Discussion
In keeping with the separate threads for different types of spacecraft, I thought that it would be worthwhile starting one purely to cover Soyuz based missions, both manned and unmanned. After all, the Soyuz series and its predecessors have been a very successful series and is currently what keeps the space station project going.
Last night a brand new and upgraded version of thee Soyuz spacecraft made its maiden flight. The new version, known as Soyuz - MS replaces the previous generation Soyuz TMA family.
Video of the launch here -
Last night a brand new and upgraded version of thee Soyuz spacecraft made its maiden flight. The new version, known as Soyuz - MS replaces the previous generation Soyuz TMA family.
Video of the launch here -
Off-topic perhaps but I've always been intrigued that the Soyuz reentry module is such a different shape (bell rather than cone) than the Apollo, I'd have thought the conditions where so harsh as to limit the options for shape/size... (on the other hand the shuttle sort-of worked and was neither small nor shaped suitably for reentry :-)
The important aspect of any re-entry vehicle is the base to which the heat shield is attached. The rest of the body can be any shape as long as the sides are kept away from the high temperature plasma that surrounds the vehicle.
Apollo (and now Orion) have quite steeply sloped sides because they re-enter(ed) the earth's atmosphere at speeds substantially higher than a spacecraft re-entering from earth orbit i.e. 25,000 mph compared to 17,500. That is what dictates their shapes.
Earlier American earth orbiting capsules (Mercury and Gemini) had sides that were not as acutely tapered as Apollo or Orion.
Soyuz is more akin to Gemini in the heat loads it experiences.
Apollo (and now Orion) have quite steeply sloped sides because they re-enter(ed) the earth's atmosphere at speeds substantially higher than a spacecraft re-entering from earth orbit i.e. 25,000 mph compared to 17,500. That is what dictates their shapes.
Earlier American earth orbiting capsules (Mercury and Gemini) had sides that were not as acutely tapered as Apollo or Orion.
Soyuz is more akin to Gemini in the heat loads it experiences.
Not really now. They definitely re-invented the wheel with the Space Shuttle. However, nearly all the current launchers in use are evolutions of pre-existing technology. Don't forget the Americans also use Atlas and Delta, which have a pedigree as old are the R-7 Semyorka rocket.
The exception is of course, the Falcon family - but even their rocket motor technology is not particularly ground breaking.
The exception is of course, the Falcon family - but even their rocket motor technology is not particularly ground breaking.
[quote=Eric McApollo (and now Orion) have quite steeply sloped sides because they re-enter(ed) the earth's atmosphere at speeds substantially higher than a spacecraft re-entering from earth orbit i.e. 25,000 mph compared to 17,500. That is what dictates their shapes.
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I assumed the Soyoz was intended to be Russia's Moon shot command and re-entry module, in which case it would have had to make a full speed re-entry from Lunar transit trajectory? (To be honest I've not looked for the planned Russian lunar mission profile, maybe they intended a different schedule than NASA used?)
I notice that most other things designed for re-entry follow the cone shape format, whether its probes entering other solar system body atmosphere's or our own.
Would we need to move to a more extreme shape for a Mars-Earth return re-entry? (Assuming that would be coming back hotter than a Moon-Earth return?)
FWIW- I had assumed the shape was just to minimise the diameter so it could ride atop a narrow rocket aerodynamically.
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I assumed the Soyoz was intended to be Russia's Moon shot command and re-entry module, in which case it would have had to make a full speed re-entry from Lunar transit trajectory? (To be honest I've not looked for the planned Russian lunar mission profile, maybe they intended a different schedule than NASA used?)
I notice that most other things designed for re-entry follow the cone shape format, whether its probes entering other solar system body atmosphere's or our own.
Would we need to move to a more extreme shape for a Mars-Earth return re-entry? (Assuming that would be coming back hotter than a Moon-Earth return?)
FWIW- I had assumed the shape was just to minimise the diameter so it could ride atop a narrow rocket aerodynamically.
scubadude said:
FWIW- I had assumed the shape was just to minimise the diameter so it could ride atop a narrow rocket aerodynamically.
It needs to be both stable in re-entry, and shielded from heat, which effects the shape a fair bit, the centre of mass needs to be below the aerodynamic centre. That is a very good point. The Soyuz was indeed designed to withstand lunar mission re-entry speeds. In fact, a number of Zond flights which looped around the moon in 1968 (unmanned) were in fact, tests of the Soyuz lunar mission profile.
So the Soyuz re-entry module COULD survive a 25,000 mph re-entry.
Like Apollo, Zond/Soyuz was also ballasted offset so that its angle during re-entry could be altered to achieve a skip glide technique, which reduced aerodynamic loads, heat loads and g-loads on the craft during re-entry.
Some of the Zonds actually splashed down American style rather than landed on land.
As you can see from the picture, Soviet recovery forces were rather less ambitious than those employed by the US.
So the Soyuz re-entry module COULD survive a 25,000 mph re-entry.
Like Apollo, Zond/Soyuz was also ballasted offset so that its angle during re-entry could be altered to achieve a skip glide technique, which reduced aerodynamic loads, heat loads and g-loads on the craft during re-entry.
Some of the Zonds actually splashed down American style rather than landed on land.
As you can see from the picture, Soviet recovery forces were rather less ambitious than those employed by the US.
Some of the best and clearest TV images I've seen on a Soyuz docking.
https://www.youtube.com/watch?v=SXmiMPmkjX4
The MS-01 craft docked with the ISS on 8 July after two days chasing.
In the past few years, the time for a Soyuz to catch up with the ISS was reduced from a few days to a few hours.
However, because this is the first flight of a new variant of Soyuz, they reverted to the slower catch up routine - presumably to give the Soyuz commander time to wring out any bugs on what was, in effect, a test flight.
https://www.youtube.com/watch?v=SXmiMPmkjX4
The MS-01 craft docked with the ISS on 8 July after two days chasing.
In the past few years, the time for a Soyuz to catch up with the ISS was reduced from a few days to a few hours.
However, because this is the first flight of a new variant of Soyuz, they reverted to the slower catch up routine - presumably to give the Soyuz commander time to wring out any bugs on what was, in effect, a test flight.
patmahe said:
Obviously they need to be as minimal as possible with wasted space, but that cabin/pod or whatever looks seriously cosy. We seem to be entering a new age for space exploration these days, some seriously interesting stuff happening.
Soyuz is positively palatial compared to its predecessors. The Russians crammed three people into Voskhod 1, basically a glorified Vostok (one-man) capsule, to achieve the first multi-manned spaceflight. It was so cramped the crew couldn't wear spacesuits, and even had to go on a diet beforehand.The crew capsule for Voshkod 1 was on display at the Science Museum earlier in the year.
It was seriously cramped. Not only were three men squeezed in to what was effectively a one man Vostok, in order to get three in, they had to rotate the crew sideways on. This meant that the main instruments were to one side of the crew - rather than directly in front of them. It was a real lash-up job and only proceeded with so the Soviets could get three men into space before the Americans launched their first two man Gemini spacecraft.
Soyuz also has a spherical "Orbital Module" attached to the front of the craft which contains storage space and, most importantly, a small loo.
It was seriously cramped. Not only were three men squeezed in to what was effectively a one man Vostok, in order to get three in, they had to rotate the crew sideways on. This meant that the main instruments were to one side of the crew - rather than directly in front of them. It was a real lash-up job and only proceeded with so the Soviets could get three men into space before the Americans launched their first two man Gemini spacecraft.
Soyuz also has a spherical "Orbital Module" attached to the front of the craft which contains storage space and, most importantly, a small loo.
Seems they are blaming a possible engine fire for the recent launch failure
http://spaceflightnow.com/2017/01/17/launch-failur...
http://spaceflightnow.com/2017/01/17/launch-failur...
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