SPACE | TECHNOLOGY
CubeSats are currently shotgunned into space as auxiliary payload piggybacking on the bigger launches done by civilian space agencies
Over the past 60 years, one defining trend has characterised the evolution of technology known for the key attributes like Smaller in size, Faster in speed, Lighter in weight, Denser in critical composition resulting to better efficiency, and Cheaper in comparison to conventional commercial technologies (SFLDC). This can be witnessed in automobiles, jet engines, computers, mobiles, small drones and a whole host of consumer electronics. Experts believe that man-made satellites are the last hold outs from a ‘mainframe era’ that have not participated in this revolution due in part to the overly regulated nature of this sector, highly niche applications of solutions and prohibitive costs of the space launches.
However, recent advances in power, sensor electronics and telemetry provide a reason to believe that this is set to radically change. Low Earth Orbit (LEO) CubeSats are particularly well placed to exploit these developments and allow space to be used for commercial and governance purpose in a viable form.
While much has been said and published on the manner in which conventional satellites have revolutionised a vast spectrum of human affairs from military surveillance to real-time broadcast and weather monitoring, the potential of multiple constellations of smaller, cheaper CubeSats working in tandem akin to terrestrial Internet servers has not yet been fully explored. In this artical, we intend to evaluate CubeSats as a low-cost technologyoption for delivering effective local governance.
The idea of miniaturising the satellites has been in the works for quite a while. The University of Surrey Satellite, weighing 52 kg, was the first small satellite in orbit. Subsequently attempts have been routinely made by research labs, universities and small groups of satellite hobbyists to build and deploy smaller satellites below 100 kg. Technological advancements in last two decades now allow reduction of essentially the entire Sputnik onto a single chip. On June 22, 2016, the Indian Space Research Organisation (ISRO) launched 14 nanosatellites, two of these CubeSats built by Indian universities — Sathyabamasat (1.5 kg-2U CubeSat ) and Swayam (1 kg-1U CubeSat)
Though an individual CubeSat is severely restricted owing to limitations of its onboard power and sensor packages, an entire constellation of smaller satellites can provide the same advantages of agility, redundancy, parallelisation and a synchronicity benefits which are the defining strengths of digital economy. Formation flying by constellation of CubeSats is being actively investigated to provide a fail-safe, redundant communications and sensor platform.
AN ENTIRE CONSTELLATION OF SMALLER SATELLITES CAN PROVIDE THE SAME ADVANTAGES OF AGILITY, REDUNDANCY, PARALLELISATION AND A SYNCHRONICITY BENEFITS WHICH ARE THE DEFINING STRENGTHS OF DIGITAL ECONOMY
Given the starkly lower cost of individual CubeSats or even a constellation of CubeSats vis-à-vis conventional satellites, the former provide much wider scope of testing experimental payloads and exploitation of a wide range of services which aren’t feasible on mainstream satellite buses many which have reached the end of their technological maturity.
The possibility of an open-ended space infrastructure could perhaps only be realised via CubeSats which would enable individual group of companies to develop service-oriented solutions for space applications much the same way as technology start-ups have revolutionised the digital economy by leveraging an ubiquitous, and for the most part standardised, Internet architecture. Even though current literature emphasises more of imagery and remote sensing applications, the spectrum of solutions for on-demand space based services is potentially limitless, having an ever present swarm of electronic Infrastructure in LEO has applications which perhaps haven’t even been imagined yet.
Cost — Economics of CubeSats Construction and Launch
The construction of a CubeSat using COTS is currently achievable and is already being done by hobbyist groups, universities, research labs and private entrepreneurs. The manufacturing cost of a 1U CubeSat kit is currently pegged at $50,000 which makes it a very affordable proposition. However, the important thing to remember is not the cost-economics of manufacturing (which are on a downward trajectory) but costs surrounding launch of CubeSats.
CubeSats are currently shotgunned into space as auxiliary payload piggybacking on the bigger launches done by civilian space agencies. This essentially binds cubesat deployment with the schedule of multimillion-dollar space launches, providing limited scope for growth. The cost-effectiveness of such a programme is debatable. The stated launch cost for CubeSats as an auxiliary payload is given to be $30,000/pound.
Even though there are studies which state that costs of individual CubeSat launch using Russian rockets is $30,000, per launch, independent studies peg the launch costs between $75,000 and $1,25,000 per 1U launch. There are a whole host of launch technologies which might come into fruition in the near future, which might see these costs come down appreciably. Some of these are discussed as following:
Plane launched platform — ALASA
This entails launching the CubeSat through a plane based missile launch. Boeing experimented ALASA for a while but owing to volatility of chemicals in the upper stage and consequent dangers posed, this had to be scrapped. A version of this Air Launched system is Cubecab which is a tiny missile riding aboard F-104 fighter jet. Experiments have shown promising results and could potentially be one way of launching it.
Elon Musk’s company SpaceX and Jeff Bezos’s Blue Origin have successfully demonstrated the feasibility of reusable satellite launch vehicles. As this launch capability moves forward and matures, it would be possible for CubeSat operators to schedule launches at a faster clip and economical rates. Blue Origin’s New Shepard design with smaller payload capacity is particularly well suited for clusters of CubeSats. Though the New Shepard reusable launch vehicle can only ferry payloads on a suborbital path till Karman line (100 km), its New Glenn stage of rockets have been earmarked for carrying payloads on an orbital flight path. Even as of today, New Shepard can ferry suborbital research payloads of 11.3 kg at an altitude of 100 km, the ideal deployment envelope for nano-satellite launch vehicles (NLV).
Chemical explosive based titanium alloy Artillery Guns
This has been seriously considered and experimentally tried only once, by the ill-fated Canadian weapons designer Gerald Bull. The unwieldy design of the guns along with limited altitude range of the projectiles are severe limiting factors with such a launch. Although unlikely to get traction in near future, advances in artillery development could potentially open up this method for commercial usage. However, this particular platform is deeply entangled with advanced weapons development, specifically — long range artillery and hence is unlikely to move ahead due to export control and MTCR regulations. Besides this, the range is severely limited, only 58-60 km straight up which falls significantly short of what’s needed for an orbital payload.
The two promising launch technologies which are likely to evolve as worthy CubeSat launch platform are:
A 40-ft launcher, which is relatively uncomplicated in design, has a fairly robust unibody structure, which has no turbopumps. The only moving parts are gimbals and valves. Recurring launch costs for 160 kg LEO are stated to be $3.5 million.
Uses a carbon composite aerospike engine which uses a pressure fed combustion cycle dispensing expensive pump-based combustion, which looks promising based on the latest tests. Similar to Demisprite it has no moving parts in its combustion cycle, which makes it more resilient against launch failures.
Propulsion, Payload and Power requirements of CubeSats
Advances in a range of technologies such as laser-based ion thrusters and solar sails allow for a radical new approaches in providing propulsion for CubeSats once they are deployed in orbit. Unlike conventional satellites with fixed predictable orbits, CubeSats are expected to have flexible orbits for reorientation towards specific geographies. Though some of the CubeSats can carry a limited chemical mass ejection propulsion systems, the severely limited payload capacity with CubeSat makes this an unviable option. Moreover, CubeSat Design Specification limits the onboard hazardous chemicals at 100 Wh (watt-hours). The associated inefficiencies with small number short duration bursts make propulsion through chemical burns an unviable option. However, the low inertial frames of CubeSats make them perfect vehicles to exploit magnetorquer and solar sails as a potential propulsion option. Several designs already exist in this regard including the IKAROS, developed by JAXA (Japanese Space Agency) which successfully demonstrated the solar sail capability in a fly-by to Venus. Other similar designs are also being actively studied .3U NanoSail D-2 and LightSail-2015 have also been successfully tested in LEO.
A CONSTELLATION OF CUBESATS RUNNING ON AN OPEN ARCHITECTURE DESIGN CAN MOST EFFECTIVELY LEVERAGE THE SKILLS AND RESOURCES OF INDIA’S TECHNOLOGY SECTOR TO CREATE A WIDE ARRAY OF SATELLITE SOLUTIONS IN ALMOST A QUASI-FREE MARKET CONDITIONS
Though payload of a single CubeSat is severely restricted, usage of COTS and stringing of CubeSats allows for leveraging a cluster computing model to enhance the overall effectiveness of the payload.
The single greatest limiting factor hindering the commercial and governance exploitation of CubeSats is lack of reliable communication infrastructure owing to low onboard power and a significant tumbling movement of CubeSats. Though a CubeSat can communicate across the full spectrum of VHF, UHF, L, C, S, and X Band, maintaining a steady and reliable uplink has proven to be challenging due to lack of appropriate infrastructure for a high gain directional antennae as found in conventional satellites. The existing helical mono/di-pole antennae are not sufficient for any sustained data uplinks. However, this problem is being successfully attacked by researchers from MIT and Caltech by incorporating an inflatable antennae which significantly amplifies and improves signal throughput.
CubeSats as a potential for Effective Governance in India
Government of India has very ambitious governance objectives, few of which include:
An Open Architecture Satellite Bus
Given the niche and capital intensive nature of satellite construction, present satellite bus are severely constrained in terms of the available range of payload and future expansion. Conventional 500 kg and above satellites do not allow room radical changes in its architecture due to physical constraints and legacy issues.
CubeSats which are designed using COTS and technology available in smartphones can be built from ground up and present no such problems. In many ways programming a CubeSat is similar to programming your smartphone. A constellation of CubeSats running on an open architecture design can most effectively leverage the skills and resources of India’s technology sector to create a wide array of satellite solutions in almost a quasifree market conditions. A constellation of ubiquitous infrastructure unhindered by geographic boundaries and weather anomalies also ensures that it will act as a pivotal infrastructure of governance delivery.
Krishnadev CS is Senior Consultant, Andhra Pradesh Economic Development Board who has vast experience in conventional energy, Nuclear with active interests in strategic defence.
Bhaskar Kanungo is Senior Consultant, Andhra Pradesh Economic Development Board. He has represented the Indian defence industry in key domestic and international forums and has contributed significantly towards an effective Defence & Aerospace Policy at the highest levels.