PUBLIC NOTICE
FEDERAL COMMUNICATIONS COMMISSION
445 12th STREET S.W.
WASHINGTON, D.C.  20554
News media information 202/418-0500
Fax-On-Demand 202/418-2830
Internet:  http://www.fcc.gov
ftp.fcc.gov
DA 07-1791
Released:  April 20, 2007
OFFICE OF ENGINEERING AND TECHNOLOGY DECLARES TETHERS UNLIMITED, INC.
APPLICATION FOR LICENSE OF STATION WE2XAH IN THE EXPERIMENTAL RADIO 
SERVICE TO BE A "PERMIT-BUT-DISCLOSE" PROCEEDING FOR EX PARTE PURPOSES
On January 3, 2007, the Experimental Licensing Branch granted the application of Tethers Unlimited, 
Inc. (TUI) (File No. 0580-EX-PL-2006) for new Experimental Radio license for Station WE2XAH.  This 
action provided for the “Multi-Application Survivable Tether” (MAST) to deploy three picosatellites to 
investigate tether survivability and dynamics in the space environment.  The three picosatellites have 
been deployed into an 803.0 x 658.5km, 98° inclination orbit. Data from the experiment will be 
transmitted to earth using the 2401.2-2483.5 MHz band.
On April 16, 2007, Orbcomm Inc. filed a Petition to revoke this grant.  Orbcomm alleges that the orbit 
proposed by TUI would place the experimental tethered satellite within the orbital envelope in which the 
current generation Orbcomm system operates and could pose an unacceptable collision hazard to 
Orbcomm’s next generation constellation.  Orbcomm asserts that TUI’s application is deficient as it did 
not include analysis of known objects in the proposed operational orbit.
On April 18, 2007, Iridium Satellite LLC filed an informal request to suspend or revoke TUI’s 
experimental license pending further investigation regarding the risk of TUI’s satellite colliding with one 
or more of Iridium’s satellites.  Iridium claims that TUI’s application did not quantify the probability that 
its satellites will collide with particular systems and that there is significant risk of collision with an 
Iridium satellite as a TUI picosatellite will pass through the Iridium orbit 11 times a day.  Further, 
Iridium states that TUI’s orbital debris mitigation proposal is defective as it relies on an operating 
altitude of 600 km and does not account for the 803 km apogee stated in the application.
Upon review of the applications and the pleadings filed, OET concludes that to permit a fuller exchange 
on the important issues raised by the above filings, the public interest would be served by classifying the 
instant proceeding as "permit-but-disclose" for ex parte purposes in accordance with Section 1.1200(a) of 
the Commission's rules and subject to the requirements under Section 1.1206(b) of the rules.
Persons making oral ex parte presentations are reminded that memoranda summarizing the presentation 
must contain a summary of the substance of the presentation and not merely a listing of the subjects 
discussed.  More than a one or two sentence description of the views and arguments presented is 
generally required.  See 47 C.F.R. § 1.1206(b)(2).  Other rules pertaining to oral and written 
presentations are set forth in Section 1.1206(b)(2).
For further information, contact Ira Keltz, Acting Deputy Chief, OET, at (202) 418-0616.
By the Chief, Office of Engineering and Technology