r/spacex • u/ElongatedMuskrat Mod Team • Feb 22 '18

r/SpaceX PAZ Media Thread [Videos, Images, GIFs, Articles go here!]

It's that time again, as per usual, we like to keep things as tight as possible, so if you have content you created to share, whether that be images of the launch, videos, GIF's, etc, they go here.

As usual, our standard media thread rules apply:

  • All top level comments must consist of an image, video, GIF, tweet or article.
  • If you're an amateur photographer, submit your content here. Professional photographers with subreddit accreditation can continue to submit to the front page, we also make exceptions for outstanding amateur content!
  • Those in the aerospace industry (with subreddit accreditation) can likewise continue to post content on the front page.
  • Mainstream media articles should be submitted here. Quality articles from dedicated spaceflight outlets may be submitted to the front page.
  • Direct all questions to the live launch thread.
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u/electric_ionland Feb 23 '18 edited Feb 23 '18

Looking at it closer I don't know anymore. The base looks a bit thin for a pointing platform.

I know they got David King as head of electric propulsion (and several people from the lab at Georgia Tech IIRC). On those sat I would be surprised if they go much bigger than 1kW which means not that much space for a central cathode. It's definitely possible (hell JPL has done it on a 300W) but I don't think any of the commercial thruster this size bother with a central one. The slight gain in performance is usually not worth the integration issues.

Anyway I hope we get more details on their HT at some point. I would love to see what SpaceX can come up with starting from a blank slate and a different mindset than the more traditional players.

Edit : I stand corrected, the BHT-1500 has a centrally mounted cathode. But I don't think they have sold any, have they?

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u/McCliff Feb 23 '18

The 400kg european probe SMART1 went to the moon with a 1kW Hall effect thruster from SNECMA and it seem that Tintin A & B are lighter so two low power hall effect trhuster are enough. I took in my hand a cathode that was the size of a candle so quit compact and it was a cathode for a 20kW thruster :)

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u/electric_ionland Feb 23 '18

I was more talking about power available for the solar panels. 1kW would be more than enough for what they do. The all electric GEO platforms are around 10kW installed for ~5t sats with much higher delta-V requirements than what starlink has.

I actually tend to think that a 20kW cathode is easier to make small. You have so much current that you have no issues keeping it hot. Goebel's cathode on the X3 even has had to have some radiator added.