Author Topic: Atmospheric re-entry  (Read 1470 times)

Offline TalentedTwin

Atmospheric re-entry
« on: 08/03/2018 04:42 PM »
Which spacecraft had more cross range while re-entering the atmosphere back in the 1960s? Was it Soyuz or Gemini?

Offline Archibald

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Re: Atmospheric re-entry
« Reply #1 on: 08/05/2018 01:00 PM »
Both are capsules, so cross range is rather marginal...
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Offline Michel Van

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Re: Atmospheric re-entry
« Reply #2 on: 08/08/2018 06:19 PM »
Gemini had cross range of 52,4 km 
Modern Soyuz have cross range of 150 km

source
https://books.google.be/books?id=31GqndM3fk8C&pg=PA294&lpg=PA294&dq=crossrange+Gemini+
capsule&source=bl&ots=9T7EleMs8Y&sig=dEQ7g6EzWSKDTe07Sdw4NShbHV0&hl=en&sa=X&ved=
2ahUKEwidgpP2ht7cAhVOZVAKHSfMAZ84ChDoATACegQICBAB

and
https://web.b.ebscohost.com/abstract?direct=true&profile=ehost&scope=site&authtype=crawler&jrnl=19940408&AN=113412299&
h=pNegojiTqGZCJDhX86HfYCi3I8KivWFr9F892tAlCqB16OkAlFD8ZCw43ERJ4IvFqJuhyo13MMEO
QrWjsvI5NA%3d%3d&crl=c&resultNs=AdminWebAuth&resultLocal=ErrCrlNotAuth&crlhashurl=login.
aspx%3fdirect%3dtrue%26profile%3dehost%26scope%3dsite%26authtype%3dcrawler%26jrnl%
3d19940408%26AN%3d113412299

(Need to tiny URL those - Mod)
« Last Edit: 08/10/2018 11:01 PM by Chris Bergin »

Offline thammond

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Re: Atmospheric re-entry
« Reply #3 on: 08/10/2018 03:16 PM »
I'm not an expert in this by any means, but this is my understanding:

To get some cross range capability as opposed to a pure ballistic reentry, some lift is required.  By manipulating that lift your can create cross range.  The L/D (Lift to Drag ratio) of a reentry vehicle is mainly dictated by it shape.  The higher the L/D the higher the reentry vehicles cross range capability.

Gemini had a L/D of about .2 while the Soyuz is about .3, which would mean the Soyuz should have a greater cross range capability.

That would make sense as the overall shape of Gemini was developed as a earth orbital spacecraft as opposed to the overall shape of the Soyuz was designed to include intended lunar missions.  A higher L/D would be desirable for a lunar mission due to higher reentry speeds, thus the higher L/D of Soyuz compared to Gemini.

Offline Dmitry_V_home

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Re: Atmospheric re-entry
« Reply #4 on: 08/16/2018 02:04 PM »
empirical formula: Lcross = 1400*(L/D)^1.5

Offline Archibald

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Re: Atmospheric re-entry
« Reply #5 on: 08/16/2018 03:47 PM »
150 km, not so marginal after all ! Soyuz is such a clever design.
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