Blue Origin Thread (merged)

[Montieth]

If you can precisely land on a large concrete field, aka a hardstand, why move it back to a pad to launch? Why not launch from the hard-stand after servicing with field movable equipment? 

 

Edited September 28, 2016 by Montieth

[Nibb31]

Why would they do that ?

They can fill a tanker with another tanker, launch the crewed ITS, fill up on the full tanker, and go.

[Nibb31]

On 10/09/2016 at 4:58 PM, WildLynx said:

May be they want videos not of the rocket, but bushes around it. May be conspiracy freaks are not that wrong this time. Saboteurs specifically trained to infiltrate protected areas, there is an ocean nearby, etc...

Because you might need the pad to launch a different booster. Or you might want to do some maintenance on it before launching it again.

[Montieth]

Musk said it would take several tanker launches to get it set for the transburn.

 

"It'll go up multiple times, anywhere from 3 to 5 times to fill the tanks of the space ship in orbit. And then once the tanks are full, the cargo has been transferred....and we reach the march rendezvous timing, roughly every 26 months, that's when the space ship departs."
 

[Ultimate Steve]

8 hours ago, n.b.z. said:

Musk mentioning the "improbability drive" from the Hitchhiker's Guide, and some of those questions in the Q&A, made me think:

"If only we could build a stupidity drive. That is a resource that we will never manage to run out of."

"You are only allowed to give 25 likes per day. You cannot give any more likes today. "

[Nibb31]

Musk said a lot of things. A lot of things in what was presented yesterday aren't practical. Expect a lot of changes in those plans in the years to come.

He said that they could potentially bring the refueling process down to a couple of weeks, in which case the crew could hang around. He also said that if it took longer they could send up the crew separately. That could be on another crewed ITS, or they could use another tanker as a depot. There are plenty of options.

One thing is for sure: the ITS can land on Earth and it's going to need maintenance. There is no reason to leave it to loiter on orbit in between synods.

Edited September 28, 2016 by Nibb31

[Frozen_Heart]

What i'm wondering is this; What is the advantage to launching one large ship that lands on mars then lands on earth? Rather than a dedicated mothership with Mars / Earth landers docked on? It seems like it would be more mass efficient to not have to stick a giant heat shield and high TWR engines on the large ship.

[magnemoe]

1 hour ago, Frozen_Heart said:

What i'm wondering is this; What is the advantage to launching one large ship that lands on mars then lands on earth? Rather than a dedicated mothership with Mars / Earth landers docked on? It seems like it would be more mass efficient to not have to stick a giant heat shield and high TWR engines on the large ship.

Simplifying the process. I'm a bit skeptical myself, an dedicated interplanetary can use high isp engines and have an centrifuge with decent living area and storm cellar, you can also refuel them in orbit.  
 

[magnemoe]

2 hours ago, Montieth said:

If you can precisely land on a large concrete field, aka a hardstand, why move it back to a pad to launch? Why not launch from the hard-stand after servicing with field movable equipment? 

 

An pad need systems for refueling and transferring crew as in launch tower, it also need an flame trench. 

[Nothalogh]

I can't wait for the legless F9 landings, because you know that's where it'll be tested

[Rakaydos]

2 hours ago, Frozen_Heart said:

What i'm wondering is this; What is the advantage to launching one large ship that lands on mars then lands on earth? Rather than a dedicated mothership with Mars / Earth landers docked on? It seems like it would be more mass efficient to not have to stick a giant heat shield and high TWR engines on the large ship.

The advantage is you can refill the tanks on your transfer ship (without needing to empty equally large tanks on your lander) if your transfer ship is your lander and you fill up on the ground.

You lose the same amount of payload lofting the extra fuel, whether its a tanker/lander refueling a mothership or a single ship. And a mothership needs enough fuel to orbit, whereas the singleship can do direct entry.

[Exoscientist]

18 hours ago, Nibb31 said:

The booster could probably be SSTO, just like the F9 booster, could be an SSTO if you wanted to, with zero payload and no getting it back. What would be the point ?

 

 I was surprised at how high the payload would be as an SSTO. Do the calculation using the rocket equation and the vacuum Isp.

 

  Bob Clark

[Chris_Pi]

8 minutes ago, Exoscientist said:

 

 I was surprised at how high the payload would be as an SSTO. Do the calculation using the rocket equation and the vacuum Isp.

 

  Bob Clark

Got to go with sea-level isp. Running a vacuum motor too low doesn't work too well.

Now I'm curious. Might just inflict some math on myself. Will report back if I survive.

[RedKraken]

I'm interested to see a Falcon 9 re-engined with the 1/4 raptors they are testing for the airforce :

Simplify propellant sourcing and infastructure.

Get rid of the helium copv weaknesses and simplify stage design.

Take advantage of increased isp .... maybe you dont need to sub-cool the lox anymore.

Practice your methane rocket operations while you build ITS.

[Bill Phil]

5 minutes ago, RedKraken said:

I'm interested to see a Falcon 9 re-engined with the 1/4 raptors they are testing for the airforce :

Simplify propellant sourcing and infastructure.

Get rid of the helium copv weaknesses and simplify stage design.

Take advantage of increased isp .... maybe you dont need to sub-cool the lox anymore.

Practice your methane rocket operations while you build ITS.

Re-engine-ing a rocket is no easy endeavor, and it gets harder if you try to do it with another propellant mixture.

[RedKraken]

8 minutes ago, Bill Phil said:

Re-engine-ing a rocket is no easy endeavor, and it gets harder if you try to do it with another propellant mixture.

Yep. Probably best to redesign both stages...and modify all the ground infastructure. Other stuff. A very big job.

But then you have a handy pad rebuild going on right now. How did that lng tank get there?

Edited September 29, 2016 by RedKraken

[_Augustus_]

It's an SSTO. It puts itself and the payload into orbit, then deorbits and returns.

[todofwar]

Can we merge all these threads? And maybe make a separate Mars colony thread?

[Chris_Pi]

So, I took the lazy way out and used an online calculator, But here's something -

Using the tanker with the 6 vacuum motors replaced with sealevel ones it's looking like just barely to not terrible of an SSTO.

So, Some assumptions:

Depending on what slide you want to use from Elon's IAC presentation the SL motor's isp is either 334 (motor slide) or 361 (ship/tanker slide).

DV needed is 8600+1800 drag losses+500 m/s for landing. I'm being less than optimistic on the last two to slant things towards underestimating payload.

90T dry weight, 2500T propellant/payload. Payload taken out of propellant load.
2590T liftoff weight. TWR 1.077 (310T/motor)
361/334 isp
10.9 km/s Target DV

334 isp:    10904m/s with 2.8T payload
361 isp:    10901m/s with 29.1T payload

If the right answer is somewhere between those two it might be about right for tossing a Dragon capsule up to ISS. Probably not cheap but it could get test flights done while hauling paying payloads and without needing either the booster or the pad built.

[tater]

2 hours ago, _Augustus_ said:

It's an SSTO. It puts itself and the payload into orbit, then deorbits and returns.

The booster doesn't put itself in orbit, it turns around and heads back, and S2 burns for orbit.

[Mitchz95]

9 hours ago, Nibb31 said:

If you have an absolute imperative to settle another planet right now. Which we don't.

If an absolute imperative comes along, I doubt we'd have the time or the resources. The colony wouldn't be self-sustaining for decades if not centuries, anyway, so it's better to get started right now while we have the will and the way.

The question isn't when we should colonize Mars, but if. And if the answer to that is yes, we should get started right away to ensure it's as far along as possible when that absolute imperative comes along. Better to have a colony and not need it yet, then to need it and not have it.

[kerbiloid]

Brakes are LES is for cowards,

 

22 hours ago, Nibb31 said:

There is no LES. The idea is that it works or it doesn't, like an airliner.

Quote

http://fusion.net/story/351658/elon-musk-wont-be-first-man-on-mars/

A second audience member, who apparently wasn’t listening to the first question, asked, “Will you be the first man on Mars?” This time around, Musk was explicit in his answer.

“The probability of death on the first mission is quite high,” he replied. He said he wanted to see his kids grow up and implied that SpaceX needs him too much as a leader to have him bite the bullet on the way to the red planet. So no.

Musk is passionate about making humans an “interplanetary species” and said the opportunity to head to space should appeal to people with a sense of adventure who are excited about the future, and who are willing to die.

“If you want to be on the frontier, where things are super exciting even if it’s dangerous, that’s who we’re appealing to,” Musk said. “I would not suggest sending children. Are you prepared to die? If that’s ok, you’re a candidate for going.”

A Rapid Unplanned Dismissing.

[Mitchz95]

If the colonists are willing to risk a potentially horrifying death on Mars, I doubt the possibility of a fatal launch failure will deter them much. Ditto with the radiation concerns.

[kerbiloid]

8 hours ago, Firemetal said:

This ITS feels strange. First of all, it looks like something out of Star Trek.

Or from buran.ru:

[blowfish]

4 hours ago, _Augustus_ said:

It's an SSTO. It puts itself and the payload into orbit, then deorbits and returns.

 

1 hour ago, tater said:

The booster doesn't put itself in orbit, it turns around and heads back, and S2 burns for orbit.

It's actually not even close to orbit to orbit at separation.  Musk's presentation gives the speed at separation as 8650 km/h, or 2400 m/s.  This is far short of orbit, which is at least 7700 m/s depending on exactly where your parking orbit is.