From the Moon to Earth
With China's first Moon probe expected to launch early this fall, and India's first Moon mission (carrying several U.S. science instruments) to follow next year, it's nice to think these new players in lunar orbiting are devoted to pure research and peaceful science. After all, the Moon is a long, long way from earthly squabbles.
But underappreciated lessons in recent space navigation should remind us the Moon has enormous value beyond its troves of knowledge and possible material wealth. It has a nearby gravity field, which commercial interests have already exploited and plan to do again. Ultimately, the potential to exploit the Moon's gravity for military purposes needs wider recognition, if only to dissuade those who might be tempted.
The technique's first success came in 1999, when a rocket malfunction stranded a commercial communications satellite in a useless transfer orbit. The satellite did not have enough fuel to reach the desired 24-hour orbit directly, and the insurance company paid off on the "total loss."
The company then boldly hired some innovative celestial mechanicians to plot a path to the Moon, where a close swing-by twisted the satellite's orbital plane into the desired orientation and sent it back toward Earth. There, a gentle rocket burn slowed the satellite into its proper operational orbit. And a commercial customer began paying for its services.
Russian space navigators had known about this potential trick for years. Their interest stems from Russian launch sites being located so far north. This means rockets need to carry lots of fuel to change a satellite's orbital plane to the highly desired equatorial final orbit. Launching one of their standard rockets from the equator would double its deliverable payload. (The Russians are now building exactly that kind of launchpad at Kourou, French Guiana.) Flying past the Moon provides similar performance benefits.
The military angle is a little frightening. China's anti-satellite rocket test in January was shocking, but not too worrisome because such a weapon can't reach high-altitude orbits. Rockets that might be launched toward critically important defense satellites in 24-hour orbits or in the 12-hour orbits used by navigation payloads would be detected easily as they flew.
But a probe rounding the Moon and headed back to Earth would be absolutely undetectable by radar or by telescope. It could slip into an orbit matching its target, and even its braking rocket burn would almost certainly pass unnoticed. The craft could lurk nearby for future activation -- or simply create the fear that it and others like it were lurking nearby -- and seriously erode confidence in the survivability of space infrastructure.
This stealth space threat, sadly, is made possible by the Moon's nearby gravity field and by human ingenuity. Another flavor of ingenuity may be able to counter such vulnerabilities one day. But either way, the Moon is much more involved in earthly affairs than most people would have dreamed, or hoped.
By Jim Oberg
But underappreciated lessons in recent space navigation should remind us the Moon has enormous value beyond its troves of knowledge and possible material wealth. It has a nearby gravity field, which commercial interests have already exploited and plan to do again. Ultimately, the potential to exploit the Moon's gravity for military purposes needs wider recognition, if only to dissuade those who might be tempted.
The technique's first success came in 1999, when a rocket malfunction stranded a commercial communications satellite in a useless transfer orbit. The satellite did not have enough fuel to reach the desired 24-hour orbit directly, and the insurance company paid off on the "total loss."
The company then boldly hired some innovative celestial mechanicians to plot a path to the Moon, where a close swing-by twisted the satellite's orbital plane into the desired orientation and sent it back toward Earth. There, a gentle rocket burn slowed the satellite into its proper operational orbit. And a commercial customer began paying for its services.
Russian space navigators had known about this potential trick for years. Their interest stems from Russian launch sites being located so far north. This means rockets need to carry lots of fuel to change a satellite's orbital plane to the highly desired equatorial final orbit. Launching one of their standard rockets from the equator would double its deliverable payload. (The Russians are now building exactly that kind of launchpad at Kourou, French Guiana.) Flying past the Moon provides similar performance benefits.
The military angle is a little frightening. China's anti-satellite rocket test in January was shocking, but not too worrisome because such a weapon can't reach high-altitude orbits. Rockets that might be launched toward critically important defense satellites in 24-hour orbits or in the 12-hour orbits used by navigation payloads would be detected easily as they flew.
But a probe rounding the Moon and headed back to Earth would be absolutely undetectable by radar or by telescope. It could slip into an orbit matching its target, and even its braking rocket burn would almost certainly pass unnoticed. The craft could lurk nearby for future activation -- or simply create the fear that it and others like it were lurking nearby -- and seriously erode confidence in the survivability of space infrastructure.
This stealth space threat, sadly, is made possible by the Moon's nearby gravity field and by human ingenuity. Another flavor of ingenuity may be able to counter such vulnerabilities one day. But either way, the Moon is much more involved in earthly affairs than most people would have dreamed, or hoped.
By Jim Oberg
Labels: astronomy, interesting
posted by Josh Prescott @ 12:07 PM
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