Spacex Falcon 9 Block 5 targets 24 hour turnaround, no refurbishment reuse and relaunch a dozen times

Spacex Chief tech officer Tom Mueller discussed the next-gen Falcon 9, called the “Block 5,” which will have a reusable thermal protection that won’t burn up the heat shielding. It will also have retractable legs that will only come out during landing.
The Falcon 9 Block 5 will have a 24-hour turnaround and be much cheaper and is expected to be flying by the end of 2017.
With a cheaper design comes a few tradeoffs. The Block 5 has a single Merlin engine on it, although it’s a fairly sophisticated version of the engine. It uses some of the same tech, like the guidance computer, from the Falcon 9 (which has 9 Merlin engines), though. Mueller says the Block 5 has a significantly lower cost but the performance is “marginal.”
The Falcon 9 Block 5 is expected to be far more reusable than the Block 3. Shotwell said a Block 5 booster could relaunch “ a dozen or so times.” The Block 3, by comparison, has an estimated life of two or three missions.
Shotwell said the Block 5 version of the Falcon 9 won’t need refurbishing, but will mainly undergo inspections prior to launch, streamlining the process compared to the first reused boosters.
Block 5 will feature:
For increased payload:
* 7–8% more thrust by upgrading the engines,
* an improved flight control system for an optimized angle of attack on descent, lowering landing fuel requirements.
For rapid reusability:
* Forged, more temperature-resistant titanium grid fins,
* a thermal protection coating on the first stage to limit reentry heating damage,
* a set of retractable landing legs for rapid recovery and shipping,
* a reusable heat shield protecting the engines and plumbing at the base of the rocket.
A recent analysis posted on reddit of Spacex costs with ten reuses suggests a maintained profit margin with costs that are about 40-50% of a non-usable Spacex flight.
SpaceX president Gwynne Shotwell told the Space Symposium conference that the cost of refurbishing the Falcon 9 rocket that originally flew the CRS-8 Space Station resupply mission last year for SES-10 was “substantially less than half” what it would have cost to build a brand new one. That’s despite doing a lot to bring the recovered rocket back to operational condition. The new Block 5 rocket that would not need refurbishment could deliver on the speed and cost saving for reusable rockets.
Arabsat will be the first customer for the Falcon Heavy when it begins commercial service in 2018, following a demonstration mission later this year.
Falcon Raptor
Shotwell has hinted at the possibility of a future version of Spacex rockets that could use the Raptor engines designed for transportation to Mars. Shotwell said Raptor, a liquid methane and oxygen engine for SpaceX’s interplanetary spaceship, has undergone “many dozens of tests” and is progressing well. “The original idea for those engines were to serve as a propulsion system for the big Mars system, but we are looking at the utility of it on the Falcon program,” she said.