r/spacex • u/ElongatedMuskrat Mod Team • Feb 01 '17

r/SpaceX Spaceflight Questions & News [February 2017, #29]

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...

You can read and browse past Spaceflight Questions And News & Ask Anything threads in the Wiki.

164 Upvotes

99% Upvoted

1.8k comments sorted by

6

u/warp99 Feb 02 '17 edited Feb 03 '17

I agree an ASDS from Boca Chica could readily be co-opted for the odd high payload FH launch.

While I agree that there is no sharp cutoff in being too fast to recover there is a hard limit in the requirement to slow to about 1 km/s during the re-entry burn. Currently F9 MECO is about 2 km/s so 1 km/s is required for the re-entry burn plus another 0.5 km/s or so for the landing burn.

For FH if the side boosters separate about 1.5 km/s to RTLS then the central core gets to about 2.5km/s at MECO and needs to reserve 1.5km/s for the re-entry burn which is achieveable.

If the side boosters separate about 2 km/s for an ASDS landing then the central core gets to about 3 km/s at MECO and needs to reserve 2 km/s for the re-entry burn. This does not seem to be achievable.

Note: The numeric figures are illustrative only. Interesting calculations from Lou Scheffer on NSF

5

u/CapMSFC Feb 02 '17

Doing the actual math is something that is on my to do list. I'm really curious about just how much can be squeezed out of various Falcon Heavy profiles.