engineering

Human-rating certification

Human-rating certification is a engineering topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Human-rating certification rather than just read about it. In short: Human-rating certification, also known as man-rating or crew-rating, is the certification of a spacecraft or launch vehicle as capable of safely transporting humans. There is no one particular standard for human-rating a spacecraft or launch vehicle, and the various entities that launch or plan to launch such spacecraft specify requirements for their particular systems to be human-rated.

Key takeaways

Human-rating certification belongs to engineering; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Human-rating certification to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Human-rating certification from memory before moving on to harder problems.

Reference excerpt

Human-rating certification, also known as man-rating or crew-rating, is the certification of a spacecraft or launch vehicle as capable of safely transporting humans. There is no one particular standard for human-rating a spacecraft or launch vehicle, and the various entities that launch or plan to launch such spacecraft specify requirements for their particular systems to be human-rated.

NASA

One entity that applies human rating is the US government civilian space agency, NASA. NASA's human-rating requires not just that a system be designed to be tolerant of failure and to protect the crew even if an unrecoverable failure occurs, but also that astronauts aboard a human-rated spacecraft have some control over it. This set of technical requirements and the associated certification process for crewed space systems are in addition to the standards and requirements for all of NASA's space flight programs. The development of the Space Shuttle and the International Space Station pre-dated later NASA human-rating requirements. After the Challenger and Columbia accidents, the criteria used by NASA for human-rating spacecraft were made more stringent.

Commercial Crew Program (CCP)

The NASA CCP human-rating standards require that the probability of a loss on ascent does not exceed 1 in 500, and that the probability of a loss on descent did not exceed 1 in 500. The overall mission loss risk, which includes vehicle risk from micrometeorites and orbital debris while in orbit for up to 210 days, is required to be no more than 1 in 270. Maximum sustained acceleration is limited to 3 g. The United Launch Alliance (ULA) published a paper submitted to AIAA detailing the modifications to its Delta IV and Atlas V launch vehicles that would be needed to conform to NASA Standard 8705.2B. ULA has since been awarded $6.7 million under NASA's Commercial Crew Development (CCDev) program for development of an Emergency Detection System, one of the final pieces that would be needed to make these launchers suitable for human spaceflight. SpaceX is using Dragon 2, launched on a Falcon 9 Block 5 rocket, to deliver crew to the ISS. Dragon 2 made its first uncrewed test flight in March 2019 and has been conducting crewed flights since Demo-2 in May 2020. Boeing's Starliner spacecraft is also part of the Commercial Crew Program since Boeing CFT in June 2024.

CMSA

The China Manned Space Agency (CMSA) operates and oversees crewed spaceflight activities launched from China, including the Shenzhou spacecraft and Tiangong space station.

Roscosmos Roscosmos, a Russian state corporation, conducts and oversees human spaceflights launched from Russia. This includes Soyuz spacecraft and the Russian Orbital Segment of the International Space Station.

ISRO

The space agency of India, ISRO, oversees planned human spaceflights launched from India. On 13 February 2024 the CE-20 engine, after a series of ground qualification tests, was certified for crewed Gaganyaan spaceflight missions. The CE-20 will power the upper stage of the human-rated version of the LVM3 (formerly known as GSLV Mk III) launch vehicle.

Private spaceflight companies Each private spaceflight system builder typically sets up their own specific criteria to be met before carrying humans on a space transport system.

See also FAA List of human spaceflight programs

References

Worked examples

Example 1 — a first encounter with Human-rating certification

Start with the simplest possible case. Write down what Human-rating certification claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In engineering, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Human-rating certification before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Human-rating certification ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Human-rating certification

In research: Human-rating certification appears in engineering research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Human-rating certification in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Human-rating certification is common in secondary-school and first-year university syllabi. It links to neighbouring topics Aerospace engineering, Astronautics, Human spaceflight, so understanding it makes those chapters shorter.
In everyday life: Look for Human-rating certification outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Human-rating certification in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Human-rating certification means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Human-rating certification out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Human-rating certification in simple terms?

Why does Human-rating certification matter?

Because it connects several engineering ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Human-rating certification?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Human-rating certification.