Cosmopolis XXI

This article has multiple issues. Please help improve it or discuss these issues on the talk page. (Learn how and when to remove these messages) This article needs to be updated. Please help update this article to reflect recent events or newly available information. (November 2018) This article includes a list of general references, but it lacks sufficient corresponding inline citations. Please help to improve this article by introducing more precise citations. (April 2024) (Learn how and when to remove this message) (Learn how and when to remove this message)

Cosmopolis XXI was a late 2000s Russian concept launch vehicle billed as a space tourism vehicle, similar to Mojave Aerospace's Tier One program. Designed and built by the Myasishchev Design Bureau, it would use the M-55X launch aircraft (derived from Myasishchev M-55), and the proposed C-21 spaceplane or its successor the Explorer. It would be a TSTSO (Two-Stage to SubOrbit) launch platform.

The Explorer spaceplane is a suborbital tourist spaceplane based on the C-21 design. The plane was being developed by Space Adventures with the Russian Federal Space Agency and was intended to carry 3 passengers. It is to be air-launched by carrier aircraft from a Space Adventures spaceport. Space Adventures abandoned the Explorer project in 2010 because "it got too expensive."^[1] It is unclear if Russia continues its development.