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Russian Mix |
Tyneside, UK 2024 Dec 14 Saturday, Day 349 | ||
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| Meteor M2-2 - Possible Collision 2019 Dec 18 2019 December 24 Russian news outlets carried stories saying that Russian newest polar orbiting meteorological satellite, Meteor M2-2 (44387/2019-038A), had collided with a piece of space debris on December 18. The collision had caused the satellite to tumble and had changed the orbital parameters slightly but the rotation had been brought under control. The satellite's condition was being assessed. The Event Data provided by Space-Track showed the orbit change clearly but it was very small. The semi-major axis had reduced by 1.1 km from its original 7192.2 km. Apogee and perigee had been changed from 813.1 x 815.1 km to a slightly more eccentric 811.4 x 814.5 km. There was no effect on either the inclination of 98°.59 or the Right Acension of the Ascending Node so post and pre-collision orbits were co-planar. Measuring the separation distance between the two trajectories has them coming together Dec 18 at 01:13 UTC. Allowing for a little bit of leeway in the orbital measurements, the time is best treated as ±3 minutes. First public indications of a problem came later on the day of the event when system users noted the absence of Meteor M2-2's imaging transmissions that are normally broadcast continuously. Its Russian owners probably became aware twenty minutes or so after the impact when Meteor rose above the horizon of the far-east tracking station at Petropavlovsk on the Kamchatka peninsula. Effects Any impact was (relatively) gentle. Collisions in the past resulted in the appearance of debris fragments spread across a range of orbits. The satellite involved has almost always been completely disabled. In this case, the 'victim' survived and limps on. No fragments have so far been catalogued, indicating that nothing of significant size broke loose. That scenario will change if any new objects are eventually detected and tracked back to Meteor. Because the impact was quite small, it is unlikely to have been the direct cause of the orbit change. Design of the Meteor satellites dates back to the 1960s and includes a hermetically sealed body filled with, probably, air at 1000 hPa pressure. The impact was in all likelihood sufficient to create a hole and it was the escaping gas that provided the thrust to modify the trajectory. It would have acted like a small rocket motor. The fact that there was no significant change in the orbit plane suggests that any collision was with an object travelling in that same plane and it approached either from behind or from in front. There is another possible scenario that does not involve a collision. Sudden failure in the hermetic sealing of the satellite body would have similarly resulted in a jet of escaping gas providing the thrust for the orbit change. Meteor's weather sensors are generally mounted on the outside of the satellite and are exposed to the vacuum of space. The cylindrical body houses control systems, radio receivers and transmitters, computers for flight control and data processing equipment for readings taken by the sensors. Air circulates within the body to redistribute heat and to allow systems to be cooled via radiation from the cylindrical walls of the satellite body on its 'cold' side. Loss of the gas component of the cooling system means that temperature control becomes difficult, if not impossible. The photograph on the right shows the body of a Meteor-2 satellite from the 1970s but the underlying design philosophy has not changed in all that time. The silver metal bands around the circumference of the 2m tall cylinder are flanges through which bolts clamp sections of the body together. The metallic discs are access ports with sealed covers, also secured by bolts. Tubes are connected to some of the covers to carry cables into the pressurised cylinder. A physical failure in any of these components or their gaskets could have released a jet of gas as the atmosphere leaked out. Prognosis The future for Meteor M2-2 as an operating satellite is not good. Even if the tumbling is fully under control, inability to cool its internal systems will probably prove fatal to one or more of them in the not too distant future. It might be possible to design an attitude control rêgime that gives some control of solar heating by rotating the satellite but it will render useless any sensors such as the push-broom imaging system that rely on the satellite's motion along the orbit to provide the vertical component of the scan. In reality, Meteor M2-2 is probably doomed. Page date: 2020 Jan 14 |
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