James Webb solar panels deploy early

[spread-tee]

That's a really neat site, thanks Dan

Desp

[spread-tee]

Reading through some of the info on that site, they say that the Webb telescope is going to orbit around the L2 point rather than live at L2 itself. The orbit will be similar to the earth/moon orbit and take six months to complete one rev. Now as I understand orbits they are a balance between the gravitational force of any object and the Centripetal force caused by the motion around said object. So how do they get the Webb scope to orbit what is essentially and empty point in space? Do they need to be continually using energy to keep it in position or is it a function of the Earth and Suns gravity combined with the solar orbit that keeps it there?? Or something else??

Whatever it will be interesting to see some really deep IR information coming back when it is all fettled.

Desp

[Stan]

As I understand it the telescope will have to use thrusters to keep itself on station for all of its working life. When it runs out of fuel its mission ends. The accuracy of the launch was so good that more fuel than expected will be available for station manoeuvering.
Am I right that in 2001 A Space Oddysey there was a monolith floating at a Legrande point?

[Oliver90owner]

Newton’s First Law of Linear Motion applies out there (not much friction to impede matters!). That means the telescope will fall directly towards the Earth according to gravitation if it were stationary - but it isn’t - its orbiting speed will be such that the fall towards the Earth is exactly balanced, by that First Law, to maintain a stable distance from the Earth.

The ‘geostationary orbit’ distance is a fixed distance from the Earth, not requiring constant alterations to remain geo-stationary.

[spread-tee]

But it is not orbiting the earth, it is orbiting the L2 point which itself is in orbit around the sun, geostationary orbits around the earth IIRC are at about 23000 miles altitude, Webb is far "higher" than that. I think Stann is correct, Webb will need to use thrusters to maintain its position.

Desp

HNY by the way

[Stan]

This short video comments on how there looks to be enough fuel left on the telescope to allow it to work for over 10 years.

[dan_b]

Scott Manley's YouTube channel is one of the best out there for info on Space and rocket science. Here's a video he made explaining Lagrange Points.
But yes, apparently the Ariane 5 performed so accurately on its launch injection that they will have to use less fuel getting up to the L2 point than predicted, which means there will be more propellant left over to extend its service life.

[dan_b]

Oh- I hope this is a good sign and not a bad one, but the Telescope deployment team has decided to delay proceeding to the next step - sunshield tensioning.

https://www.space.com/james-webb-space- ... ning-pause

Fingers crossed they can get all 5 of those layers separated and up to tension.

[nowty]

Sounds more like slowly slowly catchy monkey, there is no rush as its going to take 6 months to cool down to the ridiculously low temperature it needs to operate at, so rest your staff whilst you can.

[dan_b]

https://www.space.com/news/live/james-w ... pe-updates

According to this, there were some minor problems with the solar arrays not generating full power, and some of the solar shield motors not being at the correct temperature. But they're going to start tensioning today.

I think they need everything deployed and tested before it gets to the L2 point?