Strange maneuvers involving two Chinese satellites have some space-watchers worried — not just because the orbital maneuvers apparently resulted in a close encounter and perhaps even contact between the satellites, but also because the Chinese have said so little about the matter.
The worriers are concerned that the orbital shifts involving two Shijian ("Practice") research satellites were aimed at practicing techniques for disrupting other governments' satellites in the event of an international crisis. The nightmare scenario would involve a fleet of spacecraft that went after America's telecom and Earth-watching satellites, cutting off military communications and orbital surveillance capabilities.
There could be a far more benign explanation for the maneuvers, however: On-orbit rendezvous is a basic skill that would have to be mastered by any country seeking to build up infrastructure in orbit, as China is aiming to do. Such a skill would come into play not only for docking with a space station, but also for refueling or servicing satellites in need of help. For years, NASA and the Pentagon have been working on robotic procedures for on-orbit inspection and servicing of satellites.
Over the past couple of weeks, reports about the Shijian satellite maneuvers — and the worries about them — have shown up on a smattering of news websites. One report, based on Russian commentary, even made its way onto the website of China's Xinhua news service. But to date, Chinese officials have made no official statement explaining what's going on.
Brian Weeden, technical adviser for the Secure World Foundation, lays out virtually everything that satellite-watchers have been able to glean about the maneuvers today in a report published online by The Space Review. He says the Shijian 12 research satellite, which was launched from China's Jiuquan space complex in June, was observed going through six sets of orbital maneuvers between June 20 and Aug. 16. The final maneuver put it in nearly the same orbit and location as an older satellite in the series, known as Shijian 06F, or SJ-06F.
At some point on Aug. 19, SJ-06F's orbit appeared to undergo a relatively slight change due to an anomalous perturbation, Weeden said. It's hard to say whether the satellites touched, or whether the appearance of a shift in SJ-06F's orbit was due to other factors — ranging from the effects of space storms to inaccuracies in satellite tracking data.
"It appears as though the anomaly on August 19 does reflect an actual change in the orbit of SJ-06F, although only time will tell for certain," Weeden said. "Analysis of its orbital position over the coming weeks and months will provide further evidence as to whether its orbit was changed or whether it was simply an anomaly in the data."
In the meantime, experts on military space operations are left to wonder why Shijian 12 was put through such a complex series of moves. One of the wonderers is NBC News space analyst James Oberg, a veteran of NASA's Mission Control and the author of "Space Power Theory." In an e-mail, Oberg said he found Weeden's article "technically sound, and fairly persuasive."
"But if the article is accurate, the secrecy implies an ominous and probably military intent on the part of China," Oberg wrote. "There are potential innocuous justifications for developing the technology — but in those cases, I would have expected China to brag openly about having done it."
Chinese and U.S. space operations sparked a debate over the potential for space warfare over the past few years, beginning with a Chinese satellite knockdown in 2007 and a similar operation conducted by the Pentagon in 2008. This latest satellite story could be a cause for serious concern about international space security. It could also be a misreading of innocuous rendezvous tests, or a phantom whipped up from faulty observations.
My view is that it's way too early to start rattling the sabers — but what's your view? Feel free to weigh in with your comments below.
Update for 2:15 a.m. ET Aug. 31: Oberg sent questions about the Chinese satellite maneuvers to the U.S. Strategic Command and received this e-mailed response from a Defense Department spokesperson:
"As reflected in the United States' new National Space Policy, the DoD [Department of Defense] believes it is in the shared interest of all nations to act responsibly in space to help prevent mishaps, misperceptions and mistrust.
"Based on your questions, our analysts determined there are two Chinese satellites in close proximity of each other.
"We do not know if they have made physical contact. The Chinese have not contacted us regarding these satellites."