SpaceX Updates (Thread 8)

By DocM
in Science News & Discussion

 Share

Recommended Posts

Grand Master

DocM

Posted
  • Author
Posted (edited)

My notes & quotes

 

Early missions?

 

EM: We are still far from figuring this out in detail, but the current plan is:

 

Send Dragon scouting missions, initially just to make sure we know how to land without adding a crater and then to figure out the best way to get water for the CH4/O2 Sabatier Reaction.

 

Heart of Gold spaceship flies to Mars loaded only with equipment to build the propellant plant.

 

First crewed mission with equipment to build rudimentary base and complete the propellant plant.

 

Try to double the number of flights with each Earth-Mars orbital rendezvous, which is every 26 months, until the city can grow by itself.

 

Habitation construction?

 

EM: Initially, glass panes with carbon fiber frames to build geodesic domes on the surface, plus a lot of miner/tunneling droids. With the latter, you can build out a huge amount of pressurized space for industrial operations and leave the glass domes for green living space.

 

Materials challenges

 

EM: It used to be developing a new metal alloy that is extremely resistant to oxidation for the hot oxygen-rich turbopump, which is operating at insane pressure to feed a 300 bar main chamber.

 

Anything that can burn, will burn. We seem to have that under control, as the Raptor turbopump didn't show erosion in the test firings, but there is still room for optimization.

 

Biggest question right now is sealing the carbon fiber tanks against cryo propellant with hot autogenous pressurization. The oxygen tank also has an oxidation risk problem as it is pressurized with pure, hot oxygen. Will almost certainly need to apply an inert layer of some kind. Hopefully, something that can be sprayed. If need be, will use thin sheets of invar welded together on the inside.

 

What's been mastered?

 

EM: Not sure that we've really mastered anything yet. Maybe starting engines...

 

Sea level Raptor performance?

 

EM: Approx 360 sec vacuum Isp and 290 metric tons of thrust. It had to be 42 for important scientific and fictional reasons! The dense packing is just to max out thrust to weight, but it would be cool if there was a virtual nozzle side effect.

 

Can ITS booster hover?

 

EM: A high acceleration landing is a lot more efficient, so there wouldn't be any hovering unless it encountered a problem or unexpected wind conditions. A rocket that lands slowly is wasting a lot of fuel.

 

Max re-entry acceleration for booster?

 

EM: Aiming for 20 g's. The spaceship would be limited to around 5 g's nominal, but able to take peak loads 2 to 3 times higher without breaking up. Booster would be nominal of 20 and maybe 30 to 40 without breaking up.

 

ITS spaceship habitation layout?

 

EM: I think we need a new name. ITS just isn't working. I'm using BFR and BFS for the rocket and spaceship, which is fine internally, but...

 

Will aim to release details of the habitation section when we have actual live mockups. Maybe in a year or two.

 

Configuration for large v small crew?

 

EM: Probably just pack the pressurized space with cargo. Early missions will be heavily weighted towards cargo. First crewed mission would have about a dozen people, as the goal will be to build out and troubleshoot the propellant plant and Mars Base Alpha power system.

 

Purpose of those spherical tanks?

 

EM: The liquid oxygen transfer tube serves as the header tank for oxygen.

 

Those are the header tanks that contain the landing propellant. They are separate in order to have greater insulation and minimize boil-off, avoid sloshing on entry and not have to press up the whole main tank.

 

ITS booster v F9 landings, and coming F9 upgrade?

 

EM: The big booster will have an easier time of things than Falcon, as the mass ratio of the stages is lower and it will have lower density. Net result is that it won't come in quite as hot and fast as Falcon, so Falcon should be a bounding case on the big booster.

 

Final Falcon 9 has a lot of minor refinements that collectively are important, but uprated thrust and improved legs are the most significant.

 

Actually, I think the F9 boosters could be used almost indefinitely, so long as there is scheduled maintenance and careful inspections. Falcon 9 Block 5 -- the final version in the series -- is the one that has the most performance and is designed for easy reuse, so it just makes sense to focus on that long term and retire the earlier versions. Block 5 starts production in about 3 months and initial flight is in 6 to 8 months, so there isn't much point in ground testing Block 3 or 4 much beyond a few reflights.

 

With sub-cooled propellant, I think we can get the Falcon 9 upper stage mass ratio (excluding payload) to somewhere between 25 and 30. Another way of saying that is the upper stage would be close to 97% propellant by mass.

 

[Merlin engine lifetime?] There is no meaningful limit. We would have to replace a few parts that experience thermal stress after 40 cycles, but the rest of the engine would be fine.

 

Big LOX tank?

 

EM: The flight tank will actually be slightly longer than the development tank shown, but the same diameter.

 

That was built with latest and greatest carbon fiber prepreg. In theory, it should hold cryogenic propellant without leaking and without a sealing linker. Early tests are promising.

 

Will take it up to 2/3 of burst pressure on an ocean barge in the coming weeks.

 

Spaceship/tanker flipperons?

 

EM: Good question -- that wasn't shown at IAC. The spaceship and tanker would have split body flaps for pitch and roll. Probably just use the attitude control thrusters for yaw.

 

Favorite teacher?

 

EM: The best teacher I ever had was my elementary school principal. Our math teacher quit for some reason and he decided to sub in himself for math and accelerate the syllabus by a year.

 

We had to work like the house was on fire for the first half of the lesson and do extra homework, but then we got to hear stories of when he was a soldier in WWII. If you didn't do the work, you didn't get to hear the stories. Everybody did the work.

Edited by DocM
  • Draggendrop, BetaguyGZT, FloatingFatMan and 4 others
  • Like 7
Grand Master

BetaguyGZT

Posted
Posted

And holy crap on the Falcon 9 Block 5?! So far we're up to Block 3 (the "FT" Series) ... the FT+ (Block IV) has yet to fly, and those were going to be nifty ... now there's a FIFTH Revision?! 

 

And nice going on the mass ratio of the S2 ... damned efficient. But then again the Merlins are already the most efficient ever. :yes: Nice to see they're trying to get even more performance out of them before retirement. Maybe SpaceX is planning other uses for the Merlins after Falcon 9?

 

And it looks like we've been told HoG's Mission now. It'll be all gear for the follow-on Missions that will be manned on the next synod. Makes sense.

 

Nice ... we've got a gold mine of stuff to comb through. :) 

  • Jim K, DocM and Draggendrop
  • Like 3
Grand Master

DocM

Posted
  • Author
Posted (edited)

For those who missed it, several of the JCSAT-14 landed booster tests at McGregor included upping M1D's thrust another 10% - presumably Block 4. Currently F9 can push 22,800 kg to LEO, so Lord knows where Block 5 will end up.

 

Also,

 

Raptor isn't much larger than M1D and works at >3 times the pressure, so some lessons learned may be transferrable.

Edited by DocM
  • Draggendrop and BetaguyGZT
  • Like 2
Grand Master

BetaguyGZT

Posted
Posted

At this point, I think it's safe to say they won't be upgrading the S2's on FH to run on Raptors. All eggs are probably gonna be going into ITS's basket once they get FH flying, unless something happens where they need to revisit the design (like a defect, etc) to make changes.

 

As I said before, FH is good, great even but it's not the ITS ... way too complicated of a design (by comparison to ITS) to move forward beyond getting it flying and doing Earth SOI Ops. SpaceX is gonna need a smaller launcher to take over for FH and F9, but using Raptor. (Falcon X, perhaps?)

Grand Master

BetaguyGZT

Posted
Posted
53 minutes ago, DocM said:

For those who missed it, several of the JCSAT-14 landed booster tests at McGregor included upping M1D's thrust another 10% - presumably Block 4. Currently F9 can push 22,800 kg to LEO, so Lord knows where Block 5 will end up.

Weren't they aiming for a total net output of +20% more power from the Merlins? Seems like they've got it if they're getting ready to start production in March on the Block 5 Falcons ... or had some kind of breakthrough on an already fan-effing-tastic engine. We know SpaceX and how they like to overachieve. ;) 

  • Draggendrop
  • Like 1
Grand Master

FloatingFatMan

Posted
Posted

Thanks for the updates Doc! Man, I love that they're just getting on with gittin' 'er done and all, but man, I wish they were THERE!!

 

That landing is going to be the most watched show since Armstrong, and whoever sets foot first , will be remembered just as much. Imagine having that load on your shoulders?

  • Draggendrop, SALSN and BetaguyGZT
  • Like 3
Grand Master

FloatingFatMan

Posted
Posted

Something I've been wondering.  Would a Mars rated spacesuit need to be a full pressure suit, or would a sealed compression suit with pressurised helmet work fine?  Seems to me that the latter, if feasible, would be a lot easier to move around in, be easier to make and have longer life support capability.

Grand Master

DocM

Posted
  • Author
Posted (edited)
1 hour ago, FloatingFatMan said:

Something I've been wondering.  Would a Mars rated spacesuit need to be a full pressure suit, or would a sealed compression suit with pressurised helmet work fine?  Seems to me that the latter, if feasible, would be a lot easier to move around in, be easier to make and have longer life support capability.

The pressure is 0.6% of Earth, or .087 psi, so a pressure suit it is. That said, there has been much work done on suits which do not work like traditional pressure suits.

 

One of the most notable is a design by NASA Deputy Administrator Dava Newman (formerly MIT) which applies pressure via a tight fitting under garment rather than by air pressure - the BioSuit.

 

The Weyland Industries Bio Suit in Prometheus borrowed a lot from her design.

 

http://news.mit.edu/2014/second-skin-spacesuits-0918

 

http://www.nasa.gov/pdf/617047main_45s_building_future_spacesuit.pdf

 

cec24b29e8c123dc68f1260c9e2c203a.jpg

 

 

17m8dplcdrnwtjpg.jpg

Edited by DocM
  • BetaguyGZT and SALSN
  • Like 2
Mentor

Beittil

Posted
Posted

I wonder if they will be tanking that big ass LOX tank out on the west coast ASDS Just Read the Intructions or if they will rent another barge for it. I mean, they are taking it out to sea in order to mitigate any damage should it explode... so my best guess would be a rental that can take some blast damage. I know the ASDS can take a beating and has blastwalls and everything, but ideally you wouldn't want to risk all that equipment I think.

Grand Master

DocM

Posted
  • Author
Posted (edited)

It's their official streamer, so likely.

 

Where the tank test barge leaves from depends on where they built the beast, they aren't going to road transport it very far if at all. For now, that's known but not public.

 

Highly doubtful it's on an ASDS. Too much $$ hardware if it goes boomski, and a 12m tank going boomski would be very nasty.

  • Draggendrop
  • Like 1
Grand Master

DocM

Posted
  • Author
Posted (edited)

Now that it's public on NSF....

 

The giant 12 meter composite LOX tank for SpaceX's ITS spaceship was built with the help of Janicki Industries of Sedro-Wooley Washington, a major aerospace composites contractor also involved in,

 

NASA-Boeing composite cryo-tank project (5.5 meter)
NASA SLS launcher & Orion spacecraft 
B-2 bomber
Boeing 787 
F-22 Raptor
F-35 Lightning II
B-21 Raider stealth bomber/recon/interceptor
etc.

 

and, Janicki Industries will build composites at the customers site

 

http://www.janicki.com/capabilities/composite-fabrication/

 

Quote

 

On-site Composite Fabrication



 

JIs expert composite fabrication team is available for contract work at your facility.

Experienced production teams
Foam, putty, carbon fiber, carbon-chop, fiberglass
Resin infusion, lay-up, finishing
Time and cost savings NO hiring and training for your company

IMG_20160927_160335.jpg

 

 

Carbon Fiber Tank 2.jpg

 

 

MLA66590d_spacex_carbontank.jpg

 

Edited by DocM
Grand Master

BetaguyGZT

Posted
Posted

And check out how the tank is buttoned up at the seam ... rapidly & easily extended with a minimum of redesign needed. Just extend it and seal it up, simulate it to make sure it'll hold up to whatever it's meant to be used for. Easy peasy. Janicki really are the best at this kind of thing. :yes: I've been reading their literature, and I'm impressed.

  • Draggendrop
  • Like 1
Grand Master

Draggendrop Veteran

Posted
  • Veteran
Posted

IMHO, using the tunnel rats will be great for habitation and industrial use...using the regolith as a radiation barrier. The domes could be used for limited human exposure and time will tell how the radiation affects a short cycle plant growth. It will take time to monitor and decide on a standard for human/biological exposure...but then again....this is known by those who choose to go...it's not Hawaii....:)

 

I like the approach of boots on the ground for consumable production and power generation setup. These are the most important keys, and once set up can be monitored for change as test results dictate.

 

I assume changes will be made, the closer we get to the date, but it is a plan and achievable.....exciting times ahead.

Grand Master

BetaguyGZT

Posted
Posted
4 hours ago, DocM said:

I think we can assume the AMOS-6  investigation is over.

 

SpaceX just filed two FAA comms permit applications for launch; one from KSC and one from Vandenberg, both for early December.

Cool. Now we can get back to riding our rides. :D 

  • Draggendrop
  • Like 1
This topic is now closed to further replies.
 Share
Go to topic listing