ADVANCED MATERIALS: COMPOSITES IN ROCKETS, PROBES, AND ROVERS
The first rockets to travel to the Moon used conventional, aluminum alloy hulls—they were simple in comparison to current rockets which have landed probes on Mars and Titan. The current rockets’ hulls are more complex using composite materials. But why composite materials? A composite material is a solid that is (by definition) made of disparate components; that when taken together will outperform “conventional” materials. So, in essence, the design and construction of spacecraft has undergone a revolutionary paradigm shift. Lunar module spacecraft and the lunar rovers (of Apollo) needed different types of metal and other composite materials to function on the surface of the moon. When Armstrong and Aldrin reported of the “tacky” consistency of lunar dust (the lunar dust crept “everywhere” into their suits), NASA engineers realized that the eventual deployment of a “lunar rover” would require different types of composite materials. In contrast, Martian “dust” is ferromagnetic—so the iron in Martian dust is attracted to permanent magnetic materials. And here again, the eventual astronauts who will venture to the “Red Planet” will face an entirely different, and dangerous set of circumstances. These circumstances are reasons why traveling within the Solar System will be more difficult than initially imagined—thus technological advancements may need to be in the pipeline prior to their launching.
Currently, the outer hulls of many satellites and probes are constructed from a modified aluminum alloy, and—in recent years—however, different regions of the Solar System require disparate probe (and rocket) components. For instance, when the Messenger spacecraft orbited Mercury, conventional aluminum alloys would have rendered the interior of the probe too hot when facing the Sun and too cold when the probe was on the dark side of Mercury. Certain components in Messanger would have failed. Because aluminum is a good conductor of heat—the deployment of a “laminar composite” in place of the aluminum alloy would shield the sensitive, electronic components. The same temperature concept holds true for the New Horizons probe that is hurdling to the Pluto/Charon system.
In general, composite materials will outperform the current, modified Aluminum alloys for the following reasons:
Weight considerations are to tantamount to amount of fuel—or in other words, economic hardship. Composites can contribute 30 % less weight of the rocket at launch-time.
Keeping thermally sensitive components at nominal operating temperatures increases operating efficiency
Composite materials possess different “shielding” properties—not allowing certain cosmic and solar ejecta passage through the hull of craft.
In the forth-coming years, learning to adapt to new environments on unfamiliar planets will increase our chances for success—it, also, may foretell how likely we are to find new microbial life in the Solar System.
Physical Protection of Radiation Protection in Space Travel, in Reviews of Modern Physics, 2011, Vol. 83, No. 4., Marco Durante and Francis A. Cucinota—authors.
Deep Space Probes. 2nd ed. Springer-Praxis Publishing, 2005, Gregory L. Matloff—author.
Fundamentals of Space Systems. 2nd ed. Oxford University Press, 2005, Vincent L. Pisacane—editor. (I focused on chapters 2, 7, and 8 for my primary information.)