Sea Launch Project

High Spots

XM Radio-4 Launch

Preparations for the XM-Radio-4 mission started in September 2006.
The launch is aimed at bringing up a 5.193 t spacecraft to a GEO transfer target orbit with an inclination of 0°, estimated perigee altitude of 1239 km and apogee altitude of 36057 km.
This is the fourth spacecraft of this series, three previous satellites were launched by the Sea Launch Complex in March 2001, May 2001 and February 2005.
The spacecraft provides a digital wire broadcasting over the US and Canada.
Getting readied for the XM-Radio-4 launch were the launch vehicle Zenit-2S SL22 and upper stage DM-SL 24L. Preprocessed as "donors" were the launch vehicle Zenit-2S SL24.


September 2  October 11, 2006

Home Port activities:

  • Tests on LV Zenit-2S SL22;
  • Work on LV Zenit-2S SL24 (donor);
  • Tests, filling the upper stage DM-SL 24L with high-boiling propellants;
  • The spacecraft processing;
  • Integrated rehearsal #1 with simulations of processing contingencies;
  • ILV integration and tests;
  • ILV "dry roll-out" (installation on the launch pad and critical launch readiness checklist);
  • Loading propellant components and compressed gases onto the vessels.
October 12-24, 2006

Sea transit of the launch platform and the assembly and command ship to the launch site. Activities during sea transit:

  • Integrated rehearsal 2;
  • Integrated rehearsal 3 with comprehensive involvement of all the personnel and virtually all the standard and borrowed launch support and tracking assets.
October 24-29, 2006

Launch site activities:

  • Getting rocket segment systems ready for the launch site activities;
  • ILV processing;
  • Launch measurement system activities;
  • Integrated tests of the upper stage automated flight control system;
  • Preparing ILV for the roll-out;
  • Bringing the launch platform into the launch position;
  • Bringing the assembly and command ship into the launch position;
  • ILV roll-out and erection on the launch pad;
  • ILV electrical checkout;
  • Critical launch readiness checklist;
  • Operations with SC and PLU after performing protective operations on the ILV;
  • Testing communications links;
  • On October 26 during the automatic prelaunch processing operations 1 min 59 sec before the lift-off, the launch was automatically cancelled on the basis of "Failed automatic mating of filling lines at the prescribed time";
  • Brining ILV into a safe condition, propellant drain in the launch platform tanks;
  • Analyzing causes of off-nominal situation, replacing faulty oxidizer filling valve;
  • Brining the Complex systems into initial conditions;
  • Repeating operations at L-3 and L-2 days.
October 30, 2006

At 15 hours 49 minutes Pacific Time (on October 31 at 2 hours 49 min Moscow Time) ILV Zenit-3SL SL22 carrying XM Radio-4 spacecraft was launched.
All the flight operations have been completed normally with minimal deviations from the schedule. The spacecraft has been put into its target orbit.
After completing final operations, the vessels set out for the Home Port.


The XM Radio-4 spacecraft has been injected into the calculated orbit:

Perigee altitude,
Apogee altitude,

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