UPSC Essentials brings to you its initiative of subject-wise quizzes. These quizzes are designed to help you revise some of the most important topics from the static part of the syllabus. Attempt today’s subject quiz on Science and Technology to check your progress.As we mark the 3rd anniversary of the UPSC Essentials magazine, we thank our readers for being part of this journey. Your trust, feedback and continued support have shaped the magazine and encouraged us to keep improving with every edition. Click Here to read the UPSC Essentials magazine for September 2026. Share your views and suggestions in the comment box or write to us at manas.srivastava@indianexpress.com.QUESTION 1Consider the following statements:1. Liquid oxygen (LO2) and liquid methane (LCH4) propulsion systems have been identified as promising options for some future space vehicles.2. An integrated main and reaction control propulsion system using LO2/LCH4 propellants can provide substantial savings in overall system mass compared with conventional hypergolic systems.Which one of the following is correct in respect of the above statements?(a) Both Statement 1 and Statement 2 are correct and Statement 2 is the correct explanation for Statement 1.(b) Both Statement 1 and Statement 2 are correct and Statement 2 is not the correct explanation for Statement 1.(c) Statement 1 is correct but Statement 2 is incorrect.(d) Statement 1 is incorrect but Statement 2 is correct.Story continues below this adRelevance: The question links space technology with propulsion systems, particularly the use of cryogenic propellants such as liquid oxygen and liquid methane in future space vehicles. It is relevant to the UPSC Prelims Science and Technology syllabus, especially developments in space technology and emerging technologies associated with space missions.Explanation— China successfully launched four different orbital rockets from three separate launch sites within roughly 45 hours between September 15 and 16.— The methane- and liquid-oxygen-powered rocket carried 10 satellites into low Earth orbit for Qianfan, or “Thousand Sails”, a Chinese broadband megaconstellation. If the programme proceeds as planned, Qianfan is expected to have around 15,000 active satellites eventually.About liquid oxygen (LO2)/liquid methane (LCH4) propulsion systems— The National Aeronautics and Space Administration (NASA) has identified liquid oxygen (LO2)/liquid methane (LCH4) propulsion systems as promising options for some future space vehicles. Specifically, it is believed that an integrated main and reaction control propulsion system utilising LO2/LCH4 propellants can provide substantial savings in overall systems mass when compared to conventional hypergolic systems. To address the necessary risk reduction, the NASA Exploration Technology Development Program (ETDP) has formed the Propulsion and Cryogenics Advanced Development (PCAD) project. Hence, statements 1 and 2 are correct.Story continues below this ad— Statement 2 correctly explains Statement 1 because the potential for significant overall system-mass savings is one of the reasons LO2/LCH4 propulsion systems are considered promising for future space vehicles.Therefore, option (a) is the correct answer.(Other Source: ntrs.nasa.gov)QUESTION 2With reference to the HbA1c, consider the following statements:1. It reflects the amount of glucose attached to haemoglobin inside red blood cells.2. It is a commonly used test to assess a person’s average blood glucose levels.Story continues below this ad3. HbA1c reflects around six months of average glucose exposure.How many of the statements given above are correct?(a) Only one(b) Only two(c) All three(d) NoneRelevance: The question is relevant to Human Health and Biology, particularly the understanding of blood glucose regulation and biomarkers used in assessing metabolic health.Explanation— HbA1c is one of the most commonly used tests to assess a person’s average blood glucose levels over the previous few months. Because it does not require fasting and is widely used to screen for and monitor diabetes, it is often treated as a straightforward measure of blood sugar control. However, factors beyond glucose itself can influence the number. Hence, statement 2 is correct.— HbA1c reflects the amount of glucose attached to haemoglobin inside red blood cells, meaning that anything that changes how long these cells remain in circulation could potentially affect the result. Hence, statement 1 is correct.Story continues below this ad— Kanikka Malhotra, Consultant Dietician & Diabetes Educator, tells indianexpress.com, “HbA1c is essentially a memory stored inside red blood cells. Glucose in the blood attaches to haemoglobin, and the longer a red blood cell circulates, the more glucose it accumulates on its surface. Since these cells normally live around 120 days, HbA1c reflects roughly three months of average glucose exposure. But this only works accurately if red blood cells live their full lifespan. If cells turn over faster, they don’t stay in circulation long enough to bind as much glucose, making HbA1c appear lower than actual average sugar levels. If cells survive longer than usual, they accumulate more glucose, pushing HbA1c higher.” Hence, statement 3 is not correct.Therefore, option (b) is the correct answer.QUESTION 3Which of the following space missions are the result of engagements between the European and the Indian space agencies?1. Aditya L12. BepiColombo3. Chandrayaan-34. Proba-3Select the correct answer using the codes given below:(a) 1 and 2 only(b) 2 and 3 only(c) 3 and 4 only(d) 1 and 4 onlyRelevance: The question is useful for linking recent space missions with international partnerships, an important area of current affairs under the Science and Technology syllabus.Explanation— The Indian Space Research Organisation (Isro) and the European Space Agency (ESA) have announced the renewal of their existing cooperation till 2032.Story continues below this ad— The decision was made at the recently concluded International Space Summit in Paris, where the chiefs of the two space agencies signed a pact extending their long-standing cooperative agreement. At the summit held on September 9 and 10, the signatories confirmed and reaffirmed long-term commitment by both Europe and India to expanding cooperation in space.— Some of the recent engagements between the European and the Indian space agencies have been for missions Aditya-L1, Proba-3, and the upcoming Chandrayaan-5, to name a few.— BepiColombo is a joint mission of the European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA) to study Mercury while Chandrayaan-3 is an Indian lunar mission led by ISRO.Therefore, option (d) is the correct answer.QUESTION 4With reference to the Tarang Shakti-26, consider the following statements:Story continues below this ad1. The exercise has three aims: operational learning, greater interoperability and stronger partnerships.2. It is a domestic exercise and does not involve any foreign countries’ participation.Which of the statements given above is/are correct?(a) 1 only(b) 2 only(c) Both 1 and 2(d) Neither 1 nor 2Relevance: The question is relevant to Defence and Security, particularly India’s participation in multinational military exercises and the role of such exercises in improving operational capabilities. It is useful for current-affairs preparation on India’s defence diplomacy and international military cooperation.Explanation— The Indian Air Force (IAF) will host the second edition of its largest-ever multinational air exercise, Tarang Shakti-26, beginning later this week in Jodhpur.Story continues below this ad— 8 Friendly Foreign Countries as participating members and 32 other nations will be attending as observers, which will bring together a range of advanced combat aircraft, including the US F-35s, French Rafales and UAE F-16s, along with various other aerial assets, for joint aerial operations, tactical training and interoperability drills. Tarang Shakti-26 has three aims: operational learning, greater interoperability and stronger partnerships. Hence, statement 1 is correct.— The exercise, to be held between September 26 and October 12 at Air Force Station, Jodhpur, and adjoining air bases, will see participation from eight forces — India, Australia, Bangladesh, France, the US, Germany, Sri Lanka and UAE. Hence, statement 2 is not correct.— The exercise aims to analyse tactical employment philosophy against modern Air-to-Air and Surface-to-Air weapons, to enhance interoperability among the participating forces and to identify best practices in operations. It will involve Beyond Visual Range and within Visual Range combat missions, air mobility operations and dynamic targeting, air-to-air refuelling missions and combat search and rescue operations.— The maiden edition of the exercise took place in August-September 2024 in two phases.Therefore, option (a) is the correct answer.QUESTION 5Progress 96 cargo spacecraft was recently in the news for delivering about three tonnes of food, fuel and other supplies for the astronauts and cosmonauts at the International Space Station (ISS). The Progress 96 cargo spacecraft belongs to:(a) United States(b) Russia(c) China(d) IndiaRelevance: The question is relevant to space technology and human spaceflight, particularly the role of uncrewed spacecraft in supporting crewed missions and space-station operations. It might be useful for current-affairs-based questions linking space missions, cargo spacecraft and international cooperation in space exploration.Explanation— Russia’s Progress 96 cargo spacecraft successfully docked with the International Space Station (ISS), delivering about three tonnes of food, fuel and other supplies for the astronauts and cosmonauts aboard the orbiting laboratory.— The robotic spacecraft launched on a Soyuz rocket from the Baikonur Cosmodrome in Kazakhstan on September 16. It then spent three days travelling through orbit to catch up with the ISS, according to Space.com.— Progress spacecraft regularly transport supplies to the ISS. Unlike crewed spacecraft, these vehicles operate without astronauts or cosmonauts on board and are designed to deliver cargo before eventually being disposed of. The docking of Progress 96 marked the end of its three-day orbital journey from Baikonur to the space station.— Progress 96 is expected to remain docked to the ISS for about five months. During that period, the spacecraft will serve as part of the station’s logistics system while the crew unloads and uses its cargo, according to Space.com.Therefore, option (b) is the correct answer.Previous Daily Subject-Wise-QuizDaily Subject-wise quiz — History, Culture, and Social Issues (Week 165)Daily subject-wise quiz — Polity and Governance (Week 181)Daily subject-wise quiz — Science and Technology (Week 180)Daily subject-wise quiz — Economy (Week 180)Daily subject-wise quiz — Environment and Geography (Week 180)Daily subject-wise quiz – International Relations (Week 180)Subscribe to our UPSC newsletter and stay updated with the news cues from the past week.Stay updated with the latest UPSC articles by joining our Telegram channel – IndianExpress UPSC Hub, and follow us on Instagram and X