Last updated: October 2026
Official source notice: ISRO Assistant and Upper Division Clerk (UDC) recruitment is conducted centrally by the ISRO Centralised Recruitment Board (ICRB). The exam pattern, eligibility and Skill Test norms below are sourced from the official ICRB notification (Advt. No. ISRO:ICRB:01(A-JPA):2026). Always verify zone-wise vacancies and the latest notices on isro.gov.in.
If you are a graduate from any stream (B.A., B.Sc., B.Com., B.E./B.Tech, BCA or BBA) looking for a central government administrative career inside India's space programme, the ISRO Upper Division Clerk (UDC) and Assistant exam is one of the best non-technical opportunities available. Both posts share the same exam pattern, syllabus, pay scale and computer skill test.
Selected candidates join at Pay Level 4 (₹25,500 – ₹81,100 basic pay), which translates to an in-hand starting salary of roughly ₹42,000 to ₹48,000+ per month including DA, HRA, transport allowance, CHSS medical facilities for self and dependents, and departmental canteen/housing benefits.
| Quick facts | |
|---|---|
| Posts / pay | Upper Division Clerk and Assistant, Pay Level 4 (₹25,500 – ₹81,100) |
| Qualification | Graduation in any discipline with 60% marks or 6.32/10 CGPA |
| Age | 18 to 28 years (UR/EWS), with category relaxations |
| Written test | 200 questions, 200 marks, 150 minutes, -0.25 negative |
| Stage 2 | Computer Literacy Skill Test, 100 marks, 75 minutes, qualifying only |
In this guide
What is ISRO UDC and Assistant?
When ISRO releases its centralised administrative recruitment through ICRB, it notifies two posts at the same level:
- Upper Division Clerk (UDC): posted mainly at the Department of Space (DoS) Branch Secretariat and Headquarters offices (such as Bengaluru and New Delhi).
- Assistant: posted across operational ISRO centres and units (VSSC Thiruvananthapuram, URSC Bengaluru, SAC Ahmedabad, SDSC-SHAR Sriharikota, NRSC Hyderabad, LPSC, IPRC Mahendragiri, MCF Hassan) and autonomous bodies under DoS (PRL, NARL, NESAC, IIST).
Both sit at Level 4 of the 7th CPC pay matrix, involve administrative, establishment, purchase, stores, finance and public relations duties, and are tested through a single combined written paper.
Eligibility: the strict 60% / 6.32 CGPA rule
Unlike SSC CGL or CHSL, where passing graduation is enough, ISRO has strict academic filters.
| Requirement | Official ISRO ICRB rule |
|---|---|
| Educational qualification | Graduation in ANY discipline with a minimum of 60% marks or CGPA 6.32 on a 10-point scale, from a recognised university. |
| Course duration rule | The degree must be completed within the stipulated duration prescribed by the university (for example 3 years for B.Sc/B.Com/BA or 4 years for B.Tech). Taking extra years to clear backlogs disqualifies you. |
| Additional skill | Proficiency in the use of computers. |
| Age limit | 18 to 28 years for Unreserved/EWS; OBC up to 31 years; SC/ST up to 33 years; additional relaxation for PwBD, Ex-Servicemen and departmental candidates. |
Critical warnings on marks and CGPA
- No rounding off: 59.9% or a 6.319 CGPA is treated as ineligible.
- No percentage relaxation for SC/ST/OBC: reserved categories get age relaxation and lower exam qualifying cutoffs, but the 60% / 6.32 CGPA requirement is mandatory for all categories.
- No CGPA-to-percentage conversion: if your marksheet shows CGPA on a 10-point scale it must itself be 6.32 or above. ISRO does not accept university multiplication factors to turn a 6.1 CGPA into 60%.
Exam pattern and selection process
Per the latest ISRO ICRB exam pattern (2026), selection has two stages and no interview:
- Stage 1: Written examination (200 questions, 200 marks, 150 minutes).
- Stage 2: Computer Literacy Skill Test (100 marks, 75 minutes), strictly qualifying.
Stage 1: written test pattern (Assistant and UDC)
| Part | Subject | Questions | Marks |
|---|---|---|---|
| A | General English | 50 | 50 |
| B | Quantitative Aptitude | 50 | 50 |
| C | General Intelligence & Reasoning Ability | 50 | 50 |
| D | General Knowledge | 50 | 50 |
| Total | 4 equal sections, 150 minutes combined | 200 | 200 |
Marking scheme, qualifying cutoff and tie-breaker
- Correct answer: +1 mark. Wrong answer: -0.25 (1/4th).
- Minimum qualifying cutoff: Unreserved and EWS 50%; reserved categories (SC/ST/OBC/PwBD against reserved vacancies) 40%.
- Aim to cross 50% (25/50) in every individual section as well as overall, since sectional and aggregate thresholds are used to screen candidates in a 1:5 ratio per vacancy.
- Why Reasoning (Part C) is the secret decider: under the official ICRB tie-breaking rule, if two candidates have the same total out of 200, the one with higher marks in Part C ranks higher, followed by age/date of birth.
Section-wise syllabus and weightage
The difficulty sits between SSC CHSL and SSC CGL Tier-1, but with 50 questions per section instead of 25. Speed and stamina are your biggest assets.
Part A: General English (50 questions)
| Area | Questions | What to prepare |
|---|---|---|
| Grammar and error spotting | 12–15 | Subject-verb agreement, tenses, prepositions (fixed prepositions are heavily tested), articles, conditionals, pronouns, conjunctions |
| Voice and narration | 6–8 | Active to passive and direct to indirect speech (high-scoring, rule-based) |
| Vocabulary | 12–15 | Synonyms, antonyms, one-word substitutions, idioms and phrases, phrasal verbs, spelling |
| Sentence improvement and fillers | 6–8 | Single/double fill in the blanks, phrase replacement |
| Comprehension, cloze, para-jumbles | 8–10 | One factual or story passage (5 questions) plus a cloze test (5) or sentence rearrangement |
Part B: Quantitative Aptitude (50 questions)
Unlike SSC CGL, where advanced maths dominates, 75–80% of ISRO UDC Quant is pure arithmetic and simplification.
| Area | Questions | What to prepare |
|---|---|---|
| Number system and simplification | 8–10 | BODMAS, fractions, surds and indices, divisibility, LCM and HCF, remainders, unit digits |
| Core arithmetic | 25–28 | Percentage, ratio and proportion, partnership, ages (8–10); profit, loss and discount (4–5); simple and compound interest (3–4); time and work, pipes and cisterns (4–5); time, speed and distance, trains, boats (4–5); averages, mixture and alligation (3–4) |
| Mensuration 2D and 3D | 5–7 | Area, perimeter, surface area and volume of triangles, circles, rhombus, cylinders, cones, spheres, hemispheres |
| Algebra, geometry, trigonometry, DI | 5–8 | Basic identities (including a³ + b³ + c³ − 3abc), linear/quadratic equations, triangle and circle properties, basic trig identities, one table/bar graph DI set |
Part C: General Intelligence & Reasoning (50 questions)
| Area | Questions | What to prepare |
|---|---|---|
| Series and missing numbers | 8–10 | Number series, alphabetical series, repeated letter series, matrix missing numbers |
| Coding-decoding, analogy, odd-one-out | 10–12 | Letter shifting, number coding, word analogy, classification |
| Core logical topics | 15–18 | Blood relations, direction and distance, order and ranking, syllogisms, Venn diagrams, mathematical operations, clock and calendar, dice and cubes |
| Seating arrangement and puzzles | 4–6 | Linear and circular arrangements, simple comparison and floor puzzles |
| Non-verbal reasoning | 5–7 | Mirror and water images, paper folding and cutting, embedded figures, figure series, counting figures |
Part D: General Knowledge (50 questions)
| Area | Questions | What to prepare |
|---|---|---|
| Space technology and ISRO special GK | 5–8 | ISRO centres and roles, launch vehicles (PSLV, GSLV, LVM3, SSLV, NGLV), missions (Chandrayaan, Aditya-L1, Mangalyaan, Gaganyaan, XPoSat, NISAR), chairman history, recent launches |
| Current affairs (last 8–10 months) | 12–15 | National and international news, defence exercises, sports, awards, books and authors, government schemes, indices, appointments |
| Static GK and Indian polity | 10–12 | Articles, schedules, amendments, fundamental rights/duties, parliament, panchayati raj, dances, festivals, national parks, dams, rivers, UNESCO sites |
| History, geography, economy | 10–12 | Freedom struggle (1857–1947), Buddhism/Jainism, Mauryan/Gupta/Mughal basics, rivers, soil, climate, five-year plans, RBI, GDP, banking |
| General science and computer basics | 6–8 | Everyday physics, chemistry (acids/bases, alloys), biology (vitamins, diseases, body systems), computer abbreviations and shortcuts |
Cut-off trends and safe score target
ISRO Assistant/UDC vacancies are notified zone-wise (Ahmedabad, Bengaluru, Hassan, Hyderabad, Mahendragiri, New Delhi, Sriharikota, Thiruvananthapuram), so the cutoff varies slightly by zone and vacancy count. Based on the 2022–2023 (held in December 2023) and September 2026 recruitment cycles (200-mark pattern, -0.25 negative marking), the competitive range for the 1:5 Skill Test shortlist and final merit is:
| Category | Minimum qualifying bar | Expected shortlisting cut-off (Skill Test 1:5) | Safe target for final selection (out of 200) |
|---|---|---|---|
| Unreserved (UR) | 100 (50%) | 142 – 154 | 158 – 165+ |
| EWS | 100 (50%) | 134 – 145 | 148 – 155+ |
| OBC (NCL) | 80 (40%) | 136 – 148 | 150 – 158+ |
| SC | 80 (40%) | 124 – 136 | 138 – 146+ |
| ST | 80 (40%) | 115 – 128 | 130 – 138+ |
How to hit 160+ out of 200
| Section | Target (out of 50) |
|---|---|
| General Intelligence & Reasoning | 44 – 46 |
| Quantitative Aptitude | 42 – 45 |
| General English | 40 – 43 |
| General Knowledge | 32 – 36 |
| Total safe score | 158 – 170 |
Stage 2: the Computer Literacy Skill Test
Many candidates who score 160+ in the written exam are disqualified in Stage 2 because they take the Computer Skill Test lightly.
Official Computer Skill Test pattern (Annexure-IV)
- Total marks: 100. Duration: 75 minutes (hands-on task on a computer, with occasional objective questions on computer fundamentals inside the modules).
- Qualifying marks: 60 (60%) for UR/EWS, 50 (50%) for reserved categories.
- Merit impact: strictly qualifying (Go / No-Go). Marks are not added to your written score, but scoring below the bar eliminates you.
| Module | Marks | Tasks to practise daily |
|---|---|---|
| Microsoft Word | 35 | Typing a passage with the given font, size, bold/italics/underline, superscript (x²) and subscript (H₂O); exact margins, orientation, line spacing (1.15/1.5), indentation and justification; complex tables (merge/split cells, shading, borders); headers, footers, page numbers, watermarks, bullets and multilevel numbering, mail merge |
| Microsoft Excel | 35 | Entering a data table with proper formatting (wrap text, merge and centre, currency/percentage, borders); SUM, AVERAGE, COUNT, COUNTIF, MAX, MIN, nested IF, VLOOKUP, percentage change, absolute vs relative references; sorting, filtering, conditional formatting; a 2D bar/pie/line chart with axis titles and data labels |
| Microsoft PowerPoint | 30 | Building 4–5 slides from a printed handout; slide layouts (title, two content, comparison); themes and backgrounds; SmartArt, shapes, tables, charts imported from Excel; slide numbers, date/time, header/footer; basic transitions and animations |
Practice tip: For three weeks after the written exam, give yourself a 60-minute timer every day: reproduce a one-page official letter with a table in Word (20 minutes), a 10-row salary or marksheet calculation with a chart in Excel (25 minutes) and a 4-slide presentation in PowerPoint (15 minutes).
Best books and 12-week plan
Recommended booklist
- General English: From Plinth to Paramount (Neetu Singh, Vol. 1) for grammar rules, plus the BlackBook of English Vocabulary (Nikhil Gupta) or the Pinnacle SSC English PYQ book.
- Quantitative Aptitude: Quantitative Aptitude by R.S. Aggarwal (basics) plus Pinnacle / Kiran SSC chapter-wise solved papers, focusing on CHSL and CGL Tier-1 arithmetic.
- Reasoning: Pinnacle / Kiran SSC reasoning chapter-wise PYQs. Practise 50-question sets from SSC CPO / Stenographer / JE papers, which also have 50 reasoning questions.
- General Knowledge: Lucent's General Knowledge, monthly current affairs PDFs (last 8 months) and a 5-page note on ISRO's history, launch vehicles and recent missions from isro.gov.in.
- Previous year papers: solve the ISRO Assistant / UDC / JPA official papers from 2008, 2010, 2012, 2014, 2016, 2022 (December 2023), 2024 (PRL/SDSC) and 2026.
How to manage the 150-minute clock
With 200 questions in 150 minutes you have about 45 seconds per question. A proven allocation for your mocks:
| Order | Section | Time | Note |
|---|---|---|---|
| 1 | Part D: General Knowledge | 15–18 min | Read, click if you know it, skip if you do not. Never overthink GK. |
| 2 | Part A: General English | 25–28 min | Solve grammar, voice/narration and vocabulary quickly; keep about 8 minutes for the passage or cloze test. |
| 3 | Part C: Reasoning | 40–45 min | Maximise this section (aim for 45+/50) since it breaks ties. |
| 4 | Part B: Quantitative Aptitude | 55–60 min | With 55+ minutes saved, solve every arithmetic and mensuration problem calmly. |
Practise ISRO papers in a real CBT environment with a timer on CMB HUB.
Frequently asked questions
Can final-year undergraduate students apply for ISRO UDC / Assistant?
No. Candidates must already hold their final degree certificate or provisional degree meeting the 60% marks or 6.32 CGPA requirement on or before the closing date of online applications.
Is typing speed tested separately in the ISRO UDC / Assistant Skill Test?
Unlike SSC CHSL/CGL, which has a separate typing test, ISRO's Skill Test for Assistant and UDC is a 75-minute computer literacy test on MS Word (35), MS Excel (35) and MS PowerPoint (30). A typing speed of 30+ wpm still helps you finish the Word paragraph and table formatting quickly.
What is the difference between ISRO Assistant/UDC and ISRO Junior Personal Assistant (JPA)/Stenographer?
Assistant and UDC are general administrative posts requiring a 60% graduation plus the computer literacy test. JPA and Stenographer are secretarial posts that additionally need 60 wpm English stenography (shorthand) and have a different written pattern (100 questions on English, 50 on Reasoning, and 50 on Quant plus GK).