Human-rating certification, also known asman-rating orcrew-rating, is the certification of aspacecraft orlaunch 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.
One entity that applies human rating is theUS 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.[1] 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.[1]
The development of theSpace Shuttle and theInternational Space Station pre-dated later NASA human-rating requirements. After theChallenger andColumbia accidents, the criteria used by NASA for human-rating spacecraft were made more stringent.[2]
The NASA CCP human-rating standards require that theprobability 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 frommicrometeorites andorbital debris while in orbit for up to 210 days, is required to be no more than 1 in 270.[3] Maximum sustainedacceleration is limited to 3g.[3]
TheUnited Launch Alliance (ULA) published a paper submitted toAIAA detailing the modifications to itsDelta IV andAtlas V launch vehicles that would be needed to conform to NASA Standard 8705.2B.[2] ULA has since been awarded $6.7 million under NASA'sCommercial Crew Development (CCDev) program for development of anEmergency Detection System, one of the final pieces that would be needed to make these launchers suitable for human spaceflight.[4]
SpaceX is usingDragon 2, launched on aFalcon 9 Block 5 rocket, to deliver crew to the ISS. Dragon 2 made itsfirst uncrewed test flight in March 2019 and has been conducting crewed flights sinceDemo-2 in May 2020.[5]
Boeing'sStarliner spacecraft is also a part of the Commercial Crew Program sinceBoeing CFT in June 2024.
TheChina Manned Space Agency (CMSA) operates and oversees crewed spaceflight activities launched from China, including theShenzhou spacecraft andTiangong space station.
Roscosmos, a Russianstate corporation, conducts and oversees human spaceflights launched from Russia. This includesSoyuz spacecraft and theRussian Orbital Segment of the International Space Station.
The space agency of India,ISRO, oversees planned human spaceflights launched from India.[6]
On 13 February 2024 theCE-20 engine, after a series of ground qualification tests, was certified for crewedGaganyaan spaceflight missions.[7] The CE-20 will power the upper stage of the human-rated version of theLVM3 (formerly known as GSLV Mk III) launch vehicle.
Eachprivate spaceflight system builder typically sets up their own specific criteria to be met before carrying humans on aspace transport system.
We've separated [the "loss of crew" criteria] into what you need for ascent and what you need for entry. For ascent, it's 1 in 500, and independently for entry, it's 1 in 500... The probability for the mission itself is 1 in 270. That is an overall number. That's the loss of crew for the entire mission profile, including ascent, on-orbit, and entry. The thing that drives the 1 in 270 is really micrometeorites and orbital debris... whatever things that are in space that you can collide with. So that's what drops that number down, because you've got to look at the 210 days, the fact that your heat shield or something might be exposed to whatever that debris is for that period of time. NASA looks at Loss of Vehicle the same as Loss of Crew. If the vehicle is damaged and it may not be detected prior to de-orbit, then you have a loss of crew.