Did a US Spaceflight ever Launch Retrograde?

Spike Spiegel

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I know that normally we launch things prograde for several reasons, but I'm wondering if any US mission ever launched retrograde. Does anybody know?
 

Urwumpe

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I know that normally we launch things prograde for several reasons, but I'm wondering if any US mission ever launched retrograde. Does anybody know?

Vandenberg launches are always retrograde.
 

kwan3217

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Vandenberg launches are typically into high-inclination (near-polar) orbits. A 98deg sun-sync orbit is technically retrograde.

Missile tests from Vandenberg are definitely retrograde, but suborbital.

Explorer 38 RAE-A was launched into a 120deg orbit, but no obvious sign why. It was pretty high, too, ~5200km alt, so maybe it is still sun-sync.

The first few in the OV-1 series were piggybacked on ICBM tests, apparently mounted in a side-mount pod with an apogee kick motor on an otherwise suborbital flight. They went retrograde because that's where their ride was going. OV1-4 and OV1-5 are still up.

This OV1 thing might even make an interesting addon...
 
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Fabri91

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[ame="http://en.wikipedia.org/wiki/Artificial_satellites_in_retrograde_orbit"]http://en.wikipedia.org/wiki/Artificial_satellites_in_retrograde_orbit[/ame] This might be the answer you were looking for!
 

N_Molson

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Yep. For exemple Israël has no choice : any launch towards east could trigger a nuclear war.

We were talking about orbital debris some time ago, just imagine what could give a collision between a prograde & a retrograde satellite. That would make something like 13.000 m/s !!! Ouch !! :p

Here's an all-new one :

http://www.spaceflightnow.com/news/n1006/22ofeq9/

But yeah, of course, if you can choose and have a very interesting launch site like Cape Canaveral, there's no real reason to send satellites in retrograde orbit, so it seems logical that Vandenberg mostly launch suborbital tests.
 
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tori

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In LEO you can get close to 22 km/s if your luck is bad enough - that's when two spacecraft in highly elliptical orbits with 180° RInc meet at their common perigee at around 300 km ASL. At that speed an 80 kg dude would be worth about 1100 kg TNT :hmm:

---------- Post added at 08:33 PM ---------- Previous post was at 08:28 PM ----------

One more reason why retrograde is not done that often is increased friction - even the upper atmosphere is rotating, so the 'airspeed' of a LEO satellite is much higher (around +1 km/s), and so is its friction. Reentering into a retrograde-spinning atmosphere is also unnecessarily riskier than entering prograde.
 
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Fabri91

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Which brings me to the question: which has been the manned mission with highest inclination? SRTM at 57°?
 

tori

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Even the first one ever went higher than that (Vostok 1, 64.95°).
 

Kyle

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Vostok 3-5 featured 65 degree inclination orbits.
STS-36 with Atlantis featured a 62 degree inclination orbit. (highest achieved by America)
Highest inclination space station was Skylab too.
 
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tblaxland

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Urwumpe

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Sources I can find list Vandenberg's available launch azimuths from 147° to 201° (281° for suborbital). The range varies by a few degrees depending on the source (one lists as much as 140° to 315°).

I have 150° to 200° in a source. I think 160° or so is already the launch azimuth for 90° inclination.
 
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