All-electric propulsion and multi-satellite launch system for communication satellites
The Boeing Co. has successfully mated two 702SP (Small Platform) satellites into a stacked configuration in preparation for the first-ever conjoined satellite launch. The milestone is a significant step towards the early 2015 launch of the satellites ABS-3A and Eutelsat 115 West B, the first-ever all-electric propulsion satellites scheduled to enter service.
The 702SP, designed by Boeing Network & Space Systems satellite businesses and Phantom Works, features an all-electric propulsion system and a joint configuration for a dual-manifest launch. By eliminating chemical propulsion and using only electric propulsion, the 702SP platform offers a significant mass advantage that translates to increased revenue-generating payload performance and launch vehicle savings to customers. 1) 2)
Figure 1: Photo of the two satellites ABS-3A and Eutelsat 115 West B at Boeing premises in stacked launch configuration (image credit: Boeing)
Boeing has patented a means to place one electric-powered satellite on top of another within the rocket fairing without the need for a support structure. The deletion of this support structure allows an extra 700 kg in payload, which will make it possible to launch multiple satellites with smaller (and cheaper) launchers like the Falcon 9. The concept will first be used for Boeing's customers ABS (headquarted in Bermuda) and Eutelsat S. A. of Paris, France; both capanies are commercial communication satellite operators.
Launch: The ABS-3A and Eutelsat 115 West B communication satellites were launched on March 2, 2015 (03:50:00 UTC) on a Falcon 9 v.1.1 vehicle of SpaceX from Cape Canaveral Air Force Station SLC-40 (Space Launch Complex-40). 3) 4) 5) 6)
Due to the high payload mass of the two satellites, Falcon 9 had to fly in its fully expendable configuration without landing legs and grid fins, not attempting a first stage return.
Figure 2: Electric deployment propulsion scheme for EUTELSAT 115 West B satellite (image credit: EUTELSAT) 7)
Orbit: Geostationary orbit, altitude = 35786 km. ABS-3A will be located at 3º W. Eutelsat 115 West B will be located at 114.9° W.
For the first time, commercial satellite operators had procured satellites relying solely on SEP (Solar Electric Propulsion) for GTO-GEO transfer durations in the order of 6 months. This eliminates the conventional onboard chemical propulsion system (mass of motor plus storage tanks and support structure) for quick orbit raising. 8)
Figure 3: Artist's rendition of a deployed Boeing 702SP satellite in orbit (image credit: Boeing)
• The ABS-3A communication satellite will distribute television programming, Internet and mobile phone connectivity, and maritime services across the Americas, Europe, Africa and the Middle East for ABS (Asia Broadcast Satellite) of Bermuda and Hong Kong.
The spacecraft delivers three C-band beams and four Ku-band coverage zones. ABS-3A is outfitted with 24 active C-band transponders operating at a bandwidth of 72 MHz and a frequency range of 5.850 to 6.425 GHz for uplink and 3.625 to 4.200 GHz for downlink. The C-band transponders use TWTAs (Traveling Wave Tube Amplifiers) operating at a power of 70 W. The Ku-band payload consists of 24 active transponders also operating at a 72 MHz bandwidth. Uplink uses frequency ranges of 13.750 to 14.750 and 11.450 to 11.700 GHz while downlink is done at frequencies of 10.700-11.200 and 12.500-12.750. The Ku TWTAs have a power of 150 W with a 24 for 19 redundancy.
• Eutelsat 115 West B will provide the Americas with video, data, government, and mobile services for Paris-based Eutelsat. The Eutelsat 115 West B satellite is outfitted with 12 C- and 34 Ku-band transponders to deliver Fixed Satellite Services in the Americas. Stationed at 114.9° West in geostationary orbit, the satellite provides coverage across America. A C-band Pan-American beam provides coverage from Alaska over the western portion of Canada and the United States to Mexico, Latin America and the north-western regions in South America. The Ku-coverage is split in several beams, one covering Mexico and surrounding territories, another covers the majority of South America with the exception of the north eastern regions, and a third covers the entire United States (except Florida) and Canada.
Launch: The Eutelsat 117 West B and ABS-2A communication satellites were launched on June 15, 2016 (14:29:00 UTC) on a Falcon 9 FT (Full Thrust) vehicle of SpaceX from Cape Canaveral Air Force Station SLC-40 (Space Launch Complex-40). SpaceX's Falcon 9 rocket delivered the two commercial communications satellites to GTO (Geostationary Transfer Orbits). 9)
What makes this flight especially interesting is that the satellites are based on Boeing's 702SP series program and were the first all-electric propulsion satellites when Boeing introduced it in 2012. The satellites have no chemical thrusters. They will maneuver to their intended GEO (Geostationary Orbit) entirely using a xenon-based electric thruster propulsion system known as XIPS (Xenon-Ion Propulsion System).
SpaceX intended to recover the first stage of the Falcon9. However, the Falcon 9 was unsuccessful in its attempt to land on the drone ship in the Atlantic Ocean. The first-stage was subject to extreme velocities and re-entry heating, making a successful landing difficult, or in this case, impossible.
EUTELSAT 117 West B is the second new-generation electric satellite in Eutelsat Americas' fleet, and will be co-located with EUTELSAT 117 West A. EUTELSAT 117 WEST B will also provide video services including DTH (Direct To Home) and DTT (Digital Terrestrial Television) for the region. This newly-created multi-satellite neighborhood will strengthen the video capacities at 116.8° West and offer key services to Latin America clients in the field of telecommunications and government services.
ABS-2A will be the second of the pair of the innovative all-electric propulsion satellites. The payload for this mission is two communications satellites, both built by Boeing Satellite Systems. They each have 48 transponders and 4 dedicated Ku-band transmitters. The ABS-2A satellite is the second of the pair of the innovated all-electric propulsion satellites, manufactured by Boeing Satellite Systems International. It is equipped with an all Ku-band payload of 48 high performance transponders connecting Africa, MENA, Russia, South Asia and South East Asia regions. ABS-2A will be colocated with ABS-2 and will deliver enhanced broadcast and data services from 75º E. 10)
In 2012 Boeing introduced the newest satellite design in its product portfolio, the BSS (Boeing Satellite Systems)- 702SP (Small Platform). The 702SP is an evolution of the Boeing 702 satellite, and continues Boeing's five decades of designing and delivering satellite systems that fulfill customer requirements. The 702SP couples proven technology from Boeing's previous designs with next-generation technology and processes, resulting in an affordable, lightweight alternative design to meet customer needs. The 702SP passed its CDR (Critical Design Review) in May 2013, moving the satellites into production. 11) 12)
In March 2012, a joint procurement by ABS (Asia Broadcast Satellite) and Satmex (Satélites Mexicanos) of Mexico (acquired by Eutelsat in January 2014), resulted in Boeing's first order for the 702SP. The agreement consisted of four satellites, including ABS-3A and Eutelsat 115 West B, with options for four additional satellites. In July 2013, ABS confirmed that the third satellite would be ABS-2A, while Satmex confirmed that the fourth satellite in the original order would become Eutelsat 117 West B. Eutelsat 117 West B will also carry a WAAS (Wide-Area Augmentation System). The WAAS hosted payload will enable the U.S. FAA (Federal Aviation Administration) to enhance aviation safety.
General characteristics: The 702SP operates in the low- to mid-power ranges of 3 to 8 kW, and expands the capability of the 702 satellite family to power ranges from 3 to 18 kW. The 702SP features all-electric propulsion, which minimizes spacecraft launch mass and maximizes available payload. Able to accommodate up to five reflectors, the 702SP provides additional mission flexibility to its operators and broader services to users. It also features a next-generation avionics architecture, which simplifies operations and provides improved access to data for evaluation of the spacecraft's health.
The 702SP's low-mass system design accommodates launch on most commercial launch systems, including Falcon 9, Ariane-5, Sea Launch, Proton, Soyuz, Atlas-5 and Delta IV. Because of its lower mass and weight, two 702SP satellites can be launched on a single launch vehicle, resulting in a cost savings of up to 20 % when compared with existing launch options.
The Boeing 702SP can operate in the S-, X-, C-, Ku, and Ka-band frequencies and, as with all Boeing 702s, is designed to provide 15 or more years of satellite service with additional fuel capacity to enable multiple station changes over the life of the satellite. The 702 family of vehicles is designed to accommodate hosted payloads, such as sensors, UHF, military Ka-band and navigation L-band, resulting in additional flexibility for customers.
Figure 4: Summary of key parameters of the BSS-702SP (image credit: Boeing) 13)
XIPS (Xenon Ion Propulsion System)
The XIPS instrument assembly is being built by L-3 ETI (L-3 Communications Electron Technologies Inc.) is the company (formerly Hughes/Boeing EDD). ETI offers two qualified ion propulsion designs, the 25cm, 4.5 kW thruster and power processor used for the BSS satellites, and the NSTAR 30 cm, 2.3 kW thruster and power processor used for the Deep Space 1 spacecraft. 14)
The XIPS is a gridded electrostatic thruster system using a cathode to ionize a gaseous propellant (usually xenon) by electron bombardment. The positively-charged ions of propellant that result are then accelerated by an electric field and expelled from the thruster to provide thrust.
The 25cm ion thruster consists of a cylindrical plasma discharge chamber, discharge hollow cathode, 3-ring magnetic cusp plasma confinement, and neutralizer hollow cathode. The three grid ion accelerator utilizes domed molybdenum grids with approximately 11,000 apertures to produce the high purveyance xenon ion beam.
The XIPS-25 system used by the 702SP spacecraft consists of a central Xenon tank and four 25 cm ion thrusters. The 25cm thruster is designed to operate at two different power levels. The high power mode operates at 4.5 kW of input power to produce a 1.2 kV, 3 A ion beam. In this mode the thruster produces 165 mN thrust at a specific impulse (ISP) of 3500 seconds. The high power mode is used exclusively for the orbit insertion phase. Nearly continuous operation in the high-power mode has been achieved for times of 500 to 1000 hours. The requirements are launch vehicle and satellite dependent.
The low power mode, with a thruster input power of 2.2 kW, is used for station keeping. In this mode the thruster produces nominally 79 mN of thrust with an ISP of 3400 seconds.
Figure 5: Photo of a 25 cm thruster with a mass of <16 kg (image credit: ETI)
Table 1: Typical parameters of the 25 cm XIPS thruster
The XIPS power processor (XPC) provides all the electrical inputs and controls the functions and operation of the 25cm thrusters. The XPC functions include:
• Conditioned input voltages to the thruster
• Timing and sequencing for start-up
• Fault protection and grid clearing circuits
• Thruster and XPC telemetry .
The XPC consists of seven separate power supplies and operates from a regulated 100 V bus input voltage. The efficiency of the XPC is greater than 91%. The XPC measures 20.5 cm x 54 cm x 35 cm and has a mass of 20.9 kg.
Figure 6: Photo of the XPC (XIPS Power Processor) box (image credit: ETI)
• January 23, 2017: Having entered full, commercial service on January 21, Boeing has delivered the ABS-2A all-electric propulsion 702 satellite to ABS (Asia Broadcast Satellite). ABS-2A is providing its satellite services, including direct-to-home television services, on Jan. 21 to customers in Africa, the Middle East and North Africa, Russia, South Asia and South East Asia. 15)
- This satellite, ABS-2A, joins ABS-3A as Boeing's second all-electric propulsion 702 satellite for ABS. Boeing is the first satellite manufacturer to build and deliver all-electric propulsion satellites.
- "We have completed our three-satellite build investment in launching three satellites in three consecutive years, including ABS-2 in 2014 as well as Boeing's ABS-3A in 2015 and ABS-2A in 2016," said Tom Choi, CEO of ABS. "ABS-2A is the latest high-capacity satellite providing expansion and continuity of satellite services at ABS' prime gateway over the Indian Ocean region. It is located with ABS-2 at our premium neighborhood at 75ºE optimized for video services for the growing television community access and direct-to-home businesses."
• January 16, 2017: Eutelsat Communications of Paris, France, announced that its Eutelsat 117 West B satellite, launched on June 15, 2016, has entered into full commercial service at 117º West and is now ready to support customers across Latin America. 16)
• October 1, 2015: EUTELSAT 115 West B has completed the ascent from GTO to GEO (Geostationary Orbit) and today began in orbit tests. Eutelsat's new all-electric satellite is scheduled to enter full commercial service in mid-October, one month ahead of schedule. 17)
- EUTELSAT 115 West B is equipped with 24 C-band and 41.5 Ku-band equivalent transponders connected to beams covering Alaska, Canada, Mexico and South America, and will operate with exceptional elevation angles and coverage performances (EIRP) throughout the region.
• Sept. 10, 2015: The revolutionary all-electric ABS-3A satellite is now in full commercial use. The satellite started service on 31st August 2015 to serve the Americas, Africa, Europe and the Middle East regions. 18)
- Launched on March 2, 2015, the ABS-3A satellite built by Boeing has performed even better than expected having arrived ahead of schedule. In-Orbit tests have been successfully completed and the satellite became fully operational on 31st August 2015.
- "ABS' innovative design and procurement approach for satellites is designed to provide the best possible economics to our customers. ABS-3A and along with ABS-2A, launching in early 2016, will deliver these exceptional economics on current next-generation satellites. Both ABS-3A and ABS-2A will further strengthen and solidify our global expansion and offer flexible capacity to our growing fleet," commented Tom Choi, CEO of ABS. "We look forward to serving diverse markets using increasingly innovative and affordable solutions for many of ABS' current and future customers."
- "With a successful launch, testing and execution of orbit operations, we were able to deliver the first 702SP to ABS about one month earlier than planned," said Mark Spiwak, president, Boeing Satellite Systems International. "The 702SP product line was designed to bring the latest technology into the hands of customers seeking adaptable and affordable solutions. In addition, the 702SP's patented dual-launch capability helps customers share launch costs, which can significantly lower overall expenses for a satellite owner."
• May 14, 2015: The two commercial geostationary-orbit telecommunications satellites launched March 1 aboard a SpaceX Falcon 9 rocket — a launch that debuted the rocket's dual-launch-to-geo capability and a new all-electric satellite design by Boeing — are expected to reach their final orbits at least a month ahead of schedule, their owners said. 19)
- The owners, ABS of Bermuda and Eutelsat of Paris, said a particularly good launch injection by the Falcon 9 is the main reason why the ABS-3A and the Eutelsat 115 West B spacecraft will reach their operating stations in late August and late September, respectively.
• Thirty minutes into flight, the ABS-3A satellite deployed into a supersynchronous transfer orbit followed by EUTELSAT 115 West B approximately five minutes later. The satellites will now fire their thrusters to reach geosynchronous orbits. As the world's first all-electric propulsion satellites, they carry no liquid propellant – rather, they reach orbit entirely via a lighter and more efficient electric propulsion system (Ref. 4).
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3) Patrick Blau, "Falcon 9 makes thundering night Launch from Florida, delivers two Satellites," Spaceflight 101, March 2, 2015, URL: http://www.spaceflight101.com/spacex-falcon-9---eutelsat-115-west-b--abs-3a-launch-updates.html
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14) "XIPS: The Latest Thrust in Propulsion Technology," ETI, URL: http://www2.l-3com.com/eti/product_lines_electric_propulsion.htm
15) "Boeing's Second ABS All-Electric Propulsion Satellite Enters Service," Boeing, Jan. 23, 2017, URL: http://boeing.mediaroom.com/2017-01-23-Boeings-Second-ABS-All-Electric-Propulsion-Satellite-Enters-Service
16) "EUTELSAT 117 West B all-electric satellite fully charged and now in commercial service," Eutelsat Press Release, Jan. 16, 2017, URL: http://resources.mynewsdesk.com/image/upload/t_attachment/nteip3xrv2bd8tp1e7vg.pdf
17) "EUTELSAT 115 West B arrives in geostationary orbit," Space Daily, Oct. 1, 2015, URL: http://www.spacedaily.com/reports/EUTELSAT_115_West_B_arrives_in_geostationary_orbit_999.html
18) "ABS-3A Satellite Enters Commercial Service," ABS Press Release, Sept. 10, 2015, URL: http://www.absatellite.net/wp-content/uploads/2015/09/ABS-3A-Enters-Service-10-Sep-2015-FINAL.pdf
19) Peter B. De Selding, "SpaceX Launch Positioned Eutelsat, ABS Satellites For Faster Start," Space News, May 14, 2015, URL: http://spacenews.com/spacex-launch-positioned-eutelsat-abs-satellites-to-enter-service-sooner/
The information compiled and edited in this article was provided by Herbert J. Kramer from his documentation of: "Observation of the Earth and Its Environment: Survey of Missions and Sensors" (Springer Verlag) as well as many other sources after the publication of the 4th edition in 2002. - Comments and corrections to this article are always welcome for further updates (email@example.com).