IPB

Welcome Guest ( Log In | Register )

5 Pages V  « < 3 4 5  
Reply to this topicStart new topic
Phoenix Site
craigmcg
post Aug 31 2005, 01:06 AM
Post #61


Member
***

Group: Members
Posts: 122
Joined: 21-April 05
From: Rochester, NY
Member No.: 336



what impact will the descent thrusters have on the soil it ends up landing on?
Go to the top of the page
 
+Quote Post
Bob Shaw
post Aug 31 2005, 11:19 AM
Post #62


Senior Member
****

Group: Members
Posts: 2488
Joined: 17-April 05
From: Glasgow, Scotland, UK
Member No.: 239



QUOTE (craigmcg @ Aug 31 2005, 02:06 AM)
what impact will the descent thrusters have on the soil it ends up landing on?
*


Probably a bit less than if they turn the suckers off too early again!

Hehe.


--------------------
Remember: Time Flies like the wind - but Fruit Flies like bananas!
Go to the top of the page
 
+Quote Post
Marcel
post Aug 31 2005, 12:13 PM
Post #63


Member
***

Group: Members
Posts: 290
Joined: 26-March 04
From: Edam, The Netherlands
Member No.: 65



QUOTE (craigmcg @ Aug 31 2005, 01:06 AM)
what impact will the descent thrusters have on the soil it ends up landing on?
*


http://www.space.com/businesstechnology/05...oenix_tech.html

Which says it is of major concern to the science team.
How could they NOT have thought about this before ?
Go to the top of the page
 
+Quote Post
djellison
post Aug 31 2005, 01:56 PM
Post #64


Administrator
****

Group: Chairman
Posts: 13870
Joined: 8-February 04
Member No.: 1



"As the ice starts advancing off Marsí northern polar cap and moves southward, Phoenix will become entombed in several feet of solid carbon dioxide. The lander is not designed to survive being buried in solid ice for six to seven months, Smith said."

LOL - didnt think it would be that bad!

The exhaust plume contamination of local soil was something I read about w.r.t. MPL years ago - so I'm sure it's not something they've just thought of.

Doug
Go to the top of the page
 
+Quote Post
Marcel
post Aug 31 2005, 02:17 PM
Post #65


Member
***

Group: Members
Posts: 290
Joined: 26-March 04
From: Edam, The Netherlands
Member No.: 65



QUOTE (djellison @ Aug 31 2005, 01:56 PM)
"As the ice starts advancing off Marsí northern polar cap and moves southward, Phoenix will become entombed in several feet of solid carbon dioxide. The lander is not designed to survive being buried in solid ice for six to seven months, Smith said."

LOL - didnt think it would be that bad!

The exhaust plume contamination of local soil was something I read about w.r.t. MPL years ago - so I'm sure it's not something they've just thought of.

Doug
*

Ah, that's good to read. But what can be done ? Nothing i'm afraid.

I think the physical disturbance of the soil (stripping it's top layer) is probably not such a big issue. The real fear of it probably lies in the detection of organics and the interference that hydrazine and by-products could have on the measurements within the chromatograph column. I don't know enough about the field to know if this can be subtrancted easily from the rest. Probably the mix of unburned fuel and the products that are left after combustion are a very complex mix of organics that are hard to distinct from (possible) original (Martian) soil organic matter.

The ice layer of a meter or so also surpises me highly ! The thing will probably not wake up afterwards. It would surprise me if it did......maybe it's like freezing wet laundry:if it thaws without motion, it's intact afterwards. If it is moved (especially cables) in a brittle state, it snaps instantly. Don't know at which temp. this happens for the materials used. And most probable, the electronics itself will not survive months of exposure to -120 C. Does it have radioactive heaters like MER ?
Go to the top of the page
 
+Quote Post
RNeuhaus
post Aug 31 2005, 04:42 PM
Post #66


Senior Member
****

Group: Members
Posts: 1636
Joined: 9-May 05
From: Lima, Peru
Member No.: 385



The Phoenix's probably specific landing site will be selected based on detailed reconnaissance of candidate sites still to be conducted by spacecraft orbiting Mars. The
candidate sites will lie between the northern latitudes of 65 degrees (the equivalent of Fairbanks, Alaska) and 75 degrees (the equivalent of northern Greenland).
I am not sure if that by that zone there is permafrost snow because according to the following URL http://phoenix.lpl.arizona.edu/science/ shows that above than 80 degree has a greater change of abundance of water. Will Phoenix land on nude soil or ice surface? ohmy.gif

About the budget of Phoenix is not considered as a cheap mission comparing to MERs ones:
Phoenix's relatively low cost: $US 386 M with 90 days of high activity (primary operations) and other between 30-60 days of low activities (meteorological station). and the MER costs with $US 400 M each one with 90 days of high activity mission.

The difference is around $US14 Million. sad.gif

The extract from the dailyspace news:
QUOTE
In the descent to Mars, however, Phoenix thrusters will gulp and heave out hydrazine.

The engine effluents striking the landing spot in which Phoenix will conduct science "is a matter of some concern to those members of the science team," Smith explained. While the most ultra-pure hydrazine is to be used, some un-combusted fuel will reach the surface.

"So we are very much worried about this issue," Smith said. "We are trying to find ways that we can work with the soil and try to avoid the contamination from the hydrazine and the exhaust gases.".


Is it worth that the Phoenix has own mobility with the $US 16 M as the MER but with four hidden band rovers which will push down after landing in order to move away from its landing place in order to avoid the laboratory misleading analysis results? blink.gif

Rodolfo
Go to the top of the page
 
+Quote Post

5 Pages V  « < 3 4 5
Reply to this topicStart new topic

 



RSS Lo-Fi Version Time is now: 21st December 2014 - 03:18 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 a project of the Planetary Society and is funded by donations from visitors and members. Help keep this forum up and running by contributing here.