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11
Not sure if this has been discussed yet, but I've been wondering whether the build process we are seeing for these prototypes is going to carry over to the final, mass production versions. Specifically with consideration of the process of cryoforming that Elon has previously mentioned.

It seems like cryoforming SS would be a complicated process that SX would need time to learn and perfect (being something they have not done in the past, and the recent switch to SS).

With that in mind, is the orbital starship prototype being built out of cryoformed SS sheets (cryoformed off site, shipped to BC and welded together), or is SX going to implement cryoforming at a later time?

I'm not a rocket scientist or an expert in cryoforming SS but it seems to me like having larger sheets with less welding would be better for an orbital ship.

So, are there going to be major changes to the production process between these prototypes and the mass production version? (specifically talking about the outer shell)
I think it would be more pratical to do cryogenic treatment on plates rather than the whole ship?
12
Hey guys, been following this thread for awhile. If this is not the proper place for this question or comment I apologize. Do the leaked announcements usually line up with actual announcement? I've looked at a few launches in the past and the general timeline for official announcement seems to be about 10 days prior to launch. I have not seen anything about leaked time frames.

I ask this because I planned on flying home the 7th of April and I am now debating about extending the trip in hopes that I get to witness this launch. Not gunna lie, since watching the last FH launch I've been storing vacation for this very moment and it now just so happens to be on the tail end of my long Florida vacation. It'll be a cherry on top if it comes true.

Should I change my flights up and get an extra hotel night, or should I wait a little bit?

I'm not sure what you mean by leak in this case.  If you're asking if NET 7 April is the target launch date for ArabSat-6A, this site never posts an inaccurate launch date as we know the public relies on that information for travel. We also adjust and update the launch date in the public thread as soon as possible.

That said, a launch is always NET (No Earlier Than) until the vehicle lifts off the pad -- so the words of caution in the post above about never taking a launch date as solid and understanding that things can change rapidly (even in the last seconds of a count) is good advice..
13
For things like spherical camera gimbals under Predator drones, the heat transfer on the back side is about 6x the heat transfer on the front, because the back side is turbulent and the front is laminar.

Why do hypersonic vehicles see greater heat transfer at the front of the vehicle?
  * Is it that the air density is significantly higher there?  I can imagine that the decompression across the trailing oblique shock is quite significant.
  * Is it that the air temperature is higher at the front?  Once again, I suppose it's possible the air temp drops as it expands across the trailing shock wave.
  * Is it that the front sees radiative heating that the back does not?
Because Predators are subsonic, not hypersonic. The formation of a shockwave ahead of and bent tightly around the vehicle dramatically changes the way fluid flows about it.
14
Can someone point out key details in this mockup that should make me feel excited?

What's "exciting" about the mockup is the fact that it exists. We're looking at a prototype instead of a PowerPoint slide. Still far from launching an actual module, but it's progress.
15
Space Science Coverage / Re: JAXA Hayabusa2 Mission : General Thread
« Last post by yoichi on Today at 01:59 pm »
1) Does Jaxa have previous experience in docking spacecrafts?

https://en.wikipedia.org/wiki/ETS-VII
16
A couple pics from the launch site this morning. I also confirmed that testing for today has been scrubbed. :(

Gotta move those plastic outhouses or Raptor is going to do it for you.
17
Not sure if this has been discussed yet, but I've been wondering whether the build process we are seeing for these prototypes is going to carry over to the final, mass production versions. Specifically with consideration of the process of cryoforming that Elon has previously mentioned.

It seems like cryoforming SS would be a complicated process that SX would need time to learn and perfect (being something they have not done in the past, and the recent switch to SS).

With that in mind, is the orbital starship prototype being built out of cryoformed SS sheets (cryoformed off site, shipped to BC and welded together), or is SX going to implement cryoforming at a later time?

I'm not a rocket scientist or an expert in cryoforming SS but it seems to me like having larger sheets with less welding would be better for an orbital ship.

So, are there going to be major changes to the production process between these prototypes and the mass production version? (specifically talking about the outer shell)

- The prototypes they are currently building are, according to my calculations, overweight, so their stresses will be low enough that cryo-forming will not be needed.

- I do not believe we are seeing the final production technique.
18
Q&A Section / Re: Can we cheaply extend Hubble life ?
« Last post by Rabit on Today at 01:48 pm »

Cheap satellite from off the shelf parts launched as secondary payload on Falcon 9 or heavy will cost fraction of Hubble ;)

There are no off-the-shelf telescope systems anywhere near as good as Hubble, so you'd end up with a far less capable system.

To prolong Hubble life not to send new one.
19
Advanced Concepts / Re: Fission Fragment Rocket Viability
« Last post by aceshigh on Today at 01:46 pm »
One design would generate 13 meganewtons of thrust at 66 km/s exhaust velocity (compared to ~4.5 km/s exhaust velocity for the best chemical rockets of today).


The design and calculations discussed above are using 20 percent enriched uranium salts, however, it would be plausible to use another design which would be capable of achieving much higher exhaust velocities (4,700 km/s) and use 2,700 tonnes of highly enriched uranium salts in water to propel a 300 tonne spacecraft up to 3.6% of the speed of light.[1]


-------------

Between radioactive rockets , few can beat this beast
20
I voted SS+SH because of two things. When Erick Berger of NASA gives Starship even odds of beating SLS to space and the real pace observed in the test and flight hardware build, Starship schedules are likely to shift to the right not left as long as problems SpaceX encounters are not significant and can be quickly corrected. Unlike most LV development programs most of the gremlins will have been discovered before any hardware actually reaches orbit because as others have mentioned a vehicle that allows for incrementing challenges vs testing all at once has tremendous advantages for real schedule and costs. In modern LVs it is mostly the integration of the software to the hardware and then doing tests with the hardware in the loop to determine if the combination will actually work in the real world. I trust SpaceX software development team to deliver and update software very fast with high quality. In the end to get such software fully functional you can incrementally test in the real world and possibly loose a vehicle or several when the cost of hardware is low (estimate of hopper and other prototypes looks to be not much more than $10M). Else you can produce endless and expensive computer simulation models at high costs (each of these software models cost as much as the software) which takes time and multiplies the time to deliver working software. Note SLS is having this exact problem with ballooning costs and schedules in its software development.
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