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JUST PUBLISHED!


Cheget

Cheget chair


PU

PTK's landing gear


2013

PTK development in 2012


Sodruzhestvo

Sodruzhestvo


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


Acknowledgement:

The author would like to thank Christian Cognard and Igor Rozenberg for corrections.

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PTK

Four different types of thermal protection materials were proposed for the crew module of the future spacecraft. Credit: RKK Energia


AO

Cutaway view of the Aggregate (Instrument) Compartment, AO. Credit: RKK Energia


VA

A circa-2012 depiction of the PTK NP spacecraft in landed configuration. Credit: RKK Energia


PTK

A depiction of PTK NP released in June 2013. Credit: RKK Energia


VA

An official depiction of the Descent Module by the end of 2012. Credit: RKK Energia


Cutaway

A cutaway view of the VA module released in June 2013. Credit: RKK Energia


Niche

A full-scale prototype of the descent module of the PTK NP spacecraft in 2013. Credit: RKK Energia


entrance

Entrance into the crew module. Credit: Vesti TV channel


toilet

A toilet system for the PTK NP spacecraft as of August 2013. Click to enlarge. Copyright © 2013 Anatoly Zak


Sliding wall

A sliding wall separating the toilet area inside the descent module of the PTK NP spacecraft. Click to enlarge. Copyright © 2013 Anatoly Zak


storage

A storage section for the Neva flotation gear (top left) and for in-flight clothing (top right). Click to enlarge. Copyright © 2013 Anatoly Zak


VA

A crew module and the service compartment of the Descent Module as of 2013. Credit: RKK Energia


VP

The upper transfer section, VP, is removed from the descent module of PTK NP spacecraft. Credit: Mark Serov


KO

The pressurized cabin of the PTK NP spacecraft as seen at MAKS-2013 in August. Credit: Mark Serov


 

Previous chapter: PTK NP development during 2012


Although Russia's next-generation spacecraft was conceived to replace the Soyuz transport ship, the architecture of the future manned vehicle resembled a classic design of NASA's Apollo spacecraft consisting of the conical crew module and a cylindrical service module. Despite the Russian designation of the crew module as VA (for Vozvrashaemy Apparat -- Return apparatus, or Descent Module), it was actually served as a cabin for the crew during the entire mission, not only at the reentry into the atmosphere.

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The crew size

In 2012, the crew size of the PTK NP spacecraft was reduced to four people for both missions to the lunar orbiting station or to the outpost in the low Earth orbit. The capability to return up to six people from the Earth orbit was apparently preserved with the installation of two Kazbek chairs in addition to four new-generation Cheget chairs. The crew module retained its capability to be reused. A three-parachute landing system would provide "hot" backup, meaning that all of three parachutes would be deployed, even though less than three would actually be needed for safe landing.

A new type of crew chairs code-named Cheget (after a mountain in the Caucasus) would be used onboard PTK NP spacecraft. Unlike Kazbek chairs onboard Soyuz, the same chair would be easily adjusted for all crew members as tall as 195 centimeters.

Design of the crew capsule

After several years of early research, engineers at RKK Energia defined the structural design of the crew module during the preliminary development of the PTK NP project in 2010. The conical structure of the module was subdivided into the command compartment, KO, and the aggregate compartment, AO. In turn, command compartment would be split into a pressurized cabin and the unpressurized upper transfer section, VP. As of 2012, the VP section was expected to be manufactured out of carbon-based composite, rather than metal. To save mass, the same composite material could be used in the aggregate compartment, the thermal shield and the load-bearing structure of the propulsion module, DO.

The aggregate compartment would feature a detachable heat shield, LTI (from Russian Lobovoy teplozashitny ekran - frontal thermal shield), protecting the entire vehicle during its return to Earth. During 2012, the thermal protection of the spacecraft was drastically strengthened to enable a safe reentry of the descent module into the Earth atmosphere from lunar trajectories.

The aggregate compartment would feature openings on its side for nozzles of both soft-landing engines and thrusters of the attitude control system, SOIS. The aggregate compartment would also contain a pair of solid-fueled gas-generators designed to provide thrust during rocket-powered soft-landing of the vehicle, as well as tanks of the attitude control system, SOIS, responsible for the precise orientation of the crew module during its reentry into the atmosphere. The AO would also feature special niches for the retractable landing legs, designed to soften the touchdown of the VA module, which could be reused for as many as 10 space missions.

Most of the components of the VA module would be integrated at eight points evenly distributed along the periphery of each section.

All components of the PTK NP spacecraft, including the VA capsule, were designed to fit into An-124 transport aircraft for transportation to the launch site.


KEY ONBOARD SYSTEMS

Communications gear

In 2012, it was decided to equip the PTK NP spacecraft with a two-band communications system, which increased the mass of the vehicle along with its reliability. The communications gear was designed to avoid interference with other systems.

Flight control system, SUBK

PTK NP would carry a four-channel flight control computer along with a single-channel backup machine. To increase redundancy and reliability, the backup machine would feature a completely different design and use different type of hardware and software. It would still be capable of conducting all flight control functions onboard the spacecraft. Yet another computer would be located onboard the propulsion module and take responsibility for key functions onboard this section of the spacecraft, most importantly for placing the module onto a safe disposal trajectory after its separation from the VA crew module.

Complex of motion parameter measurements, KIPD

This system will provide all necessary data, such as an altitude and deviation angles, to a special sub-unit of the main flight control system, SUBK, dedicated to the flight control of soft-landing engines onboard the VA capsule.

Motion control and navigation system, SUDN

The motion control and navigation would include TV-camera-based Lidar system and Kurs-LA rendezvous system.

Thermal control system, SOTR

Due to a prolonged 1.5-hour descent through the Earth atmosphere after the return from the Moon, engineers had to boost the thermal control system onboard PTK NP, comparing to the Soyuz that completes the reentry in around 10 minutes.

Attitude control system, SOIS

To orient itself in space, the VA module would use the attitude control system deriving from the previous-generation hardware employed on the Soyuz spacecraft. The system is propelled by hydrogen peroxide. However unlike the SOIS system on the Soyuz, the new-generation orientation thrusters would be designed for withstanding the reentry and subsequent use in multiple missions.

Power supply system, SES

Comparative studies during the Technical Project convinced engineers to employ expendable power batteries, which were deemed cheaper and more reliable than rechargeable systems. Still, they will be in the loop with newly developed solar panels and ion-lithium charging batteries.

Life-support system, SZhO

The life-support system onboard PTK NP would resemble more that on the Zvezda service module, SM, than the systems on the Soyuz. The Vozdukh (Air) system would be used on PTK NP to maintain parameters of the ship's atmopshere and to regulate humidity. (632)

Onboard toilet system, ASU

The PTK NP spacecraft would be equipped with a new toilet system, ASU, derived from previous-generation units. While the Soyuz spacecraft was featuring a separate habitation module accommodating the ASU, designers of the future spacecraft had to tackle the problem of placing the toilet in the same module housing the crew during launch and landing.

As of August 2013, the engineers apparently found an ingenious solution to the "toilet" issue. A highly portable latrine unit would be stored in the cargo area of the crew capsule during the launch, however immediately after reaching orbit, the crew would move it to a "far corner" of the capsule, blocking the entrance hatch to the spacecraft. Since the entrance hatch is intended for use only before launch and after landing, the empty area around it would be a "dead" space during the practically entire mission.

At the MAKS-2013 air and space show in Zhukovsky, the development prototype of the descent module featured a light-weight sliding wall, providing privacy for the crew members around the toilet area.

Landing means complex, KSP

Several diverse systems of the Descent Module would have to work in unison to achieve a critical phase of the PTK NP mission -- a soft landing. The complex of landing means, KSP, will be subdivided into several components:

 

Next chapter: Sodruzhestvo heavy-lifting rocket

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APPENDIX

PTK NP spacecraft by the end of 2012:

-
Lunar orbit
Earth orbit
Launch mass
~20 tons
~12-14 tons
Crew
4
4
Cargo
100 kilograms
500 kilograms
Internal cabin volume
17 cubic meters
17 cubic meters
Time onboard the orbiting space station
365 days
365 days
G-loads during the reentry
3
3
Landing accuracy
2 kilometers
2 kilometers

 

Known specifications of the descent module, VA, as of 2010:

Height of the VA module
3.90 meters
Maximum diameter of the VA module
4.42 meters
Upper transfer section height
1.15 meters
Command compartment, KO, height
3.04 meters
Command compartment, KO, diameter
3.80 meters
Main hatch window diameter
0.22 meters
Thickness of thermal layers on the sides of the VA modules
30-52 millimeters
Thickness of thermal layer of the LTI thermal shield
35 millimeters
Internal cabin volume
18 cubic meters*

*as of April 2013

 

 

Text and illustrations by Anatoly Zak

Last update: September 6, 2013

All rights reserved

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