LIVE: SpaceX Dragon COTS Demo (C2+) FD2 and FD3 UPDATES

[ugordan]

The geometry doesn't look good for a sighting. Since it's below ISS, it would be moving against the cloudtops and hard to spot and approaching the evening terminator only means Dragon won't be lit up much and it will be generally in the direction of the sun.

Now, looking near the morning terminator sounds like a much better idea with the ground still in darkness, but Dragon fully sunlit.

[JimO]

The geometry doesn't look good for a sighting. Since it's below ISS, it would be moving against the cloudtops and hard to spot and approaching the evening terminator only means Dragon won't be lit up much and it will be generally in the direction of the sun.

Now, looking near the morning terminator sounds like a much better idea with the ground still in darkness, but Dragon fully sunlit.

It's far enogh behind that even when slightly below, it's still against dark space -- don't forget Earth's horizon is significantly depressed below 'local horizontal' at orbital altitude. Do the trig.

But your conclusion is still reasonable because the bright horizon IS not FAR from the dim Dragon, especially trailing at sunset when it's the far side of the vehicle [viewed from ISS] that's sunlit -- probably not much more than a mag 4 or 5 star, I'd swag. 

So sunrise is a much better sighting opportunity, especially as it will 'rise' several seconds AFTER ISS enters sunlight. So it can 'light up' and make itself visibly different from background stars that way.

[JimO]

I don't think they have any optics on board that are powerful enough to image something of that size if it is 800km away. It must be closer.

I should point out that I see sunlit stuff of Dragon's size at that range from my backyard regularly. But that's when I'm in the dark and my eyes are adapted. Binoculars help. But if you're looking at the sunlit side, it would be dim star bright -- not glaring, but not invisible, either.

[ugordan]

It's far enogh behind that even when slightly below, it's still against dark space -- don't forget Earth's horizon is significantly depressed below 'local horizontal' at orbital altitude. Do the trig.

Ahh, you're right, of course. I switched the 800/8 km numbers by mistake when doing the mental calculation. Other than making Dragon do some lithobraking (duh!), it meant it would be much more directly below - which it's obviously not.

[Ben the Space Brit]

I don't think they have any optics on board that are powerful enough to image something of that size if it is 800km away. It must be closer.

I should point out that I see sunlit stuff of Dragon's size at that range from my backyard regularly. But that's when I'm in the dark and my eyes are adapted. Binoculars help. But if you're looking at the sunlit side, it would be dim star bright -- not glaring, but not invisible, either.

According to the earlier slide above, closest approach will be 2500m and probably at a very low relative velocity.  It should be quite easy to image that with the cameras.

In any case, having a spacecraft on a parallel orbit coming that close, I think an optical and radar tracking is probably good safety policy.

[ugordan]

According to the earlier slide above, closest approach will be 2500m and probably at a very low relative velocity.  It should be quite easy to image that with the cameras.

Yes, but we're not discussing the flyunder photo op, but current spotting possibilities.

[Kabloona]

Google SatTracker showing Dragon approx 400 mi behind ISS.

[baldusi]

Crew is looking for Dragon (possibly for photos); ground called up that it is 9 km below and 800 km (?) behind ISS.  (Might have misheard the distance behind...maybe he said 80; doesn't look that far behind if the map is correct.)

What's on the yellow orbit? It looks like a Southern Molniya orbit!

[psloss]

Re: Dragon sightings from ISS and "current" location, the context on that and some useful info in the evening DPC from Rob's audio server:
http://www.kevin-cohen.com/nsf/iss/iss_20120523-150000-004.wav

(Guess I did hear 800 km -- that's at the end of the file, after the DPC.)

http://issaudio.servehttp.com/

Houston said that the HA2 burn is a little later (as noted in earlier post here).

[corrodedNut]

From the ISS/ground audio feed:

Dragon is healthy, is 800km behind, 9km below local horiz. Basically directly behind. Don Pettit thinks he has images. CUCU is "lit up". HA2 burn is about 1.5 hrs later than planned, due to orbital mechanics.

[DaveH62]

From the ISS/ground audio feed:

Dragon is healthy, is 800km behind, 9km below local horiz. Basically directly behind. Don Pettit thinks he has images. CUCU is "lit up". HA2 burn is about 1.5 hrs later than planned, due to orbital mechanics.

On the http://www.lizard-tail.com/isana/tracking/ site, it is closing in about 1Km every 57 seconds, at this point and shows as 663Km from ISS.

[corrodedNut]

From the ISS/ground audio feed:

Dragon is healthy, is 800km behind, 9km below local horiz. Basically directly behind. Don Pettit thinks he has images. CUCU is "lit up". HA2 burn is about 1.5 hrs later than planned, due to orbital mechanics.

On the http://www.lizard-tail.com/isana/tracking/ site, it is closing in about 1Km every 57 seconds, at this point and shows as 663Km from ISS.

Yeah, that was previously recorded. I don't know when. Also, I should edit: Dragon is 9km below, or about 3deg below local horiz.

[Jorge]

Crew is looking for Dragon (possibly for photos); ground called up that it is 9 km below and 800 km (?) behind ISS.  (Might have misheard the distance behind...maybe he said 80; doesn't look that far behind if the map is correct.)

What's on the yellow orbit? It looks like a Southern Molniya orbit!

TDRS E coverage zone. Look for the TDRS icons - they are color-coded to their respective coverage zones. They are not quite symmetric north-south because the TDRS satellite inclinations are not zero. Especially noticeable for TDRS E.

[Comga]

From the ISS/ground audio feed:

Dragon is healthy, is 800km behind, 9km below local horiz. Basically directly behind. Don Pettit thinks he has images. CUCU is "lit up". HA2 burn is about 1.5 hrs later than planned, due to orbital mechanics.

Wonder if Pettit had the chance to take long, stopped down images.  Stars should streak while Dragon would stay fixed.  (I have seen photographs of geosynchronous satellites taken from the ground in this manner.)

[arkaska]

This link has been posted earlier but I would recommend it again for whoever is following the approach of Dragon not when the distance is rapidly decreasing.

http://www.lizard-tail.com/isana/tracking/

[Hungry4info3]

"GoogleSatTrack is temporary unavailable due to heavy traffic.
Please try again later"

Everyone get off for a second

[arkaska]

"GoogleSatTrack is temporary unavailable due to heavy traffic.
Please try again later"

Everyone get off for a second

hmmm...seen people post the same thing earlier but I haven't got that error message a single time. Maybe it's harder to get in on the us servers..

[Jason1701]

Maybe it knows who the L2 members are.

[cro-magnon gramps]

Maybe it knows who the L2 members are.

Not having any problems north of the border


edit Distance 558 km and altitude variance 11 km and holding good

edit 2 - of course it has to make a liar out of me, now 10 km

edit 3 - closing seems faster, now down to 553 (ps I am an L2 member. join up and get premium content ;-) )

[cro-magnon gramps]

now crossing tip of South America  7:11 pm ET