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#100
by
knotnic
on 04 Aug, 2012 16:29
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Does anyone here know about what kind of twisting motion they might expect from the skycrane bridles. In other words I am dying to find any information about what kind of tolerance there is to the difference in angle between the descent stage and the rover might be expected?
Since the three bridles all come together at a common point where they enter the descent stage, there should be little or no effect due to twisting, but since it will nominally be stabilized in pitch and yaw and with zero horizontal velocity there isn't much that could initiate twisting or swaying. In addition because of the outward cant of the descent engines it can land on a 15deg slope with a .55m rock under the wrong end of the rover and still not have issues with plume impingement.
This document has the best info on EDL:
http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/41629/1/10-1775.pdf
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#101
by
aero
on 06 Aug, 2012 04:03
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Where is the TMI stage now, at the time of EDL? Is it visible from Gale Crator as well as Earth? If so, in the future couldn't it carry a communications transponder for "live" coverage of the landing?
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#102
by
Jim
on 06 Aug, 2012 05:35
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Where is the TMI stage now, at the time of EDL? Is it visible from Gale Crator as well as Earth? If so, in the future couldn't it carry a communications transponder for "live" coverage of the landing?
Gone and dead. It was never pointed at Mars
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#103
by
Mader Levap
on 06 Aug, 2012 06:09
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These hazcam images looks... dirty. I mean, like some dirt is on camera eye. This worries me. Did rover got sandblasted more than they expected? What about rest of instruments?
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#104
by
Silmfeanor
on 06 Aug, 2012 06:10
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These hazcam images looks... dirty. I mean, like some dirt is on camera eye. This worries me. Did rover got sandblasted more than they expected? What about rest of instruments?
They still have their dustcover on them - they took the picture through the dustcover. They'll pop up the cover and it'll be fine
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#105
by
Mader Levap
on 06 Aug, 2012 06:13
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Ah, transparent dustcover. Dev team thinks of everything, indeed.
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#106
by
PeterAlt
on 06 Aug, 2012 07:35
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What's NASA's protocol in the event that - let's say - fossilized bones are found? Would this be announced the day it's found, or will it be held from public knowledge, pending confirmation and internal debate or even presidential approval?
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#107
by
jpaulb1
on 06 Aug, 2012 08:59
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Jason Davies - 4/6/2007 10:28 AM
Do they have crosswinds on Mars? (I have no idea).
If I rememebr correctly if one of (or both(?)) the MER rovers didn't have an option to correct for some cross winds it may have crashed on landing. I believe the gusts were strong right before landing...
I saw a vid somewhere of animation of a simulated crash due to high gusts just before landing.. neat but scary.. (forget where I saw it!!)
I read a concern of the MSL rover was having it coming down and getting dragged sideways and "breaking the wheels"..as opposed to being dragged forward and back and have the wheels move... I'm fascinated by the crane..be cool if it works (I'm giving them benefit the doubt and say it will 
)..opens up some neat possibilites!!
cheers
jb
Well the question only begs more questions regarding a Martian gravity, atmospheric density and landing. A) What would terminal velocity be for a free fall? B) What is the difference in FORCE for a 200kph wind ;Earth/Mars? C) What is the atmospheric density profile through altitude?
I suspect there are far greater influences when trying to fly in an Earth atmosphere.
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#108
by
Jim
on 06 Aug, 2012 11:07
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What's NASA's protocol in the event that - let's say - fossilized bones are found? Would this be announced the day it's found, or will it be held from public knowledge, pending confirmation and internal debate or even presidential approval?
not even worth acknowledging
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#109
by
Garrett
on 06 Aug, 2012 12:20
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B) What is the difference in FORCE for a 200kph wind ;Earth/Mars? C) What is the atmospheric density profile through altitude?
general rule of thumb for me is that Mars atmosphere is about 1000 times less dense than on Earth. So a 200 km/h wind is about a 1000 times less strong, so feels like a 0.2 km/h wind. However, 200 km/h dust particles can still be very abrasive.
pressure is greater at the bottom of a crater (up to 4 times greater I believe, depending on crater depth), so winds would be 250 times less strong than on Earth, at most.
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#110
by
JohnFornaro
on 06 Aug, 2012 12:38
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What's NASA's protocol in the event that - let's say - fossilized bones are found?
I get first dibs... See my EBay page for more details...
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#111
by
andy_l
on 06 Aug, 2012 12:40
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Noting the mention in the NSF article that the entry guidance software had some heritage in Apollo, are there any decent papers (either public or L2) which discuss the guidance software development?
Cheers,
Andy
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#112
by
savuporo
on 06 Aug, 2012 15:05
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Now that it has been shown to work, i wonder what another copy of SkyCrane+basic rover platform ( minus the science package) would cost, if built right now.
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#113
by
randomly
on 06 Aug, 2012 15:49
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Wind force is proportional to the atmospheric density, but it scales as the Square of the wind velocity. Official observed gust velocities have been in the 120-160 km/h range, with higher altitude dust movement at 400-480 km/hr. So peak wind forces can still be substantial due to high wind velocities even though the atmospheric density is low.
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#114
by
Star One
on 06 Aug, 2012 16:13
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Are the upcoming MAVEN & ExoMars orbiters both designed to operate as relay satellites, just that I am concerned by the recent issues amongst the existing orbiters & redundancy in this area would seem sensible?
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#115
by
Jim
on 06 Aug, 2012 16:47
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Are the upcoming MAVEN & ExoMars orbiters both designed to operate as relay satellites, just that I am concerned by the recent issues amongst the existing orbiters & redundancy in this area would seem sensible?
All US orbiters must carry the relay package.
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#116
by
Star One
on 06 Aug, 2012 16:58
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Are the upcoming MAVEN & ExoMars orbiters both designed to operate as relay satellites, just that I am concerned by the recent issues amongst the existing orbiters & redundancy in this area would seem sensible?
All US orbiters must carry the relay package.
Thanks.
Well that covers MAVEN what about ExoMars which isn't US, will it carry this as well?
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#117
by
andy_l
on 06 Aug, 2012 20:45
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#118
by
Blackstar
on 06 Aug, 2012 20:48
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Now that it has been shown to work, i wonder what another copy of SkyCrane+basic rover platform ( minus the science package) would cost, if built right now.
Go to the planetary science decadal survey website. Look up the mission study on the MAX-C rover mission. Details in there.
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#119
by
aero
on 06 Aug, 2012 21:14
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What would it take to put 3 comm satellites in stationary equitorial orbits equally spaced around Mars? How much would that speed the investigations performed by these robot missions? By manned missions?
)..opens up some neat possibilites!!