Done a little surfing. You know, this takes a lot of time on a slow modem, and especially if one doesn't bookmark many sites! Now, I'm all for space travel, but I don't wear a NASA jumpsuit or rubber-stamp my appoval on every press release that comes out of NASA or JPL. As a taxpayer, though, I've got a right to question, even at this late date. Apparently the lander has no camera! It is a ESA craft, only the orbiter section's design and constuction was NASA managed. I had many problems even loading some of the ESA pages, but couldn't find anything on surface imaging. The entire lander science package is geared toward atmospheric measurement. There was one link that didn't work that said something like 'surface science'. Good luck, folks, you've got maybe 180 seconds, so get it right! Heck, I'd trade weather data for pictures or video on the first mission to any planetary or "dirt" target, any day. I'm also reminded that the entire lander sequence has been re-scripted since launch because it was discovered that at the relative speeds of the two craft after separation, they could'nt communicate with each other. Seems that the bandwidth on the orbiters receiver is too narrow to receive the Doppler-shifted transmitions of the lander! No kidding! So the new separation scenario calls for a much slower approach. C'mon, this is basic engineering for spacecraft. How could they have botched this? A project manager should have lost his/her job for that one. And the cost of the mission deducted from their check! And with the power situation being as tightly budgeted as it is, there won't be a second chance to transmit the lander data. Joe, the lander only has batteries, no nuke fuel. I really hope this mission works as advertised. After what I've read today, though, I'm not quite as optimistic as I was. Have we sent a K-car to Saturn? my 3 cents (and all typed with one hand!). C. __________________________________ Do you Yahoo!? Free Pop-Up Blocker - Get it now http://companion.yahoo.com/
I asked Dr. Ellis Miner from JPL about the batteries, this was his reply: The 153-minute lifetime of the Huygens batteries is a worst-case scenario. The battery capacity is several hundred Watt hours, even with the assumption of complete failure of one of the five batteries. The 153 minutes assumes a worst cast energy consumption during the descent phase (2.5 hours descent + 0.5 hour on the surface) of 326 Watt hours. More careful analysis of the actual expected consumption during that 3-hour descent phase is 235 Watt hours. While on the surface of Titan the consumption will be something on the order of 100 Watts. Furthermore, the 2.5-hour descent time is also a worst case number, and every minute earlier than that provides an additional minute of surface data. In fact, the limiting factor on the amount of surface data collected is likely to be the disappearance of the Cassini orbiter over the horizon of the Huygens Probe transmitters. That occurs nominally just under an hour after nominal landing. The present plans are too keep the probe transmitting for the full 210 minutes. Ken
Ken, what does he have to say about the lack of a camera? Thanks, Joe
Joe, apparently there is a camera and I just couldn't find any pertinent links. It may just be a "look down" camera for documenting the landing spot, but I hope that it can take panoramic shots too. C. --- Joe Bauman <bau@desnews.com> wrote:
Ken, what does he have to say about the lack of a camera? Thanks, Joe
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From the JPL Site (http://saturn.jpl.nasa.gov/spacecraft/instruments-huygens.cfm) : Descent Imager/Spectral Radiometer (DISR): This instrument will make a range of imaging and spectral observations using several sensors and fields of view. By measuring the upward and downward flow of radiation, the radiation balance (or imbalance) of the thick Titan atmosphere will be measured. Solar sensors will measure the light intensity around the Sun due to scattering by aerosols in the atmosphere. This will permit the calculation of the size and number density of the suspended particles. Two imagers (one visible, one infrared) will observe the surface during the latter stages of the descent and, as the probe slowly spins, build up a mosaic of pictures around the landing site. There will also be a side-view visible imager to get a horizontal view of the horizon and the underside of the cloud deck. For spectral measurements of the surface, a lamp that will switch on shortly before landing will augment the weak sunlight. My italics...db On Sunday, December 7, 2003, at 03:50 PM, Chuck Hards wrote:
Joe, apparently there is a camera and I just couldn't find any pertinent links.
It may just be a "look down" camera for documenting the landing spot, but I hope that it can take panoramic shots too.
C.
--- Joe Bauman <bau@desnews.com> wrote:
Ken, what does he have to say about the lack of a camera? Thanks, Joe
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Thanks, David. Let's keep our fingers crossed that all goes well with the probe. I am more excited about this one than anything since the first Mars lander that worked. And actually, I think this has the potential to be even more thrilling, because for the first time we may see an ocean or lake on an alien world. Best wishes, Joe
It looks like the Huygens probe does indeed have a camera. Check out this link: http://saturn.jpl.nasa.gov/spacecraft/instruments-huygens.cfm Then look under the "Descent Imager/Spectral Radiometer (DISR)" section and it talks about a visible and an infrared camera that will take a mosaic of pictures around the landing site and during descent. You had me worried there for a moment. I remember reading about the histories of the various problems and how so many scientists argued against having cameras on board (because they were "unscientific" and weren't there to address any specific hypothesis, rather just there to see what they could see) but the "PR" guys at Nasa (including, on some of the missions, Carl Sagan) forced them to put the cameras on. Of course, it seems to have turned out, time and time again, that the cameras gave the most useful information every time. Remember Galileo's probe that was dropped into the atmosphere of Jupiter? It took them forever to explain the strange readings they got while it descended. If they had a camera on board they would have seen right off the bat that the probe had dropped into a "hole" in the clouds. Chuck Hards wrote:
Done a little surfing. You know, this takes a lot of time on a slow modem, and especially if one doesn't bookmark many sites!
Now, I'm all for space travel, but I don't wear a NASA jumpsuit or rubber-stamp my appoval on every press release that comes out of NASA or JPL. As a taxpayer, though, I've got a right to question, even at this late date.
Apparently the lander has no camera! It is a ESA craft, only the orbiter section's design and constuction was NASA managed. I had many problems even loading some of the ESA pages, but couldn't find anything on surface imaging. The entire lander science package is geared toward atmospheric measurement. There was one link that didn't work that said something like 'surface science'. Good luck, folks, you've got maybe 180 seconds, so get it right!
Heck, I'd trade weather data for pictures or video on the first mission to any planetary or "dirt" target, any day.
I'm also reminded that the entire lander sequence has been re-scripted since launch because it was discovered that at the relative speeds of the two craft after separation, they could'nt communicate with each other. Seems that the bandwidth on the orbiters receiver is too narrow to receive the Doppler-shifted transmitions of the lander! No kidding! So the new separation scenario calls for a much slower approach.
C'mon, this is basic engineering for spacecraft. How could they have botched this? A project manager should have lost his/her job for that one. And the cost of the mission deducted from their check!
And with the power situation being as tightly budgeted as it is, there won't be a second chance to transmit the lander data. Joe, the lander only has batteries, no nuke fuel.
I really hope this mission works as advertised. After what I've read today, though, I'm not quite as optimistic as I was. Have we sent a K-car to Saturn?
my 3 cents (and all typed with one hand!).
C.
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"various problems" below should read "various probes". Sorry, I guess I should proof-read a little better. Chris Russell wrote:
You had me worried there for a moment. I remember reading about the histories of the various problems and how so many scientists argued against having cameras on board (because they were "unscientific" and weren't there to address any specific hypothesis, rather just there to see what they could see) but the "PR" guys at Nasa (including, on some of the missions, Carl Sagan) forced them to put the cameras on. Of course, it seems to have turned out, time and time again, that the cameras gave the most useful information every time.
Thanks, Chuck! It's indeed discouraging. I just wonder what in the world they were thinking. Maybe it was that quicker, cheaper, more likely to fail mentality NASA has been plagued with. -- Joe
participants (5)
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Chris Russell -
Chuck Hards -
David L Bennett -
Joe Bauman -
Ken Warner