• How many technology demonstration/certification unmanned flights does it take to man-rate a spacecraft in the US, Russia, and China?

  • What Loss-of-Crew probabilities are considered acceptable in those countries? (The question explicitly excludes the Space Shuttle) (please, provide the numbers)

  • $\begingroup$ Seems a wee bit broad to me. $\endgroup$
    – user12
    Commented Aug 17, 2013 at 20:49
  • $\begingroup$ @Undo - six numbers for three countries? Come on, this isn't like asking for $\pi$ to a billion digits :) $\endgroup$ Commented Aug 18, 2013 at 3:55

2 Answers 2


In practice, there were the following unmanned flights before a first manned attempt for each of the manned programs.

The Russians:

  • Vostok:
    • 5 unmanned flights Sputnik 4,5,6,9,10
  • Voskhod (quite similar to Vostok):
    • Kosmos-47 unmanned test spacecraft.
  • Soyuz:
    • 2 unmanned Kosmos-133, Kosmos-140.
    • Soyuz-1 a tragic disaster during the first manned attempt
    • 6 more unmanned after that: Kosmos-186,188,212,213,238; Soyuz-2.
  • Soyuz T:
    • Kosmos 1001, Kosmos 1074 without docking to Salyut
    • Soyuz T-1 unmanned with docking to Salyut
  • Soyuz TM:
    • Soyuz TM-1 unmanned
  • Soyuz-TMA:
    • all manned, new ideas are tested on similar Progress cargo spacecrafts.
  • Salyut (a space station, not intended for a manned ascend):
    • Salyut-1 flew for 5 days unmanned, then a manned Soyuz docked, but the crew could non visit Salyut-1 (although they planned to do so).
  • TKS/VA:
    • 3 unmanned docked pairs of VA reentry capsules
    • 1 complete unmanned spacecraft
    • 3 complete spacecrafts launched without a crew, the crew came in from Salyut space stations.
    • Never launched with a crew although certified for that.
  • Mir

    • The basic block is a continuation of Salyut lineage. The addon modules are essentially TKS without VA, so no additional unmanned flights before Mir have been performed.
  • Buran:

    • 1 unmanned flight
    • No flights after that.

The US manned programs:

  • Mercury:
    • 1 successful Big Joe
    • 3 successful Mercury-Redstone 1A,2(with a chimpanzee),BD
    • 1 successful Mercury-Atlas 2
  • Gemini:
    • 2 unmanned Gemini 1,2
  • Apollo:
    • 2 unmanned AS-201, AS-202
    • AS-204 a tragic disaster during the first manned attempt
    • 3 more unmanned Apollo 4,5,6 after that
  • Skylab:
    • Flew unmanned for 10 days, then it was visited by a manned Apollo.

The Chinese program:

  • Shenzhou:
    • 4 unmanned Shenzhou 1 to 4
  • Tiangong (a space station):
    • flew unmanned for 2 months
    • visited by an unmanned Shenzhou-8
    • flew unmanned for 6 more months, and then it was visited by a crew.
  • 2
    $\begingroup$ I am missing the most amazing number in this collection: Space Shuttle - zero unmanned flights! Well, yes, the question asks to exclude the shuttle, but it is a nice contrast. (Besides, what about Mercury, Gemini and Apollo?) $\endgroup$
    – s-m-e
    Commented Aug 17, 2013 at 23:04

This is a reference post for everybody to draw upon.

Source: NASA Astronauts on Soyuz: Experience and Lessons for the Future

The RSC-Energia’s Reliability Laboratory provided NASA with a briefing on Mir/Shuttle Project quality, reliability, and safety assurance. The Russians mentioned that they did not have a safety program requirement. Instead, they have a Quality and Reliability Program Requirement. In Russian standards, quality encompasses a very broad range of factors that defines the consumer value of a product. Quality includes reliability, safety, and a set of other factors described as fabrication quality, documentation quality, workmanship, etc. While reliability and safety relate to a significant extent to vehicle characteristics, other aspects of quality can describe both the hardware and other elements of the vehicle development process.

Of the two concepts, “reliability” and “safety,” the RSA narrowed the definition most for vehicle reliability. In its general meaning, dependability includes the following properties: reliability, longevity, preservability, and maintainability. Reliability is analyzed primarily by performing quantitative analysis on probability parameters.

Russian experts indicated that they rely on four levels of technical standards. At the top level are RSA and government standards. The second level defines the enterprise Rocket Space Technology. The third level is composed of standards from facilities such as NPO-Energia. The fourth level is product standards.

Safety means roughly the same thing to RSA and NASA; specifically, it is the capability to prevent damage to the health of the crew and service personnel, along with major losses of material and property. The relationship between reliability and safety can be illustrated by an expression often used at RSA: “safety is assured primarily by reliability.” Those safety assurance facilities and procedures with no relation to reliability are primarily geared toward controlling contingency (hazardous) situations, e.g., situations that arise due to a lack of hardware reliability. Russia makes far less use of quantitative indices for safety than for dependability (e.g., crew hazard probability, specific contingency occurrence probability).

The Russians consider this approach to reliability and safety as being close to the one taken by NASA. One of the main differences is in the methods and forms of reliability and safety analysis. For example, NASA emphasizes measures to prevent hazardous situations from arising in its safety analysis. The RSA essentially examines those measures as part of a reliability analysis, while focusing most of its attention on measures to control off-nominal situations in its safety analysis.

NASA and the RSA have roughly identical principles for safety and reliability assurance to include: development in stages; establishing, implementing, and monitoring compliance with requirements; redundancy principles, etc. They also have similar approaches to problem resolution to include: tasks are similar in terms of goals and content; methods and procedures for task resolution vary; and there are significant differences with respect to formats for analyses and reports generated on their results.

NASA man-rating standards (the most recent revision is 2012) http://nodis3.gsfc.nasa.gov/displayDir.cfm?t=NPR&c=8705&s=2B.

Change history: http://nodis3.gsfc.nasa.gov/displayDir.cfm?Internal_ID=N_PR_8705_002B_&page_name=ChangeHistory

The standards are effective until 2016.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.