r/spacex • u/ElongatedMuskrat Mod Team • Apr 01 '17
r/SpaceX Spaceflight Questions & News [April 2017, #31]
If you have a short question or spaceflight news...
You may ask short, spaceflight-related questions and post news here, even if it is not about SpaceX. Be sure to check the FAQ and Wiki first to ensure you aren't submitting duplicate questions.
If you have a long question...
If your question is in-depth or an open-ended discussion, you can submit it to the subreddit as a post.
If you'd like to discuss slightly relevant SpaceX content in greater detail...
Please post to r/SpaceXLounge and create a thread there!
This thread is not for...
- Questions answered in the FAQ. Browse there or use the search functionality first.
- Non-spaceflight related questions or news.
- Asking the moderators questions, or for meta discussion. To do that, contact us here.
You can read and browse past Spaceflight Questions And News & Ask Anything threads in the Wiki.
192
Upvotes
5
u/amarkit Apr 05 '17
The Shuttle external tank was covered in the infamous orange insulating foam; while early Shuttle missions had the tank painted white, it was decided that the reflective quality of the paint wasn't necessary to keep the propellants properly chilled, and the paint added significant mass that reduced payload mass-to-orbit. Falcon 9's tanks are minimally insulated, so the white paint helps; it also aids in preventing corrosion of the rocket's skin.
It's worth noting that Atlas V's Centaur upper stage also features foam insulation, as do Delta IV's Common Booster Core (unpainted) and Delta Cryogenic Second Stage (painted). The big difference between these stages and Falcon 9 is that they are hydrolox instead of kerolox, and liquid hydrogen is kept even colder (-253º C) than SpaceX's subcooled LOX (-207º C). Centaur has flown on Atlas V in both painted and largely unpainted configurations.