I've read a German news article today (Golem.de) stating that there was a conjunction between a Oneweb satellite on its ascension course and a SpaceX satellite.

The US Space Force warned Oneweb that there is a chance of 1.5 % of a collision as the satellites will be very close (58 m estimated). SpaceX turned off the automatic collision prevention and Oneweb could alter the course to prevent the collision completely.

According to their website the US Space Force has:

A global network of space surveillance sensors provide vital information on the location of satellites and space debris for the nation and the world.

And clearly it is working.

I wondered if that is normal procedure? Do companies have to pay for this service, or is it done for the greater good (like no one benefits from more space debris)?


2 Answers 2


Space Fence is what our current tracking system is called. This article claims that some companies and countries have an arrangement to receive tracking data, but few details. It appears that this in fact routine, but I don't know if companies have to pay in.

To date, Strategic Command has announced data-sharing agreements with at least seven countries and 44 companies, but few details about those agreements have been made public. Some in the space community had wondered how much of the Air Force’s new $1 billion Space Fence would be part of those agreements, if at all.

Strategic Command’s data-sharing agent is the Joint Space Operations Center (JSpOC) at Vandenberg Air Force Base, California, which receives data from the Space Surveillance Network, a combination of terrestrial and space-based sensors, both optical and radar, Haney said. The network tracks and catalogs satellites and debris, information that is used for warning operators of potential collisions, among other purposes.

Strategic Command has announced space situational awareness data-sharing agreements with Australia, Japan, Italy, Canada, France, the Republic of Korea and the United Kingdom. It also has agreements with the European Space Agency and Europe’s Eumetsat weather satellite organization, Haney said.

Haney: U.S. Partners To Have Indirect Access to Space Fence Data

Also, this process may be in flux. This recent article claims that the Department of Commerce may take over tracking space debris.

Addressing space debris purely through tracking and traffic control poses two key problems for the Space Force. The first is political: It may not be in charge of debris tracking for much longer. Space Policy Directive 3, published by the White House in 2018, directed the Department of Commerce to take over space traffic management from the Department of Defense. After allowing the directive to languish for two years, the Senate recently moved to codify the directive into law on the basis of a favorable report commissioned to study the issue. Commercial opinion of the move is supportive, albeit with qualifiers — Tim Maclay of Celestial Insight advocated for an expansion of the traffic management mission into a regulatory mitigation role, noting that the agency in charge “is less important as long as we’re making progress in doing it.”



It's routine, and done as a service for the space community at large. Companies doing official business with the U.S. Government can get access to a variety of additional services, but the basic collision warnings to owners and operators of space vehicles are provided for the good of the world.

You have to register for a free account on space-track.org to download generic orbit data, but that's the only requirement. https://www.space-track.org/documentation#odr says

As the United States government agency responsible for Space Situational Awareness (SSA) information, United States Space Command (USSPACECOM), is committed to promoting a safe, stable, sustainable, and secure space environment through SSA information sharing. As more countries, companies, and non-governmental organizations field space capabilities and benefit from the use of space systems, it is in our collective interest to act responsibly and to enhance overall spaceflight safety. To achieve effective SSA, USSPACECOM seeks to increase cooperation and collaboration with partners and space-faring entities through the exchange of SSA data and provision of SSA services.

On-Orbit Conjunction Assessment (CA) is the process for determining the point and time of closest approach of two tracked orbiting objects. 18 SPCS screens all active satellites against the satellite catalog several times per day to identify close approaches. If a close approach meets emergency reportable criteria, 18 SPCS will notify the satellite's owner/operator by email and through Space-Track.org's Operator Panel. This service is provided at no cost to promote spaceflight safety, and does not require an SSA Sharing Agreement or an ODR.

If a satellite owner/operator receives a close approach notification email from 18 SPCS, the owner/operator may submit their proposed maneuver plan and ephemeris for screening against the space catalog. Results that meet emergency reportable criteria will be provided. Collision avoidance is the responsibility of the satellite owner/operator, but 18 SPCS will support their collision avoidance efforts by screening their predictive ephemeris and providing results in the Conjunction Data Message (CDM) format.

Further details on their processes are available from their Spaceflight Safety Handbook for Operators

  • 4
    $\begingroup$ "For the good of the world". Given that more than 50% of all the satellites in orbit have been launched by the US (1897 out of 3372 as of 2020, according to ucsusa.org/resources/satellite-database), it seems like it's the least they could do. The percentage will climb a lot with Starlink and its 42000 satellites. $\endgroup$ Apr 13, 2021 at 10:47
  • 1
    $\begingroup$ I disagree... the least they could do, is nothing at all. $\endgroup$
    – CGCampbell
    Apr 13, 2021 at 12:25
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    $\begingroup$ I'll note that "for the good of the world" implies a level of altruism that is unnecessary to justify such a service. Any space collision will generate debris, making future space activities that much more difficult (or impossible, if you hit Kessler Syndrome). $\endgroup$
    – Brian
    Apr 13, 2021 at 15:09
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    $\begingroup$ @Brian that sounds like the definition of "for the good of the world" to me. $\endgroup$
    – hobbs
    Apr 13, 2021 at 21:55
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    $\begingroup$ @hobbs: To clarify, when I said collisions would make future space activities more difficult, I was referring specifically to space activities by the organizations offering collision reporting. This benefit is sufficient to justify such reporting; any benefit to the rest of the world is a bonus. This is especially true given that the governments offering such reporting have the most to lose, since they have the most satellites. $\endgroup$
    – Brian
    Apr 13, 2021 at 22:06

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