The Keppler data in tle-new.txt has changed the name for object name 2009-072A to YAOGAN8. Is this another official name for XW-1?
73's
-- With regards PE0SAT Internet web-page http://www.ham.vgnet.nl/
No, Yaogan-8 is the larger main payload, the 8th in a series of mainly civillian imaging satellites.
If we fast forward a few days with the current keps YAOGAN 8 1 36121U 09072A 09350.14442714 -.00000045 00000-0 00000+0 0 52 2 36121 100.4979 047.2280 0007533 028.3305 331.8410 13.16397965 131 XIWANG-1 (HOPE-1) 1 36122U 09072B 09350.14452292 -.00000045 00000-0 00000+0 0 77 2 36122 100.4974 047.2295 0007562 040.0327 320.1583 13.16283842 130
Yaogan takes the lead and Xiwang trails.
Is this correct that the higher mass satellite travels faster than the lower mass of XW?
OK, I'll revise my earlier question and suggest a reply.
The physically larger satellite will have more atmospheric drag which will spiral it into a lower orbit. The lower orbit, the higher the velocity and thereforeit crosses your horizon earlier.
Nigel Gunn G8IFF/W8IFF wrote:
Is this correct that the higher mass satellite travels faster than the lower mass of XW?
The influence of the drag force also depends on the mass since F=m*a, so the same drag force will cause less deceleration on a heavier satellite. You have to put this together with F=pressure*surface_area to take both the size and the mass of the satellite into account.
By the way, is there any significant atmospheric drag at 1200 km altitude?
73 Alex OZ9AEC
On Wed, 16 Dec 2009 18:56:20 +0000 Nigel Gunn G8IFF/W8IFF nigel@ngunn.net wrote:
OK, I'll revise my earlier question and suggest a reply.
The physically larger satellite will have more atmospheric drag which will spiral it into a lower orbit. The lower orbit, the higher the velocity and thereforeit crosses your horizon earlier.
Nigel Gunn G8IFF/W8IFF wrote:
Is this correct that the higher mass satellite travels faster than the lower mass of XW?
I don't know but something is causing the two satellites to drift apart. Knowing the rules helps to sort out the keplerian elements of the two.
Alexandru Csete wrote:
The influence of the drag force also depends on the mass since F=m*a, so the same drag force will cause less deceleration on a heavier satellite. You have to put this together with F=pressure*surface_area to take both the size and the mass of the satellite into account.
By the way, is there any significant atmospheric drag at 1200 km altitude?
73 Alex OZ9AEC
Nigel Gunn G8IFF/W8IFF wrote:
I don't know but something is causing the two satellites to drift apart. Knowing the rules helps to sort out the keplerian elements of the two.
Keep in mind they were in all likelihood deployed at different velocities, so it a bit more complex than just drag, mass, and surface area even.
73, Drew KO4MA
Hi,
YAOGAN 8 traveling faster could be due to possible initial orbit corrections and maneuvering that includes minor correction of injection velocity (delta V). The drag do influence even at geo-transfer and geo-synchronous orbits.
73 de Mani, VU2WMY Secretary & Station-In-Charge Upagrah Amateur Radio Club VU2URC ISRO Satellite Centre Airport Road, Bangalore-560 017. Phone:(O)91-80-2508 2054/2192/2537 Mobile: 91-80-98803 41456 E-mail ID: wmy@isac.gov.in vu2wmy_mani@yahoo.com isrohams@yahoo.com
Quoting Alexandru Csete alexc@phys.au.dk:
The influence of the drag force also depends on the mass since F=m*a, so the same drag force will cause less deceleration on a heavier satellite. You have to put this together with F=pressure*surface_area to take both the size and the mass of the satellite into account.
By the way, is there any significant atmospheric drag at 1200 km altitude?
73 Alex OZ9AEC
On Wed, 16 Dec 2009 18:56:20 +0000 Nigel Gunn G8IFF/W8IFF nigel@ngunn.net wrote:
OK, I'll revise my earlier question and suggest a reply.
The physically larger satellite will have more atmospheric drag which will spiral it into a lower orbit. The lower orbit, the higher the velocity and thereforeit crosses your horizon earlier.
Nigel Gunn G8IFF/W8IFF wrote:
Is this correct that the higher mass satellite travels faster than the lower mass of XW?
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participants (5)
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Alexandru Csete -
Andrew Glasbrenner -
Mani VU2WMY -
Nigel Gunn G8IFF/W8IFF -
PE0SAT