellites." Technical Report 69266, R.A.E. November 1969.
27. Hooper, W.P., Rogers and Whitman, "The U.S.A.-U.S.S.R. Direct Communications Link Terminal," AIAA 5th Communications Satellite Systems Conference, Los Angeles, CA, 1974.
28. Ibid.
29. Ibid.
30. Perkins, P.J. and G.E. Perry. Flight International, London, 107, Jan. 16, 1975, p. 79.
31. Perry, G.E. R.A.F. Qy., London, 17, summer 1977, p. 162.
32. Ibid., p. 159.
33. Soviet Space Programs, 1971-75, table 5-3, p. 373.
34. Cook, G.E., and Diana W. Scott. Planet. Space Science, 15, 1967, pp. 1549-1550.
35. King-Hele, D.G. Technical Report 75052, R.A.E., May 1975.
36. Flight International, London, 92, Oct. 12, 1967, p. 628.
37. Perry, G.E., Flight International, London, 107, Apr. 24, 1975, p. 686.
38. Perry, G.E., R.A.F. Qy., London, 17, autumn 1977, p. 277.
