Drama Angosata
Probably one of the biggest space New Year gifts was the restoration of communication with the satellite "Angosat-1". Now that we are not distracted by pre-New Year fuss, and the satellite is moving in close to geostationary orbit, it's time to recall its dramatic history and, at least, try to get an idea of what happened there.
Satellite preparation for launch, photo by RSC Energia
The contract for the creation of a telecommunications satellite for Angola was signed in the summer of 2009. The RSC Energia volunteered to build the satellite, which developed the Universal Space Platform (UCP). This platform was used on Yamal satellites -101, -102 and -201, -202, launched in 1999 and 2003. In 2008, due to disagreements between Gazprom Space Systems (“Gascom”) and the RKE “Yamal”, the three hundredth series built the ISC them. Reshetnev. For Energia, the contract with Angola came in very handy against the background of the court and the return of the advance payment from Gazcom. And Angola received a loan from Russian banks to create its first satellite. The contract also included the preparation of ground infrastructure, the construction of flight control centers and satellite broadcasting. After fulfilling the necessary conditions (for example, allocating the frequency range), work on the satellite began in 2012.
Angosat-1, photo by RSC Energia
Structurally, the satellite is a domestic platform, on which telecommunications equipment manufactured by Airbus is installed - 16 C-band and 6 Ku-band transponders. The satellite engines are 8 plasma SPD-70. Their total thrust is only 32 grams, but they consume fuel more than three times more efficiently than the best chemical engines and are excellently suited for the task of keeping vehicles in geostationary orbit. There is no apogee engine on the satellite, therefore the accelerating unit must bring it to a fairly close to the geostationary orbit, from where the satellite already gets to its point of standing. Angosat should be located at 14 ° east longitude, Angola is located just south of it. The total mass of the satellite is 1647 kilograms.
Installation of the launch vehicle in the launch facility, photo of Roscosmos
Initially it was expected that the "Angosat-1" will fly to the "Zenith" of the "Sea Launch" in the area of 2016. When it became clear that the Sea Launch, at best, was closed for years, the satellite was decided to be transplanted to the Angara, but it also began to move on dates. During 2017, there were regular news about the postponement of the launch date, and as a result, the satellite turned out to be on the last Zenit made earlier. In November, the launch was once again postponed, and for a rather unpleasant reason — an emergency situation occurred when refueling the Fregat accelerating unit, according to an anonymous source, rubber plugs were forgotten in the pipeline. As a result of all this, the upcoming launch of the satellite was alarming - RSC Energia was making it after a long break, the launch vehicle was in the warehouse for a long time, and on the whole , difficult times are continuing for it now. The launch took place on the evening of December 26, and the concentrated excitement of launching changed into waiting for news during the opening hours of the upper stage.
The triumphant reports about the successful separation of the satellite on the morning of December 27 in a few hours were replaced by frightening rumors about the loss of communication with it. According to incoming rumors, communication with the satellite was lost at the stage of disclosure of solar batteries. Anatoly Zak gives such a cyclogram of operations on a satellite after separation:
The situation was unenviable. The satellite was discovered in a regular orbit, fortunately, fragments did not fly away from it, but Angosat was silent. Worse, according to the available open information, the antenna of the command radio link is omnidirectional on it, and it could send a signal or hear the Earth in any position. The telemetry data and how it disappeared could have said something, but this information did not appear in open sources. The most logical version seemed to be a short circuit - after forty minutes of normal flight on batteries, the drop-down solar panels begin to produce current, and somewhere they do not withstand, despite the fact that the satellite had passed tests of opening the solar panels and turning on the electrical systems before launching. This type of accident practically didn’t give chances for the resumption of normal operation, therefore, the news of the resumption of communication became a big surprise on the evening of December 28. After some time, the information was confirmed by official sources - “Angosat” came to life. The resumption of telemetry gave rise to the second most likely version — the batteries were discharged from the satellite, and the solar panels that had opened up restored the power supply. The version also looks so-so, because the battery charge was checked before the start.
Alas, the following days not only did not clarify the picture, but confused it even more. On December 30, Interfax reported , citing another anonymous source, that the incompatibility of Russian and French equipment was allegedly a problem, and Angosat had already reached the point of standing. According to the open TLE parameters of the satellite orbit, it continues to drift without visible maneuvers and has already shifted to the west of the planned position. Also, the inclination of the orbit is increasing uniformly with it, with which operating geostationary devices must fight.
So that small changes could be seen on the graphs of the pericenter and apocenter, 35786 km were subtracted from the true values, i.e. on the graph the height relative to the geostationary orbit
In such conditions, even rumors that seem wild enough are beginning to appear that, allegedly, the solar panels did not open up, the connection was restored only for 15 minutes, and now the satellite has been completely lost. However, given the small thrust of the engines, it is possible that the device is operational, but is going to make a full circle and go to the point of standing on the other side. So far, I would not raise a panic - in any case we have no access to anything other than open sources, and rumors often lie. The latest official information is dated January 4 - the Russian ambassador in Angola reported that the satellite is functioning normally. There is more material on RIA Novosti from January 9, but it does not carry useful information - “stabilized position” refers to an orientation that is not visible on the parameters of the orbit. We will follow the news.
UPD : The latest official news from RSC Energia:
So the drift is officially recognized as scheduled, we will wait for April.
Satellite preparation for launch, photo by RSC Energia
The road is long in years
The contract for the creation of a telecommunications satellite for Angola was signed in the summer of 2009. The RSC Energia volunteered to build the satellite, which developed the Universal Space Platform (UCP). This platform was used on Yamal satellites -101, -102 and -201, -202, launched in 1999 and 2003. In 2008, due to disagreements between Gazprom Space Systems (“Gascom”) and the RKE “Yamal”, the three hundredth series built the ISC them. Reshetnev. For Energia, the contract with Angola came in very handy against the background of the court and the return of the advance payment from Gazcom. And Angola received a loan from Russian banks to create its first satellite. The contract also included the preparation of ground infrastructure, the construction of flight control centers and satellite broadcasting. After fulfilling the necessary conditions (for example, allocating the frequency range), work on the satellite began in 2012.
Materiel
Angosat-1, photo by RSC Energia
Structurally, the satellite is a domestic platform, on which telecommunications equipment manufactured by Airbus is installed - 16 C-band and 6 Ku-band transponders. The satellite engines are 8 plasma SPD-70. Their total thrust is only 32 grams, but they consume fuel more than three times more efficiently than the best chemical engines and are excellently suited for the task of keeping vehicles in geostationary orbit. There is no apogee engine on the satellite, therefore the accelerating unit must bring it to a fairly close to the geostationary orbit, from where the satellite already gets to its point of standing. Angosat should be located at 14 ° east longitude, Angola is located just south of it. The total mass of the satellite is 1647 kilograms.
Nerves
Installation of the launch vehicle in the launch facility, photo of Roscosmos
Initially it was expected that the "Angosat-1" will fly to the "Zenith" of the "Sea Launch" in the area of 2016. When it became clear that the Sea Launch, at best, was closed for years, the satellite was decided to be transplanted to the Angara, but it also began to move on dates. During 2017, there were regular news about the postponement of the launch date, and as a result, the satellite turned out to be on the last Zenit made earlier. In November, the launch was once again postponed, and for a rather unpleasant reason — an emergency situation occurred when refueling the Fregat accelerating unit, according to an anonymous source, rubber plugs were forgotten in the pipeline. As a result of all this, the upcoming launch of the satellite was alarming - RSC Energia was making it after a long break, the launch vehicle was in the warehouse for a long time, and on the whole , difficult times are continuing for it now. The launch took place on the evening of December 26, and the concentrated excitement of launching changed into waiting for news during the opening hours of the upper stage.
What was it?
The triumphant reports about the successful separation of the satellite on the morning of December 27 in a few hours were replaced by frightening rumors about the loss of communication with it. According to incoming rumors, communication with the satellite was lost at the stage of disclosure of solar batteries. Anatoly Zak gives such a cyclogram of operations on a satellite after separation:
- Branch contact - 30 seconds;
- Making radio contact with ground-based equipment - 4.5 minutes;
- Removing the latches of the antenna deployment mechanism - 30 seconds;
- Damping the residual angular velocity - 10 minutes;
- The formation of solar orientation - 15 minutes;
- Solar panel deployment - 3.5 minutes;
- Solar orientation recovery - 5 minutes;
- Test of solar panels - 10 hours;
- Telecommunication antennas deployment - 5-15 hours.
The situation was unenviable. The satellite was discovered in a regular orbit, fortunately, fragments did not fly away from it, but Angosat was silent. Worse, according to the available open information, the antenna of the command radio link is omnidirectional on it, and it could send a signal or hear the Earth in any position. The telemetry data and how it disappeared could have said something, but this information did not appear in open sources. The most logical version seemed to be a short circuit - after forty minutes of normal flight on batteries, the drop-down solar panels begin to produce current, and somewhere they do not withstand, despite the fact that the satellite had passed tests of opening the solar panels and turning on the electrical systems before launching. This type of accident practically didn’t give chances for the resumption of normal operation, therefore, the news of the resumption of communication became a big surprise on the evening of December 28. After some time, the information was confirmed by official sources - “Angosat” came to life. The resumption of telemetry gave rise to the second most likely version — the batteries were discharged from the satellite, and the solar panels that had opened up restored the power supply. The version also looks so-so, because the battery charge was checked before the start.
Drama continues
Alas, the following days not only did not clarify the picture, but confused it even more. On December 30, Interfax reported , citing another anonymous source, that the incompatibility of Russian and French equipment was allegedly a problem, and Angosat had already reached the point of standing. According to the open TLE parameters of the satellite orbit, it continues to drift without visible maneuvers and has already shifted to the west of the planned position. Also, the inclination of the orbit is increasing uniformly with it, with which operating geostationary devices must fight.
So that small changes could be seen on the graphs of the pericenter and apocenter, 35786 km were subtracted from the true values, i.e. on the graph the height relative to the geostationary orbit
In such conditions, even rumors that seem wild enough are beginning to appear that, allegedly, the solar panels did not open up, the connection was restored only for 15 minutes, and now the satellite has been completely lost. However, given the small thrust of the engines, it is possible that the device is operational, but is going to make a full circle and go to the point of standing on the other side. So far, I would not raise a panic - in any case we have no access to anything other than open sources, and rumors often lie. The latest official information is dated January 4 - the Russian ambassador in Angola reported that the satellite is functioning normally. There is more material on RIA Novosti from January 9, but it does not carry useful information - “stabilized position” refers to an orientation that is not visible on the parameters of the orbit. We will follow the news.
UPD : The latest official news from RSC Energia:
The Angosat spacecraft (SV), created at RSC Energia on the order of the Ministry of Telecommunications and Information Technologies of the Republic of Angola, is undergoing scheduled flight tests.
Telemetry coming from the satellite revealed a problem in the operation of the equipment of the power supply system of the Angosat satellites. RSC Energia specialists complete the processing of the available telemetric information and are preparing to conduct a series of tests.
In the near future, the Angosat spacecraft, moving along the geostationary orbit in a westerly direction, will leave the radio visibility zone of the Flight Control Center (Korolev).
In view of the high responsibility of maneuvers in the geostationary orbit, it was decided not to carry out an active impact on the spacecraft until it returns to the radio-visible range.
The resumption of work related to the flight tests of the Angosat spacecraft is planned in mid-April 2018.
So the drift is officially recognized as scheduled, we will wait for April.
Source: https://habr.com/ru/post/409647/