43
$\begingroup$

There is a haze on the top half of Starman's windshield? It was not there in the first day o fthe launch and the video feed. It looks like fogged window, but assume it cannot be that. What is it and how did it form? haze 1

haze 2 haze 3 haze 4

$\endgroup$
  • $\begingroup$ The glass/plastic on the headlights also looked very hazy in some camera angles $\endgroup$ – Jake Blocker Feb 12 '18 at 15:48
  • 10
    $\begingroup$ Note that Starman only orbited Earth for about 6 hours, and then left for a heliocentric orbit, at which point the video feed stopped. So these images are from the first day after the launch. (And the various "live feeds" that are still streaming are not in fact live.) $\endgroup$ – Nathaniel Feb 13 '18 at 1:22
57
$\begingroup$

My (somewhat educated) speculation: deposited contaminants due to outgassing from the various polymers on the dashboard and/or the hood. Vacuum and UV exposure tend to break down nearly every polymeric material. The volatile compounds that fly off in the process would deposit themselves as a haze on the windshield.

As a side note, this is one reason you see very strict material and process control for any space vehicle that has sensitive optics. You don't want to fog up a mirror on a telescope because you put some piece of silicone near it. See this linked question provided by uhoh for more info on the outgassing problem.

$\endgroup$
  • 1
    $\begingroup$ @uhoh Good info. I'll add the link to the other question for posterity $\endgroup$ – Tristan Feb 12 '18 at 14:34
  • 1
    $\begingroup$ I'm not sure if this or this is helpful or not. $\endgroup$ – uhoh Feb 12 '18 at 14:37
  • $\begingroup$ If it is outgassing from the dashboard, why is it only at the top of the windsheild? The answer by TCAT117 seems more logical. $\endgroup$ – James Jenkins Feb 13 '18 at 17:36
  • $\begingroup$ That may be. There may also be plastic materials near the upper frame that are outgassing. Without close-up inspection, all we can do is speculate. $\endgroup$ – Tristan Feb 13 '18 at 18:02
31
$\begingroup$

I've personally witnessed a similar phenomenon. Car Windshields are not solid glass, they are two layers of glass sandwiching a layer of urethane in a molecular bond. I was once in an armored vehicle that hit a landmine and the pressure and heat differential between the outside and inside of the windshield caused the three layers to de-laminate. It seems like an odd thing to notice during such an event but I remember the windshield (about a 4 inch thick windshield mind you) in front of me instantly "fogging" up about as fast as you can snap your fingers. It wasn't really fogged, it was the three distinct layers between the heavy plate glass and urethane separating and off gassing due to heat just enough to lose some translucency and look foggy.

Its possible that between out-gassing caused by vacuum's effects on the urethane and thermal differential between the two pieces of glass that its 3 layers would de-laminate without shattering in much the same manner.

$\endgroup$
  • $\begingroup$ This is also a very good theory on what's going on. $\endgroup$ – Tristan Feb 13 '18 at 15:01
  • 2
    $\begingroup$ Theres also no reason it cant be a combination of both our theories either. $\endgroup$ – TCAT117 Feb 13 '18 at 18:30

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.