IPB

Welcome Guest ( Log In | Register )

2 Pages V   1 2 >

ahecht
Posted on: Sep 10 2008, 02:36 PM


Junior Member
**

Group: Members
Posts: 40
Joined: 27-May 08
Member No.: 4145


QUOTE (hortonheardawho @ Sep 10 2008, 01:29 AM) *
sol 104 dust devil:
http://farm4.static.flickr.com/3188/284436...24e42c1f0_m.jpg
and a nice animation of another one moving about 1/2 hour later:
http://farm4.static.flickr.com/3023/284441...450549838_m.jpg
Er, was this expected? Have the orbiters spotted dust devil activity in the area?
It might be interesting to work out it's distance from the lander.

Another dust devil image here, which looks more impressive in the full-size version:


Click for larger image
  Forum: Phoenix · Post Preview: #125655 · Replies: 416 · Views: 268201

ahecht
Posted on: Aug 7 2008, 07:05 PM


Junior Member
**

Group: Members
Posts: 40
Joined: 27-May 08
Member No.: 4145


QUOTE (gallen_53 @ Aug 7 2008, 02:04 PM) *
I'll preface by saying that I'm totally ignorant about how an ISE operates. TheChemist mentioned that the ISE was designed to detect nitrates but instead detected perchlorates. How do we know the detected material is not some other substance, e.g. hypochlorites? I'd like to see some sort of specification for this sensor indicating its reponse to a wide range of different materials and not simply the material that the investigators had hoped to find.


Since the sensor was supplied by Thermo according to the press conference, it would appear that this is the manual for the terrestrial version of this ISE:
http://www.thermo.com/eThermo/CMA/PDFs/Art...sFile_18905.pdf

There is a section on interferences starting on page 34.
  Forum: Phoenix · Post Preview: #123005 · Replies: 377 · Views: 2690041

ahecht
Posted on: Aug 5 2008, 09:09 PM


Junior Member
**

Group: Members
Posts: 40
Joined: 27-May 08
Member No.: 4145


QUOTE (jmknapp @ Aug 5 2008, 05:03 PM) *
... the MECA team was working with an extremely important, undisclosed result directly related to habitability--contrary to speculation, tending towards less habitability than more, but whatever.


I didn't hear that in the press conference -- the consensus seemed to be no impact on habitability, with Peter Smith saying that in some ways it slightly increases the possibility of Martian life since we know of microbes on Earth that feed on perchlorates.
  Forum: Phoenix · Post Preview: #122745 · Replies: 377 · Views: 2690041

ahecht
Posted on: Aug 5 2008, 01:49 PM


Junior Member
**

Group: Members
Posts: 40
Joined: 27-May 08
Member No.: 4145


QUOTE (dvandorn @ Aug 5 2008, 01:01 AM) *
Also, a jetliner (I think it was Air Blue, but I could be wrong) was lost, with all passegers and crew, when lithium perchlorate oxygen generators caught fire in the plane's cargo hold just after takeoff, and nearly burned the plane in half before it could turn around and land.


That was ValueJet, which shortly afterwards did a reverse-merger to become AirTran (since the old ValueJet name was associated with a plane-shaped hole in a Florida swamp).

QUOTE (marsbug @ Aug 5 2008, 09:41 AM) *
Does anyone know the freezing points of perchlorate solutions? If they are within the range of temperatures at the phoenix site wouldn't we expect that perchlorate in the soil would form small quantities of liquid and wick downwards? If so that would point to an active source, which adds evidence to the 'oxidisers fall out of the martian sky' arguments.


Methoxylamine perchlorate can be mixed with hydrazine to drop its freezing point from about +1°C down to -55°C according to http://www.freepatentsonline.com/3941626.html
  Forum: Phoenix · Post Preview: #122663 · Replies: 377 · Views: 2690041

ahecht
Posted on: Aug 4 2008, 03:00 PM


Junior Member
**

Group: Members
Posts: 40
Joined: 27-May 08
Member No.: 4145


QUOTE (climber @ Aug 4 2008, 07:14 AM) *
Peter Smith said on the conference that the Atomic Force Microscope is now ready to take measurements. The AFM is part of MECA.
I'd be interested to know how they tested the instrument, I mean, did they take actual photos or not?


The AFM doesn't take photos per se. It uses microscopic needles to probe the target and then produces a 3D model of the surface. More than you'd ever care to know about the AFM is in the paper at http://www.lpi.usra.edu/meetings/polar2006/pdf/8047.pdf
  Forum: Phoenix · Post Preview: #122458 · Replies: 377 · Views: 2690041

ahecht
Posted on: Aug 1 2008, 05:18 PM


Junior Member
**

Group: Members
Posts: 40
Joined: 27-May 08
Member No.: 4145


QUOTE (teck @ Jul 27 2008, 05:45 AM) *
Because this is a strong magnet, the grains could have been there a long time ago. As I mentioned, unless there is an image showing the same target before a sample was taken, we cannot say where the grains came from. I did not find it.


From what I can tell, the photo of the clump is the "before" photo (that is, before a sample was deposited there). In the past they have done an empty image before a "full" image, and I couldn't find any earlier images of that particlular section of the sample wheel. The particles clumped around the magnet probably fell off of the other substrates as the wheel was rotated.
  Forum: Phoenix · Post Preview: #122034 · Replies: 133 · Views: 127939

ahecht
Posted on: Jun 27 2008, 07:37 PM


Junior Member
**

Group: Members
Posts: 40
Joined: 27-May 08
Member No.: 4145


QUOTE (jmknapp @ Jun 27 2008, 12:28 PM) *
Although Lowell thought he saw "man"-made canals. As for seeing evidence of water channels generally on this very dry world, Lowell has plenty of modern company. In fact, the word "water" almost seems to inhabit every other sentence in the history of Mars scientific inquiry and ruminations, relative lack of said substance notwithstanding.


The point I was trying to make is that the human brain is very good at connecting the dots, especially in low contrast images, and see lines where there are none.
  Forum: Phoenix · Post Preview: #119425 · Replies: 254 · Views: 205023

ahecht
Posted on: Jun 26 2008, 09:58 PM


Junior Member
**

Group: Members
Posts: 40
Joined: 27-May 08
Member No.: 4145


QUOTE (silylene @ Jun 24 2008, 06:01 PM) *
Do any of you know what, if any, are the possible sources of tiny fibers which could have fallen onto the collection slide from the lander? For example, thermal blankets, insulation, or a woven wrapping around a cable ?


There are many things in a clean room which could leave tiny 0.1mm fibers in the microscope: the bunny suits, hair nets, booties, kimwipes, paper, etc. Any of those that contained optical brighteners (such as white paper or laundered fabric) would also fluoresce in UV.
  Forum: Phoenix · Post Preview: #119341 · Replies: 133 · Views: 127939

ahecht
Posted on: Jun 26 2008, 09:54 PM


Junior Member
**

Group: Members
Posts: 40
Joined: 27-May 08
Member No.: 4145


QUOTE (MahFL @ Jun 23 2008, 12:15 PM) *
When I was looking at the Hi-Rise of the Phoenix Lander on the surface I can see channels that look like small river channels. Did anyone else notice this ?


I think Percival Lowell did.
  Forum: Phoenix · Post Preview: #119340 · Replies: 254 · Views: 205023

ahecht
Posted on: Jun 26 2008, 09:48 PM


Junior Member
**

Group: Members
Posts: 40
Joined: 27-May 08
Member No.: 4145


Apparently the RAC has a macro mode:


  Forum: Phoenix · Post Preview: #119339 · Replies: 355 · Views: 202765

ahecht
Posted on: Jun 16 2008, 06:10 PM


Junior Member
**

Group: Members
Posts: 40
Joined: 27-May 08
Member No.: 4145


Well, partially luck, and partially the landing legs that were designed to collapse is such a way as to keep the lander level despite uneven terrain.
  Forum: Phoenix · Post Preview: #118362 · Replies: 207 · Views: 123818

ahecht
Posted on: Jun 16 2008, 06:04 PM


Junior Member
**

Group: Members
Posts: 40
Joined: 27-May 08
Member No.: 4145


James, I was responing to jmknapp. I could've sworn I had a quote in my post, but it didn't show up originally.
  Forum: Phoenix · Post Preview: #118360 · Replies: 286 · Views: 184774

ahecht
Posted on: Jun 16 2008, 03:58 PM


Junior Member
**

Group: Members
Posts: 40
Joined: 27-May 08
Member No.: 4145


QUOTE (jmknapp @ Jun 16 2008, 08:12 AM) *
With a supposed equilibrium at just a few cm of loose dirt, it would seem that the temperature must drop very quickly in just that short distance if the ice is to be stable. If the max air temperature measured by the lander is -26C (high for Sol 17), then would it be logical that the max temperature at the surface is well above that?

Might that it's not ice be the simpler explanation in this case?

Or maybe the ice isn't stable, but is disappearing on a geologic time frame (global Mars warming), & the dirt layer is still building up?


You're thinking about temperature from an earth-centric point of view. On Earth, with a thick atmosphere, most heat transfer is done via convection, followed by conduction, and lastly followed by radiation. On Mars, however, the thin atmospher means that convection and conduction are quite minimal compared with radiation. A prime example of this is the ice that was found on the moon -- the fact that some craters were perpetually in shadow created enough of a temperature difference to prevent ice from sublimating.

On Mars the soil is light and fluffy (as we saw when Yeti was created), and there is little atmosphere between the grains, so the ice would be well insulated from conductive heating from the surface. There would be little (if any) convection, and the soil is opaque enough to prevent radiation. Therefore, the gradient in temperature could be HUGE after digging down only a few centimeters.
  Forum: Phoenix · Post Preview: #118352 · Replies: 286 · Views: 184774

ahecht
Posted on: Jun 14 2008, 06:01 PM


Junior Member
**

Group: Members
Posts: 40
Joined: 27-May 08
Member No.: 4145


QUOTE (Airbag @ Jun 14 2008, 12:26 PM) *
Unfortunately, the Optical Microscope (OM) images do not show up on the otherwise very useful Phoenix SSI raw images directory web pages so there is no obvious way to tell how many "different depth" OM images have been taken and/or downloaded so far


Give how easy it is to misidentify mircrosope images to those untrained in the art (as shown even in this thread), i'm sure they wouldn't release raw images until they had a chance to caption them. You wouldn't want a stray flourescent fiber from a laboratory Kimwipe sparking "Life Found on Mars" headlines.
  Forum: Phoenix · Post Preview: #118216 · Replies: 133 · Views: 127939

ahecht
Posted on: Jun 14 2008, 05:54 PM


Junior Member
**

Group: Members
Posts: 40
Joined: 27-May 08
Member No.: 4145


QUOTE (dvandorn @ Jun 14 2008, 01:03 PM) *
Hey -- we can nitpick Nick's and Don's theories on the emplacement processes for this ice layer that we seem to be literally unearthing, here.


If you're being literal, wouldn't it be "unmarsing"?
  Forum: Phoenix · Post Preview: #118215 · Replies: 286 · Views: 184774

ahecht
Posted on: Jun 13 2008, 08:20 PM


Junior Member
**

Group: Members
Posts: 40
Joined: 27-May 08
Member No.: 4145


The images of the first sample have come down. Click each image for a link to the full size:

phoenix.lpl.arizona.edu/images/gallery/lg_4869.jpg



phoenix.lpl.arizona.edu/images/gallery/lg_4867.jpg



phoenix.lpl.arizona.edu/images/gallery/lg_4859.jpg



phoenix.lpl.arizona.edu/images/gallery/lg_4870.jpg
  Forum: Phoenix · Post Preview: #118105 · Replies: 133 · Views: 127939

ahecht
Posted on: Jun 13 2008, 07:35 PM


Junior Member
**

Group: Members
Posts: 40
Joined: 27-May 08
Member No.: 4145


When will they learn not to wear black shirts if they are going to have a black backdrop? And how can people take them seriously when they're talking about "Humpty Dumpty National Park"? That said, excellect results, especially the microscope images and the dust movie.
  Forum: Phoenix · Post Preview: #118097 · Replies: 207 · Views: 123818

ahecht
Posted on: Jun 13 2008, 05:00 PM


Junior Member
**

Group: Members
Posts: 40
Joined: 27-May 08
Member No.: 4145


There is an updated version of the EDL movie that was uploaded a couple days ago. While it doesn't appear to have ALL the EDL info in it (such as the creation of Holy Cow), it does show the partially-deployed parachute state as it was captured by HiRISE. I would've loved to see Heimdal in the background, but I guess a video like that will come once they have all the EDL numbers crunched.

http://www.jpl.nasa.gov/news/phoenix/phx-20080611.php
  Forum: Phoenix · Post Preview: #118081 · Replies: 166 · Views: 154872

ahecht
Posted on: Jun 12 2008, 09:35 PM


Junior Member
**

Group: Members
Posts: 40
Joined: 27-May 08
Member No.: 4145


I made a little animated GIF of them focusing the RAC. Looks like there is some dirt on the lens.
  Forum: Phoenix · Post Preview: #117980 · Replies: 207 · Views: 123818

ahecht
Posted on: Jun 11 2008, 08:10 PM


Junior Member
**

Group: Members
Posts: 40
Joined: 27-May 08
Member No.: 4145


QUOTE (jmknapp @ Jun 11 2008, 02:27 PM) *
In fact, one hypothesis is that it finally went through the screen because of this sublimation of water.


Another possibility is that the exposure to UV from the sun dissipated the static charge that had built up within the soil.
  Forum: Phoenix · Post Preview: #117870 · Replies: 207 · Views: 123818

ahecht
Posted on: Jun 11 2008, 08:07 PM


Junior Member
**

Group: Members
Posts: 40
Joined: 27-May 08
Member No.: 4145


QUOTE (1101001 @ Jun 11 2008, 02:38 PM) *
(My speculation: it was a humidity change that triggered success. Is there anything else that could have changed between 6th vibe that failed and 7th that quickly worked? Temperature? The death of all the bacteria (ha!) in the sample?)


One thing that comes to mind is that the soil is electrostatically clumpy, and that prolonged exposure to UV light from the sun dissipated the charge. It could also be that the soil is icy and the ice sublimated.
  Forum: Phoenix · Post Preview: #117867 · Replies: 405 · Views: 203271

ahecht
Posted on: Jun 11 2008, 05:44 PM


Junior Member
**

Group: Members
Posts: 40
Joined: 27-May 08
Member No.: 4145


New color image of the trenches:

  Forum: Phoenix · Post Preview: #117832 · Replies: 207 · Views: 123818

ahecht
Posted on: Jun 11 2008, 02:48 PM


Junior Member
**

Group: Members
Posts: 40
Joined: 27-May 08
Member No.: 4145


Any clue what this is? They keep imaging it:

  Forum: Phoenix · Post Preview: #117808 · Replies: 207 · Views: 123818

ahecht
Posted on: Jun 10 2008, 02:04 PM


Junior Member
**

Group: Members
Posts: 40
Joined: 27-May 08
Member No.: 4145


The MET site called those images "Tactical water sky test". What they heck is a "Tactical water sky test"?
  Forum: Phoenix · Post Preview: #117699 · Replies: 207 · Views: 123818

ahecht
Posted on: Jun 10 2008, 02:02 PM


Junior Member
**

Group: Members
Posts: 40
Joined: 27-May 08
Member No.: 4145


Poor MECA, all buried in dirt. I guess they couldn't find a large enough portion of the lander deck to test this with.
  Forum: Phoenix · Post Preview: #117697 · Replies: 405 · Views: 203271

2 Pages V   1 2 >

New Posts  New Replies
No New Posts  No New Replies
Hot topic  Hot Topic (New)
No new  Hot Topic (No New)
Poll  Poll (New)
No new votes  Poll (No New)
Closed  Locked Topic
Moved  Moved Topic
 

RSS Lo-Fi Version Time is now: 19th March 2024 - 04:13 AM
RULES AND GUIDELINES
Please read the Forum Rules and Guidelines before posting.

IMAGE COPYRIGHT
Images posted on UnmannedSpaceflight.com may be copyrighted. Do not reproduce without permission. Read here for further information on space images and copyright.

OPINIONS AND MODERATION
Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators.
SUPPORT THE FORUM
Unmannedspaceflight.com is funded by the Planetary Society. Please consider supporting our work and many other projects by donating to the Society or becoming a member.