Credit: SAIC

 

A recently released report has taken a hard look at “traffic management” of the space domain – an environment increasingly cluttered by orbiting space debris.

The study – Orbital Traffic Management Study: Final Report – Report on Space Traffic Management Assessments, Frameworks and Recommendations was issued November 21 by Science Applications International Corporation (SAIC).

The report was done for NASA as required by the Commercial Space Launch Competitiveness Act.

Current framework

As noted by Marcia Smith’s SpacePolicyOnline.com: “SAIC is recommending that a civil government agency take responsibility for orbital traffic management, but it does not specify which agency that should be.”

Clutter in the cosmos.
Credit: Used with permission: Melrae Pictures/Space Junk 3D

Smith explains that the Federal Aviation Administration (FAA) and its parent, the Department of Transportation (DOT), are often the center of attention in orbital — or space — traffic management discussions, but SAIC explained that the terms of reference for its study did not ask for such a recommendation.

“SAIC concluded that the current framework — where DOD [Department of Defense] tracks space objects and provides conjunction analyses to other U.S. government as well as commercial and foreign entities — is insufficient and a ‘holistic approach’ is needed, led by a civil government agency,” SpacePolicyOnline.com observes.

In the report, no assumptions or recommendations are made as to which specific civil agency could or should be designated – such a recommendation was not specified by Congress as a report product.

Alternate frameworks

Smith notes that the study lays out five alternative frameworks:

  • Private space traffic monitoring and coordination,
  • DOD-based space traffic safety monitoring and data sharing (status quo),
  • Civil-based space traffic safety monitoring and facilitation
  • Civil-based space traffic safety monitoring and coordination
  • Civil-based space traffic management.

It compares them in terms of three objectives:

  • Ensure safety of the space domain
  • Protect and enhance national security space interests
  • Ensure the economic vitality of the space domain and space industrial base

Organizational evolution

One author of the report, David Finkleman of SkySentry, LLC, told Inside Outer Space that the space traffic management (STM) study recommends an “organizational evolution” for STM.

“This was the charge from Congress. It recognizes that STM is global, not achievable by the U.S. alone. Any satellite owner or operator who declines collaboration is a threat to all and is himself at risk,” Finkleman explains.

“The state of satellite traffic is a serious environmental concern but not a catastrophe,” Finkleman notes.

“Action recommended by the STM report will make catastrophe much less likely,” adding that this is his personal opinion, not the position of SAIC, NASA, the U.S. Government, or any organization with a stake in STM.

International problem

Similar in view, and another author of the SAIC report, is Theresa Hitchens of the Center for International and Security Studies at Maryland at the University of Maryland in College Park. “This is an international problem, and requires an international solution. A U.S. system must be coordinated with other space-faring and space-using nations,” Hitchens told Inside Outer Space.

“This also means that however a U.S. civil agency is designed,” Hitchens advised, “it must be able to relatively freely share orbital positioning data with other nations, as well as integrate data from outside the U.S. military. That is…Space Situational Awareness (SSA) must become multi-stakeholder. Otherwise, a U.S. civil agency on top of a U.S. military controlled data pool becomes only another layer of bureaucracy that industry must pass through, and does nothing much to improve the space traffic situation,” she said, also noting her views are her own, not on behalf of SAIC or NASA.

Orbital debris is a space environmental problem.
Credit: Lockheed Martin

Trackable space objects

The nearly 120-page SAIC report offers a number of interesting perspectives, such as spotlighting the likelihood of space traffic safety incidents. It is predicted that about one collision will occur per year between tracked non-maneuvering space objects and debris greater than one centime-size in the low Earth orbit (LEO) region.

The overwhelming majority of trackable space objects are categorized as orbital debris, states the SAIC study.

“Of the approximately 23,000 cataloged space objects (all greater in size than 10 cm), only about six percent are (operational) spacecraft. A little more than about one quarter of all (operational) spacecraft are U.S. private owned and operated. This is two percent of all cataloged space objects. Not all of the (U.S.) private spacecraft can be maneuvered propulsively (especially CubeSats).”

Credit: SAIC

Star-crossed constellations

The report notes that some proposed new large constellations of small satellites could add thousands more spacecraft to the space catalog over a few years. Also, it is estimated that once the new “Space Fence” satellite situational awareness radar system becomes operational, the number of space objects in the space catalog could increase by approximately 60,000.

“This estimated increase will add complexity to the current conjunction assessment process, although the additional burden may be offset by a beneficial reduction in space object orbit uncertainty used to determine probability of collisions,” the report explains.

As flagged in the report, “there are no explicit or implicit national or international–level requirements for space traffic management (STM) under treaties and other legally-binding international agreements, to which the United States is a party.”

In-orbit explosions can be related to the mixing of residual fuel that remain in tanks or fuel lines once a rocket stage or satellite is discarded in Earth orbit. The resulting explosion can destroy the object and spread its mass across numerous fragments with a wide spectrum of masses and imparted speeds.
Credit: ESA

Debris-producing events

The SAIC study compiled a list of the top worst debris-producing events, noting:

  • The Iridium/Cosmos collision is the only debris-producing incident on the list known to be caused by an unintentional collision.
  • The China anti-satellite (ASAT) test of 2007 ranks as the event causing the largest number of pieces of debris.
  • Six of the remaining seven events on the compiled list were the result of orbital breakup (explosions), and in the remaining incident, the cause is unknown.
  • The likelihood of orbital breakup is very much a function of the spacecraft design features and the physical behavior of the satellite’s systems that contain energy (propellant tanks, pressurant tanks, batteries, and momentum wheels). The recent orbital breakups of three DOD Defense Meteorological Satellite Program (DMSP) satellites caused by battery-associated events are a good example of such debris generating events (this satellite series was designed and approved before orbital debris mitigation requirements were established in the United States).
  • A recent example of an orbital breakup that was somewhat unusual is Japan’s Hitomi X-ray observatory. Because of a design error, this satellite literally spun itself out of control with such a rate of rotation that it came apart.

 

Credit: SAIC

 

Space station concerns

The SAIC report includes a look at the International Space Station and the threat of orbital debris hits to the orbiting complex.

As debris populations grow in LEO, the odds of Micrometeoroids and Orbital Debris (MMOD) root cause events on ISS will become higher (i.e. worsen); but, the SAIC study did not find any analysis that quantified this increased risk.

Chunk of junk zips by the International Space Station.
Credit: NASA

Recent analysis by the Aerospace Corporation on new large LEO constellations, the SAIC study observes, found that such constellations could increase the number of collision warnings with ISS six-fold, for example, as the decommissioned spacecraft in those constellations decay through the ISS orbit. This result does not correspond to a direct increase in the odds of a MM/OD root cause event, “but does show that risk can go up,” the SAIC report explains.

 

Resources

To access the SAIC report on Space Traffic Management Assessments, Frameworks and Recommendations, go to:

http://www.spacepolicyonline.com/pages/images/stories/Orbital%20Traffic%20Mgmt%20report%20from%20SAIC.pdf

For the informative review of the study by Marcia Smith’s SpacePolicyOnline.com, go to:

http://www.spacepolicyonline.com/news/saic-recommends-civil-agency-for-orbital-traffic-management-but-not-which-one

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