How is “Crew Dragon” fundamentally different from “Union”?


    Our mail is filled with various questions about the differences between the Soyuz and Crew Dragon ships. Therefore, today we decided to write an article about the fundamental differences between the spaceships «Crew Dragon» and «Soyuz».

    There are a large number of modern manned spacecraft that are already in service or are in advanced stages of development. They can be conditionally divided into two large groups: low-orbit and ships for long-distance space flights. The LEOs used at present include the American Crew Dragon and Starliner, the Russian Soyuz MS, the Chinese Shenzhou, and the Indian Gaganyan. For flights into deep space in the coming years it is planned to use the American «Orion», one of the versions of the Russian PTK NP «Oryol» and projects of other countries.

    But the heroes of today’s article are two low-orbit spacecraft — «Crew Dragon» and «Soyuz MS».

    NASA in 2010 announced a competition for the design of a low-orbit spacecraft for flights to the ISS. This project was supposed to eliminate the need to use the transport services of Roskosmos and the Russian Soyuz spacecraft, which arose after the closure of the Space Shuttle

    Since “Crew Dragon”, like “Soyuz”, is LEO, they have a lot in common, but there are still more differences. Let’s consider a few of them. The new «Crew Dragon» is much more massive than the «Union». The launch mass of the Crew Dragon is 12 tons, while the Soyuz is almost twice lighter, its launch mass does not even reach 8 tons, thanks to which the American spacecraft can deliver 9 times the mass of cargo to the ISS, and can also launch from orbit almost 3.5 tons of cargo. This is due to the capabilities of the launch vehicle itself: the greater mass of the Crew Dragon is possible due to the larger-lift Falcon 9 rocket. This is a big advantage of the Crew Dragon, since it can put more cargo or crew members into orbit.

    Another plus of “Crew Dragon” is its spaciousness. The ship can accommodate four people, instead of three in the Soyuz. Also on the «Crew Dragon» there is a so-called rescue mode, that is, in case of an emergency at the station, instead of cargo, you can take three more people on board, but only on condition that additional spacesuits and seats are delivered to the station in advance.

    If we talk about the disadvantages of the «Crew Dragon», then the American ship does not have an additional utility compartment, which can be used not only for the life support of the crew, but also as an airlock, thanks to which it is possible to conduct spacewalks. The ship «Crew Dragon» does not have such a function, therefore all life support systems are in the apparatus for returning to Earth. In addition, the “Crew Dragon” does not have separate fairings, it is itself a fairing, and the rescue system is implemented in a completely different way.

    Also, these ships are very different in layout. The Soyuz consists of three modules, while the Crew Dragon consists of only two. Of course, the American «Crew Dragon» has more modern control systems, interfaces and touch screens. The Soyuz ships currently do not have such upgrades, since they require significant reworking of the ship and, accordingly, large financial investments. Now all the funds Roskosmos is investing in a new ship, the Orel NPP, since this project is considered more promising and in demand.

    In addition, «Crew Dragon», unlike «Soyuz», is reusable; Endeavor and Resilience capsules have already flown into orbit twice. After each flight, the heat shield is replaced on it, as well as the outer cargo compartment, which houses the solar panels and radiators.

    An interesting fact is that a seat on the Crew Dragon ship costs an average of about $ 55 million. Almost the same amount, $ 55.7 million, was paid by NASA to Roscosmos for the delivery of one American by the Soyuz spacecraft.

    NASA astronaut Shannon Walker flew on both ships and in her impressions there are differences, but they are not very significant.

    Author: Alexey Nimchuk. Edited by Fedor Karasenko.

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