IPB

Welcome Guest ( Log In | Register )

 
Reply to this topicStart new topic
JPL prototype balloon
Del Palmer
post Aug 30 2007, 03:57 PM
Post #1


Member
***

Group: Members
Posts: 213
Joined: 21-January 07
From: Wigan, England
Member No.: 1638



Anyone have any information/speculation on when such a balloon might fly?

http://www.jpl.nasa.gov/news/features.cfm?feature=1448


--------------------
"I got a call from NASA Headquarters wanting a color picture of Venus. I said, “What color would you like it?” - Laurance R. Doyle, former JPL image processing guy
Go to the top of the page
 
+Quote Post
elakdawalla
post Aug 30 2007, 04:40 PM
Post #2


Administrator
****

Group: Admin
Posts: 5172
Joined: 4-August 05
From: Pasadena, CA, USA, Earth
Member No.: 454



The Venus community would love to see a balloon-equipped "Venus In Situ Explorer" as the next New Frontiers mission. The problem is that Venus keeps getting nicked on technology readiness -- basically, anything else you can propose to do with a New Frontiers mission will be closer to something that has been done by NASA before than a Venus balloon, so it's hard to see how it will win the competition. You can see various discussions of this in my notes from the 2005 and 2006 VEXAG meetings.

Cool photo, thanks for posting the link!

--Emily


--------------------
My website - My Patreon - @elakdawalla on Twitter - Please support unmannedspaceflight.com by donating here.
Go to the top of the page
 
+Quote Post
gndonald
post Aug 31 2007, 03:56 PM
Post #3


Member
***

Group: Members
Posts: 212
Joined: 19-July 05
Member No.: 442



Interesting article, I hope that this proposal has better luck than the one NASA considered sending(23mb) back in the late 1960's.
Go to the top of the page
 
+Quote Post
rlorenz
post Sep 1 2007, 01:08 PM
Post #4


Member
***

Group: Members
Posts: 609
Joined: 23-February 07
From: Occasionally in Columbia, MD
Member No.: 1764



QUOTE (Del Palmer @ Aug 30 2007, 11:57 AM) *
Anyone have any information/speculation on when such a balloon might fly?

http://www.jpl.nasa.gov/news/features.cfm?feature=1448


This particular incarnation is Kevin Baines' VALOR Discovery mission proposal, which
was submitted to the last round but not selected.. Kevin told me the other week that in
fact they weren't dinged too badly on the technology readiness but were hit (unfairly)
on other factors.

Disco is such a crapshoot.

But anyway, there are Venus balloon concepts out there which are less elaborate than
the New Frontiers class ideas that Emily mentions.

Something I have observed (in thinking about Titan) is that no planetary balloon has flown
(VEGA) or even got close to flying (Mars 96) as the sole element of a mission. Somehow
the science value vs risk tradeoff never seems to work. A 'politically viable' balloon IMHO has to be
an add-on, part of a broader scientific architecture (such that if the balloon tanks, the whole
mission isnt seen to fail), and quite possibly justified on technology development and outreach
grounds rather than purely scientific ones. Hence VEGAs were drop-offs with landers en route to
Halley, and Mars-96 balloon was part of a small armada of small landers, penetrators etc.

Jaques Blamont last week at Europlanet disagreed with me of course, but I contend that
often the case that science carried on balloons is important and/or has to be done from a
balloon (rather than from a platform whose perceived risk is lower, whatever the real
risks happen to be) is not well made.
Go to the top of the page
 
+Quote Post
nprev
post Sep 1 2007, 05:24 PM
Post #5


Merciless Robot
****

Group: Admin
Posts: 8783
Joined: 8-December 05
From: Los Angeles
Member No.: 602



Hmm. Projectitis rears its head yet again; interesting to see that it's not confined to the US DoD.

Maybe the balloon proposal would fare better if the platform itself multitasks to the highest possible degree. Chemical analysis of the atmosphere at various levels is obviously the most desirable data that could be obtained, as well as meteorology. Would a hi-res (cm resolution) surface radar imager add significant scientific value? You'd get swaths al a Cassini, but all the time...


--------------------
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
rlorenz
post Sep 2 2007, 01:28 PM
Post #6


Member
***

Group: Members
Posts: 609
Joined: 23-February 07
From: Occasionally in Columbia, MD
Member No.: 1764



QUOTE (nprev @ Sep 1 2007, 01:24 PM) *
Hmm. Projectitis rears its head yet again; interesting to see that it's not confined to the US DoD.

Maybe the balloon proposal would fare better if the platform itself multitasks to the highest possible degree. Chemical analysis of the atmosphere at various levels is obviously the most desirable data that could be obtained, as well as meteorology. Would a hi-res (cm resolution) surface radar imager add significant scientific value? You'd get swaths al a Cassini, but all the time...


First remember that most balloons cannot traverse large altitude ranges - maybe a scale height or
two at most. And even to do that you need clever ballasting like condensing vapor a la ALICE experiment
from JPL, or a Montgolfiere that you can control the heat to. So that's a lot of vehicular complexity
just to get chemical variation with altitude.

Note also re: multitasking that a balloon is probably more mass-constrained than a lander.

I'm not sure cm resolution radar is possible (not at cm wavelengths, anyway...) But in any case
SAR imaging is better done from orbit where you can map the whole planet. (SAR relies on
vehicle motion to synthesize the aperture in any case, so balloon SAR would not be ideal)

A sanitized (minus cost details and proprietary data) version of the Flagship mission report for
Titan (and the others) is supposed to be released to the public next month - you will see there
what the key Titan science from a tropospheric balloon (as opposed to a Lander and Orbiter)
is - high resolution imagery, subsurface radar sounding, and (only if the balloon descends
close to the ground) surface spectroscopy.
Go to the top of the page
 
+Quote Post
nprev
post Sep 3 2007, 04:29 PM
Post #7


Merciless Robot
****

Group: Admin
Posts: 8783
Joined: 8-December 05
From: Los Angeles
Member No.: 602



Very illuminating as usual, Dr. L; thanks! smile.gif

So, the case seems to be well-made that Venusian balloons in themselves do not justify a stand-alone Discovery-class mission. What about making one as a ride-along for a lander or rover? It could go off & do good things at some point during EDL with its own instrumentation...


--------------------
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
David
post Oct 19 2007, 06:07 AM
Post #8


Member
***

Group: Members
Posts: 809
Joined: 11-March 04
Member No.: 56



(From Mars & missions - past and future - Mars sample return)

QUOTE (John Whitehead @ Oct 17 2007, 06:51 PM) *
Rising through the atmosphere with a helium balloon before launching the rocket would be the ideal way to get off of Venus, if only the balloon could be kept from melting.


I presume the way to do that would be to keep the balloon (and rocket) high in the atmosphere, and lowering the sampling package to ground level. If you wanted the "lander" to remain stationary, I suppose there'd be a problem either with the balloon-lander cable breaking; the lander being dragged off by the balloon; or the lander being so heavy that it couldn't be retrieved (although I guess only *part* of it needs to be retrieved). But if the plan is merely to hit the ground (possibly in a variety of places), scoop up random samples, and return, that might not be such a big obstacle.

But with an escape velocity close to that of earth, isn't a pretty large rocket needed just to regain Venus orbit?
Go to the top of the page
 
+Quote Post

Reply to this topicStart new topic

 



RSS Lo-Fi Version Time is now: 19th March 2024 - 02:03 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 funded by the Planetary Society. Please consider supporting our work and many other projects by donating to the Society or becoming a member.