SES-8

Overview

SES-8

mission type	Communication
operator	SES
cospar id	2013-071A
satcat	39460
website	https://www.ses.com/
mission duration	15 years (planned) (elapsed)
spacecraft type	GEOStar-2
spacecraft bus	STAR-2.4
manufacturer	Orbital Sciences Corporation
launch mass	3170 kg
power	5 kW
launch date	3 December 2013, 22:41:00 UTC
launch rocket	Falcon 9 v1.1
launch site	Cape Canaveral, SLC-40
launch contractor	SpaceX
entered service	February 2014
orbit reference	Geocentric orbit
orbit regime	Geostationary orbit
orbit longitude	95° East
apsis	gee
trans band	33 Ku-band
trans bandwidth	36 MHz
trans coverage	South Asia, India, Indo-China, Thailand, Vietnam, Laos
programme	SES constellation
previous mission	SES-7
next mission	SES-9

SES-8 is a geostationary Communications satellite operated by SES SES-8 was successfully launched on SpaceX Falcon 9 v1.1 on 3 December 2013, 22:41:00 UTC.[1]

It was the first flight of any SpaceX launch vehicle to a supersynchronous transfer orbit, an orbit with a somewhat larger apogee than the more usual geostationary transfer orbit (GTO) typically utilised for communication satellites.[2]

Satellite description

The SES-8 satellite is built on the STAR-2.4 satellite bus by Orbital Sciences Corporation (OSC). It is the sixth satellite of that model to be built for SES.[3]

Launch vehicle

The launch of SES-8 was the seventh launch of the Falcon 9 launch vehicle, and the second launch of the Falcon 9 v1.1. SES paid a discounted price — "well under US$60 million" — for the launch since it was the inaugural geostationary launch on the Falcon 9. When originally contracted, in 2011 the putative launch date was early 2013.[2]

The launch was the second launch of the Falcon 9 v1.1 version of the rocket, a longer rocket with 60% more thrust than the Falcon 9 v1.0 vehicle, and the first launch of the larger v1.1 rocket using the rebuilt erector structure at SpaceX' Cape Canaveral SLC-40.[6] As a result, a number of systems on the launch vehicle was flown for only the second time, while several parts of the ground infrastructure at Cape Canaveral were used in a launch for the first time. These include:[7]

In order to maximize the propellant available for the launch of SES-8 into geostationary transfer orbit (GTO), SpaceX did not attempt a controlled descent test of the first-stage booster as they did on the previous Falcon 9 v1.1 flight in September 2013.[10]

second use of the upgraded Merlin 1D engines, generating approximately 56% more sea-level thrust than the Merlin 1C engines used on the first five Falcon 9 flights

second use of the significantly longer rocket stages, which were lengthened to accommodate the larger propellant tanks needed to carry propellant for the more powerful engines. The tanks are 60% longer, making the rocket more susceptible to bending during flight.[8]

the nine Merlin 1D engines on the first stage are arranged in an octagonal pattern with eight engines in a circle and the ninth in the center

second launch to have a jettisonable payload fairing, which has the risk of an additional separation event that has doomed many missions in the past. Fairing design was done by SpaceX, with production of the 43 ft long, 17 ft-diameter fairing done in Hawthorne, California at the SpaceX rocket factory. Testing of the new fairing design, first required on the CASSIOPE flight (the sixth flight of the Falcon 9), was done at NASA's Plum Brook Station where acoustic shock and mechanical vibration of launch, plus electromagnetic static discharge conditions, were tested on a full-size fairing test article in a very large vacuum chamber. SpaceX paid NASA US$581,296 to lease test time in the US$150 million NASA simulation chamber facility.[9]

second flight of the vehicle with upgraded avionics and flight software.[8]

Second-stage reignition

In the previous launch of the Falcon 9 v1.1 — the first launch of the much larger version of the rocket with new Merlin 1D engines — on 29 September 2013, SpaceX was unsuccessful in reigniting the second stage Merlin 1D vacuum engine once the rocket had deployed its primary payload (CASSIOPE) and all of its nanosat secondary payloads.[11] The restart failure was determined to be frozen igniter fluid lines in the second-stage Merlin 1D engine. A minor redesign was done to address the problem by adding additional insulation to the lines.[12]

A second burn of the upper stage was required, and was completed successfully, during the SES-8 mission [13] in order to place the SES-8 telecommunications satellite into the highly elliptical supersynchronous orbit for satellite operator SES to effect a plane change and orbit circularisation.[12]

SES-8

Satellite description

Specifications

Launch vehicle

Second-stage reignition

Prelaunch

Launch attempts

See also

References