[X] My Assistant

[Guest_Analyst_*]

Did nobody notice this:

Ground Team Stays Busy on 10th Anniversary of NASA Mars Launch

Ten year after launch, there is some trouble with a solar array motor and a comm problem probably resulting from this and entering safe mode. Nothing dramatic yet, but something to follow closely.

There are other things than MRO and MER

Analyst

[djellison]

The thinking behind it is probably like this :

We are sending X-Band signals, but we do not know if it is getting them as we see no evidence in return

Most likely option - the vehicle is incapacitated and/or not recieving the signals.
Less likely - the vehicle is recieving them but for some reason can not transmit on X-Band

In the second case - if we uplink a command to transmit on UHF which Spirit/Opportunity might hear, then we will have evidence of life onboard MGS.

Basically, you start at the top of the fault tree and cross out all the different failure options until you've crossed them all out....at which point you go out, have a drink, toast MGS, and then move on.

Anyone who followed the MPL post-landing story will have been through this...it's painful, as you get to the increasingly unlikely failure modes, but on which you end up pinning more and more of your hopes.

Doug

[ElkGroveDan]

Anyone who followed the MPL post-landing story will have been through this...

....that was excruciating. I never want to go through that again.

[Marz]

....that was excruciating. I never want to go through that again.

Yeah, like with Beagle...

It's so easy to take orbiters for granted, but it really shows what a knife edge dance it is to keep power and communications and camera orientation all working without a hitch.

On an quasi-unrelated note, I wonder how much it would cost to build some redundancy into the DSN. Every blue moon, there seems to be some mission-impacting loss of communication - either a mouse has chewed through a cable, or a space probe goes on the fritz during the comm window for another mission, etc... it almost seems like an achillies heel that one day could really cause a major loss of data. Maybe it's time to build some extra nodes, like in Iceland and/or south Argentina or something?

[djellison]

Maybe it's time to build some extra nodes, like in Iceland and/or south Argentina or something?

Or maybe it's just time the DSN got the investment it deserves to install multiple 70m assets at each station, or the arrays of mass produced 12m dishes suggested at IAC.
http://www.iac-paper.org/abstractcd/2006/a...-06-B3.1.03.pdf



Doug

[nprev]

Or maybe it's just time the DSN got the investment it deserves to install multiple 70m assets at each station, or the arrays of mass produced 12m dishes suggested at IAC.
http://www.iac-paper.org/abstractcd/2006/a...-06-B3.1.03.pdf
Doug

Not to beat a deceased equine excessively, but maybe this is a partial answer:

http://www.unmannedspaceflight.com/index.php?showtopic=3227

[mcaplinger]

Not to beat a deceased equine excessively, but maybe this is a partial answer...

How would you propose to fly antennas many tens of meters in diameter, much less duplicate, in flight-qualified form, the sensitive receivers and megawatt transmitters used by DSN stations? After all, these orbital comm relays would in general be little closer to Mars than Earth, and would then have to send the data to Earth.