The Ugly Side of Space Exploration

We may not want to talk about it; nonetheless, it’s happening. Before we can address it, we need to acknowledge it.

Nathaniel Enders
Jun 16 · 7 min read

We’re in a new golden age for space exploration where governments and private corporations are all jockeying for position in the future of space. NASA just announced its Artemis program to return to the Moon, and the program will serve as the first step of the agency’s plan to reach Mars (reference the figure below). Additionally, the United States (U.S.) government challenged the agency to reach the Moon by 2024, and they accepted.

NASA and the U.S. government are not alone when it comes to spacefaring aspirations. China returned to the Moon this year with their Chang’e 4 lander and became the first to land on the far side of the Moon. Next, China’s space agency, China National Space Administration (CNSA), announced plans to build a base in the “next 10 years” at the Moon’s south pole. Also in the news this year, Israel made a valiant effort to reach the Moon but wasn’t able to stick the landing. These are just a few of the headlines; meanwhile, government space agencies around the globe are active, including the European Space Agency (ESA), Japan Aerospace Exploration Agency (JAXA), Indian Space Research Organisation (ISRO), etc.

If the space exploration activities from governments weren’t exciting enough, private companies, led by their billionaire CEOs, are pushing the technological limits on what’s achievable, and by when.

Elon Musk’s SpaceX has set its target on reaching Mars as fast as possible. In parallel, SpaceX is developing its reusable and autonomous-return rocket technology as it launches government and private company satellites and payloads to the International Space Station (ISS). Recently, the company initiated its Starlink effort to provide satellite-enabled internet to Earth. Included in the recent news cycle, Musk expressed his aspirations to offer point-to-point space travel for long distance trips on Earth. He’s advertising that travel times to most cities will be “less than 30 minutes.”

Jeff Bezos’ company Blue Origin and Richard Branson’s companies Virgin Galactic and Virgin Orbit are equally active. Rather than shooting for Mars, Bezos and Branson are focusing their firms’ efforts closer to Earth (i.e., low Earth orbit and commercial activities like space tourism). In addition, Blue Origin and Virgin Orbit have initiated satellite-enabled internet programs of their own that will compete head-to-head with SpaceX’s.

Next, there are budding firms like Relativity Space and Rocket Lab. Relativity Space wants to 3D print rockets in a matter of months (see here for a video on the technology), and as reported by Bloomberg:

“[Rocket Lab] aims to make launching rockets into orbit as common as picking up your mail.”

Rounding out the headlines, NASA just announced that the ISS will be open to private astronauts soon. To understand why NASA is opening up the ISS for private business, see Bloomberg’s interview with NASA’s CFO.

It suffices to say, space exploration activities are booming, and the new golden age of space exploration is just getting started. Whether you’re a space enthusiast and/or a believer that humanity needs to become a self-sustaining, multiplanetary species, it’s easy to get caught up in the excitement. Unfortunately, when this happens, we forget to pause and ask our intrepid government space agencies and private companies to answer the tough questions.

The Tough Questions

Two questions that need to be addressed are:

  1. What is the industry doing to address the current issue that is orbital debris surrounding the Earth, and how will this issue be mitigated moving forward?
  2. Are the rocket propellants being used today releasing carbon dioxide (CO2) into the atmosphere and accelerating climate change? If so, what are the alternatives, and what are the new technologies being developed for long-term sustainability of the industry?

Question 1: Orbital Debris

Orbital debris, commonly referred to as “space trash,” is something that the industry has known about for quite some time now. Even though it puts the future viability of space travel in jeopardy, the issue is not being addressed, and the problem is getting worse. For a brief overview of this issue, ref here and here.

Question 2: Rocket Propellants and Climate Change

Climate change poses an existential threat to humanity, yet there’s little discussion about how rocket launches may be accelerating climate change. As it will be discussed in more detail below, the exhaust gases from some rocket propellants contain the greenhouse gas (GHG) CO2, whereas others release water vapor.

The remainder of this discussion will focus on Question 2 because there appears to be a gap in the mainstream discussion. This does not mean Question 1 is less important. Orbital debris is an equally significant topic, and your author reserves this discussion for a future article.

Understanding the Gravity of the Situation

Before we can discuss Question 2, we need to start with a brief explanation of rocket propellants. Generally speaking, rocket propellants can be either solid or liquid, and they are the fuel that is burned to accelerate a rocket from rest to a speed that will allow it to reach the desired orbit in space.

Rocket propellant is analogous to jet fuel in a commercial airplane. When jet fuel is burned, chemical energy is converted to mechanical energy via spinning a turbine (on the wing) that produces thrust via exhaust gases — this pushes the airplane forward. Similarly, when rocket propellant is burned, chemical energy is converted to thrust via exhaust gases out the bottom of the rocket — this pushes the rocket upwards.

The majority of rockets used by space agencies (e.g., NASA) and private companies (e.g., SpaceX) rely on liquid rocket propellants. Reference the below to see which liquid propellants some commonly known rockets use:

Liquid oxygen (LOX) and highly refined kerosene (RP-1). Used for the first stages of the Saturn V, Atlas V and Falcon, the Russian Soyuz

LOX and liquid hydrogen, used in the Space Shuttle orbiter, the Centaur upper stage of the Atlas V, Saturn V upper stages, the newer Delta IV rocket…” -Wikipedia. June 16, 2019

Referencing the above, liquid oxygen (LOX) and kerosene are common propellants used for the first stage of some rockets. Kerosene is a hydrocarbon (fossil fuel), and when LOX and kerosene are burned together, the GHG CO2 is produced in the exhaust gases.

For reference, burning any fossil fuel releases CO2 as a byproduct (gas). The chemical reactions below are entry-level and readily understood without needing a chemistry degree.

When LOX and liquid hydrogen are burned together, they produce water vapor as the exhaust gas — no CO2 is released (zero-emissions):

To summarize, two of the most common liquid rocket propellants used today are:

  1. LOX + kerosene: releases CO2 when burned
  2. LOX + liquid hydrogen: no CO2 is released when burned (zero-emissions)

When LOX and kerosene are used as propellants for the first stage, a rocket release CO2 into Earth’s atmosphere. For reference, the first stage is the portion of a rocket’s propulsion system that is burned first to lift the rocket off the ground. After it burns all of the propellants in the first stage, the rocket sheds the first stage and ignites the upper stage to continue propelling the rocket into space.

The issue with this process is that many of the rockets that we’re launching today — e.g., SpaceX’s Falcon 9 and Falcon Heavy (same engines as Falcon 9), Russia’s Soyuz — use LOX and kerosene for the first stage. This means they are releasing massive amounts of CO2 into Earth’s atmosphere during each launch. In order to avoid the existential consequences associated with rising CO2 levels in Earth’s atmosphere, we need to transition off of fossil fuels as rapidly as technologically feasible.

When we are aware of the associated damage produced by such rocket launches, it’s difficult to rationalize the dire need to become zero-emissions while having enthusiastic support for increased space activities.

Your author supports space exploration and believes we need to continue pushing humanity’s reach into the cosmos. However, we need to ask the hard questions and solve them in tandem with celebrating the other technological successes. Humanity will not become a self-sustaining, multiplanetary species by reaching Mars if we destroy the Earth in the process. If that happens, we’ve simply moved our problems to a different planet, and we’re right back where we started.


Reference “Dear Earth, From Mars: Declaration of Independence” for a futurist perspective on what will happen after humanity becomes self-sustaining on Mars.

For more information on climate change, reference “How to Discuss Climate Change w/ Family & Friends” for a beginner’s guide with talking points, questions, references, and figures.

To obtain “key reports on climate action, climate economics, and on issues that highlight climate impacts and solutions,” reference the summary provided by the United Nations (UN).


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Nathaniel Enders

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Engineer & entrepreneur, product/project/program manager, thought leader. Starting conversations about technology, society, and the future of humanity.

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