That pitter-patter on your roof may not be rain. It may be shards from satellite collisions high in the northern skies.
The sky is getting more crowded, particularly in northern climates like Alaska where scores of new low earth orbit (LEO) communications satellites are being launched in lower-altitude polar orbits, or those going over the North Pole, south to the South Pole, and back.
Because the earth rotates below, LEO satellites in polar orbits provide complete coverage of the earth multiple times a day for each satellite. Polar orbits are ideal for scientific monitoring and, increasingly, telecommunications. If there are enough of them and they are spaced out, as in constellations of satellites, coverage of all parts of the earth can be complete, continuous and in virtual real-time.
In contrast, LEO satellites in equatorial orbits circle above the earth’s equator at more southerly latitudes. They have advantages but do not offer continuous coverage of all parts of the world advantages and do not efficiently serve northern regions like Alaska or provide any coverage in high-Arctic regions increasingly important for scientific monitoring or defense.
Because of the advantages of polar orbits and increasing demand the race is on among space companies to get into the polar satellite business, particularly LEOs. Federal regulators are increasingly concerned about satellite proliferation, safety and space debris.
If LEO satellites go astray or out of control, high speed collisions could shower debris over wide areas of nearby space. The satellites aren’t tiny, either. Many are the size of your refrigerator or dishwasher.
While most debris from collisions burn up on reentering the atmosphere it’s possible that some may not. It’s unlikely, but not impossible, some could indeed land on your roof, space experts say.
A more likely problem, however, is that clouds of debris could knock several satellites out of commission and create telecommunications blackouts that will take months to repair.
Alaskans are more affected by this because the north-south lanes in space in which polar satellites travel, like lines of longitude, become narrower as they approach the pole. That will complicate the potential congestion.
To deal with this the Federal Communications Commission is considering a new rule that could go into effect next summer that would establish new safety procedures for satellite operators, “rules of the road” that would ensure proper spacing between orbital planes and monitor satellite failure rates.
Meanwhile, one major company in the business, SpaceX, is pushing the commission to fast-track an authorization allowing to launch a new array of low-earth orbit satellites in December that could be “grandfathered” in, so that the new requirements would not apply to the new satellites. SpaceX filed its application Nov. 17.
Other companies, including Alaska-based Pacific Dataport Inc., are asking the commission to delay the approval so that the new rules cover everyone in the LEO satellite business, including SpaceX.
“SpaceX uses as its primary justification the need for accelerated approval service to rural areas of Alaska,” but the benefit is overstated because how the new SpaceX satellites would do this is not made clear, Pacific Dataport, or PDI, said in a letter to the commission.
“PDI does not understand how launching 58 new satellites (hundreds are needed in polar orbit to serve Alaska with 24/7 coverage) …will provide any meaningful service to rural Alaska. The risks (of collisions in space) are far greater than any potential benefit,” PDI said in its letter. The company is urging the FCC to delay the SpaceX request at least until the new debris-control rule is in effect.
There are potential collision risks between these satellites and Amazon’s new ‘Kuiper’ satellite system, which operates mostly at higher altitudes but with some satellites at the same altitude SpaceX proposes to use, several space companies have told the FCC in filings. In its filing SpaceX said it would operate its new satellites at altitude of 580 kilometers, or 360 miles.
Amazon’s Kuiper satellites will be at 590 kilometers, or 366 miles. SpaceX, for its part, acknowledges the potential for conflict with Amazon with some of both companies’ satellites potentially at the same altitude, but told the commission it has worked out an agreement with Amazon for separation of satellites to avoid altitude congestion. The separation would be about half mile, SpaceX said.
In terms of space and satellites operating a high speed this is uncomfortably close, and other space companies including Alaska’s PDI aren’t assured by it. “While SpaceX proposes to ‘take full responsibility for physically avoiding any other satellites in these orbits,’ if even a single collision occurs, the consequences – not just to SpaceX and Kuiper, but all other space systems on a global scale – could be far greater than any responsibility SpaceX could take,” PDI said in its letter.
PDI is a partner with OneWeb, a company launching LEO satellites that will be covered by the new rule. The company will soon be in the satellite business itself with a different kind of satellite, high-altitude “geostationary HTS.” GEO HTS satellites provide affordable backhaul service and LEO satellites provide a low-latency option at a premium cost. Both PDI satellite systems, GEO HTS and LEO, will be operational and available throughout Alaska in 2021.
Geostationary satellites operate approximately 22,000 miles above the earth and appear “stationary” in the sky because the satellite’s speed in high orbit matches the earth’s rotation, so the satellite appears to be in a fixed location relative to the surface.