Blue Origin Thread (merged)

[sgt_flyer]

@hugix

problem is, the subcooled propellants (both the lox and Kerosene are subcooled) are only actively 'chilled' within the launch pad tanks. so whatever the hold reason was (safety range / weather issue is a possibility on top of any technical problems) - by the time they could lift the hold, the fuel already in the rocket would have started to warm up too much - so they have to drain the rocket before it does, then refill the rocket (+30mn)(which takes too much time for their launch windows).

with 'classic' cryo propellants, you don't have this problem, as you can top off any evaporation of the propellants (and any gas phase propellant will rise to the top before being vented out of the rocket during launch preparations) - with subchilled propellants, all the fuel in the tank can heat up (losing density in the process) while still remaining liquid, so it's much harder to keep the correct temperature ;)) (hence why spaceX only start fueling it's rocket 30mn before the launch).

Edited February 26, 2016 by sgt_flyer

[Mad Rocket Scientist]

I'm wondering if they suspected that something might be wrong when they were talking about how hard <thing> is.

[Mad Rocket Scientist]

How about this talk of no scrub?

Nevermind, looks like it's been confirmed.

[Vanamonde]

Threads merged to keep the discussion in one place. 

[andrewas]

22 minutes ago, AngelLestat said:

I did not hear, they said something about when they had the next time windows?

They haven't announced a date for the next launch attempt. In theory, they could do it tomorrow at 2343 GMT - a GTO launch like this gets a ~90 minute launch window every sidereal day. But if they do have a problem with loading the LOX quickly enough, they might need to upgrade the pad infrastructure and that could take much longer. And SES are probably keen to get their satellite in orbit, so SpaceX may wind up abandoning the landing attempt to give SES 9 a little bit more of a kick and get it into its GEO slot a bit faster.

[KerbonautInTraining]

They said the flight computer failed to start I think...?

[Camacha]

15 minutes ago, Vanamonde said:

Threads merged to keep the discussion in one place. 

That explains my confusion. Well, here's to posts that do not make sense any more.

[sgt_flyer]

9 minutes ago, andrewas said:

They haven't announced a date for the next launch attempt. In theory, they could do it tomorrow at 2343 GMT - a GTO launch like this gets a ~90 minute launch window every sidereal day. But if they do have a problem with loading the LOX quickly enough, they might need to upgrade the pad infrastructure and that could take much longer. And SES are probably keen to get their satellite in orbit, so SpaceX may wind up abandoning the landing attempt to give SES 9 a little bit more of a kick and get it into its GEO slot a bit faster.

they already upgraded the pad for faster fueling  (they only need 30mn to load the fuel) problem is that in case of hold after they started fueling, as the rocket's fuel tanks are not actively cooled, the subcooled fuel will slowly heat up and lose density - wait too long, and the density is not good enough for the launch parameters, so they have to drain the rocket and refuel it in case of hold (depending on how much the rocket was already filled at the time of hold, the process of draining and refuelling could take too long) - so if they had a problem with the fueling rate, guess that would be a technical problem of the ground support equipments, which totally warrants a scrub

Edited February 26, 2016 by sgt_flyer

[Camacha]

3 minutes ago, sgt_flyer said:

they already upgraded the pad for faster fueling  (they only need 30mn to load the fuel) problem is that in case of hold after they started fueling, as the rocket's fuel tanks are not actively cooled, the subcooled fuel heat up and lose density - wait too long, and the density is not good enough for the launch parameters

It sounds like they complicated something that was already complicated. Having only a single shot is going to tank the launch rate. It sounds like they need to implement something like fuel cycling, where a full tank gets drained and replenished continuously with cooled fuel to keep the temperatures down.

[sgt_flyer]

4 minutes ago, Camacha said:

It sounds like they complicated something that was already complicated. Having only a single shot is going to tank the launch rate. It sounds like they need to implement something like fuel cycling, where a full tank gets drained and replenished continuously with cooled fuel to keep the temperatures down.

well having a single shot would depend on how much % of the tanks were filled at the time of hold, as well as the launch window duration  - i think the commentator talked about that during the feed - in case of hold they drain the tanks then refill them (which would delay the launch by at least the time needed for the drain (depends on the %filled), the remaining hold time (if it's still on hold by the time the rocket is emptied) + 30mn to refill the rocket. for sure,on a 90mn launch window, seems really complicated...

 

[Camacha]

3 minutes ago, sgt_flyer said:

well having a single shot would depend on how much % of the tanks were filled at the time of hold, as well as the launch window duration  - i think the commentator talked about that during the feed - in case of hold they drain the tanks then refill them (which would delay the launch by at least the time needed for the drain (depends on the %filled), the remaining hold time (if it's still on hold by the time the rocket is emptied) + 30mn to refill the rocket. for sure,on a 90mn launch window, seems really complicated...

 

I have seen multiple launches where a successful launch was preceded by a couple of holds. Having to drain and refill your tanks every time would have meant a scrub in every one of those cases.

Edited February 26, 2016 by Camacha

[Motokid600]

So has there been any official word on the next attempt?

http://www.flightclub.io/world.php?watch=1&code=SES9

Says this time tomorrow.

 

[sgt_flyer]

13 minutes ago, Camacha said:

I have seen multiple launches where a successful launch was preceded by a couple of holds. Having to drain and refill your tanks every time would have meant a scrub in every one of those cases. It hardly seems the way you want to do things.

yup, with classic cryo propellants, you only have to deal with the boiloff and vent out the gases (which, due to the gases density, while rise up to the top, then top off the rest, so it's much easier to keep a filled rocket waiting. much harder to 'target' only the hotter or colder liquids mixed within a tank to replace only the fuel not cold enough

to be able to keep readiness through a hold, they would need either to have an active cooling system which retracts with the strongback (much more complex fuel tank design if you have to allow for the system to get in and out) or continous fuel cycle (which is complicated too, as the fuel you add in the rocket would create all kinds of flowpaths within the tank which could mean you're not pumping out only thr hottest fuel)

Edited February 26, 2016 by sgt_flyer

[fredinno]

4 hours ago, DerekL1963 said:

The only people afraid of deep cryogens (based on well established, well tested, well known technology) are the amateurs in the cheap seats (who prefer untested, unknown, unproven technologies).   Theoretical handwaving from the cheap seats is entertaining - but SpaceX has a business to run today.

Yeah- considering the difficulty they're having with Deepcryo, Not to mention delays (time=money), I think this is something Elon thought was a good idea and that nobody else bothered with- ignoring the fact that noone else bothered with it beacuse it is such a pain to deal with, and tank stretches are far easier.

4 hours ago, KerbonautInTraining said:

I'm still confused as to why they don't have near future plans for an LH2 upper stage. 

It requires two different engine types, increasing cost. A 3rd stage can often increase the capability of the rocket enough for high-energy destinations.

4 hours ago, KSK said:

Given the choice between persevering with a known technology (subcooled LOX isn't exactly a new thing, just new for them) or developing an entirely new rocket complete with new tooling, new engines and a new fuel, not to mention new infrastructure to support it, I can't imagine why SpaceX opted to stick with the known technology for the moment. It's not like they're short of other ongoing projects either. Or that subcooled LOX isn't going to give a performance upgrade to any LOX/CH4 they decide to build in future.

Yeah, subcooled Lox isn't used much, I'm fairly certain. Subcooled Lox isn't very useful for a Ch4 Lox rocket- the molar mass of CH4 is about half of O2, so it would be more efficient to run fuel-rich, meaning he impact of deepcryo O2 on a methane rocket is much worse than on Rp-1. Sure, you'd get smaller tanks, but that's not a major benefit when most of the volume is Ch4, not O2. The performance boost is really meh at best for methane rockets.

Also, a larger diameter, shorter 1st stage is easier to land, and the "new engines" would just be the same engines used for the F9 FT- Merlin 1D FT. They didn't need to build F9 FT so quickly, F9 1.1 was doing just fine. Sure, you'd have less opportunities to land and reuse stages, but SpaceX was (and is) doing spectaularly. The worst thing that would happen is that stage reuse would take a few months longer to implement due to needing to use a barge to land, instead of landing on land.

A larger diameter F9 would be a clear interim to a Ch4 F9, with much of the development needed for Ch4 would be done for the interim F9. Raptor still has a way to go before it sees a launch.

[Rakaydos]

3 hours ago, fredinno said:

Also, a larger diameter, shorter 1st stage is easier to land, and the "new engines" would just be the same engines used for the F9 FT- Merlin 1D FT. They didn't need to build F9 FT so quickly, F9 1.1 was doing just fine. Sure, you'd have less opportunities to land and reuse stages, but SpaceX was (and is) doing spectaularly. The worst thing that would happen is that stage reuse would take a few months longer to implement due to needing to use a barge to land, instead of landing on land.

A larger diameter F9 would be a clear interim to a Ch4 F9, with much of the development needed for Ch4 would be done for the interim F9. Raptor still has a way to go before it sees a launch.

The problem with a larger diamiter is that the Falcon 9 diamiter is already the exact maximum legally transportable (with a waiver) over interstate freeways. The cost difference between a chartered barge through Panama to get the rocket to florida, and  hiring a trucker to go directly is enough to make up for a LOT of delays on the launch end.

[fredinno]

1 minute ago, Rakaydos said:

The problem with a larger diamiter is that the Falcon 9 diamiter is already the exact maximum legally transportable (with a waiver) over interstate freeways. The cost difference between a chartered barge through Panama to get the rocket to florida, and  hiring a trucker to go directly is enough to make up for a LOT of delays on the launch end.

As I said earlier, Elon is going to need that infrastructure for Ch4 F9 anyways, so it's better to save the development money used on something that will quickly become obselete- not to mention he'll need it for MCT, if it ever is made. F9 literally is already the max. dimensions of a rocket that uses road transport, it's inevitable that barge transportation will be used in the near future.

[Rakaydos]

Where is this supposed methane falcon mentioned?

[sojourner]

1 hour ago, Rakaydos said:

Where is this supposed methane falcon mentioned?

In fredinno's fertile imagination.  SpaceX has only hinted at a possible new methane second stage for F9.  There's been no indication that they will build a methane F9 first stage.

[sgt_flyer]

@Rakaydos

yup, they have plans for a raptor upperstage for the Falcon 9 / Falcon heavy, as the airforce awarded SpaceX 33.6M$ in january for develloping a raptor engine for that so that's pretty much confirmed

http://spaceflightnow.com/2016/01/14/orbital-atk-spacex-nab-u-s-air-force-propulsion-contracts/

[fredinno]

2 minutes ago, sojourner said:

In fredinno's fertile imagination.  SpaceX has only hinted at a possible new methane second stage for F9.  There's been no indication that they will build a methane F9 first stage.

 https://en.wikipedia.org/wiki/Raptor_(rocket_engine) The raptor was also small enough for F9 1st stage, even before then. There's no way the engine will be tested first on a MCT, since it's going to require so much more new tooling not already in place. 

Also, http://space.stackexchange.com/questions/10391/how-does-spacex-plan-to-achieve-reusability-of-the-falcon-9-second-stage

Quote

The next generation vehicles after the Falcon architecture will be designed for full reusability. I don't expect the Falcon 9 to have a reusable upper stage, just because the - with a kerosene-based system, the specific impulse isn't really high enough to do that, and a lot of the missions we do for commercial satellite deployment are geostationary missions. So, we're really going very far out. These are high delta-velocity missions, so to try to get something back from that is really difficult. But, with the next generation of vehicles, which is going to be a sub-cooled methane/oxygen system where the propellants are cooled close to their freezing temperature to increase the density, we could definitely do full reusability - and that system is intended to be a fully reusable Mars transportation system. So, not merely to low Earth orbit but all the way to Mars and back, with full reusability. [Within 3 years?] Ha. I am an optimistic person, but - I think we could expect to see some test flights in the five or six year time frame. But, we're talking about a much bigger vehicle, and we're also going to be upgrading to a new generation - a harder engine cycle, which is a full-flow staged combustion. What we have right now is an open cycle engine. Right now, I'd say, engines are our weakest point at SpaceX, but they will become as strong as the structures and avionics in the next generation.

 

[Motokid600]

They need to store the falcon 9 in a huge refrigerator and at the last minute it splits in half for the launch. Kinda joking... but not really. Would such a thing be feasible?

[Rakaydos]

20 minutes ago, Motokid600 said:

They need to store the falcon 9 in a huge refrigerator and at the last minute it splits in half for the launch. Kinda joking... but not really. Would such a thing be feasible?

A Thermos is a vacuum- walled  cylinder. With some sort of cowling around the engine that maintains a near vaccum around the rocket, where the seal is broken and the cowling dropped/pulled away at, say, T-30 seconds, might help in that regard.

 

6 hours ago, fredinno said:

 https://en.wikipedia.org/wiki/Raptor_(rocket_engine) The raptor was also small enough for F9 1st stage, even before then. There's no way the engine will be tested first on a MCT, since it's going to require so much more new tooling not already in place.

 

Fredino, your quote after the video explicitly calls out the "Next generation Vehical after Falcon" as a "fully reusable Mars Transportation System."

He's pretty clearly talking about the MCT, and we already knew the MCT was going to be huge and methane powered..

 

[sojourner]

7 hours ago, fredinno said:

 https://en.wikipedia.org/wiki/Raptor_(rocket_engine) The raptor was also small enough for F9 1st stage, even before then. There's no way the engine will be tested first on a MCT, since it's going to require so much more new tooling not already in place. 

Also, http://space.stackexchange.com/questions/10391/how-does-spacex-plan-to-achieve-reusability-of-the-falcon-9-second-stage

 

And? Nothing there indicates that SpaceX is actually working on making F9 first stage methane based.  You're making suppositions. Second stage may get methane but that remains to be seen.

[DerekL1963]

4 hours ago, Motokid600 said:

They need to store the falcon 9 in a huge refrigerator and at the last minute it splits in half for the launch. Kinda joking... but not really. Would such a thing be feasible?

Not really, no.

[tater]

Apparently they're gonna try again Sunday.