Poll

How will a F9 Block 5 stage first launch?

With a new block 5 stage 2 on a new block 5 stage 1 (Because B5 S1 only works with B5 S2)
22 (55%)
With a new block 5 stage 2 on a new block 5 stage 1 (A riskier test-flight of both together)
10 (25%)
With a new block 5 stage 2 on a new (legacy block 3 or 4) stage 1  (To test-fly B5 S2 first)
0 (0%)
With a new block 5 stage 2 on a reused (block 3 or 4) stage 1 (To test-fly B5 S2 first, cheaper)
0 (0%)
With a legacy (block 3 or 4) stage 2 on a new block 5 stage 1 (To test-fly B5 S1 before B5 S2)
3 (7.5%)
With a legacy (block 3 or 4) stage 2 on a new block 5 stage 1 (Because B5 only applies to S1)
4 (10%)
Never!
1 (2.5%)

Total Members Voted: 40

Voting closed: 05/11/2017 09:41 PM


Author Topic: POLL: In what form will Falcon 9 Block 5 technology first launch?  (Read 1203 times)

Offline Zardar

  • Full Member
  • *
  • Posts: 125
  • Limerick, Ireland
  • Liked: 60
  • Likes Given: 157
According to SpaceX, production start for F9 B5 stages is imminent (say by Q2 2017), and first launch could be reasonably expected after about 6-9 months later (by Q4 2017 or Q1 2018)

Given the assumption that both S1 and S2 have been upgraded for Block5, do our forum members think that SpaceX will launch block 5 stage 1 and 2 together, or will test-fly an upgraded stage independently?

Note that Option 1 and 2 are quite similar, the difference being is that option 1 covers the case that SpaceX have to fly both stages together as (perhaps) they don't work with older blocks, and option 2 covers the case that SpaceX dont have to fly S1 and S2 B5 together (i.e. they are compatible with other versions), but they choose to take the riskier (but faster) option to test them both together anyway.

The other options cover the remaining combinations.
Option 6 is in case my assumption is deemed incorrect.



Online ZachS09

I don't think placing a Block 5 second stage atop a Block 3/4 first stage would work because Block 5 components obviously weigh more than Block 3/4 components. So, even with a liftoff thrust of over 1.7 million pounds, I can't imagine that type of hybrid flying even once.
"Falcon 9 has landed. Landing operators, move into Procedure 11.100 on Recovery Net."

Offline old_sellsword

  • Full Member
  • ***
  • Posts: 376
  • Liked: 294
  • Likes Given: 250
...Block 5 components obviously weigh more than Block 3/4 components.

Why is this so obvious?

Online ZachS09

Because Block 5 carries more propellant than Block 3/4. Plus, the stage structures are strengthened.
"Falcon 9 has landed. Landing operators, move into Procedure 11.100 on Recovery Net."

Offline macpacheco

  • Full Member
  • ****
  • Posts: 750
  • Vitoria-ES-Brazil
  • Liked: 291
  • Likes Given: 2180
Block 5 2nd stage needs to be compatible with B4 and B3 boosters. Otherwise SX would be forced to custom build older design 2nd stages to launch on top used B3 and B4 boosters.

The logic that B5 rockets are heavier doesn't make much sense. Refurb should be about things that get consumed like TPS rather than the overall rocket structure needing beefing up. If they mass more, its very little more.

So SX will launch the whole block 5 rocket when they're done testing it. People that think they'll test B5 booster or 2nd stage to take smaller steps don't understand how rockets are designed and tested. Either you know its going to work and launch it, or you designed the thing wrong. Testing is solely to confirm predictions. Nothing is intentionally left to chance for the launch. When there's margin of uncertainty, things are overbuilt and if the extra margin can be confirmed as not needed, changes can be made to reduce the extra margin. Of course stage recovery brings this to a whole new level, but none of that is about being unsure if the launch will succeed.
Looking for companies doing great things for much more than money

Offline mme

  • Full Member
  • ****
  • Posts: 919
  • Santa Barbara, CA, USA, Earth, Solar System, Milky Way Galaxy, Virgo Supercluster
  • Liked: 1106
  • Likes Given: 2563
I don't buy that testing B5 S1 and S2 together is more risky and I don't buy you can't mix and match them.  So my answer is:

(*) Whatever happens will be most cost effective or fastest to flight based on the production line.
Space is not Highlander.  There can, and will, be more than one.

Offline FutureSpaceTourist

  • Senior Member
  • *****
  • Posts: 2552
  • UK
    • Plan 28
  • Liked: 1638
  • Likes Given: 594
Cross-posting:


Will SpaceX first launch a B5 S1 together with a B5 S2,

It isn't question.  There is no mixing blocks.  Both will be produced and flying together.

Offline old_sellsword

  • Full Member
  • ***
  • Posts: 376
  • Liked: 294
  • Likes Given: 250
Because Block 5 carries more propellant than Block 3/4. Plus, the stage structures are strengthened.

1. How do you know Block 5 will have a tank stretch?

2. Strengthening a structure does not necessarily mean adding more weight. An octaweb welder on Reddit, em-power, has stated numerous times that at one point they redesigned the octaweb to be much stronger while hardly adding any weight at all.

Tags: