onetwentythree

The 90% efficiency of the wireless transmission would be on top of the efficiency of typical charging (which is mostly losses after the power reaches the vehicle).

Yes, but remember they are very different telescopes for different types of astronomy. Roman is a survey telescope with a wide field of view, designed to discover new objects, etc. JWST has a large aperture and narrow FOV to get the closest look possible at specific targets identified in advance. They will compliment each other well.

To provide more information than the others who responded: typical sprinkler systems are not automatically activated in response to a fire alarm. Each sprinkler head has a small glass vial filled with a liquid, calibrated to break at a certain elevated temperature (e.g 160 or 180 F). The flow of water starts when the glass breaks. So there has to be a significant fire near the sprinkler before it activates.

One weakness is that the glass vial is fragile. In some hotels you’ll see signs reminding guests not to hang clothes from the sprinkler head, as a clothes hanger could break the vial and activate the water flow.

You can get multi-turn absolute encoders for these applications.

I don’t think they’re in trouble for missing the deorbit target.

The concern is that the second stage didn’t perform as expected. What if that affects the primary mission on the next flight? They need to understand the root cause before they fly again.

As the article states, the upcoming Europa Clipper launch requires an upper stage relight to put the spacecraft on the desired trajectory. If the second burn does not go as expected, the mission could be in jeopardy.

That only applies to linear regulators.

The router on this page uses a switching regulator. Switching regulators have a relatively constant power draw over the entire input voltage range.

The shock typically comes from the release of the preload, not from the NEA itself.

Maybe I’m wrong, but having it classified as a planetary mission probably funds their positions and a lot of continued research (even if the research is based on data already taken). Reclassifying the mission probably means the scientists need to look for new sources of funding. So I get that they’re not happy, but it sounds like a rational decision on NASA’s part.

It uses NASA’s Deep Space Network. There are three stations around the globe (California, Australia, and Spain), spaced so that there is near continuous coverage for deep space missions. JWST points it’s antenna at the station that is currently in view.

However, the ground stations are shared between many missions, so they are not available for JWST all the time. Expectation is that JWST gets 8-12 hours/day of DSN time.

I know this is a joke but...

JWST does not use a typical flash-based SSD. The mass storage is all SDRAM. There are layers of error correction and scrubbing to handle bit flips.

There are only 8 hours of downlink time per day. DSN resources are limited and shared among many missions.

Everything was sized based on the expected volume of data that the telescope would be able to take. The instruments only generatedata at a certain rate, and there are inefficiencies involved with slewing between targets. Having a larger recorder or faster downlink would not mean that JWST could take more science data.

The antenna is steered to point towards the DSN antenna on the earth. A larger moving mass would make it harder to maintain telescope pointing while the antenna is moving.

In reality, the antenna pointing is 'paused' during each science observation, unless pointing is needed due to the length of the observation.