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### How can electronics on board JWST survive the low operating temperature while it's difficult to survive lunar nights?

Compared to the temperatures encountered in lunar nights, the desired operating temperature of the James Webb Space Telescope is very low. Lunar nights are typically -170°C while the operating ...
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### Would it have been cheaper and/or faster to put a James Webb-like Space Telescope on a balloon instead of a rocket?

I've just noticed the following items: CNET: NASA to send stadium-size balloon skyward to study the cosmos JPL/NASA News: NASA Mission Will Study the Cosmos With a Stratospheric Balloon Even in 2020 ...
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### How much can the Mars rover Curiosity do autonomously, after four years of operation?

I was under the impression (when asking this question) that over the past four years that experience by ground operators and programmers had lead to a configuration where the Mars rover Curiosity ...
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### Could JWST stay at L2 “forever”?

Using only reaction wheels powered by solar panel and the sunshield as a sail (in continuous active attitude control) to generate thrust from solar photon pressure in the desired direction, could JWST ...
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### How can the 6.5 m primary mirror of the JWST fit inside the 5.4 m fairing of Ariane 5?

All the variants of the payload fairing for Ariane 5 are 5.4 meters in diameter, the same as the core stage of the rocket. At the same time, the mirror of the James Webb Space Telescope is 6.5 meters. ...
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### Can/Will the James Webb Telescope maintain its position passively?

A recent article about the telescope states (emphasis mine): Unlike Hubble, which orbits the Earth at about 340 miles of altitude, Webb will be sent almost a million miles into space, at a ...
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### What are the sources of light at L2? How will the James Webb telescope be powered?

The James Webb space telescope will be positioned very close to L2. According to JPL, Webb will have a large solar-array to power itself. I don't understand how this works, since L2 is positioned "...
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### What happens to JWST after it runs out of propellant?

JWST will be orbiting L2 which is unstable equilibrium thus will require propellant for station keeping. JWST will carry propellant for 5-10 years. What will happen once it runs out of propellant? ...
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### Are some Halo Orbits actually Stable?

UPDATE: I found another reference! While I always enjoy a good video starring Jimmy and Linda Carter, this one has Dennis Wingo describing ISEE-3's original Halo orbit. He describes Sun-Earth $L_1$ as ...
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### What are the future prospects for spacecraft autonomy

edit: Possibly helpful information in Gizmodo and YouTube. In general spacecraft are supplied with propulsion systems often with substantial redundancy in the plumbing and engines or thrusters so ...