The fuel that will power the core (or the middle unit of the lower part) of the GSLV Mk-III, the rocket to be used in the Chandrayaan-2 mission is UDMH (Unsymmetrical Di-Methyl Hydrazine).
§ The Indian Space Research Organisation(ISRO) is using the highly toxic and corrosive fuel UDMH (Unsymmetrical Di-Methyl Hydrazine), along with the oxidiser nitrogen Tetroxide. This is called a “dirty combination”.
§ Elsewhere in the world, space programmes have moved to a cleaner and greener fuel — liquid methane or kerosene.
§ Shifting to liquid methane would mean bringing in cryogenic engine because any gas would need to be kept in extremely low temperatures to stay liquefied.
§ GSLV Mk III is a three-stage heavy-lift launch vehicle developed by ISRO. The vehicle has two solid strap-ons, a core liquid booster and a cryogenic upper stage.
§ GSLV Mk III is designed to carry 4 ton class of satellites into Geosynchronous Transfer Orbit (GTO) or about 10 tons to Low Earth Orbit (LEO), which is about twice the capability of GSLV Mk II.
Propellant Used in Rocket
§ The propellant is the chemical mixture burned to produce thrust in rockets and consists of a fuel and an oxidizer.
o Fuel is a substance that burns when combined with oxidiser for propulsion.
o The oxidizer is an agent that releases oxygen for combination with a fuel. The ratio of oxidizer to fuel is called the mixture ratio.
§ Propellants are classified according to their state - liquid, solid, or hybrid.
§ Liquid Propellants: In a liquid propellant rocket, the fuel and oxidizer are stored in separate tanks and are fed through a system of pipes, valves, and turbopumps to a combustion chamber where they are combined and burned to produce thrust.
o Advantages: Liquid propellant engines are more complex than their solid propellant counterparts, however, they offer several advantages. By controlling the flow of propellant to the combustion chamber, the engine can be throttled, stopped, or restarted.
o Disadvantages: The main difficulties with liquid propellants are with oxidizers. Storable oxidizers, such as nitric acid and nitrogen tetroxide are extremely toxic and highly reactive, while cryogenic propellants being stored at low temperature and can also have reactivity/toxicity issues.
o Liquid propellants used in rocketry can be classified into three types: petroleum, cryogens, and hypergolic.
· Petroleum fuels are those refined from crude oil and are a mixture of complex hydrocarbons, i.e. organic compounds containing only carbon and hydrogen. The petroleum used as rocket fuel is a type of highly refined kerosene.
· Cryogenic propellants are liquefied gases stored at very low temperatures, most frequently liquid hydrogen (LH2) as the fuel and liquid oxygen (LO2 or LOX) as the oxidizer. Hydrogen remains liquid at temperatures of -253 oC (-423 oF) and oxygen remains in a liquid state at temperatures of -183 oC (-297 oF).
· Hypergolic propellants and oxidizers that ignite spontaneously on contact with each other and require no ignition source. The easy start and restart capability of hypergolic make them ideal for spacecraft manoeuvring systems.
· Since hypergolic remain liquid at normal temperatures, they do not pose the storage problems like cryogenic propellants. Hypergolic are highly toxic and must be handled with extreme care. Hypergolic fuels commonly include hydrazine, monomethyl-hydrazine (MMH) and unsymmetrical dimethyl-hydrazine (UDMH).
§ Solid propellant: These are the simplest of all rocket designs. They consist of a casing, usually steel, filled with a mixture of solid compounds (fuel and oxidizer) that burn at a rapid rate, expelling hot gases from a nozzle to produce thrust. When ignited, a solid propellant burns from the centre out towards the sides of the casing.
§ There are two families of solids propellants: homogeneous and composite. Both types are dense, stable at ordinary temperatures, and easily storable.
o Composites are composed mostly of a mixture of granules of solid oxidizers, such as ammonium nitrate, ammonium dinitramide, ammonium perchlorate, or potassium nitrate in a polymer binding agent.
o Single-, double-, or triple-bases (depending on the number of primary ingredients) are homogeneous mixtures of one to three primary ingredients.
§ Advantages: Solid propellant rockets are much easier to store and handle than liquid propellant rockets. High propellant density makes for compact size as well.
§ Disadvantages: Unlike liquid-propellant engines, solid propellant motors cannot be shut down. Once ignited, they will burn until all the propellant is exhausted.
§ Hybrid propellant: These engines represent an intermediate group between solid and liquid propellant engines. One of the substances is solid, usually the fuel, while the other, usually the oxidizer, is liquid. The liquid is injected into the solid, whose fuel reservoir also serves as the combustion chamber.
o The main advantage of such engines is that they have high performance, similar to that of solid propellants, but the combustion can be moderated, stopped, or even restarted. It is difficult to make use of this concept for very large thrusts, and thus, hybrid propellant engines are rarely built.
§ A cryogenic rocket engine is a rocket engine that uses a cryogenic fuel or oxidizer, that is, its fuel or oxidizer (or both) are gases liquefied and stored at very low temperature.
§ A Cryogenic rocket stage is more efficient and provides more thrust for every kilogram of propellant it burns compared to solid and earth-storable liquid propellant rocket stages. Specific impulse achievable with cryogenic propellants (liquid Hydrogen and liquid Oxygen) is much higher compared to earth storable liquid and solid propellants, giving it a substantial payload advantage.
§ Oxygen liquefies at -183 deg C and Hydrogen at -253 deg C also entails complex ground support systems like propellant storage and filling systems, cryo engine and stage test facilities, transportation and handling of cryo fluids and related safety aspects.
§ The gauge for rating the efficiency of rocket propellants is specific impulse, stated in seconds. Specific impulse indicates how many pounds (or kilograms) of thrust are obtained by the consumption of one pound (or kilogram) of propellant in one second.
§ Specific impulse is characteristic of the type of propellant, however, its exact value will vary to some extent with the operating conditions and design of the rocket engine.
What to study?
For Prelims and Mains: Blockchain technology- what is it? How it operates? Concerns and potential.
What are Blockchains?
Blockchains are a new data structure that is secure, cryptography-based, and distributed across a network.
The technology supports cryptocurrencies such as Bitcoin, and the transfer of any data or digital asset.
Spearheaded by Bitcoin, blockchains achieve consensus among distributed nodes, allowing the transfer of digital goods without the need for centralized authorisation of transactions.
How it operates?
- The technology allows transactions to be simultaneously anonymous and secure, peer-to-peer, instant and frictionless.
- It does this by distributing trust from powerful intermediaries to a large global network, which through mass collaboration, clever code and cryptography, enables a tamper-proof public ledger of every transaction that’s ever happened on the network.
- A block is the “current” part of a blockchain which records some or all of the recent transactions, and once completed, goes into the blockchain as permanent database. Each time a block gets completed, a new block is generated. Blocks are linked to each other (like a chain) in proper linear, chronological order with every block containing a hash of the previous block.
Benefits of blockchain technology:
- As a public ledger system, blockchain records and validate each and every transaction made, which makes it secure and reliable.
- All the transactions made are authorized by miners, which makes the transactions immutable and prevent it from the threat of hacking.
- Blockchain technology discards the need of any third-party or central authority for peer-to-peer transactions.
- It allows decentralization of the technology.
What real world problem does blockchain solve?
- As of today nothing, but blockchain backers say it solves the problem of ‘trust’. Because the major cost of any transaction or exchange of services or goods is the act of verification — VISA charges fees to ensure that your card swipe is connected to your account or a property charges you for the effort of ensuring that you are entering into a genuine transaction — blockchain asks you to trust the energy-intensive nature of mathematical problems and have them masquerade them as ‘locks’ to secure your money, confidential documents or any kind of information.
- While blockchain has the aura of transparency — anybody supposedly can check the history of a ‘block’ — it is at its core impervious to common sense. However, just as the inability to grasp in a visceral sense how letters typed on a mobile phone transform and make their way into another phone instantaneously a continent away does not stop people from using WhatsApp, blockchain technology has created enough hype and drama to have drawn the world’s wealthiest to invest in it and inveigle it into ordinary lives.
How blockchain can be used in public administration?
Blockchain has the potential to optimize the delivery of public services, further India’s fight against corruption, and create considerable value for its citizens.
- By maintaining an immutable and chronologically ordered record of all actions and files (“blocks”) linked together (“chain”) in a distributed and decentralized database, Blockchain creates an efficient and cost-effective database that is virtually tamper-proof. By doing so, blockchain promises to create more transparent, accountable, and efficient governments.
- In addition to creating a more efficient government, blockchain can also help create a more honest government. A public blockchain, like the one Bitcoin uses, records all information and transactions on the decentralized database permanently, publicly, and most importantly, securely. By allowing governments to track the movement of government funds, blockchain can hold state and local actors accountable for any misappropriations.
- Blockchain not only deters corruption through accountability, but it can also do so by bypassing the middleman entirely. Earlier this year, the World Food Programme began testing blockchain-based food and cash transactions in Pakistan’s Sindh province. Refugees in Jordan’s Azraq camp are now using the same technology, in conjunction with biometric registration data for authentication, to pay for food.
- With Aadhaar cards becoming nearly ubiquitous in India, adopting blockchain could be the next logical step in India’s pursuit of becoming a digital economy. Blockchain can play an important role in storing individuals’ data, helping conduct secure transactions, maintaining a permanent and private identity record, and turning India into a digital society.
Technology has always proved to be disruptive, creating new opportunities and jobs and destroying old ones. If blockchain’s appeal lies in its appeal to destroy intermediaries — banks, courts, lawyers — it is unlikely to be smooth sailing. Moreover, there is already serious theorising by economists that shows how blockchain has its own vulnerabilities and susceptibility to creating new hegemons, power networks, cartels and challenges to global energy consumption.
Sources: the Hindu.
Mains Question: What do you understand by blockchain technology? Evaluate its prospects and challenges.
Context: Across India, activists for tribal rights have said the proposed IFA amendments will divest tribals and other forest-dwelling communities of their rights over forest land and resources.
Highlights of the draft amendments:
- The amendment defines community as “a group of persons specified on the basis of government records living in a specific locality and in joint possession and enjoyment of common property resources, without regard to race, religion, caste, language and culture”.
- Forest is defined to include “any government or private or institutional land recorded or notified as forest/forest land in any government record and the lands managed by government/community as forest and mangroves, and also any land which the central or state government may by notification declare to be forest for the purpose of this Act.”
- While the preamble of IFA, 1927, said the Act was focused on laws related to transport of forest produce and the tax on it, the amendment has increased the focus to “conservation, enrichment and sustainable management of forest resources and matters connected therewith to safeguard ecological stability to ensure provision of ecosystem services in perpetuity and to address the concerns related to climate change and international commitments”.
- Increased role of states:The amendments say if the state government, after consultation with the central government, feels that the rights under FRA will hamper conservation efforts, then the state “may commute such rights by paying such persons a sum of money in lieu thereof, or grant of land, or in such other manner as it thinks fit, to maintain the social organisation of the forest dwelling communities or alternatively set out some other forest tract of sufficient extent, and in a locality reasonably convenient, for the purpose of such forest dwellers”.
- The amendment also introduces a new category of forests — production forest. These will be forests with specific objectives for production of timber, pulp, pulpwood, firewood, non-timber forest produce, medicinal plants or any forest species to increase production in the country for a specified period.
Indian Forest Act, 1927:
- The Indian Forest Act, 1927 was largely based on previous Indian Forest Acts implemented under the British. The most famous one was the Indian Forest Act of 1878.
- Both the 1878 act and the 1927 one sought to consolidate and reserve the areas having forest cover, or significant wildlife, to regulate movement and transit of forest produce, and duty leviable on timber and other forest produce.
- It also defines the procedure to be followed for declaring an area to be a Reserved Forest, a Protected Forest or a Village Forest.
- It defines what a forest offence is, what are the acts prohibited inside a Reserved Forest, and penalties leviable on violation of the provisions of the Act.
Concerns with regard to the present Draft Bill:
- The draft Bill reinforces the idea of bureaucratic control of forests, providing immunity for actions such as use of firearms by personnel to prevent an offence.
- The hard-line policing approach is reflected in the emphasis on creating infrastructure to detain and transport the accused.
- To penalise entire communities through denial of access to forests for offences by individuals. Such provisions invariably affect poor inhabitants, and run counter to the empowering and egalitarian goals that produced the Forest Rights Act.
- For decades now, the Forest Department has resisted independent scientific evaluation of forest health and biodiversity conservation outcomes. In parallel, environmental policy has weakened public scrutiny of decisions on diversion of forests for destructive activities such as mining and large dam construction.
- Impact assessment reports have mostly been reduced to a farce, and the public hearings process has been
- The exclusion of ‘village forestry’ from the preview of Forest Right Act (forest official supersedes Gram Sabha) is legally contradictory and would add confusion on the ground.
- The draft mentions that the state governments could take away the rights of the forest dwellers if the government feels it is not in line with “conservation of the proposed reserved forest” by payment to the people impacted or by the grant of land.
The need for review:
Many reports like the MB Shah report of 2010 and the TSR Subramanian report of 2015, have talked about amending the IFA.
Sources: the Hindu.