The Encounter 2001 message was an attempt at CETI (or "active" SETI), a quarter of a century after the seminal Arecibo Message was broadcast to a giant star cluster in Hercules. This new signal, designed by Yvan Dutil and Stephane Dumas at the Defence Research Establishment Valcartier near Quebec City, was sponsored by the Houston-based company Encounter 2001 (later renamed Team Encounter) and transmitted on 24 May 1999, and again on the night of 30 June – 1 July 1999, from the Evpatoriya Deep Space Center radio telescope in the Ukraine (see references 1 and 2 below for Dutil and Dumas's on-line papers about the construction of the message and reference 3 for Zaitsev and Ignatov's on-line paper about the transmission).

 

Whereas the Arecibo Message was made up of only 1,679 bits of information, the loss of any one of which on its long journey might make the message unintelligible, the Encounter 2001 Message consists of 300,000 bits, with built-in redundancy so that even if some bits are lost to noise en route, any recipient should stand a good chance of making sense of the contents. The first part of the message is a greeting, based on what are presumed to be universal mathematical and physical laws (see mathematics, as a universal language), to tell anyone tuning in who we are and that we would like a reply. Later, the company broadcast the names and addresses of 2,000 people who signed up at their website and paid a requisite fee.

 

References

1. Active SETI: target selection and message conception (large PDF file) Y. Dutil & S. Dumas
2. Error Correction Scheme in Active SETI (PDF file) Y. Dutil & S. Dumas
3. BETI from Evpatoriya: Broadcast for Extra-Terrestrial Intelligence from Evpatoriya Deep Space Center Alexander L. Zaitsev & Sergej P. Ignatov