Might satellite constellations learn to avoid debris with sensors on satellites?

There were no artificial satellites before Sputnik in 1957.
Today there are about 5,000 with plans for thousands more.

Space debris is problematical.

The European Space Agency (ESA) reported that as of January 2019 there were about 5,000 satellites in space and 1,950 of them are still functioning. Hopefully, those functioning satellites have fuel and thrusters that will enable them to de-orbit and (mostly) burn up in the atmosphere when their useful life is finished. The remaining 3,050 are slowly drifting, along with a lot of debris.

The ESA estimates that there have been over 500 break-ups, explosions, collisions, or anomalous events resulting in fragmentation and they estimate that there are 34,000 debris objects >10 cm, 900,000 from 1 to 10 cm and 128 million from 1 mm to 1 cm. NASA says there are more than 20,000 pieces of debris larger than a softball, 500,000 the size of a marble or larger and many millions so small they can’t be tracked. (watch: NASA's Animation Shows Massive Space Junk Around Earth)

In low-earth orbit (LEO), debris circles the Earth at speeds of about 7 to 8 km/s. However, the average impact speed of orbital debris with another space object is approximately 10 km/s and can be up to about 15 km/s, which is more than 10 times the speed of a bullet. At those speeds, a collision with a small object can do significant damage. This sounds like a disaster waiting to happen and the current and planned proliferation of LEO satellites increases the likelihood of a Kessler Syndrome event -- a cascade of collisions between satellites and the ensuing debris.

As Kessler says "The cascade process can be more accurately thought of as continuous and as already started, where each collision or explosion in orbit slowly results in an increase in the frequency of future collisions." If you aren't worried yet, watch the following short video or read Kessler's 1978 paper.

Kessler's warning was taken seriously and NASA and others have been working on debris mitigation policy and technology for years, but the silver bullet has not been found. The Space Surveillance Network tracks approximately 23,000 relatively large objects and you can query the database here, but what about the millions of objects that are too small to track?

The SpaceX press release for their Starlink Mission hinted at their collision-avoidance strategy, saying that

Each spacecraft is equipped with a Startracker navigation system that allows SpaceX to point the satellites with precision. Importantly, Starlink satellites are capable of tracking on-orbit debris and autonomously avoiding a collision.

That sounds promising, but autonomously resolving and recognizing a marble-sized object that is approaching at up to 15 km/s, computing its trajectory and firing thrusters to avoid a collision can't be done -- even by Elon Musk.

Relatively few debris objects can be tracked terrestrially, but a satellite might be able to recognize a piece of debris and transmit its characteristics to a terrestrial processor, greatly expanding the tracking database. SpaceX may be approaching this as a machine-learning problem in which the entire constellation, not individual satellites, is learning to avoid collisions.

That is pure speculation, but it was triggered by a few thoughts.

For a start, at the end of 2017, SpaceX delivered a space debris sensor (SDS) to the International Space Station. As shown in the following short video, the SDS is capable of monitoring the size, speed, direction, and density of small particles that impact it.

Elon Musk also has a strong interest in machine learning -- he was a co-founder of openAI and his Tesla cars act as sensors uploading driving data that is used for training autonomous vehicles.

Going out to the very end of the limb -- Musk is a fan of science fiction and speculation on the possibility of a swarm of man-made objects learning about existential risks is reminiscent of emergent intelligence in Asimov's fictional planet Gaia or Teilhard de Chardin's noosphere).

Musk opened his Tesla patents and, if SpaceX demonstrates the feasibility of this approach to debris avoidance (and perhaps one-day removal), I expect that he would share this technology with competitors like OneWeb and Telesat and the space agencies of all nations.

Like global warming, space debris is an example of a tragedy of the commons and is a threat to all nations. As the cartoon character Pogo said, "We have met the enemy and he is us." Ironically, global tragedies of commons can unite us.

Rethinking technology policy - the 50th anniversaries of the moon landing and first ARPANET message

The anniversaries of these milestones remind us of the economic and social returns we have seen from ambitious Federal research, development and procurement programs. Why isn't this a Sputnik moment for the United States?

Log entry for the first ARPANET
message (Source)

On July 20, 1969, Neil Armstrong stepped out of the Apollo 11 lunar lander and set foot on the moon. On October 29th, Charley Kline, an ARPANET programmer at UCLA, attempted to log in to a host at Stanford Research Institute (SRI), but the system crashed after he had typed LO. After a bit of debugging, he succeeded in typing LOGIN and the rest is history.

These events were milestones in ongoing, federally-funded research and development efforts -- the manned spaceflight program and the development of digital telecommunication networks from Morse's telegraph to early electronic digital computers and telemetry experiments, the SAGE early-warning system and eventually the ARPANET and the Internet. (The previous link is to a text version of the history article. Contact me if you would like a pdf of the article as it appeared in the Communications of the ACM).

The anniversaries of these milestones remind us of the economic and social returns we have seen from Federal research, development and procurement programs. When President Franklin Roosevelt was inaugurated in 1933, he enacted many ambitious government programs aimed at ending the great depression -- a "new deal." He initiated programs like Social Security and infrastructure projects like rural electrification. Confidence in the Federal Government being able to pull off large, successful programs continued through World War II, the Berlin Airlift and Marshall Plan, the Interstate highway system and the space program.

Early ARPANET sketch, showing
UCLA and SRI nodes (Source)

President Kennedy kicked off Apollo program in 1961, saying he believed "that this nation should commit itself to achieving the goal, before this decade is out, of landing a man on the moon and returning him safely to Earth." But pendulums swing and, in a 1986 press conference, we heard President Reagan say “The nine most terrifying words in the English language are: I’m from the government and I’m here to help you.” Today we are discussing a "green new deal" -- is the pendulum about to swing back?

Update 3/14/2019

Former National Security Advisor Tom Donilon addressed technology policy in an terrific interview. The following is a paraphrase of his reflection on the emergence of collaboration between government, universities and private companies that was born when the Russians launched their Sputnik satellite:

I don't think we're having anywhere near the conversation we need to have about the missing piece of China policy which is: what is the United States going to do? Why isn't this a Sputnik moment for the United States? In the late 1950s, when the Soviets launched the Sputnik satellite, the United States undertook an enormous national effort that changed the way we taught math and established NASA and the Golden Triangle of technological and innovation development between the government and research universities and private companies.

We face a similar challenge at this point in terms of technology competition with China. That is something I think we need to be talking about and the discussion includes immigration policy, infrastructure investment, education investment and [consideration of the] impact of technology, particularly artificial intelligence, robotics and automation on labor markets. Populism is not at its peak right now -- we need a really serious discussion about how we are going to manage the future of work in the face of technology.

This comment was made at around 33:15 of the interview: