Credit: ESA

I’ve had a keen interest in orbital debris for decades – writing for various publications on this topic from SpaceNews newspaper, SPACE.com to Foreign Policy magazine, as well as the Bulletin of Atomic Scientists.

Call it a reporter’s instinct, but I believe there’s a line of research that needs exploring: The overall impact of human-made orbital debris, solid and liquid propellant discharges, and other space age substances that reenter the Earth’s atmosphere.

 As for total mass of uncontrolled objects and human-made junk that reenters each year – it’s upwards of 80 metric tons. But that’s the trackable big stuff – never mind a deluge of other types of clutter – be it particles from spent solid rocket boosters to still-radioactive coolant that has been leaked from old nuclear-powered Soviet satellites.

It’s a garbage dump of heavenly proportions.

Credit: The Aerospace Corporation/CORDS

Guilt factor

I have been guilty, as have other reporters, of using the toss away line that this incoming material “burns up” – but in my view this is far from accurate. The chemistry from high heating of spacecraft materials – including beryllium, lithium, aluminum, nickel, etc. – is worthy of review, specifically the impact of this inflow of materials into Earth’s atmosphere, top to bottom.

In the recent past, Earth has been on the receiving end of large satellites, such as NASA’s decommissioned Upper Atmosphere Research Satellite (UARS), the Roentgen Satellite, ROSAT, a Germany/US/UK collaboration, as well as the failed Mars probe, Russia’s Phobos-Grunt – a vehicle also loaded with toxic fuels.

Fast forward to the present, keep an eye on China’s Tiangong-1 space lab closing in on its uncontrolled reentry early next year.

Artist’s view of China’s Tiangong-1 space station in Earth orbit.
Credit: CMSA

 

Slight-of-hand physics

In my opinion, we have conditioned ourselves to use the words “dissipate” and “burn up” as if some celestial slight-of-hand physics is at work that causes incoming junk to simply “vanish” and “disappear.”

I continue to look into this issue – and have some new upcoming surprises to report.

One early story was my published article in SpaceNews newspaper many years in the past – in fact, now over two decades ago.

Back in June of 1995, I wrote about a series of U.S. Air Force-sponsored studies having found that space hardware re-entering the atmosphere contributes to ozone depletion. The reentry process produces materials that combine with other elements in the Earth’s upper stratosphere that can produce a chemical reaction that leads to ozone reduction.

The studies also found that conventional rocket propellants released during launches produce byproducts that also are harmful to stratospheric ozone.

Lack of analysis

A series of separate space debris and ozone impact reports completed in 1994 were prepared for the Environmental Management Division of the U.S. Air Force’s Space and Missile Systems Center in Los Angeles by TRW’s Space & Electronics Group in Redondo Beach, Calif., and The Aerospace Corporation in El Segundo, Calif.

“The impetus for these studies is to get our arms around what environmental impacts are there, potentially, in using space. This is a new frontier and a lot of this analysis hasn’t been done before,” said John Edwards, project officer of the studies and chief of the Air Force’s Environmental Management Division I noted in my SpaceNews piece.

View of the planet Earth from space during a sunrise.
Credit: SWRI

According to the TRW study entitled “Effects of the Impact of Deorbiting Space Debris on Stratospheric Ozone,” objects re-entering the atmosphere can affect ozone in several ways, but not on a significant level globally.

That said, as an object plows through the Earth’s stratosphere, a shock wave is created that produces nitric oxide, a known cause of ozone depletion. Spacecraft and rocket motors are composed of metal alloys and composite materials that melt away during re-entry. TRW researchers found that these materials, as they undergo intense heating, also form chemicals that react directly or indirectly to consume ozone.

Quadrennial assessment

Again, that was back then…but what about today?

For one, get ready for a new look at the issue of rocket emissions in an approaching United Nations 2018 Quadrennial Global Ozone Assessment that delves into substances that are responsible for ozone depletion.

Overall, given the multi-country upswing in rocket launches, the growth of spacecraft in Earth orbit, and the associated leftovers to get them there – could the Earth’s fragile atmosphere be under attack?

Clutter in the cosmos.
Credit: Used with permission: Melrae Pictures/Space Junk 3D

 

 

Just a passing thought – perhaps one not to pass by lightly.

I welcome other opinions on the role that the reentry process of human-made materials might have on the atmosphere, particularly at very high altitudes. Again, I feel that this topic area is worthy of investigation.

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