[FPSPACE] Kourou Soyuz to ISS?

Sun, 25 Jan 2004 18:48:49 +0100

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The effect of launch site latitude on the required delta-v for a
constant orbit is not that straightforward.

For two launch sites of different latitude there is a certain target
orbit inclination with identical delta-v requirements. This breakeven
inclination is always close to polar. For Baikonur and Kourou the
breakeven inclination is 87.3 degree.

For all higher inclination orbits launching from Baikonur is easier, for
all lower inclination orbits launching form Kourou is easier. For
example a launch to a 98.4 degree sun-synchronous orbit is 30 m/s easier
from Baikonur than from Kourou, while for ISS orbit Kourou has an
advantage of 93 m/s.

Regards,

Jens

----- Original Message ----- 

From: "Bob Christy" <bob@zarya.info>

To: <fpspace@friends-partners.org>

Subject: Re: [FPSPACE] Kourou Soyuz to ISS?

Date: Sun, 25 Jan 2004 16:55:37 -0000

>You are way off-beam Hugh.. Moving launches to Kourou has no
significant effect.

>

>For a given orbital inclination, the speed assistance available from
the Earth's rotation is independent of launch site >latitude - the
nearer to the equator the launch site, then the greater the northerly
(or southerly) component of the launch >azimuth. This directly offsets
the speed advantage due to lower latitude.

>

>The maximum advantage of moving nearer to the equator comes from always
launching due east. This maximises the assistance >from the Earth's
rotation but results in an orbital inclination equal to the latitude of
the launch site.

>

>A rocket launched from CSG (Kourou) to a 7 degree inclination orbit
will have a greater payload capacity than a similar one >launched from
Baikonur into an orbit at 51.6 degrees inclination.

>

>A launch from Kourou to 51.6 degrees inclination will have the same
capacity as one from Baikonur.

>

>Regards

>Bob Christy

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<div class=3DSection1>

<p class=3DMsoNormal style=3D'text-autospace:none'><font size=3D2 =
face=3D"Courier New"><span
lang=3DEN-GB style=3D'font-size:10.0pt;font-family:"Courier New"'>The =
effect of
launch site latitude on the required delta-v for a constant orbit is not =
that
straightforward.</span></font></p>

<p class=3DMsoNormal style=3D'text-autospace:none'><font size=3D2 =
face=3D"Courier New"><span
lang=3DEN-GB style=3D'font-size:10.0pt;font-family:"Courier =
New"'>&nbsp;</span></font></p>

For =
two launch sites
of different latitude there is a certain target orbit inclination with =
identical
delta-v requirements. This breakeven inclination is always close to =
polar. For Baikonur
and Kourou the breakeven inclination is 87.3 degree.

For =
all higher inclination
orbits launching from Baikonur is easier, for all lower inclination =
orbits launching
form Kourou is easier. For example a launch to a 98.4 degree =
sun-synchronous
orbit is 30 m/s easier from Baikonur than from Kourou, while for ISS =
orbit Kourou
has an advantage of 93 m/s.

<p class=3DMsoNormal style=3D'text-autospace:none'><font size=3D2 =
face=3D"Courier New"><span
lang=3DEN-GB style=3D'font-size:10.0pt;font-family:"Courier =
New"'>&nbsp;</span></font></p>

<p class=3DMsoNormal style=3D'text-autospace:none'><font size=3D2 =
face=3D"Courier New"><span
lang=3DEN-GB style=3D'font-size:10.0pt;font-family:"Courier =
New"'>Regards,</span></font></p>

<p class=3DMsoNormal style=3D'text-autospace:none'><font size=3D2 =
face=3D"Courier New"><span
lang=3DEN-GB style=3D'font-size:10.0pt;font-family:"Courier =
New"'>Jens</span></font></p>

<p class=3DMsoNormal style=3D'text-autospace:none'><font size=3D2 =
face=3D"Courier New"><span
lang=3DEN-GB style=3D'font-size:10.0pt;font-family:"Courier =
New"'>&nbsp;</span></font></p>

<p class=3DMsoNormal style=3D'text-autospace:none'><font size=3D2 =
face=3D"Courier New"><span
lang=3DEN-GB style=3D'font-size:10.0pt;font-family:"Courier =
New"'>&nbsp;</span></font></p>

<p class=3DMsoNormal style=3D'text-autospace:none'><font size=3D2 =
face=3D"Courier New"><span
lang=3DEN-GB style=3D'font-size:10.0pt;font-family:"Courier New"'>----- =
Original
Message ----- </span></font></p>

<p class=3DMsoNormal style=3D'text-autospace:none'><font size=3D2 =
face=3D"Courier New"><span
lang=3DEN-GB style=3D'font-size:10.0pt;font-family:"Courier New"'>From: =
&quot;Bob
Christy&quot; &lt;bob@zarya.info&gt;</span></font></p>

<p class=3DMsoNormal style=3D'text-autospace:none'><font size=3D2 =
face=3D"Courier New"><span
lang=3DEN-GB style=3D'font-size:10.0pt;font-family:"Courier New"'>To:
&lt;fpspace@friends-partners.org&gt;</span></font></p>

<p class=3DMsoNormal style=3D'text-autospace:none'><font size=3D2 =
face=3D"Courier New"><span
lang=3DEN-GB style=3D'font-size:10.0pt;font-family:"Courier =
New"'>Subject: Re:
[FPSPACE] Kourou Soyuz to ISS?</span></font></p>

<p class=3DMsoNormal style=3D'text-autospace:none'><font size=3D2 =
face=3D"Courier New"><span
style=3D'font-size:10.0pt;font-family:"Courier New"'>Date: Sun, 25 Jan =
2004
16:55:37 -0000</span></font></p>

<p class=3DMsoNormal style=3D'text-autospace:none'><font size=3D2 =
face=3D"Courier New"><span
lang=3DEN-GB style=3D'font-size:10.0pt;font-family:"Courier =
New"'>&nbsp;</span></font></p>

&gt;You are way
off-beam Hugh.. Moving launches to Kourou has no significant =
effect.

<p class=3DMsoNormal style=3D'text-autospace:none'><font size=3D2 =
face=3D"Courier New"><span
lang=3DEN-GB style=3D'font-size:10.0pt;font-family:"Courier =
New"'>&gt;</span></font></p>

&gt;For a given
orbital inclination, the speed assistance available from the Earth's =
rotation
is independent of launch site &gt;latitude - the nearer to the equator =
the
launch site, then the greater the northerly (or southerly) component of =
the
launch &gt;azimuth. This directly offsets the speed advantage due to =
lower
latitude.

<p class=3DMsoNormal style=3D'text-autospace:none'><font size=3D2 =
face=3D"Courier New"><span
lang=3DEN-GB style=3D'font-size:10.0pt;font-family:"Courier =
New"'>&gt;</span></font></p>

&gt;The maximum
advantage of moving nearer to the equator comes from always launching =
due east.
This maximises the assistance &gt;from the Earth's rotation but results =
in an
orbital inclination equal to the latitude of the launch =
site.

<p class=3DMsoNormal style=3D'text-autospace:none'><font size=3D2 =
face=3D"Courier New"><span
lang=3DEN-GB style=3D'font-size:10.0pt;font-family:"Courier =
New"'>&gt;</span></font></p>

<p class=3DMsoNormal style=3D'text-autospace:none'><font size=3D2 =
face=3D"Courier New"><span
lang=3DEN-GB style=3D'font-size:10.0pt;font-family:"Courier New"'>&gt;A =
rocket
launched from CSG (Kourou) to a 7 degree inclination orbit will have a =
greater
payload capacity than a similar one &gt;launched from Baikonur into an =
orbit at
51.6 degrees inclination.</span></font></p>

<p class=3DMsoNormal style=3D'text-autospace:none'><font size=3D2 =
face=3D"Courier New"><span
lang=3DEN-GB style=3D'font-size:10.0pt;font-family:"Courier =
New"'>&gt;</span></font></p>

<p class=3DMsoNormal style=3D'text-autospace:none'><font size=3D2 =
face=3D"Courier New"><span
lang=3DEN-GB style=3D'font-size:10.0pt;font-family:"Courier New"'>&gt;A =
launch from
Kourou to 51.6 degrees inclination will have the same capacity as one =
from Baikonur.</span></font></p>

<p class=3DMsoNormal style=3D'text-autospace:none'><font size=3D2 =
face=3D"Courier New"><span
lang=3DEN-GB style=3D'font-size:10.0pt;font-family:"Courier =
New"'>&gt;</span></font></p>

<p class=3DMsoNormal style=3D'text-autospace:none'><font size=3D2 =
face=3D"Courier New"><span
style=3D'font-size:10.0pt;font-family:"Courier =
New"'>&gt;Regards</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:10.0pt;
font-family:"Courier New"'>&gt;Bob Christy</span></font></p>

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