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VA

Descent Module of PTK NP spacecraft


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The author of this page will appreciate comments, corrections and imagery related to the subject. Please contact Anatoly Zak.


Above: A cutaway view of the Descent Module of the PTK NP spacecraft with its landing gear in deployed and retracted position as envisioned during its preliminary design circa 2010. (click arrow buttons to toggle the view). Copyright © 2013 Anatoly Zak

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2010

2010

2010

2010

PTK NP's landing leg deployment sequence as envisioned in the preliminary design circa 2010. Credit: RKK Energia


2012

Landing gear of the PTK NP spacecraft as of 2013. Credit: Arsenal


general view

Click to enlarge. Copyright © 2013 Anatoly Zak

Side

Click to enlarge. Copyright © 2013 Anatoly Zak

Top

The landing gear on the prototype of the PTK NP spacecraft displayed at Moscow air show in August 2013. Click to enlarge. Copyright © 2013 Anatoly Zak


Front

A main strut of the landing gear. Click to enlarge. Copyright © 2013 Anatoly Zak


Side

A side view of the landing gear assembly. Click to enlarge. Copyright © 2013 Anatoly Zak

 

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No more belly landing

One of the unique features of the PTK NP spacecraft would be its landing gear, consisting of four deployable legs. The system was officially known in Russian as Posadochnoe Ustroistvo (PU) or "landing device." No such hardware was ever present on the present-generation Soyuz spacecraft or any other Russian or Soviet vehicle. The main purpose of landing legs was to preserve a delicate body of the Descent Module, VA, during the rocket-powered landing and thus enable its reuse for at least 10 missions. As a bonus, the innovative gear would also come handy for future planetary landers.

Combined with parachutes, a rocket-powered landing system and shock-absorbing cosmonaut chairs, the PU landing gear will provide very gentle touchdown, while the rest of the crew module would never touch the ground. Cosmonauts would no longer experience a powerful jolt, let alone rolling of the capsule onto its side, often leaving crew members hanging on their seatbelts on the "ceiling" of the cabin.

Thanks to its capability to steer itself into a pre-arranged landing area, the PTK NP spacecraft would be expected to land at carefully chosen locations with dry and even surface, no trees and with only small brush acceptable for a safe landing.

Folded landing legs would be stowed in special niches of the Instrument Compartment, AO, which is a bottom section of the Descent Module. During the most of the mission landing mechanism would be covered by the protective heat shield, LPU, which would be dropped prior to touchdown as soon as the air pressure reaches right level.

Like Soyuz, (as well as most aircraft), the PTK NP would still have an option of landing on its belly, if it was forced to end its mission in a difficult terrain, such as taiga, rugged rocky surface, a body of water or if one or two legs of the landing gear failed to deploy. For such a contingency, the crushable base of the Descent Module would be designed to play a role of a shock absorber. Under such circumstances, the spacecraft could be damaged beyond repair, however, its crew would survive unscathed.

Development

During the preliminary design of the PTK NP spacecraft from 2009 to 2010, Russian engineers favored a four-legged, pneumatically deployed landing mechanism over a three-legged architecture, because the former provided better guarantee against overturning of the vehicle on any type of soil, including sand, clay and even frozen tundra of Siberia.

During 2011, ZAO Arsenal in St. Petersburg on the contract from RKK Energia manufactured a mockup of the landing gear for the spacecraft. By the end of 2012, the same company produced a test version of the landing gear and supplied it to RKK Energia for upcoming trials.

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APPENDIX

 

Known specifications of the landing gear on the PTK NP spacecraft (as of 2010-2012):

Number of legs
4
Deployment mechanism type
Pneumatic
Estimated mass (including deployment mechanism)
350-400 kilograms
Estimated mass of a single landing leg
87.5-100 kilograms
Estimated mass of the descent module at touchdown
7,310 kilograms
Landing leg span
3,422 millimeters
Achievable clearance between the ground and the descent module
200-250 millimeters
Maximum vertical acceleration at touchdown
up to 7 g
Maximum horizontal acceleration at touchdown
up to 5 g

 

Writing and graphics by Anatoly Zak;

Last edit: August 30, 2013

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