GOCE Options

[ngunn]

Set for launch today:

http://www.esa.int/SPECIALS/GOCE/index.html

Some interesting new technology here - half satellite half airplane! Well maybe mainly satellite, but an interesting concept that could have applications in other atmospheres, making lower orbiting feasible.

[Stu]

Just been writing about that GOCE has to be the most gorgeous-looking satellite ever! That thing should be on Babylon 5 and taking on The Shadows...

[Guest_PhilCo126_*]

indeed: http://www.esa.int/SPECIALS/GOCE/SEMFIYITYRF_0.html

[ugordan]

Countdown hold and scrub for the day. Possibly related to the service tower not moving as it was supposed to.

[MahFL]

The service tower did not move ? wow.

[ugordan]

It's only speculation at this point, the hold could have been called even before the tower was supposed to move. The webcast countdown timer is not directly connected to the Plesetsk launch control center.

Launch is now scheduled for tomorrow at 14:21 UTC

EDIT: According to this release, "the doors of the launch service tower did not open. Due to this anomaly, the tower was held in position and did not move back as required for a launch. "

[dmuller]

I was watching the webcast and heard them talking about "all green" and that the doors will open now and the tower move away. That was 10 minutes prior to launch. I thought something was fishy when nothing moved ... either the camera froze or the door / tower didnt move. Let's hope it will work next time!

[Guest_PhilCo126_*]

Another attempt today at 10:21 am EDT (1421 GMT) on a Rockot from the Plesetsk Cosmodrome...

[ugordan]

GOCE has just lifted off from Plesetsk.

2nd stage burning, payload fairing has jettisoned.

3rd stage has now ignited, the vehicle went out of tracking range. Expect confirmation of status in 90 minutes, so far everything looks nominal.

[dmuller]

Spacecraft signal received and separation confirmed. Well done, GOCE

[imipak]

Ditto, and well done to Eurockot too

[Guest_PhilCo126_*]

ESA's GOCE satellite was formally declared ready for work at 01:00 CET on 20 March:

http://www.esa.int/SPECIALS/GOCE/SEMZ8TJTYRF_0.html

[rlorenz]

Some interesting new technology here - half satellite half airplane! Well maybe mainly satellite, but an interesting concept that could have applications in other atmospheres, making lower orbiting feasible.

Not least for Titan.

I have to say I have a very soft spot for the concept of aerodynamic stabilization for ram-pointing coupled with electric propulsion. The very first conference paper I wrote (which I presented a couple of months after my 19th birthday at the IAF conference in Bangalore..) was about just that...

Aerodynamic attitude stabilization for a small, low-orbiting, manoeuvrable satellite,
(later published in Acta Astronautica, 19, 573-576, 1989)

I since discovered that a few early satellites did exploit aerodynamic stabilization, albeit without
ion thrusters or resistojets..

[lyford]

Fire in the hole!

GOCE's electric ion propulsion engine switched on

[stevesliva]

Fire in the hole!GOCE's electric ion propulsion engine switched on

The success of GOCE's ultra-sensitive gravity measurements depends on finely controlling the satellite's orbit and speed. The push from the thruster must be just enough to compensate for the tiny amount of drag generated by the few wisps of atmosphere at GOCE's orbital height.

No normal jet engine could do this, but GOCE's sophisticated electric ion propulsion system can.

In fact, the ESA engineer that suggested putting a jet engine on a satellite ended up working at an investment bank instead.

[Vultur]

And now the gravity instrument is on, too.

It looks like this will be doing very valuable science, though maybe not as immediately exciting as planetary exploration...

[Rakhir]

GOCE achieves drag-free perfection

I really like this amazing satellite

[gwiz]

Not quite the "first" they claim, though. Beaten by three decades:

http://oai.dtic.mil/oai/oai?verb=getRecord...ifier=AD0766456

[dilo]

Thanks for the info, gwiz! For Triad satellite, it seems they used traditional thrusters for compensatoin of non-gravitational forces, I wonder if is really effective like the continuous ion thruster...
Anyway, any link to the full article?
PS: I'm really intrigued by the final phrase "A significant bias force is found acting in the local vertical direction." Pioneer effect again???

EDIT: I found this article telling that Triad residual acceleration is within 1e-11g... any info on the actual GOCE residual acceleration? (they only claim is 10-fold better than requested).

[gwiz]

Anyway, any link to the full article?

Can't find a free copy, but the link you found is probably comparable.

[kto]

i've heard that lowering the orbit did not go as well as planned; does anybody know if this is because of the unexpected solar minimum, and what, if any, are the resulting delays?

[ngunn]

Positive news:

http://www.spacedaily.com/reports/GOCE_Del...p_Ever_999.html

[stevesliva]

ESA's got the bigger visual -- a nice reminder that I have a supervolcano in my back yard.
http://www.esa.int/images/gradient_picture.jpg
Makes me wonder what the big sharp peaks in central africa are.

From their version:
http://www.esa.int/esaCP/SEMNBNKIWZF_index_0.html

(Actually, I don't believe science daily did much other than add their own attribution.)

[stevesliva]

New BBC article.
http://news.bbc.co.uk/2/hi/science/nature/8767763.stm

Seems to be a differently balanced use of the same colors. Odd.

And of course, the same releases available at the ESA page here:
http://www.esa.int/SPECIALS/GOCE/index.html

[stevesliva]

Interesting mission-extending software patching going on with GOCE:
http://spaceflightnow.com/news/n1008/29goce/

Apparently separate and different failures in discrete components of each redundant computer system is driving them to create software patches that use the functioning components of each computer to restore operations. Neat.