Boilerplate (spaceflight)

Boilerplate version of Gemini spacecraft on display at Air Force Space and Missile Museum, Cape Canaveral, Florida October 15, 2004.

A boilerplate spacecraft, also known as a mass simulator, is a nonfunctional craft or payload that is used to test various configurations and basic size, load, and handling characteristics of rocket launch vehicles. It is far less expensive to build multiple, full-scale, non-functional boilerplate spacecraft than it is to develop the full system (design, test, redesign, and launch). In this way, boilerplate spacecraft allow components and aspects of cutting-edge aerospace projects to be tested while detailed contracts for the final project are being negotiated. These tests may be used to develop procedures for mating a spacecraft to its launch vehicle, emergency access and egress, maintenance support activities, and various transportation processes.

Boilerplate spacecraft are most commonly used to test manned spacecraft; for example, in the early 1960s, NASA performed many tests using boilerplate Apollo spacecraft atop Saturn I rockets, and Mercury spacecraft atop Atlas rockets (for example Big Joe 1). The engine-less Space Shuttle Enterprise was used as a boilerplate to test launch stack assembly and transport to the launch pad. The development of NASA's Project Constellation used boilerplate Orion spacecraft atop an Ares I rocket for initial testing. More recently, on February 6, 2018, SpaceX founder Elon Musk's Tesla Roadster was used as a dummy payload on the maiden launch of the company's Falcon Heavy rocket.

Mercury boilerplates

Mercury boilerplates were manufactured "in-house" by NASA Langley Research Center technicians prior to McDonnell Aircraft Company building the Mercury spacecraft. The boilerplate capsules were designed and used to test spacecraft recovery systems, and escape tower and rocket motors. Formal tests were done on the test pad at Langley and at Wallops Island using the Little Joe rockets.[1][2]


The term boilerplate originated from the use of boilerplate steel[3] for the construction of test articles/mock-ups. Historically, during the development of the Little Joe series of 7 launch vehicles, there was only one actual boilerplate capsule and it was called such since its conical section was made of steel at the Norfolk Naval Shipyard. This capsule was used in a beach abort test, and then subsequently used in the LJ1A flight. However, the term subsequently came to be used for all the prototype capsules (which in their own right were nearly as complicated as the orbital capsules). This usage was technically incorrect, as those other capsules were not made of boilerplate, but the boilerplate term had effectively been genericized.

Notable events

Section sources.[4][5]
  • 1959 July 22 – First successful pad abort flight test with a functional escape tower attached to a Mercury boilerplate.
  • 1959 July 28 – A Mercury boilerplate with instrumentation to measure sound pressure levels and vibrations from the Little Joe test rocket and Grand Central abort rocket/escape tower.
  • 1959 September 9 – A Big Joe Atlas boilerplate Mercury (BJ-1) was successfully launched and flown from Cape Canaveral. This test flight was to determine the performance of the heat shield and heat transfer to the boilerplate, to observe flight dynamics of boilerplate during re-entry into the South Atlantic, to perform and evaluate capsule flotation and recovery system procedures, and to evaluate the entire capsule and rocket characters and system controls.[6]
  • 1960 May 9 – Beach Abort test with a Little Joe rocket was successful.
  • 1961 February 25 – A successful drop test of the Mercury boilerplate spacecraft fitted with impact skirt, straps and cables, and a heat shield.[7]
  • 1961 March 24 – A successful Mercury-Redstone BD (MR-3) launched occurred with an apogee of 181 km (112 mi); first sub-orbital uncrewed flight.[7]


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