Quote from: Danderman on 04/25/2012 05:23 pmA technical question about the 100 series:According to the video, the spacecraft uses reaction wheels for pointing, and there is no chemical RCS (ie no thrusters). So, how does a spacecraft without propulsive thrusters de-saturate the reaction wheels?Almost certainly magnetic torquers, like Hubble. (These are really common for cubesats and probably microsats as well.)
A technical question about the 100 series:According to the video, the spacecraft uses reaction wheels for pointing, and there is no chemical RCS (ie no thrusters). So, how does a spacecraft without propulsive thrusters de-saturate the reaction wheels?
Quote from: Robotbeat on 04/25/2012 05:25 pmQuote from: Danderman on 04/25/2012 05:23 pmA technical question about the 100 series:According to the video, the spacecraft uses reaction wheels for pointing, and there is no chemical RCS (ie no thrusters). So, how does a spacecraft without propulsive thrusters de-saturate the reaction wheels?Almost certainly magnetic torquers, like Hubble. (These are really common for cubesats and probably microsats as well.)Do magnetic torquers work beyond LEO?
Since nobody seems to have posted this yet, there is a good video giving some detail on the 100 series here:
They seem like smart people who are willing to put lots of capital into their project without short-term return...The PR business plan seems to make sense in two short-term scenarios, PGMs ...and water/LH2/LOX
I'm not sure what excites me more about the potential of Planetary Resources:Having a catalogue of potentially civilization saving information (orbits of NEO's)Discovering zillions of exoplanets through optical interferometryThe new data we can collect about our solar system, including through visual observations.A map of noteable Kuiper and Oort objects along with high-res photos of many of them.The improved resolution of various interstellar phenomenonHaving very regular high-res updates (and historical database) to google earth (or perhaps it will be called PR-Earth)The potential for abundant volatiles and metals that could be processed in space and used for in-space habitation and transportation by all comersThe impact it will have on STEM outreach
a constellation aimed at finding NEOs are not going to produce a bunch of data on Kuiper Belt objects.
Quote from: Danderman on 05/04/2012 01:47 pma constellation aimed at finding NEOs are not going to produce a bunch of data on Kuiper Belt objects.I am assuming they won't be all aimed at NEO's all the time. "swarms".
Where are all these wild expectations about using the telescopes for interferometry coming from? Has the PR even hinted at that?
More to the point, the telescopes used by PR will be optimized for close object; space isn't like Star Trek, where every system can be quickly reconfigured for other purposes, like using the deflector dish as a weapon; in this case, if the telescopes are not optimized for business purposes, there will be a significant cost.
Quote from: go4mars on 05/04/2012 01:28 pmI'm not sure what excites me more about the potential of Planetary Resources:Having a catalogue of potentially civilization saving information (orbits of NEO's)Discovering zillions of exoplanets through optical interferometryThe new data we can collect about our solar system, including through visual observations.A map of noteable Kuiper and Oort objects along with high-res photos of many of them.The improved resolution of various interstellar phenomenonHaving very regular high-res updates (and historical database) to google earth (or perhaps it will be called PR-Earth)The potential for abundant volatiles and metals that could be processed in space and used for in-space habitation and transportation by all comersThe impact it will have on STEM outreachMy understanding about telescopes is that they need to be focused on a specific distance - so a constellation aimed at finding NEOs are not going to produce a bunch of data on Kuiper Belt objects.
Quote from: Danderman on 05/04/2012 01:47 pmQuote from: go4mars on 05/04/2012 01:28 pmI'm not sure what excites me more about the potential of Planetary Resources:Having a catalogue of potentially civilization saving information (orbits of NEO's)Discovering zillions of exoplanets through optical interferometryThe new data we can collect about our solar system, including through visual observations.A map of noteable Kuiper and Oort objects along with high-res photos of many of them.The improved resolution of various interstellar phenomenonHaving very regular high-res updates (and historical database) to google earth (or perhaps it will be called PR-Earth)The potential for abundant volatiles and metals that could be processed in space and used for in-space habitation and transportation by all comersThe impact it will have on STEM outreachMy understanding about telescopes is that they need to be focused on a specific distance - so a constellation aimed at finding NEOs are not going to produce a bunch of data on Kuiper Belt objects.Wouldn't the telescope simply be focused to infinity?cheers, Martin
Quote from: MP99 on 05/04/2012 07:55 pmQuote from: Danderman on 05/04/2012 01:47 pmQuote from: go4mars on 05/04/2012 01:28 pmI'm not sure what excites me more about the potential of Planetary Resources:Having a catalogue of potentially civilization saving information (orbits of NEO's)Discovering zillions of exoplanets through optical interferometryThe new data we can collect about our solar system, including through visual observations.A map of noteable Kuiper and Oort objects along with high-res photos of many of them.The improved resolution of various interstellar phenomenonHaving very regular high-res updates (and historical database) to google earth (or perhaps it will be called PR-Earth)The potential for abundant volatiles and metals that could be processed in space and used for in-space habitation and transportation by all comersThe impact it will have on STEM outreachMy understanding about telescopes is that they need to be focused on a specific distance - so a constellation aimed at finding NEOs are not going to produce a bunch of data on Kuiper Belt objects.Wouldn't the telescope simply be focused to infinity?cheers, MartinI was waiting to see who would notice that - at about 1000 focal lengths, the object is at optical infinity, once the optic is set to infinity focus all objects observed beyond that distance will be "in focus". Any telescope built in the foreseeable future orbiting near earth will be set to infinity when looking out at astronomical objects including asteroids (looking down at the earth or in near space might need to be focused).
Quote from: BrightLight on 05/04/2012 08:02 pmQuote from: MP99 on 05/04/2012 07:55 pmQuote from: Danderman on 05/04/2012 01:47 pmQuote from: go4mars on 05/04/2012 01:28 pmI'm not sure what excites me more about the potential of Planetary Resources:Having a catalogue of potentially civilization saving information (orbits of NEO's)Discovering zillions of exoplanets through optical interferometryThe new data we can collect about our solar system, including through visual observations.A map of noteable Kuiper and Oort objects along with high-res photos of many of them.The improved resolution of various interstellar phenomenonHaving very regular high-res updates (and historical database) to google earth (or perhaps it will be called PR-Earth)The potential for abundant volatiles and metals that could be processed in space and used for in-space habitation and transportation by all comersThe impact it will have on STEM outreachMy understanding about telescopes is that they need to be focused on a specific distance - so a constellation aimed at finding NEOs are not going to produce a bunch of data on Kuiper Belt objects.Wouldn't the telescope simply be focused to infinity?cheers, MartinI was waiting to see who would notice that - at about 1000 focal lengths, the object is at optical infinity, once the optic is set to infinity focus all objects observed beyond that distance will be "in focus". Any telescope built in the foreseeable future orbiting near earth will be set to infinity when looking out at astronomical objects including asteroids (looking down at the earth or in near space might need to be focused).If that were the case, wouldn't Hubble already have even better coverage of the near Earth region?
http://planetarydefense.blogspot.com/2011/02/nasa-fy2012-budget-and-neo-program.htmlNASA has money to purchase NEO data. So PR could sell its data to NASA to almost get the cost of operating and possibly developing its satelllites paid for.Especially since PR would be doing the NEO data collection with or without NASA money.
My point here is: if telescopes focused on infinity can resolve near Earth objects as well as far away stars, given that Hubble has been pointing out for some 20 years, it should have an enormous number of images of NEOs as a by-product of its star searches.