You're probably confusing aerobraking and aerocapture. Aerobraking has always been a very very gentle, protracted effort.

MGS did aerobraking in Sept & Oct '97, suspended briefly because of concerns for pressure on a solar array gimble, restarted in Nov '97 and continued until May '98 where it was suspended to allow the orbit to drift into the location they wanted, and then continued from Nov '98 to Mars '99 - a total of approx 10 months.

Mars Odyssey's aerobraking took 4 months, MRO's took 6 months. Magellan did it for more than 3 months at Venus in the mid '90s.

34.331 degrees right now ( see attachment)

Curiosity (as with MER ) typically gets its commands direct from earth at about 9.30am local time in a window up to 30 minutes long. Can't see the Earth....can't do the uplink. Can't do the uplink...can't start the rovers daily activities until later, reducing the time available for activities.

Right now Earth is an evening star. It rises just to the left of the 'northern' most base of Mt Sharp - a bearing of 69 degrees. Sunrise (in LMST) is 05:55. earthrise is 08:23 - 2.5hrs after Sunrise.

Any local topography can of course delay the Earth 'rising'.

Topography like this - http://mars.jpl.nasa.gov/msl/multimedia/ra...251M_&s=527 - could easily add a 20 degree mask to the horizon in the direction of the Earth (infact, I can see cases there of 25 degrees or more) - which would add a further 1 -> 1.5 hours to the Earth Rise time. Thus the Earth may only locally 'rise' as much as 4 hours after a nominal 'sun rise'. So that means you have to push your DFE uplink time from 9:30 to a LEAST 10am, and ideally 10:30 to allow the Earth to be well above the local horizon. Thus - between uplink and sunset, we would have lost about an hour of usable time.

This is a situation that will be even worse once we're at the base of Mt Sharp - apart from times when Earth is a 'morning' star and rises 2 - 3 hours before the Sun does. In 150 sols time, Earth will rise at 02:50 LMST, 2.5hrs before Sunrise - so the masking wont actually be a problem. But another couple of hundred sols after that - it'll eat into the day again.

Yes - orbiters can be used (and are used for pretty much every single bit of downlink) - but to forward commands onto the rover via UHF requires a longer lead-time, and interrupts the daily planning cycle significantly. You would see symptoms similar to restricted sols almost constantly.

( For those that don't have it - grab Mars 24 to see Sunrise/Sunset Earthrise/Earthset times http://www.giss.nasa.gov/tools/mars24/ )

You're seeing a symptom of no bundle adjustment. Every now and again trajectory data will be updated and nudged around to reflect the true location of the vehicle versus it's own ready-reckoning version of where it thinks it is (and where early SPICE data might show it to be)

I had a go at it with Telescope 21 on the iTelescope network. Just from preview JPG's - ( 600s L, 300s for R, G and B )

UHF is used between MODY/MRO and MER/MSL at Mars, over ranges of hundreds of miles at speeds up to 2 Mbits/sec

The problem would be line of sight over the horizon. But Yutu has DTE, so the issue doesn't actually matter.

Thought I would share the graph I plotted to help try and explain to people why sometimes the distance between Voyager 1 and 2... and Earth... sometimes shrinks.

There's also more than just drag....you can also move the center of pressure too far forward. In essence, like throwing a dart backwards...it'll want to flip on you.

Drag is a problem though - a first order approximation....a 10m fairing presents 75sqm of x-section drag...whereas a 5m fairing only 20sqm. This URL shows some numbers.....these wouldn't necessarily quadruple ( you would be going slower I'm the thicker atmosphere ) but a different and slower flight profile would also inflict higher gravity losses.

http://gravityloss.wordpress.com/2008/01/1...or-scalability/

Already done, put to paper, peer reviewed and published
http://www.sciencedirect.com/science/artic...019103513001693


Walfy's animation seemed to me to suggest it was just a steering actuator bashing something out the way - which I hope we all agree is just not going to happen.

The notion that rover motion (of any sort) could end up 'popping' a rock into motion is fine. This all falls under the tiddlywinks category, surely? It's really not a separate means of flinging material

The turning of a steering actuator flicking a rock across the ground? Have you seen how slow the wheels steer? It's incredibly slow. Sorry - I don't buy it. Moreoever - how would a steering actuator throw a rock infront of the rover? Walfy's animation shows it being throw away from the rover....not right infront of it.

I don't know if it's ejecta...it does inherently seem unlikely - but it's not that far beyond the realm of possibility. The modern day cratering rate as derived from orbital discoveries is such that I believe it was characterized thus : Within the duration of one crewed surface mission of a martian year - statistically there would be a new impact crater formed within earshot. We've been here 5 martian years. It's far far from impossible that it could be a piece of ejecta. It could be a tiddlywink's like pinging of a rock from under a wheel. But a steering actuator didn't just flick a wheel several meters....I don't buy it.

Are you aware that the front right steering actuator has been broken for 8 years? It doesn't steer - it's locked with 8 degrees of toe in.

It's big heavy arm and a lot of torque there if it's stuck out....but....if the rover moved enough for a wheel to get punctures during that process... we would see it in imagery of pre/post arm deployment. We've seen some motion...but only a tiny bit.

Those two small arrays, but at Earth distance, rather than Mars distance, are probably putting out several hundred watts - enough to run a vehicle of MER class constantly.

Use your right arm...it has the same degrees of freedom ( sort of ) as the MSL arm.

Point, with your right index finger.....at this


[X]

Now you can wiggle your elbow around, you can move your body even, whilst keeping your hand and finger in the same place, pointing the same way.

Fascinating little rock - totally different to the bedrock beneath

Are we looking at a wind polished vesicular basalt?

There are no grounds to make such an assumption. The wheels were built with many big holes in them, intentionally. The test rovers ( both VSTB and the Scarecrow ) have happily driven across soft and sandy situations with damage as bad, and significantly worse and more thoroughly distributed around all 6 wheels than we're seeing on Curiosity. Indeed - I've seen people argue that paddle like additions to rover wheels would be of benefit when trying to drive thru soft terrain, based on the notion of sand-paddle wheels for extreme off roading. Big rips and tears may even offer benefits along those lines.

I still see no damage ( nor any action by the team ) that presents any risk, whatsoever, to achieving mission goals. Nothing seen, announced or planned in any way could be considered a 'hat tip' to the doom-mongers in this place ( and elsewhere ) who were claiming mobility would soon be a thing of the past and we'd never get to the science targets at the foot of Mount Sharp.

People have been very carefully picking quotes from the JPL release....here's one worth remembering..

"The wheels can sustain significant damage without impairing the rover's ability to drive."

You've been a member here for 8 years. You really should know better.

HERE is the LRO Image.
http://lroc.sese.asu.edu/news/index.php?/a...From-Above.html

Untrue. The MDIS system has filters wheels for color imaging - hence, for example - http://messenger.jhuapl.edu/gallery/scienc...p?image_id=1226

At apoapsis perhaps - but that's typically when you're transmitting back to Earth, not doing science. Look at periapsis. MESSENGER's nominal peripasis is 200km - half that of the nominal 400km of the MPO component of B-C. Moreover - the MESSENGER team hope to operate their spacecraft at altitudes significantly lower than 200km if they continue operations for a further extension - perhaps 25km or lower.

And 8 flybys only exceeds the 7 of Rosetta by 1. ( 3 x Earth. 1 x Mars. 2 x Asteroids. )

from : http://spaceflightnow.com/china/change3/13...n/#.Ur3M2GRDuFI

"NASA's Lunar Reconnaissance Orbiter flew over the Chang'e 3 landing site this week and took pictures with the probe's high-resolution camera. NASA spokesperson Dwayne Brown said Friday the images could be released early next week, but it was too soon to determine whether the orbiter could spot the lander or rover on the lunar surface."

They may very well have done so - I'd think we've seen only a tiny fraction of the total number of images taken.

Whilst some technology could be carried across - the requirement for Mars ascent and lunar ascent are very different. 2x the gravity, plus an atmosphere to deal with. The two vehicles would be very different.

So that any signatures that are identified can be certified as not being of terrestrial origin.

This thread already includes an explanation

From Phil
http://www.unmannedspaceflight.com/index.p...st&p=205662
" there was talk of us being in a hiatus, Dec. 16-23, during the hottest part of the lunar day, so maybe a few days without pics. "