Getting Down to Earth with Satellites

Getting Down to Earth with Satellites

The space business is dirty and environmentally hostile. 

Space transportation has always been dirty. Rockets are a case in point. Get a tubefull (or several tubefulls) of propellant, make sure the tube is pointing the right way, and light the tube up. If everything goes right, it rises into the sky amidst smoke and dust to deploy a payload, and then the tube falls back to Earth. 

Some engineers tried different approaches to the tube, chiefly intending to have it returned for use again. NASA’s space shuttle program comes to mind. But, customers–especially the U.S. Department of Defense–wanted reliable orbital rockets that could lift more mass, which is why SpaceX’s Falcon 9 was such a surprise. 

No customers asked for a reusable rocket, and many still don’t appear to care. But reusability is a slight nod toward becoming a little more environmentally friendly–the whole “reuse” thing. Launching orbital rockets remains dirty and not great for the environment, but at least reusing rocket stages takes it down a notch. While SpaceX increases its annual orbital launch cadence and totals, thereby increasing the pollutive aspects of launches, at least it’s not littering the oceans with a first stage every launch. 

The company has proven that reusability is feasible. The challenge is getting other rocket manufacturers to adopt the concept. Getting some companies on board is akin to pulling teeth. They resist despite SpaceX’s apparent successes.

Throwing Away Satellites

Spacecraft might become another industry challenge, environmentally, specifically those deorbiting/reentering. That particular activity might be more challenging to address because orbiting spacecraft are typically invisible to everyday humans. That lack of visibility can result in many people not caring about what happens above them. It translates to less pressure on space operators and manufacturers to change from accepted legacy practices for disposing of satellites in low Earth orbit, which, in essence, promotes littering.

Local governments usually can fine people for littering. National governments have laws for how companies dispose of material. Treaty agreements between governments attempt to mitigate some of humanity’s impacts on the Earth. 

Somehow, it’s okay for companies to “litter” the Earth’s atmosphere with spacecraft particulates. It’s OK to have spacecraft hit the Earth and potentially spread whatever remaining propellants, metals, etc., into the environment, such as the oceans or wetlands. It’s not only okay, but most spacecraft deployed are required to do so after a certain number of years.

The companies themselves are also following in the footsteps of government spacecraft operators before them. If disposing of spacecraft that way worked for the government, then surely it makes sense to follow that example. Except…did it make sense even then? Humans are learning the hard way that oceans are not an unlimited resource (even if they seemed so not that long ago). They can’t be used as waste bins and sewage lagoons, even as spacecraft deorbit and impact the less populated ocean areas.

More Satellites=More Deorbits

I suggest that we are treating the Earth’s atmosphere about as cavalierly. It’s vast, and a few deorbiting spacecraft didn’t seem to have any impact. Maybe they didn’t. Perhaps a few hundred over a few decades weren’t enough to impact the atmosphere that much. The first few hundred candy wrappers people threw about at random probably didn’t seem too bad, either, even if it wasn’t a good habit to embrace.

But shouldn’t a standard industry practice be re-evaluated if it looks to happen on a larger scale? One company, SpaceX, already operates thousands of spacecraft in orbit, with thousands more on the way. Kuiper has plans to deploy thousands as well. Several other companies plan to deploy hundreds, if not thousands, of satellites. If they achieve low Earth orbit, almost all will be disposed of by deorbiting back to the Earth.

SpaceX (as an example) operates over 6,000 spacecraft (including SpaceBees) as of mid-May 2024. However, it deployed over 6,600 from 2018 until May 2024. Over 600 of its satellites have deorbited during that time (~100 satellites per year on average). That’s 9% of all SpaceX’s deployed satellites, an estimated 124,600 kilograms of mass reentering Earth’s atmosphere. From one company.

SpaceX deorbited ~140 Starlinks alone in 2022 (nearly 40,000 kg), the most deorbited during the constellation’s existence. At the time, the company had deployed slightly half (~55%) of all Starlinks deployed so far. In a way, the deorbits–the deliberate destruction of technology–run counter to SpaceX’s pride and messaging surrounding its reusable rocket. 

To be clear, however, SpaceX isn’t the only one; it is merely the most significant contributor. Other companies have shown what can happen if business plans depend on high satellite turnover or unreliable satellites. Planet is an example of the former. From 2018 through mid-May 2024, the company deorbited a little over 110 satellites, about 41% of the 277 it deployed. Capella, an example of the latter, deployed 12 satellites during the same span, but 67% (8) of those deorbited. Seven of those 8 deorbited less than three years after their deployment.

Imagine if 41%-67% of Starlink’s satellites were deorbited during the same timeframe. The estimated mass of Planet’s and Capella’s deorbited satellites combined was slightly over 1,700 kilograms. But 41% of 6,600 Starlink satellites comes to 2,706 satellites. If we referenced the estimated mass of the latest non-cellular version of Starlink (800 kg) and assumed they made up all of those deorbits, that adds up to nearly 2,165,000 kg. At 67%, the mass goes to over 3,500,000 kg. And make no mistake, eventually, 100% of those 6,000 Starlink satellites will deorbit.

As noted before, other companies plan to deploy significantly more, resulting in more mass deorbiting and possibly harming the atmosphere and the Earth. No one knows how reliable their satellites will be. And their business plans may hinge on deorbiting older satellites as quickly as possible. 

What Options or Solutions?

At the same time, what are the other options? Non-functional and obsolete satellites should not occupy orbital slots, especially if they can’t be controlled and present a hazard to surrounding spacecraft. They might also be the source of other issues, such as possible power supply or propellant explosions. The orbital positions they occupy are better served with operational satellites. Gravity and drag naturally cause satellites in low Earth orbit to eventually reenter the atmosphere. 

Suggested solutions vary from one-to-one satellite retrieval and revitalization to using lasers to destroy them. Whatever the proposed solutions are, the constellation growth is so one-sided that if politicians try to address it, the topic could get nasty quickly. Other nations, especially China and Russia, can correctly point out the relatively small number of spacecraft they deploy annually. Why should they change their satellite disposal practices?

However, companies in China plan to deploy more spacecraft. And Russia’s current space lead has also revealed a desire to manufacture and deploy more. Both will contribute to the increase in satellite deorbits once they implement their plans. In their self-interest, they might also eventually conclude that satellite deorbits are problematic.

While some agencies are working hard on “demisable” spacecraft, which will theoretically result in total obliteration of a spacecraft during deorbit, I’m not sure that’s the answer. How thoroughly will a satellite “demise”? Would people have to worry about micro-aluminum or micro-titanium showing up somewhere in the world?

I am not advocating a complete halt to space activities. I advocate that space companies, especially satellite operators and manufacturers, become more thoughtful in their designs and business plans. It probably would be extremely helpful if governments started pushing clearer guidelines for disposal requirements and undergirding studies to answer questions arising from millions of kilograms deorbiting through the Earth’s atmosphere.

Can spacecraft operators and manufacturers answer those questions with provable data? What happens to the material that sheds off a deorbiting spacecraft? Is it totally gone, or are there particulates to worry about? If it doesn’t get burned up, does the material negatively affect the environment into which it impacts? That kind of information (and more) should be available for reference as companies form their plans. Some have begun studying the possibilities already.

The world may not suffer from potentially thousands of spacecraft deorbiting annually. It doesn’t seem worse for the wear from the daily meteor bombardments it goes through. But meteorites are made of different stuff than satellites. They don’t have batteries, propulsion systems, solar panels, etc. 

There is another aspect to this challenge as well–it’s full of opportunities. From designing and manufacturing spacecraft parts that leave no trace during deorbit to processes that somehow tear down and recycle spacecraft fully, a few opportunities will prove viable and profitable. The space industry will always be dirty, but maybe a few innovative companies will change that somewhat.

If you liked this article (or any others from Ill-Defined Space), any donations are appreciated. For the subscribers who have donated—THANK YOU!!

I'm a Giver. Let me donate!