ESA's Sentinel-1A satellite narrowly dodges debris

There was a sigh of relief from ESA controllers over the weekend as the Copernicus Sentinel-1A satellite successfully dodged a decades-old rocket fragment. The debris' closing speed was over 50,000 km/h (∼31,068 mph) and it was expected to come close enough that controllers opted to perform a pair of thruster burns in order to …

[b0llchit]

Clutter must go

And yet we launch more into space, increasing the clutter as we go. There are numerous problems cleaning up.

The fact remains that every single launch puts debris in orbit. So a cleaning mission will add to the clutter before it can start removing some. And how exactly are we going to catch and clean a 5000+ m/s fast bullet sized particle? Lets face it, most of the small stuff will be there for a very long time generating more and more clutter as time passes. It is almost like waiting for a chain reaction to start.

[imanidiot]

Re: Clutter must go

There's some argument that we're already in a Kessler syndrome cascade, it's just a very slow process at the start. People imagine a single huge event like in "Gravity" but the reality is that a Kessler cascade would likely take several decades to develop and we might already be in one.

[b0llchit]

Re: Clutter must go

If, on average, one collision creates more than one new piece of debris, then it is a lost cause. Then we are looking at the Kessler syndrome and cascades will eventually cause all LEO and MEO positions to become filled with bullets in any direction.

Space, the final frontier. These were the adventures of less than a century of spaceflight. Now get me a vacuum cleaner that works in vacuum. Maybe a warp capable suction tube?

[Yet Another Anonymous coward]

Re: Clutter must go

>If, on average, one collision creates more than one new piece of debris, then it is a lost cause

It's a little more complicated than that

If a collision in LEO creates a lot of smaller pieces there will be more drag and they will deorbit faster than the original big piece

A collision between two similar size pieces will end up with debris with a range of kinetic energies and so some will end up in higher orbits than the original

worst case is it if some idiot shoots at an object and ends up boosting some debris into much higher longer lived orbits

[Peter X]

Re: Clutter must go

My entire knowledge of orbital mechanics is based on KSP! So with that in mind, if something was happily orbiting at a given height/velocity and it gets hit by a projectile causing it's height to be raised, wouldn't it then be more likely to de-orbit quicker due to not having the required velocity to support the new orbit?

[imanidiot]

Re: Clutter must go

In KSP terms, an impact like that only raises the orbit on the other side of the planet (could be Apoapsis or periapsis if the impact is near one of the two), but leaves the altitude at the point of impact pretty much alone. If it's an angled impact (not entirely along the trajectory vector) then you'll get a shift in orbit around the impact point as if you did a (anti)normal or (anti)radial burn. This may or may not affect the periapsis or apoapsis slightly, but is unlikely to change it very much. Basically the analogy would be like having a MASSIVE engine on a very small rocket, and then doing a very short burn somewhere vaguely pro-grade-ish. You have to burn a lot in normal or radial directions to change the orbit very much (since your orbital vector is already 2 km/s long in the prograde direction) but a change in orbit apoapsis requires far less change.

Ofcourse if the collision is head-on then things could end up in a lower orbit too but head-on prangs have so far not happened afaik. Even the ASAT tests were oblique shots coming from the side.

[Sp1z]

Re: Clutter must go

https://twitter.com/rocketn00b/status/1057679715757109250/photo/1

But raise it a few thousand km

[imanidiot]

Re: Clutter must go

Only if those pieces stay in orbit indefinitely in a perfect vacuum. The reality isn't that and for LEO orbits it's not that bad. It mostly becomes a problem in MEO and GEO orbits.

[ThatOne]

Re: Clutter must go

The solution is to print and sell bumper stickers: "Space debris must go!"... Profit (for you, not the planet).

Seriously now, as you said, catching small hypersonic objects moving in vast swarms in a mind-boggling huge 3-dimensional space is challenging at best. Especially when you consider the cost of sending anything up there -- without any hope of getting any of that money back, which means nobody will finance this. A back of an envelope calculation shows you'd have to spent at least twice the money any initial, littering mission had cost, and that without being even sure to gather all the debris since their numbers increase exponentially. Not to mention your clean-up will certainly create some new debris, which will need sweeping up too.

So, technical difficulties, lack of funds, general "why should I care" mentality, chances are business will continue as usual, even if they have to make new satellites jump around like ninjas to avoid the ever increasing buckshot volleys coming from all sides.

I'm not optimistic about this, can you tell?

[Graham Cobb]

Re: Clutter must go

So, can't we incentivize private companies to do this? In the seas, we have the concept of salvage, with the extension of the International Salvage Convention in 1989 to guarantee payments to salvors who try to prevent environmental damage.

Can't we set up a process for space salvage, to provide an economic reward to those who succeed in cleaning up space junk? Maybe based on the mass of material they manage to collect and can demonstrate to have caused to burn up in the atmosphere? The scheme would be international (like the International Salvage Convention) and would be funded by a tax on launches (proportional to their mass).

[Yet Another Anonymous coward]

Re: Clutter must go

>would be funded by a tax on launches (proportional to their mass).

So each US/Eu commercial launch will have $Bn of tax added to pay for clearing up cold war era missile tests, while 'glorious republic of Borat ex-CCCP launcher' will offer tax and regulation free launches to anyone

[Graham Cobb]

Re: Clutter must go

Yes - future users of space pay to clear up the mess left behind, so that they reduce the risk of their equipment being damaged. It is in their interest.

There is little risk of launches not paying their dues. Not only are there plenty of other examples of internationally funded services which are in everyone interests to contribute to, anyone launching without paying will find that the scalpers will quickly spot that it is easiest to collect their money on sending stuff back down before it has had a chance to reach a high orbit or deploy its payload.

[ThatOne]

Re: Clutter must go

> can't we incentivize private companies to do this?

There is only one incentive for a commercial company: profit.

Now, unlike sea salvage, where you (cheaply) "save" whole, well-insured vessels full of valuable cargo, there is little to no profit in (expensively) "saving" bolt-sized bits of flying junk.

As for the tax issue, as "Yet Another Anonymous coward" already stated, it wouldn't really work. Nobody likes paying for somebody else's errors, and there would be a lot of finger pointing and blame avoiding maneuvers. Millions would go to lawyers, nothing to actual space cleaning.

Some extremely rich person or entity would have to willingly decide to finance this entirely from their own pockets, with no hope of any return or profit, which obviously is unlikely to happen. Not only are those entities extremely rare, but also it's more likely they single-handedly decide to make the problem worse...

[Graham Cobb]

Re: Clutter must go

I disagree. The changes to the International Salvage Convention in 1989 were specifically to incentivize the (very similar) problem of encouraging salvors to address the very hard, risky, and unprofitable problem of oil pollution.

Previously they only attempted salvage if they would be able to recover either the ship or the contents. The changes encouraged them to address the marine equivalent of "bolt-sized bits of flying junk".

It may be that an initial step would be to do something to make sure that insurers for today's launches will feel great pain if they contribute to the mess, to cause them to drive the industry to solve the problem with a suitable international salvage treaty.

[ThatOne]

Re: Clutter must go

> It may be that an initial step would be to do something to make sure that insurers for today's launches will feel great pain if they contribute to the mess

I agree that might be a potential solution, but I'm not sure it addresses the problem "Yet Another Anonymous coward" raised, that of rogue operators offering cheap and hassle-free launches, not burdened by pesky laws and obligations. Just look at the present situation: The main space-faring nations are at loggerheads, so how would you enforce such a law today, if it existed? Economic sanctions? Official protests in the international institutions? Too late...

[TRT]

Re: Clutter must go

Bumper stickers? What? Like for sticking on orbital Teslas or something?

[alain williams]

100 meters at 50,000 kmph

is not a lot of room for error. I am impressed.

How large was this bit of debris ?

[David Gosnell]

Units

I misinterpreted the "kmph" as 1000 miles per hour... 7% of c would be getting into relativistic realms.

[Anonymous Coward]

Re: Units

That's why "kilometers per hour" should be written "km/h", as Europeans do. IMHO.

[John Brown (no body)]

Re: Units

Like km/h, another option is kph such as on the speedo[*] of my car

* inner ring of the dial. The outer is still in mph.

[MiguelC]

Re: the speedo[*] of my car

Why does your car have swimwear?

[Paul Crawford]

Re: the speedo[*] of my car

It helps them smuggle budgies.

[John Brown (no body)]

Re: the speedo[*] of my car

I'm guessing it's not called a speedo in other English speaking countries then?

[Anonymous Coward]

@John Brown (no body) - Re: Units

A little bit imprecise, k-what per hour ?

OK, so you're South of the border because on mine it's the other way around: km/h on the outside and mph on the inside. Funny thing is Canadians are using imperial or metric system so that the displayed price is lower: you buy gas in litres and potatoes in pounds, you measure distances in m or km but if you buy something by the length it's in '/"/ft etc.

[John Brown (no body)]

Re: @John Brown (no body) - Units

"OK, so you're South of the border"

Correct, I'm south of the border. I wasn't aware car speedos were different north of the border in Scotland though.

Maybe we are talking about different borders? :-)))

[Yet Another Anonymous coward]

Re: Units

That's why "kilometers per hour" should be written in km/s - unless you are using a sundial to do the timing

[imanidiot]

Re: Units

I have not had much reason to use kilometres per second for much outside of spacecraft velocities. I don't know about your car but mine would struggle to reach anything even approaching those speeds.

[John Brown (no body)]

Re: Units

Mines does!!! Unfortunately there's only a zero before the decimal point and the first non-zero digit is in the 100ths place :-)

[Potemkine!]

Re: Units

"The SI explicitly states that unit symbols are not abbreviations and are to be written using a very specific set of rules. M. Danloux-Dumesnils provides the following justification for this distinction:

It has already been stated that, according to Maxwell, when we write down the result of a measurement, the numerical value multiplies the unit. Hence the name of the unit can be replaced by a kind of algebraic symbol, which is shorter and easier to use in formulae. This symbol is not merely an abbreviation but a symbol which, like chemical symbols, must be used in a precise and prescribed manner.

SI, and hence the use of "km/h" (or "km h−1" or "km·h−1") has now been adopted around the world in many areas related to health and safety and in metrology"

But sadly not yet by Anglo-Saxon news websites...

[ravenviz]

Re: Units

I suspect that the speed and the flight adjustment should at least have some common scale e.g. 100 m manoeuvre to evade an object travelling at 15,000 m/s gives a better sense of scale.

[David Gosnell]

Re: Units

Updated now, anyway. Apt author name, might have been expected to know better?