Chill.

Diagnostics take time. This isnt a destruction derby.

Doug

Quite a few - I'm a bit flat out at the moment, but I'll have a poke around at lunch time at work

Doug

If the IDD breaks, then do what can be done with where-ever it is, and then just start driving. If it breaks - so what ,it's expired anyway.

Doug

I was thinking that, I imagine they can sequence things whereby the two dont listen in on one another, but there's still scope for cross talk at some point. For UHF commanding, as I understand it, you have quite a big latency, as they don't uplink to Odyssey as often as they would want to uplink to Spirit.

Doug

I imagine that a spacecraft that notices a signal on it's own channel, but can't understand it ( which is quite likely given the different bit rates the two spacecraft would be commanded with ) would probably go into a safe mode under the assumption that there is something wrong.


Doug

LOL - you knew what I meant

Doug

Well - they'd move around I assume, so between filters you would have motion - it wouldnt really work

MSL, perhaps, I dont imagine it'll be going to a polar region

Doug

Yup - it's fairly restrictive at the moment. I added XLS a few days ago ( an admin thing ) - but other than that, I've not added to the default 'payload' of allowable attachments much, ever warey of the implications.

Doug

MPL? That was a coding error that resulted in loss of the entire mission. MRO? That was a communications problem ( between people ) that again, resulted in the loss of the entire mission. Huygens still returned almost all of it's science - yes we lost a lot of images, but we also GOT a lot of images. We lost the wind data, but we rescued a fair ammount of it via ground based observations. A big mistake, yes. But there have been bigger ones. Much MUCH bigger ones.

It was a big error, and I'm sure a thorough investigation is / was underway. Much like the B2 investigation, it's clear ESA doesnt like to release the results of these things, but it will at some point I am sure.

Doug

And very 'Purgatory' They were hunting for rock to drive on around Erebus ( remember the Erebus highway? ) - better to park the IDD, have a slightly rougher ride, but stick on the rock.

Doug

[quote name='RNeuhaus' post='42269' date='Feb 19 2006, 06:14 AM']

Interesting, MRO uses HELIUM GAS to push Hydrazine away from the tank.
Pressurant Tank
[/quote]

I think just about every spacecraft I've ever seen does this.
[quote]
So many thrusters! 20. I tought it had 7!!!
[/quote]
Well - 7 main ones for the engine burn for MOI - but then lots of smaller ones for smaller manouvers and rotating the spacecraft to unload gyros.

[quote]
MRO will get very hot, up to 200 degree of centigrades at the perigee passing.
[/quote]

Ah - carefull - they say it's designed to withstand 200 degrees, not that they will nearly reach 200 degrees. They're get warm - but nothing like 200 deg. I think one of the tech papers I mentioned elsewhere shows CFD of how warm it might get.

[quote]
Comparing to MER, they have 1.2 M² of solar panel and its produces about 1000 wats when they had the best atmospheric conditions and about during the summer. The MRO has big solar panels, 10 M² and also produces about the same to MER? MRO will orbit Mars every two hours?, somewhat slower than ISS around Earth with 91 minutes.

[/quote]

Ahh - again, no - MER can produce up to about 1000 Watt-HOURS per sol, i.e. the equiv of 100 watts for 10 hours. Typically, the MER solar arrays would rarely produce more than 100 Watts at any one time - I'm not sure of the exact figures.

[quote]
Ten times faster than the previous Mars orbiters, which ones? I suppose it is refering to Odyssey?
[/quote]
and then some....

The very highest data rate I've seen quoted for Odyssey is 124425 bits per second - i.e. roughly 0.125 Mbits/sec

MRO's still a bit fluffy on quoted numbers - but the highest it can do is certainly around 5 Mbits/sec.

[quote]
Good ones: 4 reactions wheels: one for three dimension axis plus one as a spare. Even better than Hayabusa.

[/quote]
And the same as Cassini - which is already using its spare.
[quote]
Smart enough to handle by itself during if there is a fault.
[i]
[/quote]

Same as most spacecraft really.
[quote]
Whopping storage capacity in solid state record (RAM). The big computers has that amount storage. There very few computers have it.

[/quote]

Well - 160 Gbits is about 20 Gigabytes - and onboard that is equiv to the 'hard drive' for MRO - and I think we'd all be moaning if we only had that

Doug

Indeed, and I'm sure it would be well suited for discussion in Religious Education class.

But not a Biology class.

Doug

I managed to cleanly knock out one of my front teeth when I was about 10. Amazingly, they were able to put it back in and hold it there with a little bit of steelwork for a few weeks while the gum decided to 'take it back' as it were - and thus I was a temporary member of the soup's and ice cream society for a while. I was at boarding school at the time and my class mates were VERY jealous, until I reminded them that 1) picking an argument with a floor isnt very comfortable and 2) having more metalwork in your mouth than the golden gate bridge can get a 'little' uncomfortable.

Hope it all clears up toD - if not, I think there's a section in a project I was working on at work about knees

Doug

Whioch file extension did you try first time around? I'll add it to the list of allowable ones anyway. (it's a security thing so people can't upload malicious stuff)

Doiug

Being VERY unscientific, approx speed at periareion using Orbiter with these apareion's....

10000km - 4330 m/sec
18000km - 4460 m/sec
28000km - 4590 m/sec
38000km - 4650 m/sec
45000km - 4670 m/sec

So to vary between 28000 and 45000 is only a 80ish m/sec difference, in an MOI burn of I believe roughly 1000 m/sec over 25 minutes - so +/- 40m/sec is about a 4% error, or 1 minute of the burn

200 x 400km orbit is approx 3520 - 3320 m/sec ish -so aerobraking is giving us another 1000 m/sec of delta V.

All figures very VERY roughly done in orbiter.

Doug

If you hunt back in the movie archive at the JPL site, you'll see some rover driving videos - ditto the NOVA programs - and given that there's essentially a tiny tiny bit of suspension within the wheels but nothing else - it's quite a rough ride even over the fairly flat rocks and terrain we have here.

Given that suprisingly bumpy ride, the mass of the instruments on the IDD, and the leverage they'd have on the joints and motors when in the 'hover' position, there is a real risk of damage to IDD joints, motors, even the front of that array and the nearest instrument.

Hence the high-park for short drives, and the proper drive for longer driving campaigns.

Doug

Now that's actually a requirement for membership here, it's not a matter of humour - it's part of the process

Doug

Looks like a little slice of a baby Burns Cliff in places.

Doug

Incase anyone missed it - Jim's added a transit page to the Pancam projects page
http://marswatch.astro.cornell.edu/pancam_...projects_4.html

Doug

They went the other way

http://marsrovers.jpl.nasa.gov/gallery/all...C6P0705R0M1.JPG

Those rover drivers are nuts

Infact, they're quite brave - but the rover did the job - little slip in this
http://marsrovers.jpl.nasa.gov/gallery/all...C6P1212L0M1.JPG


Doug

Yup - please do - doug@rlproject.com


D

There used to be a 20k wide map at maps.jpl.nasa.gov - but it seems to have vanished.


mc's great map is, iirc, MOCWA - and thus never going to be much more than 250m/pixel - and there's very little coverage, globally, with MOCNA, which would be down at the 1.5->5m/pixel range - so a map couldnt be done at that res.

I wonder what could be done with Themis imagery

Any idea if CTX and MARCI imagery is going online in the same fashion as HiRise?

Doug

You average compression for 'earth' use isnt going to be robust enough to withstand a the odd bit error, so I image they do use a subset of j2k, but just modified for robustnes s:)

Doug

Is that video upsidedown? I thought Sprites were the things they'd seen from orbit that go upwards?

D

Thing is - only a tiny tiny change in the altitiude at MOI, and the duration of MI will produce quite a large change at aphelion (it's a very eliptical orbit) and so a tiny fraction of a change to either of those numbers, will put quite a different bit of Mars under the spacecraft 5 days later

Doug