Those who are familiar with climate change may remember that carbon dioxide (CO2) is a powerful greenhouse gas that can trap heat in the atmosphere. Now Elon Musk announced that SpaceX will conduct a carbon capture program that can remove CO2 from the atmosphere and use it to make rocket fuel.
Carbon dioxide can be removed from the atmosphere with a variety of methods, including air scrubbers, absorption, and chemical catalysts. Then it can be combined with water (H2O) to create hydrocarbons that form the basis for petroleum and methane.
Environmentalists have criticized the aerospace industry for the greenhouse gases that rocket launches can release into the atmosphere. Some experts say that a single Falcon 9 launch generates between 200 and 300 metric tons of carbon dioxide.
The ability to remove carbon dioxide from the atmosphere to create rocket fuel could address some of the critics, however.
It could also be useful for creating alternative fuels for other applications, even though Tesla’s electric vehicles are unlikely to get much use out of it.
“Will be useful for Mars”
The concept of In-Situ Resource Utilization (ISRU) has increasingly been seen as critical for cost-effective and sustainable human exploration of other worlds, including Mars. ISRU involves using local resources in situations in which importing resources from “back home” might be prohibitively expensive or impossible.
The most successful historical explorers of Earth often traveled light and used something like ISRU – harvesting essential resources like food and water from local sources – while they were exploring the frontier.
Mars’ atmosphere is thin but still 95% carbon dioxide. As part of ISRU efforts, air scrubbers could remove carbon dioxide from Mars’ atmosphere and store it to create fuel. In some places on Mars, it may also be possible to harvest frozen water from the planet’s surface for both drinking water and the creation of rocket fuel. This could save the expense and difficulty of sending rocket fuel to Mars for the journey home.
NASA plans to use the Moon to test some ISRU techniques, including the extraction of water at the lunar south pole. SpaceX is a subcontractor for some robotic lunar lander missions commissioned by NASA to scout for water and conduct science efforts on and around possible crewed landing sites for Artemis. SpaceX will launch lunar landers and rovers on the Moon for Firefly Aerospace, Astrobotic, and Intuitive Machines.
Elon Musk cited ISRU when announcing the CO2 removal program: “Will be useful for Mars.”
Musk plans to make his Starship rocket capable of refueling in Earth orbit. SpaceX has a contract with NASA to demonstrate this capability. However, possibly Starship-derived Mars landers are likely to be capable of refueling on Mars using ISRU-related techniques.
Musk’s ultimate goal is to establish a self-sustaining city on Mars. His development of reusable hardware seems geared toward bringing the costs of such a venture down. Musk says he could send as many as 100 Spaceship spacecraft to Mars during every launch window, which happens about once every two years.
And, yes, it does bring the costs of rocket launches down for other parties interested in sending hardware and people into space. Launches of the reusable Crew Dragons cost NASA only $55 million a seat, as opposed to as much as $95 million a seat on the Russian Soyuz.