Close encounters of the Asteroidal Kind
Next week (Feb 15) the earth will be visited by asteroid 2012 DA14 passing inside the gestationary satellite orbits. To quote from http://echo.jpl.nasa.gov/asteroids/2012DA14/2012DA14_planning.html,
2012 DA14 was discovered by the La Sagra Sky Survey in Spain on February 23, 2012. This object will make an extremely close approach to within 0.00023 AU of Earth at 19:25 UT (11:25 AM PST) on February 15, 2013. That is only 0.09 lunar distances or 5.4 Earth radii from the center of the Earth. The close approach will be about 28000 km above Earth's surface. That's inside the distance to geosynchronous satellites but thousands of kilometers above the elevation for low-Earth-orbit spacecraft such as the International Space Station. At the time of closest approach, the asteroid will move about 0.8 degrees per minute.
There is considerable interest in the astronomy community over plans to do radar tracking of the asteroid. The Goldstone 70M dish will be running MAX QRO with 435 kW.
73 de Tom, K3IO
At 01:06 AM 2/7/2013 -0500, k3io@verizon.net wrote:
Next week (Feb 15) the earth will be visited by asteroid 2012 DA14 passing inside the gestationary satellite orbits. To quote from http://echo.jpl.nasa.gov/asteroids/2012DA14/2012DA14_planning.html,
2012 DA14 was discovered by the La Sagra Sky Survey in Spain on February 23, 2012. This object will make an extremely close approach to within 0.00023 AU of Earth at 19:25 UT (11:25 AM PST) on February 15, 2013. That is only 0.09 lunar distances or 5.4 Earth radii from the center of the Earth. The close approach will be about 28000 km above Earth's surface. That's inside the distance to geosynchronous satellites but thousands of kilometers above the elevation for low-Earth-orbit spacecraft such as the International Space Station. At the time of closest approach, the asteroid will move about 0.8 degrees per minute.
There is considerable interest in the astronomy community over plans to do radar tracking of the asteroid. The Goldstone 70M dish will be running MAX QRO with 435 kW.
73 de Tom, K3IO
I know some might think this is off topic, but I enjoy seeing reports like these on the BB.
Thanks Tom.
KB7ADL
maybe "asteroid bounce"? (EAE) 73 Bob W7LRD
----- Original Message ----- From: "Vince Fiscus, KB7ADL" vlfiscus@mcn.net To: amsat-bb@amsat.org Sent: Thursday, February 7, 2013 7:18:47 AM Subject: [amsat-bb] Re: Close encounters of the Asteroidal Kind
At 01:06 AM 2/7/2013 -0500, k3io@verizon.net wrote:
Next week (Feb 15) the earth will be visited by asteroid 2012 DA14 passing inside the gestationary satellite orbits. To quote from http://echo.jpl.nasa.gov/asteroids/2012DA14/2012DA14_planning.html,
2012 DA14 was discovered by the La Sagra Sky Survey in Spain on February 23, 2012. This object will make an extremely close approach to within 0.00023 AU of Earth at 19:25 UT (11:25 AM PST) on February 15, 2013. That is only 0.09 lunar distances or 5.4 Earth radii from the center of the Earth. The close approach will be about 28000 km above Earth's surface. That's inside the distance to geosynchronous satellites but thousands of kilometers above the elevation for low-Earth-orbit spacecraft such as the International Space Station. At the time of closest approach, the asteroid will move about 0.8 degrees per minute.
There is considerable interest in the astronomy community over plans to do radar tracking of the asteroid. The Goldstone 70M dish will be running MAX QRO with 435 kW.
73 de Tom, K3IO
I know some might think this is off topic, but I enjoy seeing reports like these on the BB.
Thanks Tom.
KB7ADL
_______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
On 8/02/13 7:49 AM, Bob- W7LRD wrote:
maybe "asteroid bounce"? (EAE) 73 Bob W7LRD
Someone on the moonbounce reflector crunched the numbers and came up with a path loss figure something like 51dB worse than EME, if I recall. The small cross section area was the killer.
Still, nothing ventured, nothing gained. :)
At 09:01 AM 2/8/2013 +1100, Tony Langdon vk3jed@gmail.com wrote:
On 8/02/13 7:49 AM, Bob- W7LRD wrote:
maybe "asteroid bounce"? (EAE) 73 Bob W7LRD
Someone on the moonbounce reflector crunched the numbers and came up with a path loss figure something like 51dB worse than EME, if I recall. The small cross section area was the killer.
-- 73 de Tony VK3JED
Well from the original post:
The Goldstone 70M dish will be running MAX QRO with 435 kW.
That ought to be enough for EAE. HAAAA. CQ asteroid, CQ asteroid!
KB7ADL
On 8/02/13 9:33 AM, Vince Fiscus, KB7ADL wrote:
Well from the original post:
The Goldstone 70M dish will be running MAX QRO with 435 kW.
That ought to be enough for EAE. HAAAA. CQ asteroid, CQ asteroid!
There's your 51+ dB! :D Slightly outside amateur power levels or the antennas available to hams. :D
What frequency do they use to ping space rocks? Do they use different frequencies when they are pretty certain if it is rock, metal or ice and dirt?
Jeff WB3JFS
----- Original Message ----- From: "Tony Langdon" vk3jed@gmail.com To: amsat-bb@amsat.org Sent: Thursday, February 07, 2013 5:09 PM Subject: [amsat-bb] Re: Close encounters of the Asteroidal Kind
On 8/02/13 9:33 AM, Vince Fiscus, KB7ADL wrote:
Well from the original post:
The Goldstone 70M dish will be running MAX QRO with 435 kW.
That ought to be enough for EAE. HAAAA. CQ asteroid, CQ asteroid!
There's your 51+ dB! :D Slightly outside amateur power levels or the antennas available to hams. :D
-- 73 de Tony VK3JED http://vkradio.com
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
I wonder what 435kw at 28,000 km will do to the surface temperature on that rock? (Assuming it's an icy thing...)
Greg KO6TH
Vince Fiscus, KB7ADL wrote:
At 09:01 AM 2/8/2013 +1100, Tony Langdon vk3jed@gmail.com wrote:
On 8/02/13 7:49 AM, Bob- W7LRD wrote:
maybe "asteroid bounce"? (EAE) 73 Bob W7LRD
Someone on the moonbounce reflector crunched the numbers and came up with a path loss figure something like 51dB worse than EME, if I recall. The small cross section area was the killer.
-- 73 de Tony VK3JED
Well from the original post:
The Goldstone 70M dish will be running MAX QRO with 435 kW.
That ought to be enough for EAE. HAAAA. CQ asteroid, CQ asteroid!
KB7ADL
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
I wonder what 435kw at 28,000 km will do to the surface temperature on
that rock?
Let's see, power goes down as 1/R squared. So lets compare it to a candle. A candle is about 50 Watts or about (435000/50W) or about 10,000 times less power. Take the square root of that to get about 100/th the range.
So that radar at 28,000 km will heat the surface about as much as a candle would at 280km. (unless I screwed up before my morning coffee)...
Bob,WB4APR
Is the 435KW an EIRP number, or power into their feed. I was thinking the later. No?
Greg. KO6TH On Feb 8, 2013 6:53 AM, "Robert Bruninga" bruninga@usna.edu wrote:
I wonder what 435kw at 28,000 km will do to the surface temperature on
that rock?
Let's see, power goes down as 1/R squared. So lets compare it to a candle. A candle is about 50 Watts or about (435000/50W) or about 10,000 times less power. Take the square root of that to get about 100/th the range.
So that radar at 28,000 km will heat the surface about as much as a candle would at 280km. (unless I screwed up before my morning coffee)...
Bob,WB4APR _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
On 9/02/13 2:26 AM, Greg Dolkas wrote:
Is the 435KW an EIRP number, or power into their feed. I was thinking the later. No?
If you read the link that was recently posted, their transmitter uses 2x250kW klystrons, so it'd be RF power. :)
I wonder if they considered that it may be significantly more reflective?
73, Drew KO4MA
Sent from my iPhone
On Feb 7, 2013, at 5:01 PM, Tony Langdon vk3jed@gmail.com wrote:
On 8/02/13 7:49 AM, Bob- W7LRD wrote:
maybe "asteroid bounce"? (EAE) 73 Bob W7LRD
Someone on the moonbounce reflector crunched the numbers and came up with a path loss figure something like 51dB worse than EME, if I recall. The small cross section area was the killer.
Still, nothing ventured, nothing gained. :)
-- 73 de Tony VK3JED http://vkradio.com
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
On 8/02/13 11:11 AM, Andrew Glasbrenner wrote:
I wonder if they considered that it may be significantly more reflective?
I can't see it being more than 15-20db to get from the moon's reflectivity to a perfect reflector. Still, every bit helps. :)
participants (9)
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Andrew Glasbrenner -
Bob- W7LRD -
Greg D -
Greg Dolkas
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Jeff Yanko -
Robert Bruninga -
Tom Clark -
Tony Langdon -
Vince Fiscus, KB7ADL