Press Release

The Planetary Society Asks “Where is Cosmos 1?” – Received Signals May Have Come from Solar Sail Spacecraft in Orbit

By SpaceRef Editor
July 6, 2005
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The Planetary Society continues to investigate the mystery of what happened to its Cosmos 1 spacecraft – a joint project with Cosmos Studios – that launched last week on a Russian Volna rocket.  While the Volna failed to place the spacecraft in its intended orbit, some data indicates the solar sail spacecraft may have made it to a lower orbit.

Cosmos 1 was the first solar sail spacecraft, designed to sail on light, using photons for propulsion in Earth orbit.

The manufacturer of the rocket, Makeev Rocket Design Bureau, stated that the first stage of the rocket fired improperly and prematurely shut down, sending the entire vehicle – rocket and payload – into the Barents Sea after a flight of only several hundred kilometers.  However, Cosmos 1 scientists at the Space Research Institute (IKI) in Moscow and at The Planetary Society have been analyzing signals received at ground stations after the launch to determine if they have come from the spacecraft, perhaps in a low orbit. 

Dr. Viacheslav Linkin, project Science Manager from IKI, stated, “It appears almost certain that we have received signals from the spacecraft after it was injected into orbit.”

The IKI team is continuing to review the data and provide additional calibration measurements to rule out other possible sources for the signals. 

“We have scientists in both the US and Russia looking at the signals,” said Louis Friedman, the Project Director and Executive Director of The Planetary Society, “and a strong case can be made that at least some of the signals are from the spacecraft.”

Friedman cited, as the strongest example, a measurement of Doppler shift in the frequency of the signal from the Kamchatka tracking station which correlated very well with the magnitude and time of the planned orbit insertion motor firing. 

Other data received at Panska Ves, in the Czech Republic, and in Majuro, the Marshall Islands, were less convincing, but still correlated well with planned spacecraft transmissions.  The Panska Ves signal, although noisy, even shows an apparent response to a ground command sent to the spacecraft during the first orbit. 

“We cannot be certain this data is from the spacecraft,” said Dr. Gregory Delory of the University of California Space Sciences Laboratory.  “It is very noisy, but it does correlate well with known spacecraft information, and other possible explanations are not as compelling,” he added.  Delory led The Planetary Society Data Analysis team.

Friedman noted that if a spacecraft signal were received from orbit, it would contradict the report that the spacecraft did not separate from the rocket.  If Cosmos 1 did go into orbit, it most likely was one that was too low to be sustained, and the spacecraft would have quickly re-entered the atmosphere.  The fact that the US Strategic Command apparently did not observe the spacecraft indicates that its orbital lifetime would have been short, perhaps only hours.

“During the launch sequence,” he said, “we were informed by a launch team member that first stage separation had occurred.   Later, however, we were told by Lavochkin Association flight controllers that this was a mistake, and that the separation had not occurred.”

The Russian government will organize a commission to investigate the accident. 

Friedman concluded, “The lack of data from the launch trajectory makes it hard to know what happened to the spacecraft.  Knowing that the spacecraft actually began working in orbit would help The Planetary Society team determine its next steps in planning a new solar sail mission.” 

LAUNCH VIDEO: Launch video is available on The Planetary Society’s website at and may be requested on DVD for broadcast purposes.


Now celebrating its 25th anniversary, The Planetary Society has inspired millions of people to explore other worlds and seek other life. Today, its international membership makes the non-governmental Planetary Society the largest space interest group in the world.  Carl Sagan, Bruce Murray and Louis Friedman founded The Planetary Society in 1980.


Cosmos Studios was founded in 2000 by Ann Druyan, Joe Firmage and Kent Gibson, to create science-based entertainment designed to engage the broadest possible television, film and Internet audience.  Among its achievements thus far are the DVD of the epochal 13-part television series COSMOS and the documentary films “COSMIC AFRICA” and “COSMIC JOURNEY,” which was nominated for the Emmy Award for the best long form science documentary in 2004.  Cosmos Studios is based in Ithaca, New York.


The Planetary Society   

Solar Sail               

Cosmos Studios   and

SpaceRef staff editor.