How did those prototype 787 APU batteries end up in orbit?!?!
AT&T’s satellite telly service DirecTV will push one of its birds beyond its geostationary orbit – before it has a chance to explode into a million pieces. The broadcaster fears the batteries on board its Boeing-built Spaceway-1 satellite, which has been aloft since 2005, may detonate, spewing debris into the Clarke Orbit – …
Satellites either use chemical thrusters or electric thrusters (ion or Hall effect). Russia has largely switched to using electric propulsion when possible.
Large geostationary satellites usually use Monomethylhydrazine (MMH) for the fuel and Nitrogen Textroxide (N2O4) for the oxidizer.
Compressed gas would have a very low mass-to-energy ratio (the mass being the pressure vessel it is kept in).
How often does an event like this happen? What kind of batteries are these, anyway? I had a poke around, but it seems that such technical information isn't easy to find.
Boeing hasn't been very forthcoming with information either, refusing to say what caused the thermal event that damaged the battery. The mentioning of the satellite exploding/breaking up would suggest some kind of serious outgassing event, conceivably inflammable?
Damage to the batteries was probably caused by over-charging. Spacecraft batteries are a whole lot more complex than your standard AAAs; they have incredible power storage density and are designed to literally last decades. However, you have to be careful on the charge-discharge cycles, and when charging them you typically monitor the battery temperatures - when the temperature starts going up there is either a serious problem or the battery has reached full charge. Over-charging results in the battery over-heating, which damages the case (which is normally sealed and pressure-resistant).
The batteries release hydrogen gas when they are discharged; this is kept in the battery gas (this is why it is pressure-resistant. If the case has been damaged by heat, it is possible that the extra pressure generated during a discharge cycle will rupture the case. Spacecraft are pretty fragile things, so this could result in it breaking up.
But many people as forgetting that this device is *already* past its Use By date; a battery going bad after 15 years on a device promised for 12 isn't a manufacturer-derived failure. Things that are old, fail, even here back down on planet Earth. A cell phone or laptop battery 3 years past its prime, and failing, wouldn't be taken with any surprise. This battery may explode, as others have, and mods certainly the level of detonation is simply due to size - this can't be a small battery if it runs a communications satellite for many hours at a time.
So, I'm sorry, I can't blame Boeing here, even if doing so would be highly convenient or extremely popular right now. Old, super high capacity batteries are notorious trouble makers.
The risk is not "1%" or any such fixed value. Remember, it's *geostationary orbit*. Something exploding there will likely mean debris staying there, for a looooong time, with small, random, variants of that orbit. Which means crossing it at regular intervals. Any other satellite in that orbit could then be at risk at some point.
On this important orbit, that would be a really big deal.
Being in geostationary orbit makes absolutely no difference so far as the behaviour of the debris is concerned (practically none of which will remain in that orbit anyway, having all been given pretty large accellerations in random directions).
The big difference is that it is a pretty crowded orbit, so there are other satellites relatively close by that could be hit by debris on its way to its new orbit.
This satellite and laptops both use things called "batteries". That's about where the relevance of your comparison ends.
Boeing knew those batteries would end up in space, at least 36000 kms away from the nearest Boeing Store or wherever it is they fix their gadgets. So I can very much blame Boeing for not being able to tell the buyer that the batteries would fail in such a way. If they had, it would obviously had been integrated in the satellite's life-cycle, and it would obviously have been decommissioned earlier, safely, and without causing an emergency.
They are only moving it 500km higher from it's present 35780km orbit. All they could do if they wanted to lower the orbit is come down about the same amount as all they have for propulsion are station keeping thrusters. Either way the orbital velocities are almost the same.
> about 3,000 m/s, or approximately 11,000 km/h
Wait, there must be an error there: 3 km/s can't possibly be 11000 km/h.
3000 m/s would be 180 km/h, which seems awfully slow to me. That's a speed any/most cars can easily reach.
So, what's the real speed required to keep something in geosynchronous orbit please? A casual Wikipedia search didn't yield any result.
This is Brexit Britain (well it will be in six days).
We MUST have the velocity expressed in miles per hour. No other units are acceptable (well maybe feet per second). We don't want ANY of this bloody European talk here -- metres per second indeed.
We didn't vote to LEAVE THE EU just to see all that effort lost by sensible people using sensible measurements. I'm guessing you're not a white-haired white male. Bring back £sp. If it was good enough for the Romans (bloody Europeans... etc).
This is Brexit Britain (well it will be in six days). We MUST have the velocity expressed in miles per hour. No other units are acceptable
Piss off - It's"furlongs per fortnight" or the whole bloody thing simply hasn't been worth it.
The one with the foolscap notebook in the pocket. The velum one ->
What I want to know is when are they going to re-introduce rods, poles and perches a.k.a 5 and a half yards?
We're British and will have nothing to do with all this decimal nonsense! Yes, yes I'm being sarcastic in case you are wondering.
The trouble is I've actually had encounters with people actually advocating going back to using pounds and ounces, feet and inches and Fahrenheit etc. I'm in my 70s and was never taught SI units of measurement but I had no trouble adapting so why all the angst?
"all they have for propulsion are station keeping thrusters"
The report also says they have a lot of fuel on board. If so then presumably they could just keep going and no limit themselves to another 500km and at the same time avoid worries about discharge of the spare fuel by using it. There should be plenty of room up there above geostationary plus 500km.
Most of the bits would go into mildly elliptical orbits, with a spread of periods around the one at the time. Few of those orbits would extend beyond 500km from the original, and few of the battery pieces would be both big and fast enough to have significant kinetic energy relative to another geostationary sat, so moving out 500km reduces the risk of collision from very tiny to near-background level.
TBH there is an awful lot of emptiness in geostationary orbit, it being a quarter of a million kilometers (150,000 miles) round trip and all that. Your nearest neighbours are probably around 1,000 km away. Although the battery might explode, the sudden outgassing would not rip that much fully away from the main structure, it's not like an atmospheric explosion. In all honesty, the risk of damage to another geo satellite appears negligible anyway.
If I were feeling cynical I might suggest that if the battery dies then the sat's 24/7 coverage is gone and it needs replacing anyway, so why not make a PR stunt out of it and play the good guys?
There isn't very much useful geostationary.
While it's a thin line 260,000 km long, the bits people want are over the Americas, Africa and Indian ocean. Hardly anyone wants the 1/3 or so over the Pacific Ocean, as there'd be nobody under the sat.
Plus you want to be as far away as possible from your neighbours, in case they explode.
So there's a lot of good reasons for clearing dying sats out of the way while they're still under control. After all, the dying sat is almost certainly very near a place someone very much wants to put their own sat.
It would be even worse to leave a cloud of debris in the orbit instead. As orbits drift, that mess will slowly expand, denying a large area of geostat.
Given that a higher orbit needs more energy wouldn't slowing it down to lower orbit be better?
What matters is the delta-V: getting it into a low enough orbit that it wouldn't cause problems is tremendously more expensive than getting it into the graveyard orbit geostationary satellites are put into, which is going to be devoid of anything anybody care about anyway(so if it does explode up there, the most it can do is make flinging things to the moon or beyond slightly more awkward, assuming the orbit isn't avoided already).
It will only (potentially) explode if the batteries are used. Elsewhere I read only if they attempt to charge them, but the effect is the same either way.
So they haven't used the batteries since they learned that, and won't need to use them if they can put it into a parking orbit by Feb. 25th. Which is why they filed with the FCC to do just that, and since it only takes a few weeks for the process that shouldn't be an issue.
First they will lower its orbit a bit and let it drift eastward to about 50W or so as Directv has dishes that can see it only to about 40W, then begin raising its orbit and have it stabilized in its parking orbit by the time it passes 155W or so which is how far their dishes can see west.
The article mentions an Intelsat facility in Riverside - Directv already has two in the LA area, but I guess the Intelsat facility has a dish with a wider arc (if parabolic) or is able to aim further west if movable. Maybe they won't let the satellite drift as far east as they have done with other retirements to reduce the total time required since unlike most retirements this one has a hard deadline.
OK, I appreciate this isn't the "environmentally friendly" option, but why don't they just keep pushing until the fuel runs out? Isn't that the least dangerous option?
A parking orbit is a great idea if you make the assumption that in the future someone develops the technology to undertake the recovery. That's pretty much the world of cryogenics, gambling that someone in the future wants to spend money to get you back.
The earth is neither spherical nor homogenous. Satellites in the graveyard orbit do not have any stationkeeping adjustments as they have no fuel. They drift around the Earth until they end up in one of two graveyard spots. I think these are over the Indian Ocean and the Eastern Pacific near to South America. (I could check, but can't be bothered, you can all use search engines!)
Presumably, once we have the technology, clean up will consist of a very large butterfly net and a trash can. You won't have to clean up the entire orbit, just the two hotspots.
According to the wiki article, this was launched in 2005 with a 12 year lifetime and was currently being used as a backup satellite.
While the battery issue is undesirable - are there any details of the fault (i.e. overcharging due to a damaged component or control system?) as bashing Boeing for this seems a little harsh unless I'm missing something.
If Boeing designed an aircraft for a 12 year lifespan without ensuring that it would not still be flying around at the same altitude fifteen years later, you might think someone had been careless.
The specifier if not the manufacturer.
The US approach to dumping stuff in space seems to resemble that approach of the former Soviet Union to dumping stuff in Siberia. And that does not denote approval.
We will just have to differ on that one. To me it's like saying "It would be OK if after 12 years a team of travellers was sent out to take your old refrigerator and dump it in a hedge where you can't see it."
Calling it a "graveyard orbit" is marketing speak. Satellites are being put up in large numbers without real thought for long term consequences. Remember that US plan years ago to dump a load of small gold needles into orbit? Now it is lots of small satellites.
"If Boeing designed an aircraft for a 12 year lifespan without ensuring that it would not still be flying around at the same altitude fifteen years later, you might think someone had been careless."
Is the comparison to an aircraft valid? An aircraft is maintained as part of normal operations while a satellite is almost entirely unserviced during its lifetime. Aircraft parts prone to stress are regularly replaced to minimise risk and anything with an operational life is replaced before it is likely to fail.
And aircraft operate in a less hostile environment than space - the fault that has end the life of this satellite is likely repairable if it occurred in an aircraft and if it was caused by being hit by an unknown object, then that is a risk satellite manufacturers take and attempt to workaround with additional resilience. But resilience doesn't protect you from multiple failures particularly as you reach the later stages of your mission where you may already be operating with failed components.
It was recently given a clean bill of health and an extension to 2025
Is it going UP to a graveyard orbit or being unusually de-orbited into the atmosphere?
Often the limiting factor on satellite life is station keeping fuel, not solar panels or batteries. There have been other satellites with battery failures that stayed in orbit but at reduced or no transmission power when in the dark, which oddly isn't every night.
Maybe when it was launched the fuel reserve might have been calculated to last significantly longer than it's initial intended life span, but since then, new regulations on moving "dead" sats out of orbit mean it must be moved now while there enough fuel to move it to a safe orbit. It was launched 15 years ago and probably designed and specified at least 5 years prior to that when there was probably a lot less concern about what happens to expired sats.
"Is it going UP to a graveyard orbit or being unusually de-orbited into the atmosphere?"
Any movement between orbits takes energy. Geostationary orbit is a long way up, far higher than the ISS or spy satellites. To pull something all the way from geosynchronous orbit to the atmosphere takes a lot of energy. But we have nothing important further away than geostationary, so sod it, just send it further out.
"Is it going UP to a graveyard orbit or being unusually de-orbited into the atmosphere?"
It's going up - there is a significant quantity of fuel remaining (73kg at present) which may account for the life time extension.
Regarding the batteries, the satellite appears to be OK operating on solar panels but the concern is that the coming eclipse season will require battery operation leading to the potential for catastrophic failure. Eclipse season starts on Feb 25th.
Satellites typically last longer than their design life. Sometimes MUCH longer (Directv has one satellite launched in 2005 with a 12 year expected life that has fuel reserves until 2034)
Usually running out of fuel for station keeping (plus reserve to boost into parking orbit) is what causes geosynchronous satellites to be retired. They have a fair amount of redundancy so failures for things like gyroscopes, TT&C antennas and so forth can be tolerated, but not much you can do about a battery pack that may burst if used other than retire the satellite so you never you have to use it.
Why not take that last 70+ kg of propellant and just push the damn thing OUT of orbit and into the direction of eternal travel thataway? Plunge into the sun, etc., or into the cold void of outer space? If it decides to blow up then, it's heading outward (or inward if burny-burny fate is opted)? Why just park it out a bit and leave it?
They can't throw this satellite into the sun either. Only Superman does things like that.
I suppose that, rather counter intuitively, it's slowing something down enough in space so that it drops into the sun that takes lots of energy - and mass - that isn't there on board to be used.
You and I are in orbit around the sun at a fair rate. If the earth somehow popped out from under us, we'd carry on much the same. But with evident inconveniences.
Why just park it out a bit and leave it?
One doesn't just park a decommissioned satellite "somewhere out there" in (deep) space.
Ever heard of "billiard balls"? What happens if a comet should collide with this junk? A chain reaction would occur making space like a gunfight in a concrete room with your eyes covered -- in short, not a good idea.
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Gravity is amazing.
If my laptop batteries were going to explode in Southampton and I had to scoot up to Aberdeen to be on the safe side I'd be rather annoyed ...
Thank heavens for gravity and a toast to Newton, who decided things fall down and was obviously English. Up until that time Europe must have been a confused place with all that not falling in any predictable direction ... Come to think of it, if we invented it, did we copyright falling down? Perhaps a lever in the Brexit land grab negotiations ... "we demand Europe returns everything that falls down to us".
<Particularly strappy coat already on, sound of trolley wheels echoes in the corridor ... :-) >
I think Newton missed a trick here. When he invented gravity, he should have patented it in the US!. just imagine how much money he'd have now! As he was a Brit though, i agree with the whole "we own everything that falls down" bit. Just think of what we could get! We'd own colder temperatures in winter, tree leaves, litter, rain............ oh. That's Britain already, isn't it?
They figured it would last out until the people responsible were drawing their pensions.
The Emergency escape plan was drawn up with that in mind, i.e. Someone elses problem.
I wonder if it is fitted with some kind of unexpected climb defeat sensor?
What could possibly go wrong?
“This satellite is a backup and we do not anticipate any impacts on consumer service as we retire it. We are replacing it with another satellite in our fleet,” DirecTV told The Register.
Translated it means "something will bork badly, but we will scream at our technicians until the problem is fixed".
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