March 6, 2009 at 5:30 pm | Posted in Space Law Current Events | Leave a comment

by Joanne Irene Gabrynowicz with the blog faculty

Source: Space News


Space News Staff Writer 

PARIS — The U.S. Air Force has agreed to provide wider access to its high-accuracy catalog showing the whereabouts of orbital debris and operational satellites as part of an effort to enable commercial and non-U.S. government satellite operators to better avoid in-orbit collisions, according to U.S. Air Force officials.

The new policy, whose exact contours are not yet known, reflects recognition by the Air Force that a failure to stem orbital collisions of the kind that destroyed an operational Iridium mobile communications satellite Feb. 10 ultimately could render certain orbits of high strategic and public service value unusable for decades.

The new policy, which one Air Force official said should be announced before June, also may be seen as a response to growing efforts in EuropeRussia and elsewhere to coordinate existing radar and optical telescope assets into a coordinated space situational awareness network.

As the owner of the world’s most sophisticated network of ground-based radars tracking space traffic, the U.S. Air Force is faced with the choice of leading such an effort, joining it or letting it develop without active American involvement.

Air Force officials have long said they are struggling to reconcile the need to help coordinate a global space traffic management system and the natural disinclination of the military to make public what is still considered strategically sensitive information. Air Force officials have also pointed out that any major new effort at space traffic management could require investment in expertise and perhaps computing power.

In a March 3 response to Space News questions, the U.S. Air Force Space Command said: “In the near future, the public will also receive more advanced services to include End-of-Life support, Anomaly Resolution support, and potential threat notification support. The vision is to provide these advanced services via the same website as the [collision-risk analysis] and Launch support service is provided.”

The Web site in question, http://www.space-track.org, is where the basic U.S. Air Force Space Surveillance Network data is published, but only in a form that satellite operators have long said is not useful for space traffic management. This data, called Two-Line Elements (TLEs), has too great a margin of error to permit operators to act.

Some satellite operators, particularly those with satellites in geostationary orbit, complement the U.S. Air Force TLE data with information from other sources. The Russian-led International Scientific Optical Network, based at Moscow‘s Keldysh Institute of Applied Mathematics, includes some 25 optical telescopes, mainly in the former Soviet Union, that can be deployed on a case-by-case basis as part of commercial transactions. But this network’s focus is on objects in geostationary orbit, the operating orbit for most commercial satellites but far above low Earth orbit regions where debris is of most concern.

In Europe, French radar and German optical systems have been used to verify close satellite encounters in low Earth orbit once TLE data has spotted a potential problem, but the European assets have nowhere near the reach of the U.S. Space Surveillance Network.

Another service is provided by the Center for Space Standards and Innovation, the Colorado SpringsColo., research arm of Analytical Graphics Inc. In operation since 2004, the Satellite Orbital Conjunction Reports Assessing Threatening Encounters in Space, or SOCRATES, service is likewise based on U.S. Air Force TLEs. As was the case with the Feb. 10 Iridium collision with a retired Russian satellite, it is unable to warn of a pending collision in low Earth orbit. The Iridium collision with Russia‘s Cosmos satellite occurred at about 790 kilometers in altitude.

The U.S. Air Force statement suggests that it will furnish more information to the public to enable operators to make a more highly informed decision.

Current policy is for satellite operators seeking threat assessment data from the U.S. Air Force to fill out a form online to request more-detailed information. The procedure is relatively straightforward, but again does not give operators of satellites in low orbit, where the debris population is much higher, enough time to react. Here, too, the Air Force statement raises hope that the policy will be modified: “In the near future we will provide a capability to provide timelier, streamlined processes by posting all potential conjunctions on the Space-Track.org website. Our first step will be to regularly post approximately fifteen [Commercial and Foreign Entities] satellite constellations on the Space-Track website.

One U.S. Air Force official said a full review of how space traffic management is conducted is being readied for completion before this summer. It is unknown whether non-U.S. government operators with satellites in low Earth orbit will be given access to the high-accuracy catalog of orbiting objects, or be permitted to ask the Air Force for daily updates based on the high-accuracy catalog.

Bethesda, Md.-based Iridium Satellite LLC has been given special access to otherwise nonpublic Air Force Space Surveillance Network information, but only for limited periods, according to John Campbell, Iridium’s vice president for government affairs.

In a March 2 interview, Campbell said Iridium was given access to the high-accuracy data starting in January 2007, following a China anti-satellite missile firing that destroyed a retired Chinese weather satellite operating in an orbit near Iridium’s, spewing thousands of pieces of debris that will make Iridium more vulnerable to collision.

Campbell said that access to the high-accuracy data was only for the debris from the Chinese anti-satellite test. The access ended in January 2008, but has been renewed since the Feb. 10 collision to aid Iridium in repositioning an in-orbit spare satellite to replace the one that was destroyed. Iridium operates a constellation of 66 satellites.

Campbell said the data furnished by Air Force Space Command has been based only on the Air Forces catalog, and has not included inputs from Iridium on the exact location of its satellites. Operator input makes even the most precise Air Force information more accurate because operators know the exact position of their own spacecraft.

“We are exploring how we could provide our data on a regular basis,” including a study of how data formats and other compatibility issues could be harmonized, Campbell said.


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