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

[ugordan]

Brightened to show a bit of the inside of the trunk. No mylar visible. It appears the white trunk we saw on the ground was all jettisonable panels?

[Lars_J]

Nope, that appears to be the trunk exterior. It is the lighting conditions that give it a darker color. Look at your previous picture - the external trunk umbilical port is visible jutting out.

Dragon is facing the sun in all of these pictures, so the trunk will look much darker in comparison, since its surfaces are almost 90 degrees to the sunlight.

[ugordan]

You're probably right. Interesting what a changed lighting angle and different surface coating can do to the appearance.

[Maciej Olesinski]

Nope, that appears to be the trunk exterior. It is the lighting conditions that give it a darker color. Look at your previous picture - the external trunk umbilical port is visible jutting out.

That iss my opinion too. Dragon has to be in perfect line facing the Sun. Capsule is bit bigger than trunk and gives shadow that covers it giving dark colour

[corrodedNut]

Ditto. The heat shield is a slightly larger diameter than the trunk, just enough to shade the trunk when Dragon's nose is pointed directly into the sun. This may also be the ideal orientation for solar power generation and thermal managment, but that's just my speculation.

[Robotbeat]

Here's a full-resolution photo of Dragon from ISS. The trunk just looks like it's white (but mostly in shadow). (I didn't adjust contrast, because I think adjusting the contrast makes the trunk look darker than it actually is... I just cropped it.)

[tigerade]

Ditto. The heat shield is a slightly larger diameter than the trunk, just enough to shade the trunk when Dragon's nose is pointed directly into the sun. This may also be the ideal orientation for solar power generation and thermal managment, but that's just my speculation.

Ah yeah, that could be it.  Also the lack of air molecules in space makes a shadow much darker. 

[saturnapollo]

I'm not so sure. The photo shows very delineated shadows on the trunk and the rest of the trunk is obviously in sunlight, yet remains a different shade. Could be a different thermal covering than the capsule. This schematic shows the trunk section to be different from the capsule, though I'm not one to assume these schematics are necessarily the same as the flight article.

I guess we will only know for sure once we see it closeup tomorrow (all being well).

Keith

[Lars_J]

I'm sure the trunk will look just as white as the capsule when viewed with light from the side.

Note the picture below - Both parts are white. However, the trunk appears to have a shinier coat, compared to the matte exterior of the capsule. That also plays a part in extreme light conditions to give a different impression.

[robertross]

Cropped and sharpened a bit

very nice, thanks!

(and thanks to Lars)

[Chris Bergin]

Still well over eight hours until the GO to move into the approach ellipsoid 1.4 kilometers around the space station, so going to get some sleep and start the live thread a few hours before the event.

[AnalogMan]

Still well over eight hours until the GO to move into the approach ellipsoid 1.4 kilometers around the space station, so going to get some sleep and start the live thread a few hours before the event.

Chris, posting this now since its getting late for me, but maybe it would be useful to copy over to the new live thread when you set it up.

Graphic attached showing the various Dragon thruster burns during Friday's rendezvous with the ISS.  Go/No Go decisions are made prior to all the Height Adjustment (HA) burns on this profile - and there are four more during the R-Bar demonstration maneuvers.

NASA TV begins coverage at 2:00 am EDT which is about a quarter of an hour before the "start of integrated operations" point on the rendezvous profile based on Bill Harwood's original timeline from May 21.  SpaceX posted event times on May 24 that seem to range from half to one hour behind Bill's timeline.

[robertross]

Still well over eight hours until the GO to move into the approach ellipsoid 1.4 kilometers around the space station, so going to get some sleep and start the live thread a few hours before the event.

Enjoy that well earned sleep!

[Jorge]

Still well over eight hours until the GO to move into the approach ellipsoid 1.4 kilometers around the space station, so going to get some sleep and start the live thread a few hours before the event.

Chris, posting this now since its getting late for me, but maybe it would be useful to copy over to the new live thread when you set it up.

Graphic attached showing the various Dragon thruster burns during Friday's rendezvous with the ISS.  Go/No Go decisions are made prior to all the Height Adjustment (HA) burns on this profile - and there are four more during the R-Bar demonstration maneuvers.

NASA TV begins coverage at 2:00 am EDT which is about a quarter of an hour before the "start of integrated operation" point on the rendezvous profile based on Bill Harwood's original timeline from May 21.  SpaceX posted event times on May 24 that seem to range from half to one hour behind Bill's timeline.

Probably worth pointing out that the dimensions of the KOS and AE on the diagram are inconsistent. The 200 m listed for the KOS is the radius while the 4 km and 2 km listed for the AE are the major and minor axes, respectively. For consistency, they could have used the semimajor/semiminor axes of the AE (2 km and 1 km, respectively).

[rst]

Just shadows, it seems.

Could the shadows look darker than expected because we're out of the atmosphere, and other surrounding objects?  Computer graphics folks generally render images assuming that at least a little light will be coming in from any direction, because light can bounce off stuff several times.  In orbit, there's a lot less stuff around to light the out-of-the-sun portion of an object...

[AnalogMan]

Still well over eight hours until the GO to move into the approach ellipsoid 1.4 kilometers around the space station, so going to get some sleep and start the live thread a few hours before the event.

Chris, posting this now since its getting late for me, but maybe it would be useful to copy over to the new live thread when you set it up.

Graphic attached showing the various Dragon thruster burns during Friday's rendezvous with the ISS.  Go/No Go decisions are made prior to all the Height Adjustment (HA) burns on this profile - and there are four more during the R-Bar demonstration maneuvers.

NASA TV begins coverage at 2:00 am EDT which is about a quarter of an hour before the "start of integrated operation" point on the rendezvous profile based on Bill Harwood's original timeline from May 21.  SpaceX posted event times on May 24 that seem to range from half to one hour behind Bill's timeline.

Probably worth pointing out that the dimensions of the KOS and AE on the diagram are inconsistent. The 200 m listed for the KOS is the radius while the 4 km and 2 km listed for the AE are the major and minor axes, respectively. For consistency, they could have used the semimajor/semiminor axes of the AE (2 km and 1 km, respectively).

Thanks for spotting Jorge - AE now fixed in original post.

[Lars_J]

Just shadows, it seems.

Could the shadows look darker than expected because we're out of the atmosphere, and other surrounding objects?  Computer graphics folks generally render images assuming that at least a little light will be coming in from any direction, because light can bounce off stuff several times.  In orbit, there's a lot less stuff around to light the out-of-the-sun portion of an object...

Certainly. From this angle (above), the shiny trunk reflects mostly the black of space. Combined with being shaded from the sun, you get a trunk that almost looks black.

[Norm38]

Based on all the images on page 34, this is my opinion.

The white panels on the side of the trunk between the solar panels were jettisoned along with the array covers.  That exposes the radiators, and it's less mass to push around.

The ideal thermal management orientation is directly into the sun.  The arrays don't have to track.  The white nose reflects the heat while the sides of the smaller, darker trunk can radiate heat.  Black body radiators for vacuum need to be black.

Just like the Shuttle opening the doors on reaching orbit, looks like Dragon sheds it's trunk aeroshell, and points towards the sun.

[Lars_J]

Based on all the images on page 34, this is my opinion.

The white panels on the side of the trunk between the solar panels were jettisoned along with the array covers.  That exposes the radiators, and it's less mass to push around.

The ideal thermal management orientation is directly into the sun.  The arrays don't have to track.  The white nose reflects the heat while the sides of the smaller, darker trunk can radiate heat.  Black body radiators for vacuum need to be black.

Just like the Shuttle opening the doors on reaching orbit, looks like Dragon sheds it's trunk aeroshell, and points towards the sun.

We'll certainly see who is right in a couple of hours, but looking at the Dragon stack assembly pictures, there is absolutely no indication than there are panels that fall off the trunk. And radiators don't have to be black. While you can make black-body materials which radiate mostly in the IR spectrum, most radiators are white or light colored. (see ISS)

It is just a lighting effect. How black does the trunk look in this picture?

[MikeAtkinson]

Additionally after launch Dragon, 2nd stage and the two array covers were being tracked (i.e. no trunk panels of any size).