A Software Engineer at Relativity Space operates at the unique intersection of advanced software development, additive manufacturing, and aerospace engineering. Unlike traditional tech companies where software exists purely in a digital sandbox, software at Relativity Space directly controls, monitors, and optimizes physical hardware. From the massive Stargate 3D printers to the automated test stands at the Stennis Space Center and the flight computers guiding vehicles like Terran R, software is the fundamental nervous system of the company's launch operations. As a Software Engineer, your work will have a direct impact on the speed and reliability of rocket design and manufacturing. You will be tasked with building high-performance control loops, developing data pipelines that process gigabytes of sensor telemetry, or creating intuitive tools that allow aerospace and materials engineers to analyze complex geometries. The role requires a systems-thinking mindset, where you must understand not only how your code executes in a container or on an embedded processor, but also how it influences physical systems subject to extreme thermal, structural, and fluid dynamics. This position is highly collaborative and intellectually demanding. You will work alongside flight control teams, integration engineers, and manufacturing specialists to translate complex physical constraints into robust, testable software.
Recruiter Phone Screen
reportedInitial call to assess basic fit, verify citizenship requirements, and discuss career goals.
What to demonstrate
- Initial call to assess basic fit, verify citizenship requirements, and discuss career goals
- Depth in Engineering mechanics: stress & strains
How to prepare
- Be able to walk your CV end to end in two minutes, and say why this company specifically.
- Have your salary expectations, notice period and location constraints ready, and ask for the rest of the loop in writing.
Technical Phone Screens
reportedOne or two rounds focusing on coding challenges, system design discussions, and engineering concepts.
What to demonstrate
- One or two rounds focusing on coding challenges, system design discussions, and engineering concepts
- Depth in Engineering mechanics: stress & strains
How to prepare
- Be able to walk your CV end to end in two minutes, and say why this company specifically.
- Have your salary expectations, notice period and location constraints ready, and ask for the rest of the loop in writing.
Onsite Interview
reportedComprehensive multi-hour interview simulating a real workday, including technical portfolio presentation and 1:1 sessions.
What to demonstrate
- Comprehensive multi-hour interview simulating a real workday
- Including technical portfolio presentation and 1:1 sessions
How to prepare
- Answer aloud and timed: Implement a basic rate-limiter to control the frequency of commands sent to a simulated hardware controller.
- Answer aloud and timed: Design a distributed telemetry ingestion system that can handle real-time data from thousands of sensors during a test fire.
PracHub editorial advice for the preparation topics above.
Brush up on your fundamentals
Do not neglect basic college-level physics and mechanics. Reviewing the Fundamentals of Engineering (FE) handbook for topics like fluid mechanics, statics, and thermodynamics can give you a significant edge.
Own your presentation
Treat your portfolio presentation like a product launch. Practice your timing, ensure you can explain every diagram on your slides, and be prepared for deep, probing questions from the panel.
Respect your NDAs
Interviewers will actively watch to ensure you do not share proprietary designs, code, or sensitive data from your current or former employers during your presentation.
Choose a category, try a prompt, then open its approach, worked solution or follow-up when you need it.
Implement a custom data structure using a hash map and explain its runtime complexity for read and write opera
Implement a custom data structure using a hash map and explain its runtime complexity for read and write operations.
Approach
- Restate the input: its shape, its size, and what is guaranteed about it.
- Name the brute-force solution and its complexity before improving on it.
- Choose the data structure from the access pattern, not from familiarity.
- State the target complexity and say which constraint rules the naive version out.
Follow-up
- How does this change if the input no longer fits in memory?
- What is the worst case, and how likely is it on real data?
Write a program to parse and analyze a stream of sensor telemetry data, filtering out anomalies based on a rol
Write a program to parse and analyze a stream of sensor telemetry data, filtering out anomalies based on a rolling average.
Approach
- Restate the input: its shape, its size, and what is guaranteed about it.
- Name the brute-force solution and its complexity before improving on it.
- Choose the data structure from the access pattern, not from familiarity.
- State the target complexity and say which constraint rules the naive version out.
Follow-up
- How does this change if the input no longer fits in memory?
- What is the worst case, and how likely is it on real data?
Given a set of overlapping time intervals representing rocket component test windows, merge the overlapping in
Given a set of overlapping time intervals representing rocket component test windows, merge the overlapping intervals to find the total active test duration.
Approach
- Restate the input: its shape, its size, and what is guaranteed about it.
- Name the brute-force solution and its complexity before improving on it.
- Choose the data structure from the access pattern, not from familiarity.
- State the target complexity and say which constraint rules the naive version out.
Follow-up
- How does this change if the input no longer fits in memory?
- What is the worst case, and how likely is it on real data?
Explain the difference between stack and heap memory allocation, and describe how you would optimize memory us
Explain the difference between stack and heap memory allocation, and describe how you would optimize memory usage in a resource-constrained embedded environment.
Approach
- Say what the runtime actually does before reasoning about the code.
- Name what is shared across threads and what owns each piece of state.
- Identify the window where an invariant is briefly untrue.
- Distinguish a value from a reference to it, and say which one you handed out.
Follow-up
- What happens if two callers reach this at the same time?
- Where could this allocate more than you expect?
Implement a basic rate-limiter to control the frequency of commands sent to a simulated hardware controller.
Implement a basic rate-limiter to control the frequency of commands sent to a simulated hardware controller.
Approach
- Restate the input: its shape, its size, and what is guaranteed about it.
- Name the brute-force solution and its complexity before improving on it.
- Choose the data structure from the access pattern, not from familiarity.
- State the target complexity and say which constraint rules the naive version out.
Follow-up
- How does this change if the input no longer fits in memory?
- What is the worst case, and how likely is it on real data?
Hold a per-tenant active cap against concurrent creates
A tenant on the standard plan may hold at most 50 resources with status='active'. The create handler runs SELECT count(*) FROM resource WHERE tenant_id = $1 AND status = 'active', compares to 50, then inserts. Two creates arrive 3 ms apart on different instances and the tenant lands at 51. Name the anomaly, say whether PostgreSQL 16 READ COMMITTED or REPEATABLE READ prevents it and why, then give an implementation that holds the cap at READ COMMITTED with the exact statements. Finally, say what changes when the cap is 'at most one running export per tenant' on job_run.
Approach
- Name it: write skew. The two transactions read an overlapping set and write disjoint rows, so there is no row-level conflict for the engine to detect and each commit is individually legal.
- Rule out the levels precisely. READ COMMITTED takes a fresh snapshot per statement and takes no lock on the counted rows, so both see 49. PostgreSQL's REPEATABLE READ is snapshot isolation: it removes non-repeatable reads and phantoms within the snapshot but still admits write skew, because the anomaly is not a re-read of a changed row, it is a read of a set that a concurrent transaction invalidates. Only SERIALIZABLE closes it, by tracking the read dependency and aborting one transaction with SQLSTATE 40001 — a guarantee that exists only if the application re-runs the whole transaction from the read.
- Convert the set predicate into a single-row conflict: keep tenant.active_resource_count and run UPDATE tenant SET active_resource_count = active_resource_count + 1 WHERE tenant_id = $1 AND active_resource_count < 50 in the same transaction as the INSERT. Zero affected rows is the cap, returned as 409. The row lock serialises the decision at any isolation level, and contention is bounded to one tenant's row — which is also the fair-scheduling unit, unlike a global counter that would convoy every tenant behind one row.
- State the cost you just took on: a counter is a second source of truth that can drift, so every path that changes status must adjust it inside the same transaction, and a periodic reconciliation has to exist, with resource_revision as the authority for what the count should have been.
Follow-up
- A resource moves from archived back to active. Which statements change, and what breaks if the counter update and the status change land in different transactions?
- The cap becomes plan-dependent and a plan can change mid-month. Where does the number 50 live, and who reads it?
Find version gaps and relay lag with window functions
outbox_event holds event_id, aggregate_type, aggregate_id, aggregate_version, event_type, payload, status ('pending','published','dead'), attempts, created_at, published_at. A projection is missing rows and you must decide whether the relay skipped events or the consumer dropped them. Write three queries over the last seven days: one listing every aggregate_id whose published aggregate_version sequence has a hole, one giving per-day counts with a running total, and one returning the newest published event per aggregate. For each, say where the window function is evaluated relative to WHERE and LIMIT. PostgreSQL 16.
Approach
- Gaps: compute lead(aggregate_version) OVER (PARTITION BY aggregate_id ORDER BY aggregate_version) in a subquery, then filter next_version <> aggregate_version + 1 in the outer query. Window functions are evaluated after WHERE, GROUP BY and HAVING and before the outer ORDER BY and LIMIT, so the predicate cannot sit in the same WHERE clause and PostgreSQL 16 has no QUALIFY.
- Say what the seven-day filter does to the answer: it truncates every partition, so the first row per aggregate has no predecessor inside the window and a hole spanning the boundary is invisible. Widen the window, or join to resource.version as the authority for the true maximum.
- Running total: SELECT date_trunc('day', created_at) AS d, count() AS n, sum(count()) OVER (ORDER BY date_trunc('day', created_at) ROWS UNBOUNDED PRECEDING). An aggregate inside a window call is legal because grouping runs before windowing. The grouping key is unique per row here so ROWS and RANGE agree, but write the frame anyway — over ungrouped rows with tied timestamps the default RANGE frame pulls in every peer row and the total jumps.
- Newest per aggregate: DISTINCT ON (aggregate_id) ... ORDER BY aggregate_id, aggregate_version DESC is the cheap PostgreSQL-only form when an index matches that order; row_number() OVER (PARTITION BY aggregate_id ORDER BY aggregate_version DESC) = 1 is the portable form and needs a subquery for the same evaluation-order reason as the gap query.
Follow-up
- Relay failover redelivers events. Does a duplicate break the gap query, and how would you detect one from this table alone?
- Turn the gap check into a continuous monitor rather than a query someone runs after an incident. What does it watch?
Design a distributed telemetry ingestion system that can handle real-time data from thousands of sensors durin
Design a distributed telemetry ingestion system that can handle real-time data from thousands of sensors during a test fire.
Approach
- Fix the scope first: who calls this, how often, and what they do when it fails.
- Name the read and write paths separately; they rarely have the same bottleneck.
- Choose a partition key and say what query it makes expensive.
- State the consistency you need, and where you are willing to be stale.
Follow-up
- What breaks first when traffic grows ten times?
- How does this behave when that dependency is down for an hour?
Walk through the architecture of a Hardware-in-the-Loop (HIL) testing framework. How do you ensure low latency
Walk through the architecture of a Hardware-in-the-Loop (HIL) testing framework. How do you ensure low latency and deterministic behavior?
Approach
- Fix the scope first: who calls this, how often, and what they do when it fails.
- Name the read and write paths separately; they rarely have the same bottleneck.
- Choose a partition key and say what query it makes expensive.
- State the consistency you need, and where you are willing to be stale.
Follow-up
- What breaks first when traffic grows ten times?
- How does this behave when that dependency is down for an hour?
How would you design a software deployment pipeline that safely updates software on a fleet of robotic 3D prin
How would you design a software deployment pipeline that safely updates software on a fleet of robotic 3D printers without interrupting active builds?
Approach
- Fix the scope first: who calls this, how often, and what they do when it fails.
- Name the read and write paths separately; they rarely have the same bottleneck.
- Choose a partition key and say what query it makes expensive.
- State the consistency you need, and where you are willing to be stale.
Follow-up
- What breaks first when traffic grows ten times?
- How does this behave when that dependency is down for an hour?
Design a tooling system that manages and tracks physical rocket components as they move through various manufa
Design a tooling system that manages and tracks physical rocket components as they move through various manufacturing and testing phases.
Approach
- Fix the scope first: who calls this, how often, and what they do when it fails.
- Name the read and write paths separately; they rarely have the same bottleneck.
- Choose a partition key and say what query it makes expensive.
- State the consistency you need, and where you are willing to be stale.
Follow-up
- What breaks first when traffic grows ten times?
- How does this behave when that dependency is down for an hour?
Describe how you would implement a fault-tolerant communication protocol between a ground control station and
Describe how you would implement a fault-tolerant communication protocol between a ground control station and an autonomous launch vehicle.
Approach
- Fix the scope first: who calls this, how often, and what they do when it fails.
- Name the read and write paths separately; they rarely have the same bottleneck.
- Choose a partition key and say what query it makes expensive.
- State the consistency you need, and where you are willing to be stale.
Follow-up
- What breaks first when traffic grows ten times?
- How does this behave when that dependency is down for an hour?
Describe how you would transfer fluid from one propellant tank to another tank that is positioned at a higher
Describe how you would transfer fluid from one propellant tank to another tank that is positioned at a higher elevation.
Approach
- Clarify what is being asked and what a complete answer contains.
- State your assumptions explicitly before working the problem.
- Say what you would check first and why it is the highest-information step.
- Work from the requirement backwards to the design.
Follow-up
- What assumption would you test first?
- How would you know your answer was wrong?
Explain the ideal gas law and describe how pressure, volume, and temperature interact when a gas is compressed
Explain the ideal gas law and describe how pressure, volume, and temperature interact when a gas is compressed inside a closed system.
Approach
- Clarify what is being asked and what a complete answer contains.
- State your assumptions explicitly before working the problem.
- Say what you would check first and why it is the highest-information step.
- Work from the requirement backwards to the design.
Follow-up
- What assumption would you test first?
- How would you know your answer was wrong?
Walk through a standard stress-strain curve and explain what the yield point, ultimate tensile strength, and e
Walk through a standard stress-strain curve and explain what the yield point, ultimate tensile strength, and elastic deformation region represent.
Approach
- Clarify what is being asked and what a complete answer contains.
- State your assumptions explicitly before working the problem.
- Say what you would check first and why it is the highest-information step.
- Work from the requirement backwards to the design.
Follow-up
- What assumption would you test first?
- How would you know your answer was wrong?
Describe how you would analyze and test a thermal system within a rocket engine, identifying key parameters fo
Describe how you would analyze and test a thermal system within a rocket engine, identifying key parameters for software monitoring.
Approach
- Clarify what is being asked and what a complete answer contains.
- State your assumptions explicitly before working the problem.
- Say what you would check first and why it is the highest-information step.
- Work from the requirement backwards to the design.
Follow-up
- What assumption would you test first?
- How would you know your answer was wrong?
Explain Archimedes' principle and how it applies to buoyancy calculations in fluid systems.
Explain Archimedes' principle and how it applies to buoyancy calculations in fluid systems.
Approach
- Clarify what is being asked and what a complete answer contains.
- State your assumptions explicitly before working the problem.
- Say what you would check first and why it is the highest-information step.
- Work from the requirement backwards to the design.
Follow-up
- What assumption would you test first?
- How would you know your answer was wrong?
One customer endpoint stalls deliveries to every other destination
The egress service delivers about 1.5k webhooks/second across 40,000 destinations, with a per-destination concurrency cap of 4 and a 10-second connect-plus-read timeout. Throughput falls to 300/second, queue depth climbs, and p99 delivery latency for unaffected destinations goes from 200 ms to minutes, while the error rate barely moves. One tenant holds 900 destination rows whose URLs share a hostname that now answers in 9.5 seconds. Explain the mechanism with the arithmetic, then give the containment in the order you would apply it.
Approach
- Look at saturation before errors. A flat error rate with collapsing throughput says nothing is failing, things are waiting, so the first signal to pull is in-flight request count or pool wait time rather than the error counter. This is the distinction that decides the whole investigation.
- Group in-flight work by resolved host, not by destination id. The cap is keyed per destination row, so 900 rows sharing one hostname buy 3,600 concurrent slots against a single host, each held for 9.5 seconds. The bulkhead was never a bulkhead for that host, and grouping by the wrong dimension is why the dashboard looked healthy.
- Do the arithmetic in both directions. Required concurrency is arrival rate times latency, so 1.5k/second at 200 ms needs about 300 in flight, which is entirely consumed by 3,600 slow slots; conversely whatever concurrency is left sustains rate equals concurrency divided by 9.5 seconds, which is the 300/second you are seeing. Matching both numbers is what promotes this from a plausible story to the mechanism.
- Explain why the circuit breaker never helped. It opens on consecutive failures, and a 9.5-second response inside a 10-second timeout is a success. Slow is not failing, so an error-rate breaker cannot see this; you need a slow-call ratio, a deadline propagated from the caller's remaining budget, or a concurrency limiter.
Follow-up
- The host recovers to 80 ms. How long does the queue take to drain, and what does the drain do to the recovered host?
- Where should the 10-second timeout number actually come from?
Built from the rounds and topics Relativity Space candidates report.
Prepare, practise & reflect
One practical outcome each day. Spend longer where you need it.
0 / 7 done01Map the Relativity Space loop
- Write out the reported sequence: Recruiter Phone Screen, Technical Phone Screens, Onsite Interview.
- For each round, write one sentence on what it is judging, from the description above, and mark the one you are least ready for.
Deliverable: A one-page map of the 3 reported rounds, with the weakest marked.
02Work Engineering mechanics: stress & strains
- Spend the session on Engineering mechanics: stress & strains, which Relativity Space candidates report being tested on.
- Write one worked example in Engineering mechanics: stress & strains and time yourself on it.
Deliverable: One timed worked example in Engineering mechanics: stress & strains.
03Work Coding interviews (practice-ready problem solving)
- Spend the session on Coding interviews (practice-ready problem solving), which Relativity Space candidates report being tested on.
- Write one worked example in Coding interviews (practice-ready problem solving) and time yourself on it.
Deliverable: One timed worked example in Coding interviews (practice-ready problem solving).
04Work Presentation skills (technical project storytelling)
- Spend the session on Presentation skills (technical project storytelling), which Relativity Space candidates report being tested on.
- Write one worked example in Presentation skills (technical project storytelling) and time yourself on it.
Deliverable: One timed worked example in Presentation skills (technical project storytelling).
05Answer out loud: Coding and Data Structures
- Answer aloud, timed: Implement a custom data structure using a hash map and explain its runtime complexity for read and write operations.
- Answer aloud, timed: Write a program to parse and analyze a stream of sensor telemetry data, filtering out anomalies based on a rolling average.
Deliverable: Spoken answers to 2 reported Coding and Data Structures question(s), under time.
06Answer out loud: System Design and Architecture
- Answer aloud, timed: Design a distributed telemetry ingestion system that can handle real-time data from thousands of sensors during a test fire.
- Answer aloud, timed: Walk through the architecture of a Hardware-in-the-Loop (HIL) testing framework. How do you ensure low latency and deterministic behavior?
Deliverable: Spoken answers to 2 reported System Design and Architecture question(s), under time.
07Answer out loud: Engineering Fundamentals and Physics
- Answer aloud, timed: Describe how you would transfer fluid from one propellant tank to another tank that is positioned at a higher elevation.
- Answer aloud, timed: Explain the ideal gas law and describe how pressure, volume, and temperature interact when a gas is compressed inside a closed system.
Deliverable: Spoken answers to 2 reported Engineering Fundamentals and Physics question(s), under time.
Expand any day for tasks and deliverables. Your progress is saved on this device.
Behavioural rounds judge the decision you made and what it cost.
Tell me about a significant technical challenge you overcame. What were the trade-offs you made, and what did
Tell me about a significant technical challenge you overcame. What were the trade-offs you made, and what did you learn?
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- Name the disagreement and how you resolved it with evidence.
Follow-up
- What would you do differently if you ran that again?
- How did you know your change caused the improvement?
Describe a situation where you had to work with a difficult stakeholder or team member. How did you resolve th
Describe a situation where you had to work with a difficult stakeholder or team member. How did you resolve the conflict to deliver the project?
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- Name the disagreement and how you resolved it with evidence.
Follow-up
- What would you do differently if you ran that again?
- How did you know your change caused the improvement?
How do you approach designing a system when the initial requirements provided by the hardware team are vague o
How do you approach designing a system when the initial requirements provided by the hardware team are vague or incomplete?
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- Name the disagreement and how you resolved it with evidence.
Follow-up
- What would you do differently if you ran that again?
- How did you know your change caused the improvement?
Tell me about a time you made a technical mistake or incorrect assumption during a project. How did you identi
Tell me about a time you made a technical mistake or incorrect assumption during a project. How did you identify the error, and how did you correct it?
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- Name the disagreement and how you resolved it with evidence.
Follow-up
- What would you do differently if you ran that again?
- How did you know your change caused the improvement?
Why do you want to work at Relativity Space over other aerospace or traditional technology companies?
Why do you want to work at Relativity Space over other aerospace or traditional technology companies?
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- Name the disagreement and how you resolved it with evidence.
Follow-up
- What would you do differently if you ran that again?
- How did you know your change caused the improvement?
- 01
Tell me about a significant technical challenge you overcame. What were the trade-offs you made, and what did you learn?
- 02
Describe a situation where you had to work with a difficult stakeholder or team member. How did you resolve the conflict to deliver the project?
- 03
How do you approach designing a system when the initial requirements provided by the hardware team are vague or incomplete?
- 04
Tell me about a time you made a technical mistake or incorrect assumption during a project. How did you identify the error, and how did you correct it?
How much physics or mechanical engineering do I need to know as a software engineer?
You do not need an aerospace degree, but you must be comfortable with basic engineering concepts. Be ready to discuss general principles like pressure, temperature, stress, and feedback loops, as your software will directly interact with these physical realities.
Relativity Space Software Engineer candidate reports ↗What is the most common reason candidates fail the interview process?
Candidates often struggle with the technical portfolio presentation, either by failing to clearly define their individual contributions or by failing to explain the deeper "why" behind their architectural decisions. Additionally, struggling with basic coding fundamentals during live exercises is a common pitfall.
Relativity Space Software Engineer candidate reports ↗How long does the entire interview process typically take?
The process generally takes between 3 to 6 weeks from the initial recruiter screen to a final decision, depending on scheduling availability for the multi-hour onsite panel.
Relativity Space Software Engineer candidate reports ↗Are the onsite interviews conducted in person?
Yes, Relativity Space highly values in-person collaboration, especially given the proximity to physical manufacturing facilities like the Long Beach headquarters. Onsite interviews typically include a tour of the factory floor or lab spaces.
Relativity Space Software Engineer candidate reports ↗What topics does Relativity Space test in interviews?
Relativity Space interviews most often cover Python, Object-Oriented Programming (OOP), Technical Presentation, Technical Recruiter Screening, and Data Engineering (core responsibilities). The exact emphasis depends on the specific role you apply for.
Relativity Space Software Engineer candidate reports ↗Sources & methodology 3 sources ↗
No official company page is cited. Rounds and questions come from candidate reports and PracHub editorial material; each source shows the date it was read.
- 01Relativity Space Software Engineer candidate reports ↗
Company-reported rounds, questions and FAQ.
Candidate reports · Accessed 2026-09-22 - 02PracHub Software Engineer practice ↗
PracHub practice material, not company-reported.
PracHub page · Accessed 2026-09-22 - 03PracHub preparation framework ↗
PracHub preparation guidance.
PracHub page · Accessed 2026-09-22
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