Comments on: Spacevidcast 2.20 – Guinness in space, JAXA Space Power, Ulysses is dead! http://www.spacevidcast.com/2009/07/03/spacevidcast-2-20-guiness-in-space-jaxa-space-power-ulysses-is-dead/ Making Space Commonplace Tue, 07 Feb 2012 06:02:46 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: Robert Horning http://www.spacevidcast.com/2009/07/03/spacevidcast-2-20-guiness-in-space-jaxa-space-power-ulysses-is-dead/#comment-769 Robert Horning Wed, 08 Jul 2009 01:23:02 +0000 http://www.spacevidcast.com/?p=1738#comment-769 It turns out that the Earth is fairly uniform in terms of its mass distribution (with a few exceptions.... there are mascons on the Earth as well, but they aren't nearly so pronounced as the lunar ones... Antarctica being one of them on the Earth... that impact the Southern Ocean as well). One of the side effects of this is that there are only 4 stable orbital "inclinations" or paths that can be used to orbit the Moon for a long period of time. (See http://science.nasa.gov/headlines/y2006/06nov_loworbit.htm for some additional details) These orbits work at 27º, 50º, 76º, and 86º, with the last one that is perhaps the best one for lunar mapping efforts like the LRO. NASA happen to get very lucky with Apollo 15 when a "sub-satellite" or a satellite was launched from the Apollo 15 command capsule while David Scott and James Irwin were having fun on the surface of the Moon. It happen to be released in one of these more stable orbits (at about 28º inclination from the lunar equator), while a similar satellite launched on Apollo 16 crashed almost right away. "Stable" is relative as well, but it is significant that this information is something that was discovered by the Apollo program and wasn't even considered as something worth bothering about by engineers who had only previous experience orbiting stuff around the Earth. BTW, after digging around, it appears as though the LRO is going to have an inclination of more or less 90º (with some adjustment of about a degree or two during its expected lifetime in orbit). I think that the engineers are sacrificing some time in orbit to get more accurate maps... and trying to map the polar regions of the Moon. It is hoped that water ice is going to be found in the lunar polar regions in what is called an "ocean of eternal darkness" (see http://en.wikipedia.org/wiki/Peak_of_Eternal_Light for details... cool names if I ever hears of some). It turns out that the Earth is fairly uniform in terms of its mass distribution (with a few exceptions…. there are mascons on the Earth as well, but they aren’t nearly so pronounced as the lunar ones… Antarctica being one of them on the Earth… that impact the Southern Ocean as well). One of the side effects of this is that there are only 4 stable orbital “inclinations” or paths that can be used to orbit the Moon for a long period of time. (See http://science.nasa.gov/headlines/y2006/06nov_loworbit.htm for some additional details) These orbits work at 27º, 50º, 76º, and 86º, with the last one that is perhaps the best one for lunar mapping efforts like the LRO.

NASA happen to get very lucky with Apollo 15 when a “sub-satellite” or a satellite was launched from the Apollo 15 command capsule while David Scott and James Irwin were having fun on the surface of the Moon. It happen to be released in one of these more stable orbits (at about 28º inclination from the lunar equator), while a similar satellite launched on Apollo 16 crashed almost right away. “Stable” is relative as well, but it is significant that this information is something that was discovered by the Apollo program and wasn’t even considered as something worth bothering about by engineers who had only previous experience orbiting stuff around the Earth.

BTW, after digging around, it appears as though the LRO is going to have an inclination of more or less 90º (with some adjustment of about a degree or two during its expected lifetime in orbit). I think that the engineers are sacrificing some time in orbit to get more accurate maps… and trying to map the polar regions of the Moon. It is hoped that water ice is going to be found in the lunar polar regions in what is called an “ocean of eternal darkness” (see http://en.wikipedia.org/wiki/Peak_of_Eternal_Light for details… cool names if I ever hears of some).

]]> By: Rick Boozer http://www.spacevidcast.com/2009/07/03/spacevidcast-2-20-guiness-in-space-jaxa-space-power-ulysses-is-dead/#comment-768 Rick Boozer Sun, 05 Jul 2009 22:24:37 +0000 http://www.spacevidcast.com/?p=1738#comment-768 Thanks, Ben! Thanks, Ben!

]]> By: Benjamin Higginbotham http://www.spacevidcast.com/2009/07/03/spacevidcast-2-20-guiness-in-space-jaxa-space-power-ulysses-is-dead/#comment-767 Benjamin Higginbotham Sun, 05 Jul 2009 20:54:58 +0000 http://www.spacevidcast.com/?p=1738#comment-767 Rick, I fixed that for you. Rick, I fixed that for you.

]]> By: Rick Boozer http://www.spacevidcast.com/2009/07/03/spacevidcast-2-20-guiness-in-space-jaxa-space-power-ulysses-is-dead/#comment-766 Rick Boozer Sun, 05 Jul 2009 19:48:07 +0000 http://www.spacevidcast.com/?p=1738#comment-766 Sorry, I meant to italicise Rand's comments rather than bold face them. Too little time and in too much of a hurry, as usual! :( Sorry, I meant to italicise Rand’s comments rather than bold face them. Too little time and in too much of a hurry, as usual! :(

]]> By: Rick Boozer http://www.spacevidcast.com/2009/07/03/spacevidcast-2-20-guiness-in-space-jaxa-space-power-ulysses-is-dead/#comment-765 Rick Boozer Sun, 05 Jul 2009 19:46:17 +0000 http://www.spacevidcast.com/?p=1738#comment-765 The cause of commercial manned spaceflight has been dealt a political blow. The Orlando Sentinel reports: <i>For months, a powerful Republican senator from Alabama has fought the Obama administration to block $150 million that the White House wanted to spend to help private companies build rockets capable of reaching the international space station. Now, it appears that U.S. Sen. Richard Shelby has won, in a decision that could have a major impact on the Cape Canaveral work force and America's continued access to space. According to administration and industry sources, Shelby insisted that $100 million of the money — part of $1 billion set aside for NASA under this spring's economic-stimulus bill — be diverted to Constellation, the troubled rocket program meant to replace the space shuttle after its 2010 retirement.</i> Read more about it here: http://www.orlandosentinel.com/news/space/orl-shelby-private-rockets-070309,0,4053077.story Even the very conservative, pro-Republican Rand Sindberg on his Transterrestrial Musings website remarked: <i>"It (Constellation) can’t use it in any way that’s beneficial to either the taxpayer, or a space enthusiast. I almost weep when I think of the useful things we could do with a mere hundred million dollars. Shelby is quickly making himself public enemy number one of anyone who wants a sane and cost-effective space program. More over at the Sentinel. "</i> See: http://www.transterrestrial.com/?p=20151 The cause of commercial manned spaceflight has been dealt a political blow.

The Orlando Sentinel reports:
For months, a powerful Republican senator from Alabama has fought the Obama administration to block $150 million that the White House wanted to spend to help private companies build rockets capable of reaching the international space station.

Now, it appears that U.S. Sen. Richard Shelby has won, in a decision that could have a major impact on the Cape Canaveral work force and America’s continued access to space.

According to administration and industry sources, Shelby insisted that $100 million of the money — part of $1 billion set aside for NASA under this spring’s economic-stimulus bill — be diverted to Constellation, the troubled rocket program meant to replace the space shuttle after its 2010 retirement.

Read more about it here: http://www.orlandosentinel.com/news/space/orl-shelby-private-rockets-070309,0,4053077.story

Even the very conservative, pro-Republican Rand Sindberg on his Transterrestrial Musings website remarked:
“It (Constellation) can’t use it in any way that’s beneficial to either the taxpayer, or a space enthusiast. I almost weep when I think of the useful things we could do with a mere hundred million dollars. Shelby is quickly making himself public enemy number one of anyone who wants a sane and cost-effective space program. More over at the Sentinel.
“
See: http://www.transterrestrial.com/?p=20151

]]> By: Shanuson http://www.spacevidcast.com/2009/07/03/spacevidcast-2-20-guiness-in-space-jaxa-space-power-ulysses-is-dead/#comment-764 Shanuson Sun, 05 Jul 2009 13:25:26 +0000 http://www.spacevidcast.com/?p=1738#comment-764 You are right, i think, you dump it, so you can control it's end, you free your space around moon, and you can get some science in crashing something into the moon. http://de.wikipedia.org/w/index.php?title=Datei:MoonLP150Q_grav_150.jpg&filetimestamp=20061118170205 <- a map of the mascon's on the moon. In theory you could leave orbiters cycling the moon a lot longer, even with no fuel to do corrections but your orbit would change unpredictable. So LRO will crash because there is no fuel left, LCROSS will crash because its mission need it to crash. greetings Shanuson You are right, i think, you dump it, so you can control it’s end, you free your space around moon, and you can get some science in crashing something into the moon. http://de.wikipedia.org/w/index.php?title=Datei:MoonLP150Q_grav_150.jpg&filetimestamp=20061118170205 <- a map of the mascon's on the moon.
In theory you could leave orbiters cycling the moon a lot longer, even with no fuel to do corrections but your orbit would change unpredictable.
So LRO will crash because there is no fuel left, LCROSS will crash because its mission need it to crash.

greetings
Shanuson

]]> By: Stefan http://www.spacevidcast.com/2009/07/03/spacevidcast-2-20-guiness-in-space-jaxa-space-power-ulysses-is-dead/#comment-763 Stefan Sat, 04 Jul 2009 22:49:02 +0000 http://www.spacevidcast.com/?p=1738#comment-763 @Shanuson, or should I say Hello neighbour ;-) The reason why they dump a moon satellite in this way is quite interesting, a real topic for SVD. It is simply not possible to have a moon satellite for a long time in the moon orbit. The reason is that you have to have enough fuel left to make corrections, because of the mascons. Mascon stands for mass concentration and you can look it up on wikipedia (both in German or English). The mascons are located inside the big craters and they disturb the flight of the satellite quiet frankly. So the gravitational field around the moon is not as spherical as around the earth. The first map of the mascons was made by Lunar Prospector. I'm not an expert in this field, but I think that's the reason you have to dump when the fuel is left. Greetings Stefan @Shanuson, or should I say Hello neighbour ;-)

The reason why they dump a moon satellite in this way is quite interesting, a real topic for SVD. It is simply not possible to have a moon satellite for a long time in the moon orbit. The reason is that you have to have enough fuel left to make corrections, because of the mascons. Mascon stands for mass concentration and you can look it up on wikipedia (both in German or English). The mascons are located inside the big craters and they disturb the flight of the satellite quiet frankly. So the gravitational field around the moon is not as spherical as around the earth. The first map of the mascons was made by Lunar Prospector.

I’m not an expert in this field, but I think that’s the reason you have to dump when the fuel is left.

Greetings
Stefan

]]> By: Shanuson http://www.spacevidcast.com/2009/07/03/spacevidcast-2-20-guiness-in-space-jaxa-space-power-ulysses-is-dead/#comment-762 Shanuson Sat, 04 Jul 2009 20:24:52 +0000 http://www.spacevidcast.com/?p=1738#comment-762 Thanks, looked it up, and i cant found it on nasas lro page how LRO's live will end, but i think LRO will crash into the moon too. But unlike LCROSS LRO's mission isn't designed around that "i will hit the moon" part, it is just the way to dump a moon satellite. And while LCROSS will hit the moon in around 7 month i believe, LRO's mission is at least one year long. And hi Stefan, like you, i'm from Heidelberg, Germany too. Funny that the only other german "SVCer" i know now, is also form Heidelberg. Thanks, looked it up, and i cant found it on nasas lro page how LRO’s live will end, but i think LRO will crash into the moon too. But unlike LCROSS LRO’s mission isn’t designed around that “i will hit the moon” part, it is just the way to dump a moon satellite. And while LCROSS will hit the moon in around 7 month i believe, LRO’s mission is at least one year long.

And hi Stefan, like you, i’m from Heidelberg, Germany too. Funny that the only other german “SVCer” i know now, is also form Heidelberg.

]]> By: David R Haslam http://www.spacevidcast.com/2009/07/03/spacevidcast-2-20-guiness-in-space-jaxa-space-power-ulysses-is-dead/#comment-761 David R Haslam Sat, 04 Jul 2009 15:46:07 +0000 http://www.spacevidcast.com/?p=1738#comment-761 You guys are awesome! Don't listen to the trolls! :-) All the best, David. You guys are awesome! Don’t listen to the trolls! :-)

All the best,
David.

]]> By: cariann http://www.spacevidcast.com/2009/07/03/spacevidcast-2-20-guiness-in-space-jaxa-space-power-ulysses-is-dead/#comment-760 cariann Sat, 04 Jul 2009 14:37:45 +0000 http://www.spacevidcast.com/?p=1738#comment-760 Stefan, There is no need to apologize. I understood everything you said. It was perfectly clear! And thank you for the clarification. I appreciate it. Welcome from Minnesota, USA! -Cariann Stefan,
There is no need to apologize. I understood everything you said. It was perfectly clear!

And thank you for the clarification. I appreciate it.

Welcome from Minnesota, USA!

-Cariann

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