Author Topic: Another reminder of the ever present threat of NEOs  (Read 45478 times)

Offline Star One

  • Senior Member
  • *****
  • Posts: 13497
  • UK
  • Liked: 3747
  • Likes Given: 220
Any why we need more missions dedicated to their detection.

'Bright flash' seen in skies over Scotland

http://www.bbc.co.uk/news/uk-scotland-north-east-orkney-shetland-35689551

You can see it more clearly in this video.


Offline jg

  • Full Member
  • **
  • Posts: 296
  • Liked: 174
  • Likes Given: 7
Re: Another reminder of the ever present threat of NEOs
« Reply #1 on: 02/29/2016 11:27 pm »
I don't think space based systems are economic for NEO detection.

See http://fallingstar.com/home.php

ATLAS, coming on line as I type this, is far, far cheaper than any satellite system would be, and can be replicated many times around the globe once it is proven.

Not everything can/should be done from orbit.

P.S. the PI on ATLAS is a good friend of mine.  It's very clever and very cool...

Offline Blackstar

  • Veteran
  • Senior Member
  • *****
  • Posts: 14175
  • Liked: 6381
  • Likes Given: 2
Re: Another reminder of the ever present threat of NEOs
« Reply #2 on: 03/01/2016 02:53 am »
You want to detect smaller NEOs and more NEOs, you need aperture. In space. Nothing else really works.

Offline jg

  • Full Member
  • **
  • Posts: 296
  • Liked: 174
  • Likes Given: 7
Re: Another reminder of the ever present threat of NEOs
« Reply #3 on: 03/01/2016 03:03 am »
You want to detect smaller NEOs and more NEOs, you need aperture. In space. Nothing else really works.

It's way more complicated than that...  It turns out to be a serious data processing/storage problem.  You'd have serious trouble getting the images down (the data rate is quite high), and you can't afford the power to process the images on orbit.  Lots of things are much easier down here, and much cheaper.  Don't let your love of space blind you to economics and technology.

I recommend you dig deeper into the ATLAS project if you are interested.
http://fallingstar.com/


Offline FinalFrontier

  • Senior Member
  • *****
  • Posts: 4366
  • Space Watcher
  • Liked: 1133
  • Likes Given: 171
Re: Another reminder of the ever present threat of NEOs
« Reply #4 on: 03/01/2016 03:40 am »
You want to detect smaller NEOs and more NEOs, you need aperture. In space. Nothing else really works.

It's way more complicated than that...  It turns out to be a serious data processing/storage problem.  You'd have serious trouble getting the images down (the data rate is quite high), and you can't afford the power to process the images on orbit.  Lots of things are much easier down here, and much cheaper.  Don't let your love of space blind you to economics and technology.

I recommend you dig deeper into the ATLAS project if you are interested.
http://fallingstar.com/
Advances in computing have and are continuing to negate the data problem. Downstream transmission rate remains an issue however if spacecraft bus power is an issue build a bus that uses both a nuclear system and a solar system for added amps and watts. Either that or build better solar systems, many modern spacecraft bus now incorporate far more powerful systems for electrical generation than they did even ten years ago.

I don't see either of these as limiting factors. As for economics and technology?

Economically speaking its easier to build in space observation platforms than ones the ground. Much more easily available real-estate, and you don't have to build atmosphere and ionosphere counteracting systems into the platform.
3-30-2017: The start of a great future
"Live Long and Prosper"

Offline Star One

  • Senior Member
  • *****
  • Posts: 13497
  • UK
  • Liked: 3747
  • Likes Given: 220
Another reminder of the ever present threat of NEOs
« Reply #5 on: 03/01/2016 06:27 am »
The plan by the B612 Foundation to send a telescope out towards Venus & then look back towards the Earth still sounds a good one for NEO spotting. Though they don't seem to be progressing much at the moment themselves with it.
« Last Edit: 03/01/2016 06:28 am by Star One »

Offline kevin-rf

  • Elite Veteran
  • Senior Member
  • *****
  • Posts: 8744
  • Overlooking the path Mary's little Lamb took..
  • Liked: 1241
  • Likes Given: 299
Re: Another reminder of the ever present threat of NEOs
« Reply #6 on: 03/01/2016 01:46 pm »
You want to detect smaller NEOs and more NEOs, you need aperture. In space. Nothing else really works.
You also need the correct wavelength(s), aka IR.
If you're happy and you know it,
It's your med's!

Online Lee Jay

  • Elite Veteran
  • Global Moderator
  • Senior Member
  • *****
  • Posts: 8180
  • Liked: 3081
  • Likes Given: 293
Re: Another reminder of the ever present threat of NEOs
« Reply #7 on: 03/01/2016 01:57 pm »
I think you guys should have read the fallingstar site before commenting.

They are only trying to detect medium sized rocks (50m-150m or so) in near-Earth orbits.  They aren't looking for larger rocks and comets coming in from the outer solar system, as Panstarrs is.  And, yes, IR can be quite helpful especially for more distant and less well illuminated objects, but that isn't what the fallingstar folks are looking for.  That's what NEOWISE is doing.
« Last Edit: 03/01/2016 01:58 pm by Lee Jay »

Offline Ben the Space Brit

  • Senior Member
  • *****
  • Posts: 7202
  • A spaceflight fan
  • London, UK
  • Liked: 801
  • Likes Given: 894
Re: Another reminder of the ever present threat of NEOs
« Reply #8 on: 03/01/2016 02:18 pm »
Following spaceweather.com and its links at the JPL small body database, it has gradually dawned on me that a lot of these objects have only been tracked for a few days, making their orbits conjectural to a greater or lesser extent (which is why the predicted perigee of 2013 TX68 was wrong by several days and about 1.3 million miles).

I'm guessing that there is a concrete maximum detection and tracking distance for objects of any given size. The obvious question is: Can this be augmented somehow? Maybe specialist tracking satellites at SEL1, 2, 4 and 5 using basically a high-resolution version of Hipparcos satellite's technology - identify any object that moves from two photos of the same area of space and use that to estimate distance and motion?
"Oops! I left the silly thing in reverse!" - Duck Dodgers

~*~*~*~

The Space Shuttle Program - 1981-2011

The time for words has passed; The time has come to put up or shut up!
DON'T PROPAGANDISE, FLY!!!

Offline the_other_Doug

  • Senior Member
  • *****
  • Posts: 3011
  • Minneapolis, MN
  • Liked: 2188
  • Likes Given: 4624
Re: Another reminder of the ever present threat of NEOs
« Reply #9 on: 03/01/2016 02:47 pm »
...either that or build better solar systems...

If we could do that, I don't think we'd be worried about finding undocumented rocks flying on collision courses towards our planet...

:D
-Doug  (With my shield, not yet upon it)

Offline whitelancer64

Re: Another reminder of the ever present threat of NEOs
« Reply #10 on: 03/01/2016 03:08 pm »
The plan by the B612 Foundation to send a telescope out towards Venus & then look back towards the Earth still sounds a good one for NEO spotting. Though they don't seem to be progressing much at the moment themselves with it.

Yes, B612's Sentinel telescope would be able to discover some 90% of all near-Earth asteroids approximately 140 meters across and larger - the "city killers" - in its first 4 years of operation, with that going up over 95% with a few more years of operation. It would also discover thousands of Apollo, Aten, and Apohele asteroids, the ones that spend the majority of their orbit closer to the Sun than the Earth does, these groups of asteroids we currently only have a few examples of, and we know very little about them.
"One bit of advice: it is important to view knowledge as sort of a semantic tree -- make sure you understand the fundamental principles, ie the trunk and big branches, before you get into the leaves/details or there is nothing for them to hang on to." - Elon Musk
"There are lies, damned lies, and launch schedules." - Larry J

Offline Blackstar

  • Veteran
  • Senior Member
  • *****
  • Posts: 14175
  • Liked: 6381
  • Likes Given: 2
Re: Another reminder of the ever present threat of NEOs
« Reply #11 on: 03/01/2016 04:38 pm »
You want to detect smaller NEOs and more NEOs, you need aperture. In space. Nothing else really works.

It's way more complicated than that...  It turns out to be a serious data processing/storage problem.  You'd have serious trouble getting the images down (the data rate is quite high), and you can't afford the power to process the images on orbit.  Lots of things are much easier down here, and much cheaper.  Don't let your love of space blind you to economics and technology.

I recommend you dig deeper into the ATLAS project if you are interested.
http://fallingstar.com/



I see your recommendation and recommend that you read the National Academies' study on NEOs:

http://www.nap.edu/read/12842/chapter/1

Offline Blackstar

  • Veteran
  • Senior Member
  • *****
  • Posts: 14175
  • Liked: 6381
  • Likes Given: 2
Re: Another reminder of the ever present threat of NEOs
« Reply #12 on: 03/01/2016 04:41 pm »
The plan by the B612 Foundation to send a telescope out towards Venus & then look back towards the Earth still sounds a good one for NEO spotting. Though they don't seem to be progressing much at the moment themselves with it.

According to Amy Mainzer, the PI for the NEOWISE mission and the PI proposing the NEOCam mission, the B612 proposal to go inside Earth's orbit and look outward doesn't really buy much capability, and it requires cooling systems that complicate the whole thing (and--this is me speaking--probably limit the useful lifetime of the spacecraft). It's just not necessary.

Offline whitelancer64

Re: Another reminder of the ever present threat of NEOs
« Reply #13 on: 03/01/2016 04:57 pm »
The plan by the B612 Foundation to send a telescope out towards Venus & then look back towards the Earth still sounds a good one for NEO spotting. Though they don't seem to be progressing much at the moment themselves with it.

According to Amy Mainzer, the PI for the NEOWISE mission and the PI proposing the NEOCam mission, the B612 proposal to go inside Earth's orbit and look outward doesn't really buy much capability, and it requires cooling systems that complicate the whole thing (and--this is me speaking--probably limit the useful lifetime of the spacecraft). It's just not necessary.

In my opinion, it's worth it to discover Sun-side NEAs that we just would not find otherwise. I agree that you don't absolutely need a Venus-like orbit to do that (it could be at .9 AU or so rather than .7 AU) but our knowledge of asteroids that orbit interior to the Earth is very poor. It would be nice if we had even a little bit of warning rather than be blindsided from the Sun-side like the Chelyabinsk incident.
"One bit of advice: it is important to view knowledge as sort of a semantic tree -- make sure you understand the fundamental principles, ie the trunk and big branches, before you get into the leaves/details or there is nothing for them to hang on to." - Elon Musk
"There are lies, damned lies, and launch schedules." - Larry J

Offline Burninate

  • Full Member
  • ****
  • Posts: 1145
  • Liked: 360
  • Likes Given: 74
Re: Another reminder of the ever present threat of NEOs
« Reply #14 on: 03/01/2016 05:20 pm »
While a wide-field space telescope is inordinately useful, synoptic all-sky surveys have lower-hanging fruit than that, cheaper goals which are easier to achieve and could be built in a year or three if they were to be funded.
I don't think space based systems are economic for NEO detection.

See http://fallingstar.com/home.php

ATLAS, coming on line as I type this, is far, far cheaper than any satellite system would be, and can be replicated many times around the globe once it is proven.

Not everything can/should be done from orbit.

P.S. the PI on ATLAS is a good friend of mine.  It's very clever and very cool...
Scaling up small wide-angle telescope projects like ATLAS to many sites and many telescopes is one, perhaps the cheapest possible option after purely software fixes like running a MOPS network on underutilized existing hardware - figures for an observatory run about $100k-$1M.  Finishing PAN-STARRS is another.  Replicating PAN-STARRS (or similar designs) globally is the next thing after that.  Only then do you start to get into a region where a solid wide-angle space telescope (or preferably, a network of them;  Design once, build many) would be required.  A small telescope can be used on Earth's surface and get its full optical resolution, or close to it, but larger telescopes really need to be beyond the atmosphere.  Around the atmospheric seeing limit, their survey power stops growing as aperture to the fourth power, and starts growing as aperture to the second power.  Narrow-angle pinhole views can be corrected with adaptive optics, wide fields cannot.   PAN-STARRS was designed to be as small & wide as it was possible to be without inducing any greater blurring optically than atmospheric seeing does.  Something like https://www.eso.org/sci/meetings/2012/surveys2012/Posters/Cote.pdf  really gives us a good look at our surroundings in general, and is probably the smallest optical wide-angle space telescope that makes sense for general purposes.

Only after you have that sort of thing in place in Earth orbit does it really make sense to send something further into the inner Solar system.

Laser communications are extraordinarily useful here, increasing data collection rate by several orders of magnitude for rapidly scanned fields.  Rapidly scanning wide fields turn out to be really useful for fighting the thermal noise floor of CCD/CMOS sensors in the specific context of asteroids that move around during an exposure.
« Last Edit: 03/01/2016 05:27 pm by Burninate »

Offline kevin-rf

  • Elite Veteran
  • Senior Member
  • *****
  • Posts: 8744
  • Overlooking the path Mary's little Lamb took..
  • Liked: 1241
  • Likes Given: 299
Re: Another reminder of the ever present threat of NEOs
« Reply #15 on: 03/01/2016 05:29 pm »
I believe Chelyabinsk sized window killers at ~20-30m are below most search detection thresholds. While they are picked up near to earth, mapping 99.9995% of them are not the goal of any of the searches... yet.

I think the key for asteroids inside earths orbit is developing a HEO spaced based capability that can look reasonably close to the sun. That could find many of the larger more threatening objects.

As for data, may I make a suggestion. Looking at some of Midas/DSP histories it was pointed out that the bandwidth just wasn't originally available to constantly stream full images. So they took the scan line data approach with the IR sensors. Just return the location (x,y), shape, and intensity of the IR objects found. Greatly reduces the data that needs to be transferred. Couple in a map of known IR emitters and Venus data rates seem reasonable.
If you're happy and you know it,
It's your med's!

Offline FinalFrontier

  • Senior Member
  • *****
  • Posts: 4366
  • Space Watcher
  • Liked: 1133
  • Likes Given: 171
Re: Another reminder of the ever present threat of NEOs
« Reply #16 on: 03/01/2016 05:37 pm »
...either that or build better solar systems...

If we could do that, I don't think we'd be worried about finding undocumented rocks flying on collision courses towards our planet...

:D
Hah. I meant panels ofc but that was funny.

Yes yes what we need is kerbal space program in real life. Rebuild our own solar system.
3-30-2017: The start of a great future
"Live Long and Prosper"

Offline kevin-rf

  • Elite Veteran
  • Senior Member
  • *****
  • Posts: 8744
  • Overlooking the path Mary's little Lamb took..
  • Liked: 1241
  • Likes Given: 299
Re: Another reminder of the ever present threat of NEOs
« Reply #17 on: 03/01/2016 05:51 pm »
Yes yes what we need is kerbal space program in real life. Rebuild our own solar system.
Class 5 meter cleanroom?
If you're happy and you know it,
It's your med's!

Offline jgoldader

  • Full Member
  • ****
  • Posts: 759
  • Liked: 321
  • Likes Given: 166
Re: Another reminder of the ever present threat of NEOs
« Reply #18 on: 03/01/2016 07:05 pm »
The plan by the B612 Foundation to send a telescope out towards Venus & then look back towards the Earth still sounds a good one for NEO spotting. Though they don't seem to be progressing much at the moment themselves with it.

They never got the money.  Great idea, though, and I'm hoping NEOCAM wins its competition so we can get down to doing some of that science.
Recovering astronomer

Offline whitelancer64

Re: Another reminder of the ever present threat of NEOs
« Reply #19 on: 03/01/2016 07:18 pm »
The plan by the B612 Foundation to send a telescope out towards Venus & then look back towards the Earth still sounds a good one for NEO spotting. Though they don't seem to be progressing much at the moment themselves with it.

They never got the money.  Great idea, though, and I'm hoping NEOCAM wins its competition so we can get down to doing some of that science.

The B612 Foundation still exists and is still raising money, though they are very far from the approximately $450 million they need.

Looks like they recently redesigned their website, though!

https://b612foundation.org/
"One bit of advice: it is important to view knowledge as sort of a semantic tree -- make sure you understand the fundamental principles, ie the trunk and big branches, before you get into the leaves/details or there is nothing for them to hang on to." - Elon Musk
"There are lies, damned lies, and launch schedules." - Larry J

Tags:
 

Advertisement NovaTech
Advertisement SkyTale Software GmbH
Advertisement Northrop Grumman
Advertisement
Advertisement Brady Kenniston
Advertisement NextSpaceflight
Advertisement Nathan Barker Photography
1