Intelsat 27

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Intelsat 27
Start date February 1, 2013, 06:56 UTC
Launcher Zenit-3 SL
Launch site Sea Launch Odyssey
COSPAR-ID : 2013-F01
Takeoff mass 6241 kg
Mass in orbit approx. 3800 kg
Dimensions 6.9 × 3.3 × 3.2 m
Span in orbit 36.85 m ( solar panels ),
9.25 m ( antennas )
Manufacturer Boeing Satellite Systems
model BSS-702MP
Satellite bus Boeing 702
lifespan 15 years (planned)
Stabilization Triaxial
operator Intelsat
Playback information
Transponder 20 in the C band ,
20 in the Ku band ,
20 in the UHF band
Bandwidth 25 kHz ( UHF band )
Electrical power 11.8 kW (end of operation)
Power storage Lithium ion batteries
First position 55.5 ° West (planned)
drive LEROS-1C engine
List of geostationary satellites

Intelsat 27 (or IS-27) was a commercial communications satellite owned by the satellite operator Intelsat . The satellite was lost due to a false start.


Intelsat 27 was based on the Boeing 702 - satellite bus of Boeing built. It had a planned lifespan of around 15 years. The satellite accommodates a total of 60 transponders , 20 in the C-band , 20 in the Ku-band and 20 as the UHF band . It is supplied with electricity by two solar panels , each with three panels made of gallium arsenide solar cells that store their energy in Li-ion batteries.


Intelsat 27 was ordered from Boeing in 2009 as one of four communications satellites. The then unnamed satellite only got its name Intelsat 27 when Intelsat announced in August 2010 that construction of the Intelsat 27 satellite had begun.

Intelsat 27 had a hybrid C- and Ku-band system for media and network customers and was expanded with a UHF payload of 20 transponders for government purposes. The satellite was intended to replace the Intelsat 805 in the Atlantic region.

The UHF payload should offer the opportunity to complement the existing UFO and future MUOS satellites. The UHF payload will functionally correspond to the Navy's UFO-11 satellite .

Mission history

Intelsat signed a contract with Boeing in August 2010 to manufacture Intelsat 27. Intelsat authorized Boeing to continue the UHF payload for long-haul construction in Q2 2010, with a 2012 launch date.

In March 2010, the Navy submitted a UHF expansion plan to Congress. The Italian government agreed to take control of the UHF band's military payload in October 2012 after Intelsat failed to take care of the interests of the US Department of Defense.

The launch took place on 1 February 2013, a Zenit-3 - launcher from the launch platform Odyssey of the company Sea Launch . The satellite was 55.5 ° West with Intelsat 805 and Galaxy 11 operate. This did not happen, however, because after 40 seconds in flight the rocket was destroyed and fell into the Pacific 56 seconds after takeoff . The reason was a fault in a hydraulic pump .

Timeline of events

approx. T- 0.5 The hydraulic pump unit fails and deactivates the gimbal mechanism on the engine
T- 0 begin
T + 11.3 Planned pitching maneuver ( not carried out )
T + 14 Rolling maneuver begins
T + 16 The rolling movement exceeds the permitted 30 ° deviation and triggers emergency procedures
T + 20 Safety algorithm switches off the engines
T + 40 Security officers initiate self-destruction of the missile
T + 56 Missile fragments fall into the Pacific Ocean

Web links

Individual evidence

  1. Peter de Selding: Sea Launch Rocket Failure Destroys Intelsat IS-27 Satellite ,, February 1, 2013, accessed on January 12, 2018.
  2. Chris Bergin: Sea Launch Zenit 3SL with Intelsat 27 fails during first stage flight ,, February 1, 2013, accessed on January 12, 2018.
  3. Timeline after Zenit fails in Sea Launch accident ,, February 1, 2013, accessed on January 12, 2018.