March 26, 20265 min read

ISRO Scientist/Engineer Exam Pattern 2025-26: Written Test, Interview and Selection Process

Complete ISRO Scientist/Engineer exam pattern covering the ICRB written test (80 questions, 240 marks), interview process, minimum qualifying marks, and selection criteria for CS, EC, ME, and EE streams.

ISRO exam pattern scientist engineer ICRB space

ISRO Scientist/Engineer (SC) recruitment is one of the most prestigious technical exams in India. Conducted by the ISRO Centralized Recruitment Board (ICRB), this exam recruits engineers and scientists at the entry level (SC grade) for the Indian Space Research Organisation's various centres — VSSC, ISAC, SAC, LPSC, SDSC, and others.

Unlike GATE-based PSU recruitments where you just need a score, ISRO conducts its own independent written test followed by an interview. Let's break down exactly how the selection process works.

Selection Process Overview

The ISRO Scientist/Engineer selection has three stages:

Stage	Nature	Marks	Duration
Written Test	MCQ (CBT/OMR)	240	90 minutes
Interview	Technical + Personal	100	30-45 min
Document Verification	Verification only	—	—

Candidates are shortlisted from the written test at approximately 1:10 ratio (10 candidates per vacancy, depending on the discipline). Final selection is based on a combined merit of Written Test + Interview.

Written Test — Structure and Marking

Total: 80 questions | 240 marks | 90 minutes

The written test is entirely branch-specific. There is no general awareness, English, or aptitude section. Every single question is from your engineering discipline.

Parameter	Details
Total Questions	80
Total Marks	240 (3 marks per question)
Duration	90 minutes
Question Type	MCQ (4 options, single correct)
Negative Marking	1/3 of marks allotted (i.e., -1 mark per wrong answer)
Mode	CBT (Computer Based Test) or OMR-based

Branch-Wise Written Test Subjects

Computer Science (CS)

Data Structures and Algorithms
Operating Systems, Computer Networks
Database Management Systems
Theory of Computation, Compiler Design
Digital Logic, Computer Architecture
Software Engineering, Object-Oriented Programming
Discrete Mathematics

Electronics & Communication (EC)

Analog and Digital Electronics
Signals and Systems, Control Systems
Communication Systems (Analog + Digital)
Electromagnetic Theory, Microwave Engineering
VLSI Design basics, Microprocessors
Network Theory

Mechanical Engineering (ME)

Engineering Mechanics, Strength of Materials
Theory of Machines, Machine Design
Thermodynamics, Heat Transfer
Fluid Mechanics, Turbomachinery
Manufacturing Processes, Industrial Engineering
Engineering Materials

Electrical Engineering (EE)

Circuit Theory, Network Analysis
Electrical Machines (DC and AC)
Power Systems (Generation, Transmission, Distribution)
Control Systems, Power Electronics
Electrical Measurements, Instrumentation
Analog and Digital Electronics

The difficulty level is comparable to GATE, sometimes slightly easier in certain topics. However, the time pressure is significantly higher — you get roughly 67 seconds per question, which is much tighter than GATE's 180 minutes for 65 questions.

Minimum Qualifying Marks

ISRO specifies category-wise minimum qualifying marks for the written test:

Category	Minimum Qualifying (%)
UR (General)	60% (144 out of 240)
OBC (NCL)	50% (120 out of 240)
SC / ST	40% (96 out of 240)
PwBD	40% (96 out of 240)

These are hard minimums. Even if there are vacancies remaining, candidates below these marks are not considered for shortlisting.

Interview — 100 Marks

Shortlisted candidates are called for an interview at ISRO headquarters in Bengaluru or at the recruiting ISRO centre.

Parameter	Details
Marks	100
Duration	30-45 minutes
Panel	Senior ISRO scientists and engineers
Focus	Technical depth + project knowledge + personality

The interview is heavily technical. Expect detailed questions on:

Your B.Tech/B.E. final year project — they will go deep into methodology, results, and your personal contribution
Core subjects from your engineering discipline
Recent ISRO missions and their technical aspects (Chandrayaan, Gaganyaan, PSLV/GSLV launches)
Basic aptitude and problem-solving approach
Why ISRO specifically — they want candidates genuinely interested in space technology

Minimum qualifying marks in the interview are typically 60% for UR, 50% for OBC, and 40% for SC/ST.

Final Merit Calculation

Component	Marks
Written Test	240
Interview	100
Total	340

The final merit list is prepared discipline-wise based on the combined score. Post allocation depends on your rank and the vacancies available at different ISRO centres.

Important Points to Remember

No GATE score required. ISRO conducts its own independent exam through ICRB.
Age limit is strict. Upper age limit is typically 28 years (with standard relaxations for reserved categories).
B.E./B.Tech is mandatory. Diploma holders are not eligible for Scientist/Engineer posts.
Service bond. Selected candidates typically sign a bond to serve ISRO for a minimum of 3 years.

FAQ

What is the salary of ISRO Scientist/Engineer SC?

ISRO Scientist/Engineer SC is placed in Pay Level 10 (Rs. 56,100 - 1,77,500). With DA and HRA, the in-hand salary is approximately Rs. 70,000-85,000 per month at the starting level, depending on the posting location.

Can final year students apply for ISRO Scientist/Engineer?

Yes. Students appearing in their final year/semester of B.E./B.Tech can apply, provided they complete their degree before the joining date specified in the notification.

How does ISRO recruitment differ from GATE-based PSU hiring?

ISRO does not use GATE scores at all. It conducts its own written test through ICRB. The exam pattern, syllabus focus, and interview process are entirely independent of GATE.

Is there any physical fitness test for ISRO Scientist/Engineer?

No physical fitness test is required for Scientist/Engineer posts. However, candidates must be medically fit as per the medical examination conducted after selection.

For ISRO recruitment notification updates and admit card alerts, check SarkariNaukriHub.