The researchers assumed that a fast-growing suborbital space tourism market will develop over the next decade and examine the climate impact of soot and carbon dioxide emissions from 1,000 suborbital rocket flights per year, the approximate number advertised in recent materials promoting space tourism.
"Rockets are the only direct source of human-produced compounds above about 14 miles [22.5 kilometers] and so it is important to understand how their exhaust affects the atmosphere," says the study's chief author, Martin Ross, of The Aerospace Corporation in El Segundo, California. He and his colleagues describe their findings in a scientific paper that has been accepted for publication in Geophysical Research Letters, a journal of the American Geophysical Union.
The study provides the first detailed look at how rockets using hydrocarbon fuel might affect Earth's climate system The researchers find that soot particles emitted by the proposed fleet of space tourism rockets would accumulate in a stratospheric layer at about 40 kilometers (25 miles) altitude, three times the typical altitude of airline traffic. These particles efficiently absorb sunlight that would otherwise reach the earth's surface, causing projected changes in the circulation of the earth's atmosphere from pole to pole. Unlike soot from coal power plants or even jet aircraft, which falls out of the atmosphere in days or weeks, particles injected by rockets into the stratosphere remain in the atmosphere for years.
"The response of the climate system to a relatively small input of black carbon is surprising," says Michael Mills of the National Center for Atmospheric Research in Boulder, Colorado, a study coauthor, "and our results show particular climate system sensitivity to the type of particles that rockets emit." Even though the rockets are assumed launched from just one site in North America, the entire atmosphere adjusts to the rocket soot with a complex global pattern of change.The study, which utilized a sophisticated computer model of the earth's atmosphere, finds that beneath the thin stratospheric layer of rocket soot, which remains relatively localized in latitude and altitude, the earth's surface could cool by as much as 0.7 degrees Celsius (1.2 degrees Fahrenheit).
Meanwhile, Antarctica could warm by 0.8 degrees C (1.5 degrees F).
Ozone is also affected, with equatorial regions losing about one percent and the poles gaining about 10 percent. The globally integrated effect of these changes is, as for carbon dioxide, to increase the amount of solar energy absorbed by the earth's atmosphere. In this case, as long as the launches continue at the assumed rate, soot from the suborbital rockets contributes to atmospheric heating at a rate significantly higher than the contribution from the carbon dioxide from those same rockets.
"The assumptions driving our calculations are consistent with business plans for commercial suborbital space travel in the year 2020" says Ross, "and perhaps they will not materialize. Nevertheless, our findings would also apply to the global fleet of hydrocarbon-fueled orbital rockets used today, though they emit about one tenth of the soot that we assumed in this study."
"Climate impact assessments of suborbital and orbital rockets must consider black carbon emissions, or else they ignore the most significant part of the total climate impact from rockets," he adds. "This includes existing assessments that may need to be brought up to date."
Darin Toohey of the University of Colorado in Boulder, also a coauthor, says the team based its work on reasonable assumptions about rocket chemistry and atmospheric physics. "Yet we are unsure about actual rocket emissions," he notes, adding that "measurements in actual rocket plumes and further climate modeling will be needed to gain confidence in these results."
The research was funded by The Aerospace Corporation and NASA.Title:
Peter Weiss | American Geophysical Union
The Great Unknown: Risk-Taking Behavior in Adolescents
19.01.2017 | Max-Planck-Institut für Bildungsforschung
A sudden drop in outdoor temperature increases the risk of respiratory infections
11.01.2017 | University of Gothenburg
An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
19.01.2017 | Event News
10.01.2017 | Event News
09.01.2017 | Event News
20.01.2017 | Awards Funding
20.01.2017 | Materials Sciences
20.01.2017 | Life Sciences