The PTK project completes paper phase

Key design concepts and flight scenarios evaluated by Russian engineers within the PTK NP project by the beginning of 2013. Besides the Moon, similar architectures could be used to reach the Lagrangian points.

From paper to metal

Russian efforts to build a next-generation manned spacecraft reached a crossroads at the beginning of 2013, with the completion of a largely "paper" phase of the development, known as the Technical Project. Now, the Russian government had to commit the PTK NP spacecraft to metal (and real expenses), postpone its development or cancel it altogether. Ironically, the Russian space agency, Roskosmos, was facing this critical decision, as NASA's leadership publicly rejected a leading role for the US in any foreseeable lunar-landing effort.

On February 1, in Korolev, RKK Energia, the prime contractor in the PTK NP project, hosted a meeting of the Scientific and Technical Council, NTS, which included all leading industry and agency officials involved in the manned space program. Nikolai Bryukhanov, the head of the PTK NP development at RKK Energia, formally presented the spacecraft design, described all major aspects of the work and the latest status of the project. He declared the Technical Project officially completed and proposed to transfer all the materials to the TsNIIMash research institute (the agency's chief certification center) for review.

According to a development schedule finalized at the end of 2012, the general plan for the manufacturing of the PTK NP spacecraft would start on Jan. 1, 2013. However the implementation of this timeline would depend on actual funding. At the time, the first unmanned launch of PTK NP was expected in 2018 and the first manned mission in 2020, on the condition that full-scale funding would start no later than 2014. (632) The entire program was expected to cost 100 billion rubles ($3.2 billion) or twice the original estimates made in 2008-2009.

One potential stumbling block during the formal review of the project came from Andrei Pronkevich, a representative of the Ministry of Defense. He criticized the project for lacking a systemic approach, the Izvestiya daily reported. Pronkevich claimed that a formal technical assignment for the project and its components had not been approved and demanded the review of various elements before the whole system would get the green light. The head of RKK Energia Vitaly Lopota reportedly characterized this demand as "absurd." Such an active engagement of the Ministry of Defense with the PTK NP project looked somewhat surprising, giving the historically disinterested attitude of the military toward manned space flight. Recently, the Russian Air Force even surrendered to Roskosmos the oversight of cosmonauts' training at Star City, the last and largely symbolic involvement of the military in the manned space program.

The controversy apparently revolved around the Angara-based launch vehicle dubbed Amur (a.k.a. Angara-5P) that was expected to carry the PTK NP into low Earth orbit. Despite the completion of the spacecraft design, little has apparently been done on the launch vehicle. In turn, Aleksandr Sileverstov, head of GKNPTs Khrunichev, the Angara developer, said that the company would start work on the Amur rocket as soon as it gets specifications for the spacecraft. Given the similarity of the Amur to the Angara launcher, which was in final stages of development, the new rocket had a good chance of reaching the launch pad before the spacecraft it was suppose to carry.

At the beginning of February 2013, RKK Energia submitted to Roskosmos all the documentation for the determination of the timeframe and funding levels of the PTK NP project. However, as of April, the company's leadership did not expect the beginning of funding until 2014. (641)

Comparing mission scenarios

Even with the decision to adopt Angara-5 as a carrier of the PTK NP to low Earth orbit, the future spacecraft would still need a much bigger rocket to fulfill its primary mission of reaching lunar orbit or the Lagrangian points. As a result, Roskosmos would also have to commit to the development of a heavy-lifting launch vehicle.

In order to send the 20-ton spacecraft toward the Moon, it would have to be launched by a rocket with a payload capacity of around 75-80 tons. Alternatively, a pair of smaller, cheaper rockets with payloads ranging from 45 to 55 tons could be used. The first rocket could launch the manned spacecraft, while another would carry a space tug, designed to boost the manned vehicle from an initial parking orbit around the Earth toward the Moon.

While the exact capability of the future "Moon rocket" remained foggy, RKK Energia evaluated at least six flight scenarios for reaching lunar orbit with one or two launch vehicles. When relying on two rockets, a rendezvous in low Earth orbit between the manned spacecraft and the space tug would be required. When comparing different architectures, engineers looked at a single space tug that would be responsible for sending the spacecraft toward the Moon and inserting it into lunar orbit and at two-stage architectures. In the latter case, the first stage would enable escape from Earth orbit, while the second would be responsible for a braking maneuver near the Moon. In addition, the use of cryogenic stages powered by liquid oxygen and liquid hydrogen was compared to the off-the-shelf space tugs burning less efficient kerosene fuel. Multiple engines versus a single propulsion unit on each stage were likely also compared.

Practically all scenarios conceived for missions to lunar orbits could also be applied to flights to Lagrangian points. Similar designs could also be employed to deliver lunar landers to lunar orbit or to build a lunar orbital station, LOS.

As of the beginning of 2013, engineers at RKK Energia reportedly favored an architecture featuring a single rocket capable of launching the manned spacecraft together with a two-stage space tug. The combined stack would have a mass of 76 tons in low Earth orbit. By May, both options relying on two launches were ruled out. However the ultimate flight scenario would depend on the approved strategy and available budgets.

Le Bourget

A few more details on the status of the PTK NP project were made available in a leaflet released by RKK Energia at the Paris Air and Space Show in Le Bourget in June 2013. Newly revealed design features were concentrated in the propulsion module. The latest depictions showed two main engines and six auxiliary thrusters. Notable were also a dual thorus tank structure and a deployable boom with rendezvous targets.

On the crew module, some rearrangement of the attitude control thrusters was evident and the main hatch lost its window, which instead moved to a higher position on the capsule.

Released specifications confirmed a mass of the Earth-orbiting "flavor" of the spacecraft, first reported on this web site in 2012, as 14.4 tons. The mass of lunar version was reported at 20 tons -- slightly lower than 21.4 tons known since 2012, however this number could be rounded down. All other specifications were previously known and remained unchanged, notable was the "accuracy of landing" quoted at five kilometers. (See table in the appendix). However the most notably, both versions of the spacecraft now listed a crew of four, meaning that developers had finally abandoned hopes for carrying two extra crew members on the Earth-orbiting variation of the spacecraft.

Russia showcases its next-generation spacecraft in Moscow

By the end of June, the TsNIIMash research institute provided its feedback on the Technical Project of the PTK NP spacecraft and requested additional changes to be completed by the middle of July. The review of those changes took place on July 23, resulting in more refinements of the design requested by TsNIIMash. At the time, there was no official statement on the status of the project. Sources at RKK Energia said that as many as 800 design changes or clarifications in the PTK NP project had been requested by various entities, including TsNIIMash and Gagarin Cosmonaut Training Center, TsPK. Changes apparently dealt with minute details of the design, such as the position of the hatch and windows and their exact sizes.

A new image showing the full-scale prototype of PTK NP's descent module was released on July 24. It revealed a cluster of five downward-facing nozzles at the bottom section of the vehicle. This configuration was only slightly different from the previous depiction of the rocket-powered landing system of the PTK NP spacecraft last seen in Le Bourget in June.

In the meantime, RKK Energia put the first real prototype of the next-generation spacecraft on display at the Moscow Air and Space Show, MAKS-2013, held at the Ramenskoe Airfield in the town of Zhukovsky from August 27 until September 1. The vehicle, representing the descent module, VA, of PTK NP was shipped to Zhukovsky at the beginning of August.

It was subdivided into three sections, representing the actual design of the PTK spacecraft:

  • The unpressurized upper composite, VP;
  • The pressurized command compartment, KO, housing the crew;
  • The bottom aggregate compartment, AO, containing soft-landing engines and the landing gear, PU.

At MAKS-2013, top RKK Energia officials declared that Roskosmos had approved the PTK NP spacecraft for development and that a federal contract for the construction of the vehicle had been imminent. Top engineers leading the PTK NP project said that very last design changes had been in final stages and the design documentation would be submitted to TsNIIMash before the end of September. Many of the "changes" included bureaucratic paperwork required to certify documentation corrections, as well as additional cross references to the already completed paperwork.

With the conclusion of this work, RKK Energia expected by the end of the year to enter a new phase of the work known as the development of design documentation, RKD. It would involve the production of most hardware of the PTK NP spacecraft for full-scale testing.

Notable design features in the final design of PTK NP

As of August 2013, the PTK NP spacecraft featured an ablative non-reusable thermal protection system attached to removable panels. In their turn, panels carrying ablative layers would be attached to the metal skin of the spacecraft with a special glue. After each flight, the descent module would be stripped of its partially burned heat shields and new panels would be glued to the reusable metal structure of the module. A special chemical solution was developed to remove glue residue from the metal skin of the vehicle without any damage to the structure. RKK Energia engineers said that a tradeoff analysis had shown little benefit to using a fully reusable thermal protection system. In addition, latest studies showed that using a single type of thermal protection panels on all sides of the conical module would greatly simplify the manufacturing of the thermal protection layers, even at the price of a small increase in a total mass of the spacecraft.

Previously, the conical surface of the descent module was to be covered with two types of protective shielding: a thicker and heavier layers on the side exposed to the most intensive thermal effects of the reentry and thinner, lighter layers on the opposite side of the vehicle. RKK Energia specialists noted that unlike the Space Shuttle and other winged vehicles, the temperature difference on the underside and on the top side of the capsule-like spacecraft would be less drastic to justify the cost of developing two types of shielding. PTK NP would still have more capable protective system on the bottom heat shield bearing the brunt of thermal pressure at the reentry.

The PTK NP spacecraft would still feature the rocket-propelled landing system, however its role was reduced to an auxiliary propulsion following the deployment of a triple cascade of parachutes. A simultaneous opening of each of three main parachutes would be preceded by a deployment of trio of pullout parachutes and braking parachutes. The rocket-propelled landing system would be activated at an altitude of only 10 meters above the surface and provide soft landing. Unlike small soft-landing engines on the Soyuz spacecraft, which fire a moment before the touchdown, PTK NP's solid-propellant motors would still have a sophisticated thrust control and much more capable in controlling the landing speed and the exact point of landing.

However, initial plans for a complete reliance on rocket engines during landing were dropped. RKK Energia representatives disclosed that the stiff resistance to the rocket-powered landing system came not only from veteran managers at TsNIIMash but also from cosmonaut ranks. "The (concept) of falling like a stone from the sky down to an altitude of just under a kilometer sounded way too radical to many cosmonauts," an RKK Energia representative said.

Under all circumstances, the descent module of PTK NP spacecraft would land as a single vehicle with all its components in place, for the exception of a detachable bottom heat shield. However between the flights, the descent module would be split into three main segments for easy access and servicing.

Ground simulations

During 2013, a series of new and ongoing simulations and tests brought the PTK NP project ever closer to the full-scale development of the next-generation spacecraft.

A special test tower at the State Robotics Center, TsNII RTK, in St Petersburg was renovated for upcoming trials of the Complex of motion parameter measurements, KIPD, designed to support rocket-powered landing of the descent module.

On October 11, a four-person team practiced launch pad ingress and emergency egress procedures onboard the PTK NP spacecraft. Led by cosmonaut Yuri Usachev, the team members dressed in Sokol safety suits climbed inside the prototype of the descent module at RKK Energia in Korolev. They then used a parachute canopy to facilitate an egress from the free-standing capsule through its main hatch, testing an emergency procedure at a landing site.

Flight testing

By 2013, various sources enabled to compile an emerging picture of the flight test program aimed to validate the PTK NP spacecraft for manned missions. According to official statements, up to three launches of the Zenit rocket beginning as early as the middle of 2018, would carry unmanned prototype of the spacecraft into low Earth orbit, possibly, culminating with a docking at the International Space Station.

Russia goes ahead with the development of the next-generation spacecraft

On October 23, Roskosmos finally committed to a new phase in the development of the Soyuz replacement. A 9.536-billion-ruble contract would cover the production of the design documentation and the experimental version of the next-generation spacecraft by November 2015. Although the move was announced as a "tender," the contract was practically guaranteed to go to RKK Energia.

The technical assignment accompanying the tender specified the ability of the PTK NP spacecraft with a crew of four to conduct a month-long missions beyond the Earth orbit with a nominal duration of lunar expeditions reaching 22 days. The lunar (interplanetary) expeditionary complex was listed as a destination for the PTK NP spacecraft in the lunar orbit. In order to reach the lunar orbit, the PTK NP would be first inserted into the 200-kilometer parking orbit around the Earth with an inclination of 51.6 degrees toward the Equator. During its flight testing, PTK NP would travel to the ISS, the documentation said.

The spacecraft would have to be able to conduct Earth-orbiting missions reaching altitudes from 200 to 480 kilometers and inclinations 51.6, 51.7, 64.8, 72 and 83 degrees toward the Equator.

The documentation quoted the capability of the Earth-orbit missions of PTK NP "to launch and return 4-6 people," even though the crew size exceeding four people seemed doubtful.

Roskosmos formally awarded a contract to RKK Energia on December 19.


Reported budget of PTK NP spacecraft as of 2012-2013:

PTK NP spacecraft development
100.0 billion rubles
Emergency escape system and fairing
40.0 billion rubles
Launch processing systems
14.4 billion rubles
160.0 billion rubles


Specifications for the PTK NP spacecraft as of June 2013:

Earth orbit
Liftoff mass
Mass of delivered and returned cargo
500 kilograms
100 kilograms
Internal crew cabin volume
17 cubic meters
17 cubic meters
Flight duration when docked to a space station (Earth-orbiting or lunar)
365 days
180 days
Nominal g-loads during descent from orbit
Landing accuracy
5 kilometers
5 kilometers


Comparison of six lunar mission architectures considered within the PTK NP project in 2013:

Option 1
Option 2
Option 3
Option 4
Option 5
Option 6
Number of launches
Number of stages
Total mass in the low Earth orbit
82 tons
~76 tons
81 tons
~70 tons
Propellant type in Stage 1
Propellant type in Stage 2
Total mass of propellant in Stage 1
~38 tons
~50 tons
36-40 tons*
Total mass of propellant in Stage 2
~8.2 tons
~7.5-10 tons

*Jettisonable external tank; ** Block DM-derived stage



The article, interactive graphics, animation and artwork by Anatoly Zak; Last update: February 5, 2024

Research and technical estimates by Claude Mourier, Vladimir Shtanin and Igor Rozenberg

Page editor: Alain Chabot; Last edit: May 4, 2013

All rights reserved

insider content


A photo possibly taken at the Scientific and Technical Council on Feb. 1, 2013, reveals the architecture and flight scenarios considered for Russia's next-generation manned spacecraft, PTK NP, and aimed to reach lunar orbit and the Lagrangian points. Credit: Za Novuy Tekhniku



In March 2013, an official photo-release about visit of a regional official to RKK Energia facility in Korolev provided a glimpse of a full-scale prototype of the crew module built during the technical development of the PTK NP spacecraft in 2011 and 2012. A solid-propellant motor of the soft-landing system can be seen on the foreground. Credit: RKK Energia


Russian cosmonauts review the entrance hatch of the PTK NP spacecraft at RKK Energia facility in Korolev in April 2013. Credit: RKK Energia



Depictions of the PTK NP spacecraft released in June 2013. Credit: RKK Energia



A scale model of PTK NP spacecraft presented in Le Bourget in June. Credit: RKK Energia


A cluster of soft-landing engines on the PTK NP spacecraft as of July. Credit: Mark Serov


The descent module of PTK NP spacecraft is being prepared for display at MAKS-2013 show in August. Credit: Mark Serov


The descent module of the PTK NP spacecraft at the Moscow Air and Space Show in August. Copyright © 2013 Anatoly Zak


Cosmonaut Mark Serov demonstrates a new-generation Cheget chair inside the PTK NP spacecraft prototype. Copyright © 2013 Anatoly Zak

Flight controls

Flight controls inside the descent module. Copyright © 2013 Anatoly Zak


A practice of a post-landing emergency egress procedure on October 11. Credit: RKK Energia


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