VC12 Operations, availability and end of life
Depth of coverage
At its target depth of L2. What the depth levels mean.
What this layer covers
Ground segment operations, availability and outage, degradation over life, disposal, deorbit, debris generation by the system itself
Where it ends
The debris environment as a shared risk is XC03
Operations, availability and end of life
Lifetime figures for a power satellite are design assumptions. The 1978 US design assumed its mirrors would lose reflectivity from 0.90 to 0.72 over 30 years, but another passage gives 0.83 for its GaAlAs option, and which figure is final has not been resolved (CLM-0337). Raytheon's 1981 case that a magnetron, a microwave tube, could last over 50 years extrapolates from oven-tube and 1950s valve data. No such magnetron had been life-tested (CLM-1049). ESA reports that nothing naturally removes objects from geostationary orbit, the high orbit where a satellite stays over one point on Earth. Its mitigation standard says a retiring satellite should be moved to an orbit clear of that region (CLM-0752). This site's own calculation shows that for highly reflective structures lighter than about 8.5 kg per square metre of sun-facing area, the push of sunlight may set how far out they must be moved. This is untested against any space solar power design (CLM-0751). The debris guidelines of the Inter-Agency Space Debris Coordination Committee (IADC) are not legally binding, though national licences may impose them (CLM-0756).
Every lifetime figure for a power satellite in these records is a design assumption, and none has been measured in orbit. Disposal from geostationary orbit has a defined rule, but the rule is advice, not binding in itself (CLM-0752, CLM-0756). How hard it is for a large, light structure is open.
Scope. A solar power satellite must work for decades, and then be moved safely away. The scope is day-to-day running of the ground segment, how much of the time power is available, how parts wear out over life, and disposal at the end, including any debris the system itself would make.
What is settled. Geostationary orbit is the high orbit where a satellite stays over one point on Earth. Nothing removes objects from geostationary orbit naturally, unlike in low orbit (CLM-0752). ESA's Annual Space Environment Report, issue 10.0 of 1 May 2026, states the mitigation rule it measures against: a retiring payload should be moved in a controlled way to an orbit wholly outside the protected region, the band around geostationary height kept clear for working satellites. It should meet one of two conditions: a perigee-raise formula of the IADC (Inter-Agency Space Debris Coordination Committee), or a perigee (the orbit's lowest point) high enough that disturbing forces do not bring it back within 100 years. The same report notes that sunlight pressure makes long-term predictions uncertain (CLM-0752). A 2010 ITU-R Recommendation puts collision speeds there at the order of 500 m/s. That is less severe than in low orbit, but still enough to do significant damage. It adds that a satellite has little chance of surviving a collision (CLM-0748).
The debris guidelines are advice. ESA's report calls them a baseline for national rules, and it is up to each nation, operator and maker to apply them. National licences may impose them. No national licensing rule specific to space solar power is held in these records, and none was looked for (CLM-0756).
What is uncertain. The first doubt is the size of the disposal burden for a very large, light structure. This site's own calculation works through the IADC and ITU formula. The formula adds a term for sunlight pressure, which grows with the area-to-mass ratio (sun-facing area per kilogram) and the reflectivity coefficient, which depends on the surface. Across the area-to-mass range of 0.01 to 0.1 m2/kg that ITU gives as typical, and a reflectivity coefficient of 1 to 2, the required rise in perigee is 245 to 435 km (CLM-0751). At the top of the range that is 1.85 times the formula's fixed 235 km term. For a highly reflective structure lighter than about 8.5 kg per square metre of sun-facing area, or a dull one lighter than about 4.3, the sunlight term is larger than the formula's fixed 235 km (CLM-0751). This is arithmetic on a published formula. It is not a finding about any design. No cited source gives the area-to-mass ratio of a space solar concept, and the calculation does not test the second compliance route (CLM-0751).
The second doubt is how long parts last. The 1978 US design assumed its aluminised-plastic mirrors would fall in reflectivity from 0.90 to 0.72 over 30 years. Another passage of the same report gives 0.83 at end of life for the gallium aluminium arsenide case. Which figure is final has not been resolved, and neither is a measurement (CLM-0337). The same design sized its attitude-control thrusters, for one solar-cell option, to cover an assumed yearly maintenance visit, a 5,000-hour thruster grid life and a 5-year mean time between failures. This passage sets no figure for how much of the time the whole system would be available (CLM-0338).
For the transmitter, Raytheon's 1980 and 1981 reports argued for a life of more than 50 years for a magnetron, the microwave tube used in ovens and proposed to make the beam (CLM-1049). The case rests on one measured cathode temperature in 1 kW oven tubes, scaled to a 20 kV (20,000 volt) design. It also rests on life curves from 1950s triode valves, extrapolated by a factor of about 27, and on twelve radio time-signal valves that ran 850,000 tube-hours without failing (CLM-1049). The 1980 report states that no comparable life data existed for such magnetrons at low cathode temperature. Its windowed test tubes poisoned and stopped within about 40 minutes. The 1981 report judged it premature to start developing the space tube until its noise and inefficiency were understood (CLM-1049).
What is missing. No cited source gives on-orbit degradation data, a life test of a tube at the conditions of a space solar design, a ground-station availability study, ground operations or outage rates, or an area-to-mass figure for a current concept.
Read next. Threats to a GEO solar power satellite. Why the beam frequency was chosen, and what the radio rules say. Efficiency of power beaming at range. Could it be attacked or misused?, for debris as a shared risk. From direct current to beam, for the transmitter tubes.
Records
22 of the 18 records tagged to this layer are published. The rest are not yet published. A record is published only after a second reader has checked it and it has passed every publication check. What the gate checks.
| Record | In plain language | Tier | Confidence |
|---|---|---|---|
| CLM-0336 | Different design studies over four decades have each simply assumed a different working lifetime for a solar power satellite, from about 15 years to 30 years; none has actually operated one long enough to know which is right. | T5 | MED |
| CLM-0337 | The 1978 study expected the satellite's mirrors to lose about a fifth of their reflectivity over 30 years in space, though the same document gives two different numbers for this in two different places. | T3 | MED |
| CLM-0338 | The 1978 design assumed each steering thruster would fail on average once every five years, and that its grids would wear out after about 5,000 hours (roughly seven months) of running. It carried 64 thrusters so that spares could cover failures between yearly maintenance visits. | T3 | MED |
| CLM-0339 | A 2019 paper said solar power satellites are often assumed to need visits in orbit for repairs and refuelling, but that no system yet existed to service satellites at geostationary orbit, though one was being developed. | T2 | MED |
| CLM-0748 | The international radio standard says collisions in geostationary orbit happen at around 500 metres per second, far slower than in low orbit, so they are less catastrophic, but it also says a satellite has little chance of surviving any collision. | T3 | HIGH |
| CLM-0749 | A 2010 international radio recommendation said the smallest object that could then be tracked in geostationary orbit was just under a metre across, against 30 centimetres in low orbit, so smaller debris up there went unseen, and it said other break-ups at that altitude had quite likely gone unnoticed. | T3 | HIGH |
| CLM-0750 | The 2020 edition of the international debris guidelines says a retiring geostationary satellite should climb at least 235 km above its working orbit, plus an extra allowance that depends on how large and light it is, and the 235 km is made of 200 km of protected zone plus 35 km for the way gravity nudges the orbit back down. | T3 | HIGH |
| CLM-0751 | Working the international disposal formula through by hand shows that for a very large and very light satellite the extra height it must climb at retirement is dominated not by the fixed 235 km allowance but by the push of sunlight on it, and that for anything lighter than about 8.5 kilograms per square metre facing the sun that sunlight term is the larger of the two. | T0 | HIGH |
| CLM-0752 | ESA's 2026 report says that nothing naturally removes objects from geostationary orbit the way the atmosphere slowly clears low orbit, so a retiring satellite there has to be deliberately moved out and kept out for at least a century. | T3 | HIGH |
| CLM-0753 | ESA's 2026 report says the world is not clearing satellites out of orbit well enough, that even the usual 90 per cent success target would not reduce the amount of debris on its own, and that the figure needs to rise to nearly 100 per cent. | T3 | HIGH |
| CLM-0754 | ESA's 2026 report projects that collisions between existing pieces of debris will keep making more debris in low Earth orbit even if nothing else is ever launched, and it makes no such projection for geostationary orbit at all; nothing in the register says whether the same runaway effect would happen up there or not. | T3 | HIGH |
| CLM-0755 | NASA's July 2026 debris bulletin counts 33,098 tracked objects in orbit as of 4 May 2026, of which 18,189 are satellites and 14,909 are spent rocket stages and debris, but it gives no figures at all for geostationary orbit specifically. | T3 | HIGH |
| CLM-0756 | The international space debris guidelines are advice, not law: ESA's own report says they are a starting point for national rules and technical standards, and that it is up to each country, operator and manufacturer whether and how to apply them. | T3 | HIGH |
| CLM-1049 | The fifty-year magnetron rests on a cathode that runs cool because the tube heats it only as much as it needs, on tube-life curves from 1950s transmitter valves, and on twelve radio-station valves that ran ten years without failing. No magnetron had been life-tested that way, and the test tubes Raytheon looked into poisoned themselves in under an hour. | T3 | MED |
| CLM-1183 | ESA's 2026 report counts about 960 catalogued objects in geostationary orbit at the end of 2025, about 800 of them satellites, but nearly 9,700 objects pass through the protected zone around it at some point in their orbits. A separate chart counts about 1,870 satellites near geostationary orbit in 2025, more than half of them drifting. | T3 | HIGH |
| CLM-1188 | Over the past ten years, almost every satellite retiring from the geostationary belt has tried to move itself out of the way as the debris rules ask, but only about seven to nine in ten have managed it, and the report notes two bad years, 2015 and 2022. | T3 | MED |
| CLM-1214 | The company says its beam will be on 99.9 per cent of the time, and that a 2 million dollar development agreement with a US government energy agency (ARPA-E) supports its work. It plans a public power-beaming demonstration in March 2027 and says it expects record efficiency. None of this is independently confirmed. | T6 | LOW |
| CLM-1470 | Britain's capacity market does not count gas or nuclear power stations at their full size. It counts a gas plant at about 88 to 92 per cent of its capacity, and a nuclear plant at about 75 to 85 per cent. Government advisers say the nuclear figure now rests on too few plants to be reliable. | T3 | MED |
| CLM-1471 | Britain's nuclear power stations were not running at full output for much of the time. From 2012 to 2022, planned and unplanned shutdowns cost the older reactors about a fifth to a third of the electricity they could have made, and the newest, Sizewell B, about a seventh. | T3 | HIGH |
| CLM-1472 | The designer of the UK's CASSIOPeiA satellite says it has no moving parts and is built from many small identical pieces, so when pieces fail it loses power gradually rather than stopping. It is meant to run for 20 years or more with no planned repairs. A 2020 UK government study repeats this and treats the satellite's upkeep as a slow loss of power rather than a repair bill. | T4 | MED |
| CLM-1473 | A 2020 UK government study expects early test satellites to be left to wear out slowly. For full-size satellites, it assumes robots would swap out faulty modules, using the same robots that built the satellite. Those robots do not exist yet. NASA's 2024 study instead plans to replace all of a satellite's hardware every 10 years. | T4 | MED |
| CLM-1477 | The UK government's 2021 cost study for a power satellite assumes that parts fail and wear over the satellite's life, costing it between nothing and a quarter of a per cent of its output each year. | T4 | MED |