Posts: 691 From: Salzburg, Austria Registered: Jun 2003
posted 04-19-2012 03:57 AM
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 Member
Posts: 1966 From: Atlanta, GA Registered: Feb 2007
posted 04-19-2012 06:25 AM
Many planetary spacecraft go behind the sun as they travel to their final destinations. The Ulysses spacecraft orbited the sun some time ago.
Posts: 691 From: Salzburg, Austria Registered: Jun 2003
posted 04-19-2012 07:44 AM
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 Member
Posts: 1463 From: Cape Canaveral, FL Registered: Mar 2010
posted 04-19-2012 08:42 AM
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 Member
Posts: 176 From: Golden, Colorado, USA Registered: Nov 2006
posted 04-19-2012 12:14 PM
And I assume none of them ever ran into "Planet X"?
Blackarrow Member
Posts: 3120 From: Belfast, United Kingdom Registered: Feb 2002
posted 04-19-2012 03:41 PM
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 Member
Posts: 691 From: Salzburg, Austria Registered: Jun 2003
posted 04-28-2012 07:10 AM
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 Member
Posts: 1463 From: Cape Canaveral, FL Registered: Mar 2010
posted 04-28-2012 08:29 AM
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 Member
Posts: 1463 From: Cape Canaveral, FL Registered: Mar 2010
posted 04-28-2012 09:55 AM
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 Member
Posts: 691 From: Salzburg, Austria Registered: Jun 2003
posted 04-19-2012 03:57 AM
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