Author Topic: Soviet/Russian space programs Q&A  (Read 638602 times)

Offline tnphysics

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Re: Soviet/Russian space programs Q&A
« Reply #100 on: 10/15/2007 12:48 am »
How much delta-V will the KVRB (cryo stage) provide?

If it is optimised correctly then it will provide the majority.

This assumes that it is only for Angara-5.

Offline Citabria

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Re: Soviet/Russian space programs Q&A
« Reply #101 on: 10/16/2007 04:26 pm »
About the two-day Soyuz or Shuttle approach to ISS: Why does it take two days? Is there a technical reason or is it for space-adaptation time for the crew? I doubt that it is for fuel efficiency - the total delta vee is about the same for a two-burn Hohmann transfer as for multiple intermediate transfers, is it not?

Offline Citabria

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Re: Soviet/Russian space programs Q&A
« Reply #102 on: 10/16/2007 04:33 pm »
A question that Korolev's team answered more than fifty years ago, but I have not seen a satisfactory answer: How do the R-7/Soyuz strap-on boosters separate in flight? Do they simply slip backward out of their forward sockets when thrust is cut off? (I saw a film once of a failed launch where one of the boosters lost thrust and slid downward and the rest of the rocket flew for some time before failing!) Does the release of LOX tank pressure push the boosters' noses away from the core? Are there pyrotechnics involved?

Offline Jorge

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Re: Soviet/Russian space programs Q&A
« Reply #103 on: 10/16/2007 05:12 pm »
Quote
Citabria - 16/10/2007  11:26 AM

About the two-day Soyuz or Shuttle approach to ISS: Why does it take two days? Is there a technical reason or is it for space-adaptation time for the crew? I doubt that it is for fuel efficiency - the total delta vee is about the same for a two-burn Hohmann transfer as for multiple intermediate transfers, is it not?

Maximize launch window and standardize the terminal part of the rendezvous.
JRF

Offline Citabria

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Re: Soviet/Russian space programs Q&A
« Reply #104 on: 10/16/2007 05:38 pm »
Quote
Jorge - 16/10/2007  1:12 PM

Maximize launch window and standardize the terminal part of the rendezvous.

So you're saying that a launch delay would cost little extra fuel and cause no docking delay if the error is spread over two days? I guess that makes sense. Thanks.

Offline DarthVader

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Re: Soviet/Russian space programs Q&A
« Reply #105 on: 10/16/2007 06:54 pm »
I believe one of the reason is that it also help the cosmonaut to get used to "living" in 0g. Which is apparently much easier to get used to if you are in a small area such as the Soyuz.

Offline Satori

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Re: Soviet/Russian space programs Q&A
« Reply #106 on: 10/18/2007 04:23 pm »
Hello!

I'm searching for the launch time of a 11K77 Zenit-2 launch vehicle that failled to launch a Tselina-2 sat on February 5, 1992. Any help?

Offline William Graham

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Re: Soviet/Russian space programs Q&A
« Reply #107 on: 10/18/2007 08:14 pm »
Hi, I'm interested about carrier rockets which are currently in service, but out of production, and specifically how many of each are left. As I see it:

Tsyklon-3: 1-2 launches remaining
Molniya-M: 3 launches remaining
Proton-K: 5 launches remaining

Could somebody please check the accuarcy of the above, and give me information on the numbers of launches believed to be remaining for any other types approaching the end, particuarly the following:

Tsyklon-2
Kosmos-3M
Soyuz-U (if it is on the way out)

Thanks.

Offline sammie

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Re: Soviet/Russian space programs Q&A
« Reply #108 on: 10/18/2007 10:20 pm »
I believe Kosmos 3M production has restarted. During the mid-nineties only 14 remained in stock, and I'm pretty sure that at their current launch rate, they would have run out of stockpiled rockets long ago.

I'm not so sure whether there is a big difference between the Tsyklon 3 and 2, other then the upper stage. I think it's safe to say that only a few remain in stock and that there is the option to launch to as a either a 2 or a 3.
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Offline Skyrocket

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Re: Soviet/Russian space programs Q&A
« Reply #109 on: 10/19/2007 01:24 pm »
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sammie - 19/10/2007  12:20 AM
I'm not so sure whether there is a big difference between the Tsyklon 3 and 2, other then the upper stage. I think it's safe to say that only a few remain in stock and that there is the option to launch to as a either a 2 or a 3.

No, these are not interchangeable.

Tsiklon-2 uses RD-251 (= 3 x RD-250) engine on the first stage, while Tsiklon-3 uses RD-261 (= 3 x RD-260)  - don't ask me for the differences.


Offline darkenfast

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Re: Soviet/Russian space programs Q&A
« Reply #110 on: 10/22/2007 03:38 pm »
I noticed that no one has answered this question, so I'll give it a shot from memory (and I may be wrong).  The strap-ons (Blocks B, V, G and D), are attached by a ball and socket at the forward tip, and straps at the base.  The straps are blown when there is still some residual thrust, and the boosters rotate up and out, causing the ball to come out of the socket.  There is also some venting of residual oxygen to aid in separation.  This discription was from a history that was referring to the original R-7 rocket, and I'm assuming that the method is still used.  Others, with better information may correct me.

Edited: this is in reply to a previous question about strap-on separation on the Soyuz launcher.
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Offline Nicolas PILLET

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Re: Soviet/Russian space programs Q&A
« Reply #111 on: 10/22/2007 05:22 pm »
Quote
Satori - 18/10/2007  6:23 PM

Hello!

I'm searching for the launch time of a 11K77 Zenit-2 launch vehicle that failled to launch a Tselina-2 sat on February 5, 1992. Any help?

Encyclopedia Astronautica has no information.
United Nations have no information.
Jonathan McDowell has no information.
Novosti Kosmonavtiki has no information.

Sorry... :frown:
Nicolas PILLET
Kosmonavtika : The French site on Russian Space

Offline Satori

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Re: Soviet/Russian space programs Q&A
« Reply #112 on: 10/22/2007 05:32 pm »
Quote
Nicolas PILLET - 22/10/2007  12:22 PM

Quote
Satori - 18/10/2007  6:23 PM

Hello!

I'm searching for the launch time of a 11K77 Zenit-2 launch vehicle that failled to launch a Tselina-2 sat on February 5, 1992. Any help?

Encyclopedia Astronautica has no information.
United Nations have no information.
Jonathan McDowell has no information.
Novosti Kosmonavtiki has no information.

Sorry... :frown:

Yes, that's strange I have also look for it there but no info there... humm, a mistery to be resolved!!!!

Offline mark147

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Re: Soviet/Russian space programs Q&A
« Reply #113 on: 10/22/2007 06:11 pm »
Can someone explain the difference between a normal Suyuz re-entry and a ballistic re-entry?

Offline Jim

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Re: Soviet/Russian space programs Q&A
« Reply #114 on: 10/22/2007 06:19 pm »
Ballistic entry means aerodynamics are not involved with the flight path.  Soyuz, Apollo and Gemini use a lift entry to modify the flight path with the lift generated by an offset CG.

 A guidance system is a requirement to manipulate the lift vector.  A way of canceling the lift force is to roll the vehicle.

Offline Citabria

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Re: Soviet/Russian space programs Q&A
« Reply #115 on: 10/23/2007 05:11 pm »
Quote
darkenfast - 22/10/2007  11:38 AM

The straps are blown when there is still some residual thrust, and the boosters rotate up and out, causing the ball to come out of the socket.  There is also some venting of residual oxygen to aid in separation.  This discription was from a history that was referring to the original R-7 rocket...


Thank you for replying to my question. I read that same explanation in Asif Siddiqi's history but I don't believe it (his history is not very technically oriented). If they rotate up and out with some residual thrust, the boosters would likely have different levels of thrust and different angles of rotation and the nose of the core would get pushed to one side. That seems like it would interfere too much with stability of the core.

Also, I saw a close-up photo of a booster nose and socket on a museum R-7 and it is definitely not ball-shaped, although there was not enough detail visible to fully explain the mechanism.

It seems more likely that cutting booster thrust and blowing the aft-end straps would cause the nose to depart the socket rearward, but I'm not sure. No one else has replied, so maybe it's still a Soviet secret. Just kidding! Is this kind of info available on L2? Or anywhere in English?

Offline NotGncDude

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Re: Soviet/Russian space programs Q&A
« Reply #116 on: 10/23/2007 06:28 pm »
Also, in ballistic entry you have little control of where you land, and higher G's.

Offline darkenfast

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Re: Soviet/Russian space programs Q&A
« Reply #117 on: 10/24/2007 04:14 am »
Oh, well...I was remembering the same source!  I quite enjoyed Siddiqi's book, but I wouldn't mind a better explanation either.
[/QUOTE]

Thank you for replying to my question. I read that same explanation in Asif Siddiqi's history but I don't believe it (his history is not very technically oriented). If they rotate up and out with some residual thrust, the boosters would likely have different levels of thrust and different angles of rotation and the nose of the core would get pushed to one side. That seems like it would interfere too much with stability of the core.

Also, I saw a close-up photo of a booster nose and socket on a museum R-7 and it is definitely not ball-shaped, although there was not enough detail visible to fully explain the mechanism.

It seems more likely that cutting booster thrust and blowing the aft-end straps would cause the nose to depart the socket rearward, but I'm not sure. No one else has replied, so maybe it's still a Soviet secret. Just kidding! Is this kind of info available on L2? Or anywhere in English?
[/QUOTE]
Writer of Book and Lyrics for musicals "SCAR", "Cinderella!", and "Aladdin!". Retired Naval Security Group. "I think SCAR is a winner. Great score, [and] the writing is up there with the very best!"
-- Phil Henderson, Composer of the West End musical "The Far Pavilions".

Offline DarthVader

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Re: Soviet/Russian space programs Q&A
« Reply #118 on: 11/02/2007 10:17 pm »
AFAIK there's no clear and definitive description of how the strap-ons detach. Personally, I think that your are correct darkenfast since there is some video evidence which show clearly how a strap-on simply fell away during a launch (in the 60s I'll said). So what I think happen is that once the thrust in the booster start to decline and that it's time to let them go, the straps that hold them at the bottom is blown, allowing them to simply fall down from the core, all the while some venting at the top of each strap-on push them gently away of the core .. so they rotate  head first away from the core. The bottom line is that it's not like the SRB on the shuttle that are bolted to the tank. On a Soyuz rocket, the strap-ons are only hold in place because they push the core and that the strap at the bottom avoid them from rotating up-wards while pushing the core .... also I seem to recall that the strap-ons reach full thruste before the core ... If that is correct, that'll could confirm this theory since you will not want the core to start building thrust before the strap-on ... anyhow .. I'm no rocket scientist so I could be (very) wrong ...

I wish we could have some definitive explanation on the subject.

Offline tnphysics

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Re: Soviet/Russian space programs Q&A
« Reply #119 on: 11/05/2007 01:04 am »
Why does the Breeze-M have such a low thrust/weight ratio?

I assume that it is almost in orbit prior to engine start.

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