OKA-T

[Danderman]

So, what do the experts here know about this proposed system?

:cool:  

 

 

[Satori]

Danderman - 20/3/2007  12:52 PM

So, what do the experts here know about this proposed system?

:cool:  

 

 

Well, the only reference I've got was that OKA-T was a free-flying module dedicated to the material processing research based on the ISS russian segment.

[Danderman]

Hopefully, I can attach an image of OKA-T, so everyone knows what we are talking about!

[Jim]

Danderman - 22/3/2007  5:14 PM

Hopefully, I can attach an image of OKA-T, so everyone knows what we are talking about!

Just like the "The Space Review" article.   Nothing more than powerpoint charts

[dmitrik]

OKA-T-MKC is included in Federal Space Program 2006-2015. There  is a govt purchase order for it:
http://roscosmos.ru/GosOrdersList.asp?NORDER=100 (in russian)

Requirements are clearly written with some sort of Progress derivative in mind
Launch on Soyuz (launch mass 7800)
Self-propelled, with the usual complement of engine compartment, solar arrays, radiator etc.
5 years on-orbit lifetime with periodic docking to ISS
Pressurised compartment, "Progress-M" docking system (short-sleeve environment while docked)
Microgravity better than 1E-6 g
External airlock and mechanism for deploying samples
Screen 3 meters in diameter to to shield samples from molecular flow to ensure vacuum 1E-12..1E-14 torr
Launch dates: 1'st - 2012, 2'nd - 2015

Present status of the project is unclear, there were media reports some time ago that Samara (TsSKB "Progress") has won the tender but there is no mentioning of that fact on either roscosmos.ru or samspace.ru  In any case it is certainly a lot more than just powerpoint charts.

[Danderman]

Satori - 22/3/2007  10:04 AM Well, the only reference I've got was that OKA-T was a free-flying module dedicated to the material processing research based on the ISS russian segment.

I found this old image some years ago, and had no idea what it was supposed to be. Now I think it is an early version of OKA-T.

[Danderman]

http://www.arms-expo.ru/site.xp/049057054050124049049049056054.html

This article is dated from 2009, and implies that its not dead yet.

[B. Hendrickx]

This is what I wrote about OKA-T in my article "The Future of Russia's Manned Space Programme", published in the BIS journal "Space Chronicle" earlier this year. I haven't seen any updates since I submitted this for publication :

The Russians also intend to launch free-flying spacecraft that will orbit in the vicinity of the ISS and periodically dock with it. The rationale behind this is that many experiments are much easier to perform on a free-flying platform than on a multimodular space station. This is especially the case for sensitive materials processing experiments, which require a vibration-free environment, and astronomical observations, which demand accurate pointing of telescopes. The idea is that such spacecraft regularly dock with the station for maintenance, upgrading and both loading and unloading of experiments. Plans for such free-flyers have been around for a long time. For instance, back in the 1970s the Soviet Union had plans for a giant N-1 launched space station called MKBS which would have been joined by several such co-orbiting free-flyers. An outgrowth of these was the Progress-based Gamma astrophysics satellite, launched in July 1990.

Free-flyers put forward for ISS in the 1990s were MAKOS-T and AKA-T, both for materials processing experiments, and SLK for submillimetre astronomy, but none of these ever appear to have received government funding [13]. All that changed with the inclusion of а free-flyer project called OKA-T in the FSP 2006-2015. A tender for the development of the vehicle was won on 20 February 2006 by the Central Specialized Design Bureau (TsSKB-Progress) in Samara, which develops Soyuz rockets, reconnaissance satellites and the recoverable Bion and Foton satellites.

According to the requirements laid out by the Federal Space Agency in 2005, two OKA-T vehicles were to be launched in 2012 and 2015. The vehicle must weigh about 7.8 tons and be launched by a Soyuz-2 rocket. It will consist of a service module (containing among other things manoeuvring engines, solar panels and a radiator panel) and a pressurized compartment with a Progress M type docking system, allowing it to dock with the ISS about every three-four months during a mission lasting five years.

Extending from the spacecraft will be a small boom with a 3 m diameter shield that creates a near-perfect vacuum in its wake. The purpose of this is to employ a technique called molecular beam epitaxy to produce ultrathin layers of semi-conductor materials for the microelectronics industry. Similar experiments were planned for RKK Energiya’s AKA-T and they are also reminiscent of those performed with the US Wake Shield Facility, a free-flyer flown on three Space Shuttle missions between 1994 and 1996. Samples for these experiments are to be deployed on the outside via a small airlock.
 
Other objectives are to produce small parties of cartilaginous structures to be used in medicine, mercury-cadmium-telluride monocrystals for use in new-generation sensor equipment and to receive biologically active substances and other medicines with better characteristics than those obtained on Earth. There will also be experiments to study phase transitions (mainly crystallization in melts and solutions) and heat and mass transfer in fluids [14].

Funding of the OKA-T vehicles began in 2006. It looks like RKK Energiya is a subcontractor in the project and that early on there was some disagreement with TsSKB-Progress on the actual division of labour. Apparently, the original idea was that the pressurized compartment would be derived from the return capsule of TsSKB’s Foton satellites (essentially modified Vostok re-entry capsules) and that the service module would be that of RKK Energiya’s Parom space tug [15].

Speaking at an aerospace congress in August 2009, Roskosmos deputy head Vitaliy Davydov said that the first OKA-T will not be ready for launch in 2012 due to the global financial crisis and that the project’s fate will depend on funding in 2010-2011 [16].  If the project survives, Roskosmos is apparently hoping to fly OKA-T vehicles even in the post-ISS era [17].

[B. Hendrickx]

The attached drawing in the previous post is from a TsSKB/Progress brochure distributed at the MAKS 2009 aerospace show, so I presume this is still the currently planned configuration of the spacecraft.

[Stan Black]

So if it docks several times over five years will it need to be refueled?

http://www.oosa.unvienna.org/pdf/pres/stsc2010/tech-13.pdf

[B. Hendrickx]

So if it docks several times over five years will it need to be refueled?

http://www.oosa.unvienna.org/pdf/pres/stsc2010/tech-13.pdf

It probably will. I understand it is possible to transfer propellant from the FGB and Service Module tanks to the Progress service module (at least some of the ISS orbit corrections using Progress thrusters are said to be performed with propellants drawn from those tanks), so I would guess a certain amount of propellant can also be transferred to the OKA-T service module for manoeuvres in between dockings.

[hop]

If it has the same propellant capacity as a regular Progress, I doubt it would need to re-fuel. Progress normally brings ~1000kg of propellant for ISS use. (870 in the refueling tanks, plus a few hundred for reboost and attitude control)

[zaitcev]

Honestly I'm shocked to learn that the shell of Parom is going to be reused. Or maybe not so much shocked. BTW, it's quite different from Progress because it has a TKS-style tunnel going through it, so that it docks with the "butt" to the station. This was so that a large diameter cargo canister would not obscure any docking antennas. If this configuration is kept, the propellant capacity can be anything.

[Danderman]

It probably will. I understand it is possible to transfer propellant from the FGB and Service Module tanks to the Progress service module (at least some of the ISS orbit corrections using Progress thrusters are said to be performed with propellants drawn from those tanks), so I would guess a certain amount of propellant can also be transferred to the OKA-T service module for manoeuvres in between dockings.

Although propellant can pass from the ISS prop tanks to the Progress mid-thrusters, Progress cannot have its prop tanks replenished from ISS.

[B. Hendrickx]

It probably will. I understand it is possible to transfer propellant from the FGB and Service Module tanks to the Progress service module (at least some of the ISS orbit corrections using Progress thrusters are said to be performed with propellants drawn from those tanks), so I would guess a certain amount of propellant can also be transferred to the OKA-T service module for manoeuvres in between dockings.

Although propellant can pass from the ISS prop tanks to the Progress mid-thrusters, Progress cannot have its prop tanks replenished from ISS.

Ok, so the propellant goes directly from the Zarya or Zvezda tanks to the Progress thrusters. Thanks for pointing that out.

[Lars_J]

It probably will. I understand it is possible to transfer propellant from the FGB and Service Module tanks to the Progress service module (at least some of the ISS orbit corrections using Progress thrusters are said to be performed with propellants drawn from those tanks), so I would guess a certain amount of propellant can also be transferred to the OKA-T service module for manoeuvres in between dockings.

Although propellant can pass from the ISS prop tanks to the Progress mid-thrusters, Progress cannot have its prop tanks replenished from ISS.

Well this "OKA-T" would have to have a radically different propellant tank system from a Progress anyway. Is it not the tank systems on Soyuz/Progress that limit them to a ~6-9 month orbital lifespan?

If this thing is designed for a 5 year lifespan, it has to be a very heavily modified Progress or something completely different (perhaps TKS based as zaitcev noted). It needs the orbital maneuvering and refueling capability similar to the Zarya module.

[hop]

Is it not the tank systems on Soyuz/Progress that limit them to a ~6-9 month orbital lifespan?

No, the 6 month limit is only for Soyuz, because the descent module uses H2O2 for attitude control. Progress don't have such a limit AFAIK, they are just discarded to make room for the next one.

[Danderman]

It should be noted that Progress and its variants have flown for more than one year in orbit.

[Lars_J]

Ok, I stand corrected!

[zaitcev]

If this thing is designed for a 5 year lifespan, it has to be a very heavily modified Progress or something completely different (perhaps TKS based as zaitcev noted).

I did not mean to say that OKA-T is based on TKS. After all, TKS was made by Energiya's (and TsKB's) arch-rival Khrunichev. They would rather eat broken glass than base designs on TKS. Instead, it's based on Parom, that has a configuration with a TKS-style tunnel.