Tuesday, April 24, 2018

With A Hughes Satellite, ISRO Moves Closer To Joining The "Ka-Band"wagon

Shining the "Sun" on its future  High Throughput Satellites [HTS] to meet growing domestic demands.

Commercial Communications Satellites - GSO - 01
ISRO's more than half a decade old quest, of being a full-fledged Ka-band Satellite operator, seems to be approaching fructification. 6 years ago, it evinced public interest in acquiring Ka-band based Satellite, an interest it would renew every now & then.
It, recently, put out a notice, seeking observation "on an application to CAISS for registering an Indian Satellite System". The High Throughput Satellite [HTS], called Surya, would have 67 Beams in all - 13 Gateway beams & 54 Subscriber beams of Ka-band, covering the entire extent of the Indian territory, while orbiting in the 104o E longitude. Equipped with 54 Transponders, it would have a total Bandwidth of 1250 MHz, to handle communication.
ISRO - Ka Band Satellite - Observation - CAISS - 01
The Delhi-based Jupiter Satellite India Ltd., a subsidiary of the US-based Hughes Network Systems LLC,  has submitted it's application, for which it is in process of receiving an "In-principle Authorisation" from the Committee for authorising the Establishment and Operation of Indian Satellite Systems [CAISS]. Given the name, one assumes that the satellite being offered would be based on its JUPITER™ high-throughput technology, that was utilised in its EchoStar XIX/JUPITER 2 satellite, be it on a scale a shade smaller.
This delay in acquiring the Ka-band Satellite was, partly, a fallout of the undefined policies with regards to private sector satellite builders in the country, that vexed interested parties post-announcement of ISRO's initial intent. That, subsequently, sorted out, one hopes this deal goes through without further delays.
The benefits of using Ka-band based HTS for Communication can not be overemphasised in India. Increasing number of industries are adopting high-speed Broadband-centric solutions to address issues, that is driving up requirement in unprecedented manners. A recent news report noted that, of the 300 Transponders needed to barely meet India's communication requirements, 100 are being leased from foreign satellite operators, a major cost drain. Adding to that, it noted that, "India at least needs another 200 transponders to meet the growing communications demand".
Communication & connectivity have a direct bearing on National well-being. A World Bank report estimated that a country can register around 1.4 percent growth in GDP, if it achieves a 10 percent increase in Broadband penetration#. The industry body overseeing the profligate expansion of televised entertainment in Indian, estimates that Indian are being entertained 37% less than what they ought to.
The last snark aside, it is, therefore, imperative for India to find solutions to mitigate the looming crisis. The, then, Chairman of ISRO, A.S. Kiran Kumar had, himself called for the need to more than double the number of Indian satellites in orbit to meet domestic requirement. Adopting new, capacity-building technology is the way forward. Tangentially, getting more entities involved in activities that, previously, had been the sole domain of Govt. organisation will help achieve more, while lessening the burden on one.
ISAC - Satellite System Alignment - India - EoI - 01
This is exemplified by the recent ISAC-issued EoI notice, in which it seeks supply of manpower from the private sector "to take up Spacecraft Alignment & associated activities".
Overview of the type of alignment activities involved during a satellite build,
ISAC - Satellite System Alignment - India - EoI - 02
A conventional Ka-band satellite, such as the Hughes SPACEWAY® 3, for example, can handle as much data as around Eight Ku-Band Satellites, the kind ISRO presently builds. Not only would they help mitigate the Bandwidth issues, but also effect a 97 percent reduction in the unit cost of data transmission - compared to the $100 Million USD per Gbps throughput it costs to communicate using a Ku-band satellite, a Ka-band satellite will incur end-user no more than $3 Million USD per Gbps.
C-Ku-Ka Band Beam Size Comparison - 01
Satellite builders apply various techniques to optimise available bandwidth, to pass greater volumes of data through it. One among them is frequency reuse. It primarily involves generating multiple Beams of the same frequency, thereby enabling use of the same hardware to generate them, reducing cost. In C-band, or Ku-band, frequency reuse isn't implemented owing to signal interference that will be experienced due to the large Beam sizes. Ka-band beams, on the other hand, have much smaller footprint, known as Spot Beams, allowing for practical application of frequency reuse to be implemented, without adverse fallouts [more details]. Beam Hopping is another method to cater to varied demand, using finite available resource to provide high-speed service.
According the RFP notice it put out in 2015, ISRO intended to acquire 2 such satellites, through a single contract, that would be put into orbit in any longitudes between 48o E & 112o E. Similar to the stipulations laid in the EoI notice earlier, ISRO would have to be consulted & be an active participant in each & every aspect of the satellite, following contract awardment. The 1st could be constructed by the Contractor, at its own facility, while the second would be done at & by ISRO.
Ka-Band Satellites - Worldwide - Till 2018 - 01
Interestingly, it has asked that the Contractor provide them with a Satellite Simulator. It, typically, allows developers of Satellite Network application, to validate their designs & procedures, be it for the Ground Stations or a future orbiting satellite, without having to use an actual satellite, a prized resource, itself. The original RFP notice also asked 88 Spot Beams, of which, 4 could be steerable. The Surya, however, is detailed to have a total of only 67 Beams. Limiting considerations of size & power consumption may have influenced this configuration selection for now. With a focus on making the satellite as fail-safe as possible, it should be able to operate independently for up to 48 hours, in the event of communication breakdown with Ground Station.
ISRO - GSAT-19 Satellite - Antenna Test Facility - 01 - TN
India, on its part, ventured into the Ka-band territory with the GSAT-19 satellite*. Launched in 2017, it primarily serves as a technology test-bed, to validate a host of goodies including Ion Thrusters, indigenous Lithium-ion Battery, MEMS accelerometer, and more. Among the "and more" is the Ku x Ka Transponder, that provides 10 Beams: 2 Gateway Beams in Ka-band & 8 Ku-band Subscriber Beams, catering to communication requirements. A small step in the right direction - commercial Ka Band HTS, such as the Eutelsat's KA-SAT satellite, in comparison, generates 90 beams, with a 90 Gbps throughput.
Later this year, ISRO would see its ~5.6 MT GSAT-11 satellite, launched into Space, via Arianepace's Ariane-5 Launch Vehicle [Update: Unconfirmed report indicates, launch delayed further. The GSAT-11 Satellite is to be returned back to India - reason undisclosed, yet]. Scaling up the earlier Ka*Ku hybrid Transponder model, the satellite would generate 8 Gateway Ka-band Beam & 32 Subscriber Ku-band Beams - a 4-fold capacity increase vis-a-viz the GSAT-19. The satellite would have a throughput capacity of 10-14 Gbps.
GSAT-11 Satellite - Reflector Beam Antenna Test - 01
The GSAT-29 is another Indian satellite, employing the hybrid Ka*Ku design, that is also scheduled for launch this year. In addition to the high-resolution imaging technology [read, "Spy Stuff"] demonstrator onboard, it will also feature steerable Ka-band beam - a first for an Indian Communication Satellite - it's Earth Observation CARTOSAT-1 satellite uses a phased array antenna with steerable beam to transmit data back to Ground Stations [Trivia: it generates 120 GB of data for 9 minutes of observation]. ISRO has announced that it would launch the GSAT-29 this year, atop the second development flight of its GSLV Mk. III launch vehicle, the GSLV-MKIII-D2. Given the constantly shifting timelines - the GSAT-11 was to go up in 2016 - it's hard to predict which of the 2 satellites would go up first.
India's first wholly Ka-band based satellite will, however, be the GSAT-20, that will deploy Ka-band beams for, both, the User & Gateway. Planned to be launched with the 1st operational variant of the LVM3, the satellite would weigh around 3.65 MT. While no other official detail of the GSAT-20 is available, so far, a SAC paper titled, "Payload System Design and Configuration for High-Throughput Satellite (HTS) over Indian Sub-continent", talks of a Ka-band HTS with 1 GHz of total user spectrum, that "will provide ~80 Gbps of overall throughput with 72 spot beams over India". Difficult to say if the paper is referring to the GSAT-20, though, comparing its weight & capacity with that of the GSAT-11, likelihood appears slim. Design configurations for a successor satellite, perhaps.
One wonders, if Ka-band is all so good & the next best thing to sliced bread [it is not], then why does ISRO not go ahead with building only Ka-band satellites of its own, instead of buying them from elsewhere. Well, a switch to Ka-band communication would require a major overhaul of infrastructure on the ground, for a vast majority of industries have their gears rigged solely to communicate using non-Ka-band beams. A big CAPEX in their Account Books. Also, C-band & Ku-Band have some inherent advantages that, for some industrial sectors, suits them just fine - their wider beams help broadcast television content over wider area with a single beam. Add to that Ka-band comes with some of its own set of baggages, some inherent, some a trend - Rain fade affects the high frequency Ka signals much more than the C & Ku-band. In case of satellite Ka-band satellite failure, there isn't as many other similar Satellites in orbit that can take up the load, not so much of the Ku-band-based communication, of which there are plentiful satellites in orbit. Thus, ISRO will have to continue catering to its existing end-user, till the time Ka-band becomes a stable platform, incurring them tangible benefits w.r.t. their bottom-lines. Given its present satellite building capacity, it seems like a sensible route.
Bharat Broadband - Satellite Broadband Network - 01
In the meanwhile, India is getting ready to reap the Bandwidth bounty once the two satellites become operational. The Govt.-owned Bharat Broaband Network Limited, recently, initiated a Tendering process for executing a "Turnkey Project for Supply, Installation, Commissioning and Maintenance of Satellite based Broadband Network and Solar Power Equipment". As part of this, it aims to inter-connect around 5,000 Gram Panchayat centres through high-speed broadband Internet, by bouncing the signal off either the GSAT-11, GSAT-19 or, even the Surya.
India sits on the cusp of witnessing an explosive growth of Internet connectivity capacity with the wide-scale adaption of Ka-band connectivity. If optimised correctly, its advent will revolutionise the way India does things, opening up wide-ranging opportunities to develop solutions, riding on Broadband connectivity backbone, to address some of long-standing pain points in India's social & economic governance.
The full notice, that appeared in Indian Newspapers recently
ISRO - Ka Band Satellite - Observation - CAISS - 02

GSAT-14 Satellite - ISRO - India - 01
* - Technically, ISRO first tryst with the Ka-band happened with the GSAT-14, launched in 2014. It carried 2 Ka-band beacons, to undertake studies of the effect of rain & other atmospheric factors on the its signal - higher the signal frequency, greater its susceptibility to be affected by these factors, known as Atmospheric Attenuation. Since it had no end-user application, one doesn't consider it for the matter under discussion.
# - "study concludes that a 10 percentage point increase in fixed broadband penetration would increase GDP growth by 1.21% in developed economies and 1.38% in developing ones" ~ Exploring the Relationship Between Broadband and Economic Growth