Quote from: MP99 on 06/18/2016 09:00 pmPerhaps this could be suitable for a BEO cubesat mission. Duration should be reasonably short, distance for communicating back is fairly low. No issue with distance from the Sun for solar panels. Flyby would give useful info, and might not have to be at huge speed (depending on SC lifetime). Cheers, MartinA big problem is propulsionIt is safe to assume that the delta-V in the NHATS models is equally distributed among the three.That means the flyby needs ~2.5 km/sec.That's a lot of propulsionCubesats rarely have any, and none have had 1% of this. And you know the tyranny of the rocket equation.And no cubesats have had high Isp SEP.
Perhaps this could be suitable for a BEO cubesat mission. Duration should be reasonably short, distance for communicating back is fairly low. No issue with distance from the Sun for solar panels. Flyby would give useful info, and might not have to be at huge speed (depending on SC lifetime). Cheers, Martin
Quote from: Nilof on 06/18/2016 07:05 pmQuote from: dror on 06/18/2016 06:05 pmQuote from: Nilof on 06/18/2016 12:14 pmQuote from: MP99 on 06/18/2016 11:35 amWhat sort of image could we expect from Hubble of this object? Cheers, MartinA dot. Resolution of Hubble at that distance should be 5 km for violet/soft UV wavelengths.What sort of image could we expect from JWST of this object?JWST is bigger, but it's also restricted to longer wavelengths so its maximum resolution should still be >4 km. You'd need a diffraction limited telescope with a 100m main mirror (or an interferometer with a baseline of that magnitude) to resolve this asteroid. For pretty pictures, sending something close to it is the only real option.......so I wonder if any of these would work for resolving the size:https://en.wikipedia.org/wiki/List_of_astronomical_interferometers_at_visible_and_infrared_wavelengths...what's the apparent magnitude of 2016 HO3?
Quote from: dror on 06/18/2016 06:05 pmQuote from: Nilof on 06/18/2016 12:14 pmQuote from: MP99 on 06/18/2016 11:35 amWhat sort of image could we expect from Hubble of this object? Cheers, MartinA dot. Resolution of Hubble at that distance should be 5 km for violet/soft UV wavelengths.What sort of image could we expect from JWST of this object?JWST is bigger, but it's also restricted to longer wavelengths so its maximum resolution should still be >4 km. You'd need a diffraction limited telescope with a 100m main mirror (or an interferometer with a baseline of that magnitude) to resolve this asteroid. For pretty pictures, sending something close to it is the only real option....
Quote from: Nilof on 06/18/2016 12:14 pmQuote from: MP99 on 06/18/2016 11:35 amWhat sort of image could we expect from Hubble of this object? Cheers, MartinA dot. Resolution of Hubble at that distance should be 5 km for violet/soft UV wavelengths.What sort of image could we expect from JWST of this object?
Quote from: MP99 on 06/18/2016 11:35 amWhat sort of image could we expect from Hubble of this object? Cheers, MartinA dot. Resolution of Hubble at that distance should be 5 km for violet/soft UV wavelengths.
What sort of image could we expect from Hubble of this object? Cheers, Martin
Quote from: Robotbeat on 06/19/2016 02:25 amQuote from: Nilof on 06/18/2016 07:05 pmQuote from: dror on 06/18/2016 06:05 pmQuote from: Nilof on 06/18/2016 12:14 pmQuote from: MP99 on 06/18/2016 11:35 amWhat sort of image could we expect from Hubble of this object? Cheers, MartinA dot. Resolution of Hubble at that distance should be 5 km for violet/soft UV wavelengths.What sort of image could we expect from JWST of this object?JWST is bigger, but it's also restricted to longer wavelengths so its maximum resolution should still be >4 km. You'd need a diffraction limited telescope with a 100m main mirror (or an interferometer with a baseline of that magnitude) to resolve this asteroid. For pretty pictures, sending something close to it is the only real option.......so I wonder if any of these would work for resolving the size:https://en.wikipedia.org/wiki/List_of_astronomical_interferometers_at_visible_and_infrared_wavelengths...what's the apparent magnitude of 2016 HO3?Its apparent magnitude should be about 19 when the object is closest to earth, if I did the math right. So it looks like none of the existing interferometers are up to the task.
Currently no cubesats have high Isp SEP.However"With a ~2U package (including 300cc/1.5kg iodine propellant), the {BUSEK} BIT - 3 system can provide 3km/s delta-V to a 6U/12kg CubeSat."http://www.nasa.gov/sites/default/files/files/Vlad_Busek_Iodine_RF_Ion_Thruster.pdfThis is one of the thrusters in the Technology Development Project Selections announced on September 4, 2013. These should be available soon and in need of a mission (unless they were cancelled).http://www.nasa.gov/content/technology-development-project-selections/#.V2YKmDVaHIV
The fact that the solar wind doesn't perturb it much (hundreds of years stability) suggests a high density.
Since it is close for such a body
As to how you'd get something into such an orbit, it would likely be from debris from the Earth or Moon, either from formation or as part of a collision, where such escaped but not by much, and by accident entered a weak stability region between the Earth Moon Sun ensemble, staying there ever since.
The most interesting part of this is "how long" has it been there? During the formation of the solar system, much has been swept away, so if it has been there a long time, why wasn't it dislodged?
Magnitude per JPL Horizons won't get brighter than recently, in the near future won't get brighter than ~22nd mag. Might change with better obs but going on prior results it's hard to find. See attached for plot of predicted mag and distance. Later it gets closer again but phase angle is worse.
the orbit is locked into a very odd figure-8 pattern that does not seem realistic to be either an artificial satellite launched from Earth or a natural satellite of Earth or asteroid. Taking into consideration [all of the] gravitation and solar forces on the object, this orbital pattern is about as strange as has ever been seen.
Quote from: Comga on 06/16/2016 09:49 pmthe orbit is locked into a very odd figure-8 pattern that does not seem realistic to be either an artificial satellite launched from Earth or a natural satellite of Earth or asteroid. Taking into consideration [all of the] gravitation and solar forces on the object, this orbital pattern is about as strange as has ever been seen. Thought you all might like a link to the original source of this. It's a very strange orbit indeed. Always roughly in the direction of Leo / Virgo, in a figure of eight orbit as seen from Earth - so sometimes closer to the sun, sometimes further away but always in roughly the same absolute direction from Earth. It's very accessible from Earth, in terms of delta v anyway if not bothered about the duration - seems to be slightly easier to reach than the EML2 for its minimum energy orbit and slightlier easier to reach than the Moon for the minimal duration orbit. See delta v table
As to visiting it, a lunar encounter with a phased entry into the same gravitational equipotential would be the obvious choice, like entering a Lissajous orbit. If your US were long lived enough for a post lunar burn you could save much time (down to a few months), but if we're being economical, a hundred kilogram SEP craft that shared a GTO-1800 ride as a secondary might make it in a few years or less, depending on launch and if you could coax a third burn post primary payload, and the moon's position. Such a mission would take longer to design/fund/build/launch then to fly
Quote from: jgoldader on 06/18/2016 02:06 pmQuote from: edkyle99 on 06/18/2016 01:06 pmQuote from: Bynaus on 06/17/2016 06:18 amEven more strange claim. I strongly doubt anyone has been able to measure the mass of this object.Of course they have.http://www.scientificamerican.com/article/how-do-scientists-measure/ - Ed KyleThe OP was asking about THIS object, and since we haven't had a spacecraft near it, there's nothing for it to perturb gravitationally to get a mass. What you'd do is figure a few 1000 kg/m^3 density, give a factor of 2 uncertainty (mostly on the low side in case it's like Mathilde). Given the uncertainty in the size, there's probably about a factor of 10 uncertainty in mass right now. I suspect the size can be measured pretty accurately by radar from the intensity of a reflected signal.Given that Congress seems to want to kill ARRM, it would probably be more useful to think of a low-cost way to get a probe to the asteroid. The Japanese Procyon would likely be a good departure point for a design, but of course its SEP failure would have to be diagnosed and remedied.If the orbit is known, the mass is known. - Ed Kyle
Quote from: edkyle99 on 06/18/2016 01:06 pmQuote from: Bynaus on 06/17/2016 06:18 amEven more strange claim. I strongly doubt anyone has been able to measure the mass of this object.Of course they have.http://www.scientificamerican.com/article/how-do-scientists-measure/ - Ed KyleThe OP was asking about THIS object, and since we haven't had a spacecraft near it, there's nothing for it to perturb gravitationally to get a mass. What you'd do is figure a few 1000 kg/m^3 density, give a factor of 2 uncertainty (mostly on the low side in case it's like Mathilde). Given the uncertainty in the size, there's probably about a factor of 10 uncertainty in mass right now. I suspect the size can be measured pretty accurately by radar from the intensity of a reflected signal.Given that Congress seems to want to kill ARRM, it would probably be more useful to think of a low-cost way to get a probe to the asteroid. The Japanese Procyon would likely be a good departure point for a design, but of course its SEP failure would have to be diagnosed and remedied.
Quote from: Bynaus on 06/17/2016 06:18 amEven more strange claim. I strongly doubt anyone has been able to measure the mass of this object.Of course they have.http://www.scientificamerican.com/article/how-do-scientists-measure/ - Ed Kyle
Even more strange claim. I strongly doubt anyone has been able to measure the mass of this object.
Quote from: Space Ghost 1962 on 06/20/2016 12:07 amThe fact that the solar wind doesn't perturb it much (hundreds of years stability) suggests a high density.I had assumed that the hundreds of years was based on projecting back from current orbit. If it is low enough density to be perturbed, then that just seems to invalidate the assumption, IE it could be a man-made object that seems to be long term stable due to a fluke of current position.
25 - 113 meters:Estimated diameter in meters showing the minimum and maximum likely size based on assumed maximum and minimum albedos of 0.60 and 0.03, respectively. If the size is "known", a single value is shown instead. If a single value is shown, it should still be considered an estimate.