Artificial Skies

Look up on a clear night and you might see the moon, stars, an airplane, a Pentagon observation balloon, police drone, one of Elon Musk's Starlink communication satellites, or a Loon balloon from Google's Alphabet fleet that can provide wireless internet access to rural and remote areas.

     Shortly after a Starlink rocket launch, a satellite is almost as bright as the North Star, a magnitude 2. When it reaches its orbiting height 342 miles above Earth, unless sunlight hits just the right angle, the satellite dims to magnitude 5 to 7. Beginning three to four hours after sunset in a summer, satellites can be visible to the naked eye all night.

     With U.S. Federal Communications Commission (FCC) approval, Musk's SpaceX program is in the process of launching 12,000 satellites in a Starlink network designed to facilitate high-speed, global broadband internet access. Sometime in June, 2020, a SpaceX Falcon 9 rocket is expected to launch the eighth batch of satellites, about 60 more, for the broadband network.  His artificial satellite constellation raises concerns about space safety and the impact on ground-based telescopes exploring deep space.

     At different heights above Earth, the orbits of satellites pose different problems. At about 300 miles or less, atmospheric drag downs and vaporizes satellites. Starlink system satellites designed to orbit 700 miles above Earth are too high for a quick and disintegrating re-entry. If satellites carry fuel, working ones can be maneuvered back to higher levels, and high-level ones that no longer work can be lowered and subjected to disintegration. Of course, the presence of fuel in a satellite increases the chance of an explosion.

     Whether working or out-of-service, at any level above Earth satellites can collide and break apart into "space junk." Fragments of debris go into their own separate orbits ready to cause additional collisions and, therefore, even more space junk. That is what happened when the Chinese sent a missile to hit a satellite no longer in use. Resulting shrapnel fanned out into numerous orbits of space junk. Potentially, damaged debris could necessitate avoiding whole regions of space.

     Besides the danger of collisions, bright satellites that compete with the stars are a problem for astronomers who have been exploring deep space for centuries. Since photographing objects light years away can require exposing an image for hours, satellites orbiting the Earth already spoil the view. Those who use radio telescopes to study the universe expect interference from satellite transmissions that use frequencies close to the radio waves from distant objects.

     Loon's internet balloons fly at 10 to 15 miles above Earth. With five to 10 balloons, Loon is especially useful in providing temporary service to an area in need of communication after a disaster. Service is now provided in Puerto Rico, Peru's rainforest, and Kenya.

     Problems associated with space, including satellites, balloons, spacecrafts, and military applications, are expected to worsen. In addition to the approximately 5000 satellites already orbiting Earth and 12,000 launched by SpaceX, the OneWeb company plans to add 650 and Amazon's broadband project would deploy 3200. Along with the satellites powering the U.S. GPS, other navigation systems: Russia's GLONASS, China's BeiDou, the EU's Galileo and OneWeb, now owned by the UK and India's Bharti Global, also have launched satellites. Unless atmospheric drag is allowed to remove space junk and satellites no longer in use, the likelihood of collisions and interference with deep space research will increase unchecked.

     At present, no international agreements govern the safe use of space, observes Dr. Lisa Ruth Rand, a research associate at the Smithsonian's National Air and Space Museum and post doctoral fellow at the University of Wisconsin. To date, the use of space seems to rely on the ambitions of Elon Musk, individual countries and companies, and aliens exploring new frontiers. Urgent international negotiations are needed, at least by Earthlings.