IPB

Welcome Guest ( Log In | Register )

10 Pages V  « < 8 9 10  
Reply to this topicStart new topic
Venera Images, VENERA 13 fully calibrated image
nprev
post Nov 4 2015, 02:29 AM
Post #136


Senior Member
****

Group: Admin
Posts: 7946
Joined: 8-December 05
From: Los Angeles
Member No.: 602



Understood. My question was quite poorly constrained. smile.gif Thanks!


--------------------
A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
Go to the top of the page
 
+Quote Post
hendric
post Nov 4 2015, 03:40 PM
Post #137


Director of Galilean Photography
***

Group: Members
Posts: 827
Joined: 15-July 04
From: Austin, TX
Member No.: 93



Ralph, that report sounds promising for powering a long-duration lander with wind power. 90 times Earth's atmospheric density, would mean the .4 m/s wind is equal to ~3.8m/s, close to cut-in speed for a decent wind turbine. And I would assume windier times and locations are possible? Would it be a good assumption that windspeeds on Venus' surface don't change quickly, since the rotation is so slow?

I guess a space-based instrument won't be able to monitor windspeeds - on Earth the __Scat family of satellites use ocean roughness as a proxy for surface windspeed. I propose a mission to drop a load of neutrally buoyant reflective strips onto Venus along with a radar platform to monitor their distribution. smile.gif


--------------------
Space Enthusiast Richard Hendricks
--
"The engineers, as usual, made a tremendous fuss. Again as usual, they did the job in half the time they had dismissed as being absolutely impossible." --Rescue Party, Arthur C Clarke
Mother Nature is the final inspector of all quality.
Go to the top of the page
 
+Quote Post
tanjent
post Nov 5 2015, 05:34 AM
Post #138


Member
***

Group: Members
Posts: 169
Joined: 30-December 05
Member No.: 628



QUOTE (rlorenz @ Nov 3 2015, 10:45 PM) *
Where terrain (or meteorological) factors introduce an entirely stochastic element to the landing
dynamics, an optimal mission solution may be to build two 90% landers to achieve an overall 99% chance of safe landing.


If the (total) cost of an estimated p=99% mission success is more than double that of a p=90% mission, that formula presents an excellent argument for building and launching duplicate missions, as in the case of Viking or Voyager or MER. Because 81% of the time, you may then hope to realize not one but two successes. (In each case, the second success might be considered partially redundant, but only partially.)
Go to the top of the page
 
+Quote Post
mcaplinger
post Nov 5 2015, 05:52 AM
Post #139


Senior Member
****

Group: Members
Posts: 1572
Joined: 13-September 05
Member No.: 497



Unfortunately, here in reality the relationship between cost and probability of mission success is not quantifiable with any precision. I'm not even sure that spending more money increases probability of success in all cases.


--------------------
Disclaimer: This post is based on public information only. Any opinions are my own.
Go to the top of the page
 
+Quote Post
JRehling
post Nov 5 2015, 05:42 PM
Post #140


Senior Member
****

Group: Members
Posts: 1957
Joined: 20-April 05
Member No.: 321



QUOTE (mcaplinger @ Nov 4 2015, 10:52 PM) *
Unfortunately, here in reality the relationship between cost and probability of mission success is not quantifiable with any precision.


Agreed. Many in-situ hazards are of unknown incidence, and knowledge of their incidence is exactly the kind of knowledge that the mission is meant to acquire, so there's a Catch-22 there in principle.

Not only Huygens but also an early Venera lander were designed to float. This was overly cautious in both cases, as it turned out. The designers could have thought and spent all they wanted, but ultimately, some exploration had to be done to ascertain whether or not flotation was required. They could have spent a trillion dollars on it and not gotten a better answer than they did by actually flying a mission and seeing what the surfaces of Venus and Titan are like.

Then again, the next Venus lander may unluckily sink into a pond of molten tin. It's hard to prove otherwise until we've explored Venus thoroughly.
Go to the top of the page
 
+Quote Post

10 Pages V  « < 8 9 10
Reply to this topicStart new topic

 



RSS Lo-Fi Version Time is now: 22nd June 2017 - 02:23 PM
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.