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  Spacecraft positioned behind the Sun

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Author Topic:   Spacecraft positioned behind the Sun
cosmos-walter
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Posts: 406
From: Salzburg, Austria
Registered: Jun 2003

posted 04-19-2012 03:57 AM     Click Here to See the Profile for cosmos-walter   Click Here to Email cosmos-walter     Edit/Delete Message   Reply w/Quote
I wonder: Was there ever a space probe behind the Sun? This means, the Sun hid this spacecraft completely during a short period observed from Earth. Is such a constellation expected for the close future?

garymilgrom
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From: Atlanta, GA, USA
Registered: Feb 2007

posted 04-19-2012 06:25 AM     Click Here to See the Profile for garymilgrom   Click Here to Email garymilgrom     Edit/Delete Message   Reply w/Quote
Many planetary spacecraft go behind the sun as they travel to their final destinations. The Ulysses spacecraft orbited the sun some time ago.

Currently NASA’s STEREO spacecraft are in solar orbit.

cosmos-walter
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From: Salzburg, Austria
Registered: Jun 2003

posted 04-19-2012 07:44 AM     Click Here to See the Profile for cosmos-walter   Click Here to Email cosmos-walter     Edit/Delete Message   Reply w/Quote
Gary, Thank you very much for your comment. I am aware, many spacecraft orbited the Sun like a planet. However, I wondered, whether ever Earth - Sun - spacecraft were in a straight line causing that the sun hid the spacecraft completely (viewed from Earth).

Jim Behling
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From: Cape Canaveral, FL
Registered: Mar 2010

posted 04-19-2012 08:42 AM     Click Here to See the Profile for Jim Behling   Click Here to Email Jim Behling     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by cosmos-walter:
However, I wondered, whether ever Earth - Sun - spacecraft were in a straight line causing that the sun hid the spacecraft completely (viewed from Earth).
In the course of orbiting the sun, it happens many times to all these spacecraft.

Saturn V
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Posts: 170
From: Golden, Colorado, USA
Registered: Nov 2006

posted 04-19-2012 12:14 PM     Click Here to See the Profile for Saturn V     Edit/Delete Message   Reply w/Quote
And I assume none of them ever ran into "Planet X"?

Blackarrow
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Posts: 2024
From: Belfast, United Kingdom
Registered: Feb 2002

posted 04-19-2012 03:41 PM     Click Here to See the Profile for Blackarrow     Edit/Delete Message   Reply w/Quote
Forty-two years ago, Mariners 6 and 7 (having made close encounters with Mars shortly after the "giant leap for mankind") passed very close to the Sun as seen from Earth. The spacecraft were on the opposite side of the sun and were used to test Einstein's Theory of Relativity.

The radio signals passed so close to the Sun that the Sun's gravity bent the path of the radio signals and slowed them down by a fraction of a second. I believe the results were exactly in accordance with predictions, thus providing the first proof of relativity by a NASA spacecraft.

cosmos-walter
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Posts: 406
From: Salzburg, Austria
Registered: Jun 2003

posted 04-28-2012 07:10 AM     Click Here to See the Profile for cosmos-walter   Click Here to Email cosmos-walter     Edit/Delete Message   Reply w/Quote
Thank you very much for the interesting comment, that Mariners 6 and 7 passed very close to the Sun as seen from Earth. I am looking for a spacecraft which passed right behind the sun as seen from Earth.

Jim Behling
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Posts: 537
From: Cape Canaveral, FL
Registered: Mar 2010

posted 04-28-2012 08:29 AM     Click Here to See the Profile for Jim Behling   Click Here to Email Jim Behling     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by cosmos-walter:
I am looking for a spacecraft which passed right behind the sun as seen from Earth.
MER, MRO, Galileo, Cassini, Pioneer, Mariners, Stardust, Deep Impact, Messenger, PNH, etc.

They all have and many more have been on the opposite side of the sun. It is called solar conjunction and it happens a lot.

Anytime a spacecraft leaves earth orbit, it is going to have different period orbiting the sun than Earth's. Eventually, they will be on opposite sides of the sun.

Messenger has gone "behind the" sun many times as Mercury laps Earth. Same goes for any spacecraft in orbit around Venus.

You need to define "right behind."

Jim Behling
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Posts: 537
From: Cape Canaveral, FL
Registered: Mar 2010

posted 04-28-2012 09:55 AM     Click Here to See the Profile for Jim Behling   Click Here to Email Jim Behling     Edit/Delete Message   Reply w/Quote
Here is a perfect demonstration of being "behind" the sun:

This too: Helios - Trajectory. It shows trajectory of Helios 2 and its position relative to earth and Helios 1 in days of launch.

You see that the spacecraft will be "right behind" the sun at many times.

cosmos-walter
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Posts: 406
From: Salzburg, Austria
Registered: Jun 2003

posted 04-29-2012 12:20 PM     Click Here to See the Profile for cosmos-walter   Click Here to Email cosmos-walter     Edit/Delete Message   Reply w/Quote
Thank you, Jim.

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