Updates GOCE Mission News

[MaverickSawyer]

Going over Antarctica right now... 2-5 hours left.

---------- Post added at 11:56 ---------- Previous post was at 11:48 ----------

Update: Orbit below 130 km at 18:30 UTC.
Source

---------- Post added at 12:03 ---------- Previous post was at 11:56 ----------

Hot off the press!
Altitude: 126 km at 1950 while over Kiruna. Nose of the spacecraft is now over 50*C!
Source: http://blogs.esa.int/rocketscience/2013/11/10/update-from-esoc-2015-cet/

 

[Urwumpe]

Nose of the spacecraft is now over 50*C!

Not the nose - the computer compartment - the nose did during normal operations already reach 250°C in sunlight.

 

[ADSWNJ]

I use this tracker...any good?
http://www.satflare.com/track.asp?q=34602#TOP

Looks more timely than the feeds from N2YO, but the data is consistent between the two.

Having watched the orbit for a few laps now, off and on between real life, it's still doing something I don't quite understand. On each full orbit, there are two low-alt points (around the equator, give or take 3 degrees), and two high-alt points (around 82N and 82S). The low points on the ascending side are trending down from 139.7km alt (3 passes ago south of Oman), to 137.8km a few mins ago (over Liberia). On the descending side, the altitude is around 134km. On the high side, the orbits are 153/154 km.

I'm assuming it's a radio alt above the mean sea level, and with the Earth being oblate, the Equatorial altitudes look lower than the polar altitudes. It would be interesting to see the radius distances from the Earth's COG instead.

 

[Urwumpe]

Reentry window is between 22:30 and 0:30 CET.

 

[garyw]

It's coming down quite rapidly.......

Sun 10 Nov 20:30UT #GOCE orbit 87.16 minutes 126.0 x 138.4 km Position 82.3N,71.0W alt=159.2km Unlit Re-entry window

Sun 10 Nov 20:40UT #GOCE orbit 87.16 minutes 125.8 x 138.2 km Position 52.4N,172.9E alt=148.9km Lit Re-entry window

 

[MaverickSawyer]

Reentry window now 2330 to 0130 CET (2230 to 0030 UTC)

 

[ADSWNJ]

ESA now predicting 22:30 UTC +- 1 hour. (Source: Satflare)

 

[MaverickSawyer]

Contact from Troll station in Antarctica. Still in flight, computer and battery compartment temps now 64*C, with localized temps of 80*C. Next possible sighting at Troll at 2242 UTC.

 

[garyw]

From ESOC:

Spacecraft still functioning nominally in Fine Pointing Mode, as seen in the last Troll pass just made at 22:16 CET (21:16 UTC). Temperature of central computer and battery now around 64 degC (some converters of the central computer already at 80 degC). Next possible visibility again over Troll at 23:42 CET (22:42 UTC).

Sun 10 Nov 21:45UT #GOCE orbit 87.01 minutes 119.4 x 130.5 km Position 36.6N,36.8W alt=137.0km Unlit Re-entry window

Last orbit or two now.....

and from ESA:

Probable #GOCE reentry area on descending orbit pass that mainly runs across the Pacific and Indian Oceans http://bit.ly/1acamyE

 

[MaverickSawyer]

Another (probably final) pass over Troll just occured... Altitude 122 km!

Reentry expected between 2250 and 0050 UTC, somewhere over the Pacific or Indian Oceans.

Spacecraft systems continue to operate at remarkably high performance, and data was collected during the pass.

One more pass possible, and another download will be attempted to gather data from the ultra-low "orbit".

Source: http://blogs.esa.int/rocketscience/2013/11/11/update-from-esa-space-debris-office-at-2310cet/

 

[ADSWNJ]

ESA's timing now pushed back 1hr 20 to 23:50 UTC +1 1 hour. US Strategic Command says 00:00 +1 2 hours. Looks like the window is firming up.

 

[DaveS]

Troll AOS as planned:

ESA Operations ‏@esaoperations
#GOCE's alive! #ESOC teams acquired signal from spacecraft (as planned) via Troll station at 23:42CET. The flight continues! #AOS

 

[Quick_Nick]

Given the inclination > 90 degrees, I can't seem to figure out why the track is moving eastward each orbit.

EDIT: Ignore that... hehe, I was looking at the path in the wrong direction.

 

[MaverickSawyer]

Awaiting word from ESOC about whether or not it will come back around...

 

[Urwumpe]

Awaiting word from ESOC about whether or not it will come back around...

According to Professor Klinkrad, this orbit will be its last. But so far, the attitude control system managed to keep it in a nice low drag position, I would not be surprised, if it does a short second one.

 

[MaverickSawyer]

Altitude 120 km.

Personally, I think the old girl still has one more orbit in her.

 

[garyw]

According to Professor Klinkrad, this orbit will be its last. But so far, the attitude control system managed to keep it in a nice low drag position, I would not be surprised, if it does a short second one.

Agreed. I am surprised they haven't altered the drag profile to try and target the impact point.

 

[MaverickSawyer]

Computer compartment temps now over 80*C. Battery now at 84*C.

---------- Post added at 15:08 ---------- Previous post was at 15:04 ----------

Agreed. I am surprised they haven't altered the drag profile to try and target the impact point.

From what I've seen, they only have passive stability control now. The active system relied on the engine. So, based off the design, it may naturally hunt for the most aerodynamic position.

 

[Urwumpe]

Agreed. I am surprised they haven't altered the drag profile to try and target the impact point.

Wouldn't change much there, since the drag mostly depends on the exosphere conditions now. Even doubling the effective surface would have less effect than some geomagnetic activity.

 

[Screamer7]

I may be wrong, but why do I get this gut feeling it headed for the USA?