James Webb Space Telescope to Launch on December 25th at 7:20 AM EST

And then Aliens?

Very curious to see what results.  Especially if they do another deep field test (shoot into a blank spot for a very long time), or maybe get a decent shot of planets orbiting another star.

alfadriver said:

The last major burn for the telescope was successful- JWST is now in orbit around L2.  

All that is left it final mirror aiming and instrument calibration.

Was just digging for this thread to post the same thing. 
 
Given the extreme cold this thing operates in and the journey it took:

In reply to aircooled :

Either aliens or the beginning of time.

What about aliens at the beginning of time? 

barefootskater5000 said:

 
Given the extreme cold this thing operates in and the journey it took:

Extreme cold and heat.  The telescope mirrors are at -347 deg F, the sun side is at 129 F (not super hot, but not cold).

Heat dissipation is a huge issue in space (much worse than a TR3).

In reply to aircooled :

I've often wondered about heat in space. If there's no air, what pulls the heat out of things. It's all energy, and the tiny movement of atoms is what we use to measure heat (absolute zero being perfectly still) does that make machines more efficient in a vacuum? Less heat dissipated? Or would it cause havoc not being able to shed excess heat? Fun things to think about. 

Type Q said:

What about aliens at the beginning of time? 

barefootskater5000 said:

In reply to aircooled :

I've often wondered about heat in space. If there's no air, what pulls the heat out of things. It's all energy, and the tiny movement of atoms is what we use to measure heat (absolute zero being perfectly still) does that make machines more efficient in a vacuum? Less heat dissipated? Or would it cause havoc not being able to shed excess heat? Fun things to think about. 

Yes, there is almost zero convective heat transfer, it's all radiant heat. You can still get rid of heat but shedding it by convection is far more efficient (in an atmosphere).  Once the Apollo moon missions where on there way to the moon, they where put into a slow "barbecue roll" which keep the heating and cooling even.

It is far worse than a fan less TR3 not moving.  Just sitting in air will still cause a good amount of convection (if nothing else a sort of chimney effect).

Probably a good thing the British never really got into spacecraft development (electrics are also important of course)!

aircooled said:

barefootskater5000 said:

In reply to aircooled :

I've often wondered about heat in space. If there's no air, what pulls the heat out of things. It's all energy, and the tiny movement of atoms is what we use to measure heat (absolute zero being perfectly still) does that make machines more efficient in a vacuum? Less heat dissipated? Or would it cause havoc not being able to shed excess heat? Fun things to think about. 

Yes, there is almost zero convective heat transfer, it's all radiant heat. You can still get rid of heat but shedding it by convection is far more efficient (in an atmosphere).  Once the Apollo moon missions where on there way to the moon, they where put into a slow "barbecue roll" which keep the heating and cooling even.

It is far worse than a fan less TR3 not moving.  Just sitting in air will still cause a good amount of convection (if nothing else a sort of chimney effect).

Probably a good thing the British never really got into spacecraft development (electrics are also important of course)!

One of the most fascinating parts of the sun shied is that it's designed to direct that radiant heat out the sides- in between the layers.  And each layer will direct more radiant heat out.  I knew that the extra layers were there to add insulation layers, but I didn't know until after the launch how they were designed to reject the heat out the sides.  

Very clever.

In reply to alfadriver :

I heard another reason for the multiple layers was so when the inevitable micro-asteroids make holes in the shield, those holes won't drastically affect the effectiveness of the shield.

Had this video pop up in my feed detailing the very clever actuators used to adjust the mirror position on the JWST, definitely worth the watch.