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SpaceX techs work towards Falcon 9 fairing recovery with wacky series of experiments
By Eric Ralph
Posted on September 25, 2018

Over the course of the past week, Teslarati photographer Pauline Acalin has captured a multitude of unusual occurrences at SpaceX’s Port of Los Angeles dock space, each time involving a Falcon fairing recovery vessel like Mr Steven or NRC Quest, a Falcon fairing half (flight-proven or otherwise), and one of several attenuating circumstances.

Photo caption:

A mystery Falcon fairing – perhaps new, perhaps flight-proven – appeared at SpaceX’s old Port of San Pedro berth in the last few days. (Pauline Acalin)
SpaceX BFR - Earth to Deep Space / Re: BFS Engineering Thread
« Last post by Crispy on Today at 10:48 AM »
If you have no lift, your reentry is similar to the John Glenn experience - 8G.

Isn't that dependent on the ballistic coefficient? Which for the mostly-empty-air BFS will be quite low?
Historical Spaceflight / Re: KSCVC Saturn 1B's restortation
« Last post by jacqmans on Today at 10:44 AM »
This is presumably SA-209, the backup launch vehicle for ASTP (Apollo Soyuz Test Project).

It is the back up vehicle...

Over 29 years, the workhorse Delta II rocket launched 155 missions for the U.S. Air Force, National Reconnaissance Office and commercial customers. Landmark Delta II missions include every GPS satellite through the constellations of 21 GPS II-R missions for the U.S. Air Force; NASA's Spirit, Opportunity, Phoenix and Stardust missions; and commercial missions for Iridium, Globalstar and DigitalGlobe.

 Image credit: United Launch Alliance
Hiroyuki Sanada.
Historical Spaceflight / Re: KSCVC Saturn 1B's restortation
« Last post by TripleSeven on Today at 10:24 AM »
thanks for the report and the pictures...I build models these are very very helpful...nice work
By the way, the Soviets' first staged-combustion engine flew a long time ago. I don't have my copy of Sutton's book on the history of rocket engines handy, but I think it was way back in the early 1960's.

According to Wiki, the first oxidiser rich staged combustion engine was the S1.5400, which was used on the Molniya fourth stage. First successful flight was on 12 February 1961 carrying Venera 1.
SpaceX BFR - Earth to Deep Space / Re: BFS Engineering Thread
« Last post by speedevil on Today at 10:15 AM »
The graphs look remarkably similar up to around mach 4, when STS pitches down from an AOA of 40 degrees rapidly to 10.
The AOA of BFS is broadly comparable up until that period.

If you go so broad that 80 degree angle of attack is similar to 40 degrees, there is no room left for criticism.

BFS is doing a hypersonic glide as much as Dragon or Apollo are gliding.

Look at the altitude/time graphs.
Compare with a non-lifting reentry.
If you have a non-lifting reentry, you have decelerations in the 8g range, not the 3g range mentioned.

From the FAAs document on reentry

Note that Dragon and Apollo both flew non-ballistic trajectories.
A SpaceX Engineer
The 0.18 L/D allows a very narrow reentry corridor and keeps deceleration loading on the crew below approximately 5g

If you have no lift, your reentry is similar to the John Glenn experience - 8G.
Will the material used for the BFR heat shield be composed of stick on tiles or paint on layers? Roughly how thick will it be and how reparable / refurbishable? I know it’s supposed to last a long time but if there’s a problem with part of the heat shield for whatever reason at any point, is that the end of the BFR shell or can they reasonably be expected to repair or replace sections of it safely?
We don't know.
There are aspirations, and hopes - up to 'thousands of flights' - but little has been said about refurbishment or replacement.
There have been job vacancies for desginers of certain sorts of heatshield, and ... - but these don't go as far as addressing any of the issues.
It seems at least plausible that given the vast advances in adhesives and robotics, that the absolute worst case would not be scrapping a hull, but putting the vehicle into a large machine to strip off absolutely all of the heatshield and reapply.

For this not to work, the heatshield would have to be a formed-in structural element, or reliant on glue bonds that can only be achieved at assembly time.

More information on this would be great, but I suspect little will be known until much closer to (or even after) initial testing.

Since we know the size weight and velocity, has anyone calculated the heat flow on just the body. After all this thing is going to make a huge shock wave.

No, but looking at the sky dive re-entry video it looks like the BFR rolls left then right early on as if to spread the heat across a greater area.
SpaceX BFR - Earth to Deep Space / Re: BFS Engineering Thread
« Last post by tyrred on Today at 10:12 AM »
Take a look at Scott Manley's latest effort in the KSP

 He found that the vertical fin can cause some interesting interactions

Aerodynamics, especially hypersonic, is not exactly KSP's strong suit, even with mods.
Agreed.  KSP is fun for a while, but it's ultimately a video game.   I accept the CFD simulations from SpaceX in a heartbeat.  SpaceX does appear to know how to land a few rockets and reuse them. 
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