Mars solar conjunction downtime

: bob haller
: think of the mars probes lost when out of contract with earth, they
: just go silent forever...

OK, I'm thinking of them. Probably about one in twelve, right?
Most of them go dead and are never heard from again when still
in contact. Or so I expect. Did you even check before recommending
an expensive solution to a non-problem?

On Mar 22, 5:27*am, Fred J. McCall wrote:
bob haller wrote:
On Mar 22, 12:08*am, (Wayne Throop) wrote:
:: What's a "heliospheric orbit"?
:: You just made that up, didn't you?
:: And have no idea what you really mean by it, right?

I googled it also, fwiw. *It's used in a few places, but incoherently.
Possibly Bob picked it up from some other orbital-mechanics-challenged
individual.

: Jochem Huhmann
: I think it's pretty clear that he means a relay in an orbit around the
: sun that would allow continious communications between Earth and Mars.

In which case, I conclude you need an orbit in either an earth-sun L[45]
point, or an earth-mars L[45] point. *Otherwise, it's difficult to ensure
that you can always send a message without expensive fuel use. *Or, naict.

: Which probably isn't worth the money, especially for aging flaky
: rovers. *If something's suspect of not surviving a month of not being
: closely monitored it's probably hardly worth saving anymore.

Yes, if that's the only application.

think of the mars probes lost when out of contract with earth, they
just go silent forever...

Well, that is the expected end for the things.



a couple robust comm sats in order could at minimum supply info when
such losses occur, hopefuly prerventing *a reoccurence at a later
date, while being useful other *activities

It would be cheaper to just keep sending new rovers to replace the old
ones.

Bobbert, you have no concept at all of costs or difficulties, do you?

--
"Some people get lost in thought because it's such unfamiliar
*territory."
* * * * * * * * * * * * * * * * * * * --G. Behn

There were a bunch of mars probes that on the way to the planet were
never heard from again thanks to poor communication a lot of guessing
had to be done in a attempt to know what went wrong, so mistakes could
be prevented in the future.....

the sats could be designed for ultra long life, do some science while
in orbit too.

it should be possible to build them for a 20 year operational life,
awhile hoping they last longer

"bob haller" wrote in message
...


There were a bunch of mars probes that on the way to the planet were
never heard from again thanks to poor communication a lot of guessing
had to be done in a attempt to know what went wrong, so mistakes could
be prevented in the future.....

There were a bunch? And we don't know what happened due to poor
communication?

Good, start naming them.

I'll wait.

Now, of that list, please explain how having your special satellite would
have helped at all.

Again, I'll wait.



the sats could be designed for ultra long life, do some science while
in orbit too.

it should be possible to build them for a 20 year operational life,
awhile hoping they last longer



--
Greg D. Moore http://greenmountainsoftware.wordpress.com/
CEO QuiCR: Quick, Crowdsourced Responses. http://www.quicr.net

: bob haller
: There were a bunch of mars probes that on the way to the planet were
: never heard from again thanks to poor communication

said poor communication, of course, having nothing to do with
being obscured by the sun, or anyhthing the satellite you propose
would help with.

: the sats could be designed for ultra long life, do some science while
: in orbit too.

True, as you say just above, they could be made vastly more expensive.
To you, this is a good thing?

: it should be possible to build them for a 20 year operational life,
: awhile hoping they last longer

You know this because of your extensive engineering expertise.

On 21/03/2013 1:35 AM, bob haller wrote:
A month long solar conjunction downtime is about to effect
Curosity......

It will be out of communication for about a month, given its flakey
computer we will be lucky if communications are restored after the
conjunction.

It has two computers, one of which has a memory problem. That computer
is now functioning as a backup, with the other computer being the primary.

There was an unrelated software problem the other day.

that brings about the question....

how about a relay sat in heliospheric orbit so at least engineering
communications can continue?

other than cost are there any other issues preventing this?


Any reason to think that maintaining communication would help?

Sylvia.

On Mar 22, 9:52*pm, Sylvia Else wrote:
On 21/03/2013 1:35 AM, bob haller wrote:

A month long solar conjunction downtime is about to effect
Curosity......

It will be out of communication for about a month, given its flakey
computer we will be lucky if communications are restored after the
conjunction.

It has two computers, one of which has a memory problem. That computer
is now functioning as a backup, with the other computer being the primary..

There was an unrelated software problem the other day.



that brings about the question....

how about a relay sat in heliospheric orbit so at least engineering
communications can continue?

other than cost are there any other issues preventing this?

Any reason to think that maintaining communication would help?

Sylvia.

Well if a vehicle goes silent at mars or any other place, real time
engineering data up till the point of lost contact might help
regaining contact or help diagnose what went wrong, so it can be
prevented in the future.......

Mars lander 6 fire engines for orbital insertion, then immediately
goes silent......

Without a communication link it went dead over a 3 day period

With comm link it went dead right after this engine system showed a
big spike on chamber pressures.

Such data can be very helpful...

Curositys landing time was coordinated with satellite in orbit to get
a real time link back to earth of its engineering systems......

On Wed, 20 Mar 2013 07:35:02 -0700 (PDT), bob haller
wrote:

A month long solar conjunction downtime is about to effect
Curosity......

It will be out of communication for about a month, given its flakey
computer we will be lucky if communications are restored after the
conjunction.

that brings about the question....

how about a relay sat in heliospheric orbit so at least engineering
communications can continue?

other than cost are there any other issues preventing this?

Need.

Fortunately, orbital dynamics being what they are, we always launch
from Earth to Mars when Earth and Mars are closest together (on the
same side of the Sun.) So unless we're taking the scenic route, it is
almost impossible to go from Earth to Mars and have a landing at a
time when Mars is passing behind the Sun as seen from Earth. For
example, Mars passing "behind" the Sun is eight months after
Curiosity's landing. ) So communication during critical moments of
landing is not and never will be a solar conjunction issue.

For other times of the mission, simply having the probe go into
standby works well. All of our Mars orbiters and landers have safely
survived many solar conjunction communications blackouts, which happen
at about the same period as Earth-Mars launch opprtunities... every 26
months, at about the half-way point between Earth-Mars launch
opportunities.

Really, your idea of a relay satellite, say 90 degrees ahead or behind
the Earth in its orbit, is interesting. But it is premature. We
probably won't want/need/be able to justify it until we have human
exploration of Mars. And that will be for routine communications, not
for coverage during landing or return-trip launch.

Brian

On 23/03/2013 1:07 PM, bob haller wrote:
On Mar 22, 9:52 pm, Sylvia Else wrote:
On 21/03/2013 1:35 AM, bob haller wrote:

A month long solar conjunction downtime is about to effect
Curosity......

It will be out of communication for about a month, given its flakey
computer we will be lucky if communications are restored after the
conjunction.

It has two computers, one of which has a memory problem. That computer
is now functioning as a backup, with the other computer being the primary.

There was an unrelated software problem the other day.



that brings about the question....

how about a relay sat in heliospheric orbit so at least engineering
communications can continue?

other than cost are there any other issues preventing this?

Any reason to think that maintaining communication would help?

Sylvia.

Well if a vehicle goes silent at mars or any other place, real time
engineering data up till the point of lost contact might help
regaining contact or help diagnose what went wrong, so it can be
prevented in the future.......

Mars lander 6 fire engines for orbital insertion, then immediately
goes silent......

Without a communication link it went dead over a 3 day period

With comm link it went dead right after this engine system showed a
big spike on chamber pressures.

Such data can be very helpful...

Curositys landing time was coordinated with satellite in orbit to get
a real time link back to earth of its engineering systems......


Spacecraft are somewhat prone to sudden catastrophic failures that occur
during high energy operations. With Curiosity sitting on the ground,
such an event is much less likely. While one obviously not rule out a
failure that kills Curiosity during the month, the much more likely
scenario is that it will put itself into safe mode while trying to
perform its planned science program, and will stay in that mode until
the moratorium on sending commands to it ends.

Curiosity will continue to send status reports, and Mars will never be
eclipsed by the sun. Curiosity will also continue to send data to the
MRO which will be recorded for sending later.

Sylvia.

"Brian Thorn" wrote in message
...

On Wed, 20 Mar 2013 07:35:02 -0700 (PDT), bob haller
wrote:

A month long solar conjunction downtime is about to effect
Curosity......

It will be out of communication for about a month, given its flakey
computer we will be lucky if communications are restored after the
conjunction.

that brings about the question....

how about a relay sat in heliospheric orbit so at least engineering
communications can continue?

other than cost are there any other issues preventing this?

Need.

Fortunately, orbital dynamics being what they are, we always launch
from Earth to Mars when Earth and Mars are closest together (on the
same side of the Sun.) So unless we're taking the scenic route, it is
almost impossible to go from Earth to Mars and have a landing at a
time when Mars is passing behind the Sun as seen from Earth. For
example, Mars passing "behind" the Sun is eight months after
Curiosity's landing. ) So communication during critical moments of
landing is not and never will be a solar conjunction issue.

And this continues to show Bob's continued lack of understanding of orbital
mechanics.


Brian



--
Greg D. Moore http://greenmountainsoftware.wordpress.com/
CEO QuiCR: Quick, Crowdsourced Responses. http://www.quicr.net