Monday, June 08, 2020

Can SpaceX launch 30,000 second-generation Starlink satellites? Maybe.

The bottom line is that success is not guaranteed, but neither is failure -- there is a non-zero probability of success.

On May 26th, SpaceX applied for permission to launch 30,000 "second-generation" Starlink broadband Internet satellites. (Note that the software on Starlink satellites is updated about once a week). The application narrative states that the second-generation satellites will be configured as follows:                                                                                                                                                                                                                                                                                                                                     

(The offsets of the single-satellite planes are set to form a uniform pattern so when a satellite crosses the equator another satellite in the adjacent plane will cross the equator a short, constant time later). The following snapshots from a simulation created by Richard Cole illustrate the coverage.

The application narrative describes the ground and space segments and addresses the problems of debris mitigation and interference with astronomical observation. Here are some points that caught my eye
  • The second-generation satellites "will have three times the data capacity of SpaceX’s current satellites." 
  • Polar regions are covered.
  • The second-generation satellites will have optical inter-satellite links.
  • Low altitudes "will enable smaller spot beams and greater satellite diversity, achieving the intensive frequency reuse needed to heighten capacity available anywhere in the world."
  • Low altitudes will allow SpaceX to use high E-band frequencies for communication with ground stations.
  • Low altitudes will reduce latency.
  • Terminal setup will be plug and play -- "point it at the sky and plug it in."
  • SpaceX promises to make sure that "Starlink has no material effect on discoveries in astronomy."
  • SpaceX will extend its debris data sharing and collision-avoidance activities and "encourages all operators to follow these same practices."
Can they pull it off?
The FCC demands that half of the satellites for an approved constellation be launched within 6 years and all to be launched within 9 years. Can SpaceX manufacture, launch, and fund 30,000 second-generation satellites that quickly while continuing to launch first-generation satellites and replacements for those that are de-orbited after approximately five years of useful life?
When asked about Starlink during an interview at the Satellite 2020 Conference in March, Elon Musk said his goal for Starlink was to remain in the "not bankrupt category." If Elon is not sure, I can't be either, but they have a few positive things going for them.
Today, SpaceX is manufacturing about 120 satellites per month, which is far too few to satisfy the FCC. That being said, it is safe to say that Elon Musk knows more about modern, automated manufacturing than anyone alive today, having learned from his experience making cars, solar tiles, batteries, satellites, and rockets. He has learned the importance of building "the machine that builds the machines," which includes the factory, equipment, staffing, processes, and supply chain. SpaceX may already be able to make satellites faster than 120 per month and they will surely improve the manufacturing "machine" and the design of second-generation satellites for manufacturing ease. If that is not sufficient, they can open another factory -- maybe acquire OneWeb's.
How about launching the satellites? SpaceX President and COO Gwynne Shotwell said in a recent interview that if their Starship was not ready to take astronauts to the International Space Station within three years, it would be "a major company fail" and in an earlier interview, she said that Starships will be able to carry 400 satellites at a time. In his Satelite 2020 interview, Elon Musk set a goal of three launches per day with Starships landing back at the launch sites within a few days of launch. If they can achieve that cadence, launching will not be a problem.
Can they fund the project? It will take around three years for SpaceX to complete the first phase of the first-generation satellites and Shotwell and Musk have both recently said that low-cost end-user terminals are critical for global success and those are perhaps three years away. During those three years, SpaceX will have income from their launch business, government contracts, and Starlink customers as well as private investment.
They have been collaborating on Starship with NASA for six years and recently flew two astronauts to the International Space Station. Colonel Eric Felt, head of the Air Force Research Laboratory’s Space Vehicles Directorate, characterized that as the "culmination of perhaps the most successful private-public partnership of all times” so it seems safe to say they will be getting funding from the Defence Department as well as NASA.
How about private investment? SpaceX has succeeded in attracting Starlink investors recently, but Starlink's financial performance during the first three years of operation will impact their ability to continue raising capital. During the next three years, the majority of the satellites they launch will be at latitudes that deliver the most capacity in the relatively affluent regions of North America and Europe, and Internet service in the US and Canada is relatively expensive. Hopefully, they will be able to serve those markets without losing too much on expensive terminals while improving terminal technology. (They may also be interested in acquiring OneWeb antenna technology).
Debris is my biggest worry. The SpaceX application says their propulsion system will allow them to autonomously avoid collisions with tracked objects. Furthermore, over 85% of their satellites will be lower than the International Space Station and will be relatively quick to burn up in the atmosphere. They also promise to share all ephemeris data and encourage others to do the same.
But, what about objects that are too small to track? What if another operator is actively trying to avoid collisions -- don't they need to coordinate with SpaceX? What about other companies that are planning to launch low-Earth orbit satellites? With the numbers of satellites being launched, it seems that international regulation and coordination are required and even then a debris solution is not obvious. Orbiting debris is clearly a global (not US) tragedy of the commons.
The bottom line is that success is not guaranteed, but neither is failure -- there is a non-zero probability of success.

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