Blue Origin Thread (merged)

[ment18]

Could they mount extremely high thrust, low burn time srbs in the "fins" of the spaceship?  This would allow them to lift off the booster with a good t/w and not have to use the engines in a fairing right in top of the booster.  They could drop the srbs midway during the flight.

[Nibb31]

15 minutes ago, ment18 said:

Could they mount extremely high thrust, low burn time srbs in the "fins" of the spaceship?  This would allow them to lift off the booster with a good t/w and not have to use the engines in a fairing right in top of the booster.  They could drop the srbs midway during the flight.

The fins already contain the landing gear. Jettison goes against the reusability requirement.

[ment18]

2 minutes ago, Nibb31 said:

The fins already contain the landing gear. Jettison goes against the reusability requirement.

Ok, yeah, there wouldn't be room for the SRBs because the entire bottom of the fins is covered in the landing feet.

[Kerbart]

There's probably a waiver people need to sign.

There's also a slight possibility that there is some redundancy in case one of the engines fails (as long as it doesn't set of a violent chain reaction of explosions).

[DerekL1963]

7 hours ago, Kryten said:

In the presser after the conference, Musk confirmed that the craft can act as it's own LES in launches from earth. No abort ability for Mars launches.

So, as long as the failure isn't in the craft itself...  you're good.

[Kryten]

Aye, therein lies the rub. He's assuming aircraft levels of reliability to keep the chances of that down, but it's pretty doubtful he can achieve that in the timeframe he wants. Especially if he goes straight from F9 and FH to this thing, with all the new tech and procedures that that implies.

[Jimbodiah]

So,  the question on many people's mind no doubt: who is gonna mod this?  

[Gaarst]

42 of these on the ITS first stage. Might as well call it N-2...

[CSE]

The Falcon 9 legs contribute something like 2t to the dry mass of the first stage, so I definitely see the potential benefit in fitting them to the planet instead of to the rocket and in the case of perfectly reliable perfect accuracy, there'd be no question about it. The approaches differ in how they tolerate errors in accuracy. Legs fitted to the planet have to aim for a very small contact area on the rocket; legs fitted to the rocket can tolerate several meters of error and still land the booster in one piece. Therefore there is a level of landing accuracy at which it's worth paying the cost of the few crashed boosters in exchange for an enhanced payload of all the flights; I expect that rocketry will reach this level of accuracy in the not too distant future.

But the launch pad is not the only part of the planet that you could attach the landing gear to.

If the booster crashes, it's not just the cost of the booster than has to be paid - the cost includes whatever else the booster hits: from something cheap like flat concrete with circles painted on it, to something more expensive like a barge, or worst case something that is valuable, scarce, and needed right now - such as a Mars launch pad just before the transfer window. The higher the landing accuracy, the less chance of paying this cost, of course. With perfect accuracy the cost of errors would not matter, it'd never be paid. The benefit to landing on the launch pad isn't saving carrying the legs - either choice of landing site could be equipped with these - it's only saving a trip of a kilometre or two from the landing site.* I just don't see the known accuracy ever getting so high compared to the difference in cost of the assets in the at-risk area. Even if the real accuracy were 99.9999% and you therefore had a perfect flight record, you'd need many many flights before you had the data that proved it.

4 hours ago, Nefrums said:

Having a paved landing field a few km from the pad makes more sense.

Exactly.

 

* There's also a performance benefit to landing the boosters downrange of the launch site, whether that's a barge, or transcontinental (Vandenberg to Canaveral?), or transatlantic like the shuttle abort mode.

[tater]

I said this in the other thread, but I think that the ITS component is interesting as a VTVL transport concept---Earth transport. Let;s spitball a minute...

The ITS has a usable passenger volume (including the cargo space) that is roughly twice the passenger volume of a 747. So it could theoretically hold several hundred people, possibly approaching 1000 in an airline seating configuration. They say that the cost to build on is about 200M$, and 130M$ for the tanker. That's slightly more than a 747. Their total reuse as a Mars vehicle is said to be 12 times, but for this application, but the tanker says 100 for a similar profile. My guess is a lot of the cost must be LS stuff, and other long-duration mission redundancies. So call it closer to a 747 at ~150M$. Even with just 100 uses, that's a vehicle cost of 1.5M$/launch. They said 0.5M maintenance per use for the tanker, let's go with that. 2M$ a flight. That's $2500/seat if it seats 800. First class to the other side of Earth is nearly 10X that. Business class is more than 2X that. There might be no coach class, but it's not an impossible business model. Perhaps start with air cargo until you have many flights with no issues, then mess with air travel.

[Gaarst]

The last thing that had a ridiculous amount of engines on the first stage, that was rushed to reach surrealistic goals, and that was supposed to send people further than before, blew up 4 times on 4 launches. And it had a LES...

I'll skip my turn for that one.

[Rakaydos]

4 minutes ago, tater said:

I said this in the other thread, but I think that the ITS component is interesting as a VTVL transport concept---Earth transport. Let;s spitball a minute...

The ITS has a usable passenger volume (including the cargo space) that is roughly twice the passenger volume of a 747. So it could theoretically hold several hundred people, possibly approaching 1000 in an airline seating configuration. They say that the cost to build on is about 200M$, and 130M$ for the tanker. That's slightly more than a 747. Their total reuse as a Mars vehicle is said to be 12 times, but for this application, but the tanker says 100 for a similar profile. My guess is a lot of the cost must be LS stuff, and other long-duration mission redundancies. So call it closer to a 747 at ~150M$. Even with just 100 uses, that's a vehicle cost of 1.5M$/launch. They said 0.5M maintenance per use for the tanker, let's go with that. 2M$ a flight. That's $2500/seat if it seats 800. First class to the other side of Earth is nearly 10X that. Business class is more than 2X that. There might be no coach class, but it's not an impossible business model. Perhaps start with air cargo until you have many flights with no issues, then mess with air travel.

That's the beauty of Musk's plan. every step except the last one is economically justifiable, but it all moves toward his ideological goal, bringing it closer to fruition. If noone else steps foreward to put research stations on mars, then with a few years profit  from earth based endevores like this and the BFR UHLV, he can send his own corporate enclave out of his own pocket.

[tater]

1 minute ago, Rakaydos said:

That's the beauty of Musk's plan. every step except the last one is economically justifiable, but it all moves toward his ideological goal, bringing it closer to fruition. If noone else steps foreward to put research stations on mars, then with a few years profit  from earth based endevores like this and the BFR UHLV, he can send his own corporate enclave out of his own pocket.

Very little of it is economically justifiable, IMO. If the announcement had been about a suborbital passenger vessel, then that would be true... then he could later say, "oh yeah, it's actually a Mars vessel, but we wanted to test it."

I'm trying to retrofit utility to it, since there is no utility for a Mars settlement transport, because settling Mars makes no sense.

[KAL 9000]

Settling Mars makes sense... It's the closest planet to Earth that's not hell (seriously, Venus? Why?), it has plenty of resources, and terraforming it (although still insanely difficult) would be easier than any other planet.

[Nibb31]

Just now, KAL 9000 said:

Settling Mars makes sense... 

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

[todofwar]

34 minutes ago, KAL 9000 said:

Settling Mars makes sense... It's the closest planet to Earth that's not hell (seriously, Venus? Why?), it has plenty of resources, and terraforming it (although still insanely difficult) would be easier than any other planet.

Nope, terraforming won't be easy. Easier to terraform Venus. 

[KAL 9000]

18 minutes ago, todofwar said:

Nope, terraforming won't be easy. Easier to terraform Venus. 

Actually, Carl Sagan's thesis (I think) was on terraforming Venus, and he proved it to be ridiculously difficult, even by terraforming standards.

[todofwar]

3 minutes ago, KAL 9000 said:

Actually, Carl Sagan's thesis (I think) was on terraforming Venus, and he proved it to be ridiculously difficult, even by terraforming standards.

At least it has the correct gravity. I see that as being a bigger problem. Also, already has the right atmosphere, just need to convert 20% (edit: some, 20% will be too much) of the CO2 to o2, and then trap the rest as coal and sulfates. The hard part is speeding up rotation, but I've heard a couple well placed mirrors might do the trick. 

Edited September 28, 2016 by todofwar

[Montieth]

Given that it launches to LEO more or less empty of fuel and needs tankers to bring fuel AND presumably the cargo/food stuff and passengers, the safety of the launch of the large craft is probably not the issue. You're not going to launch 100 people to orbit and have them twiddle their tumbs while you move CH4/O2 to orbit along with food over the 2 years to the next Earth/Mars transfer window. 

So, I suspect its more:
1. Launch ITS craft to orbit. Perhaps with a basic command crew but I don't see why that would necessarily be important. 
2a. Launch Dragon craft and cargo craft up with crew, workers to get the ship loaded and setup for the transfer window. 
2b. Launch ITS tankers to fuel and stow the heavy bulk for getting the ship ready for the transfer window.
2c. Launch Dragon craft with passengers for the trip to mars.
3. Window arrives and ITS space craft performs ejectionburn/transfer burn to mars. 

 

[tater]

Launching 20 Dragons to load the ship up would eliminate any cost reduction of making a large craft.

[Firemetal]

This ITS feels strange. First of all, it looks like something out of Star Trek. Second, in the animation, that looked like a good 10 people going into it. Each one of them would need to be comfortable sitting, sleeping and living. And if this is a one-way trip, Where are they going to live once they have landed? They must have somewhere else to go besides the gloomy crew cabins.

Now I didn't watch the presentation yesterday. I came in as it was ending. I didn't even know when it was!

So is this thing a one way trip or a round trip? First of all it would make sense as a one way trip as it hasn't a centrifugal ring on it. Once they come back, keep in mind this is 5+ years, they will be in a wheel chair for the rest of their life or until they recover. 

One way trip makes this whole thing make a lot more sense but we still have a long way to go. Elon is getting a bit impatient. I doubt they'll have this thing complete within 6 years.

Fire

[FishInferno]

2 minutes ago, Firemetal said:

So is this thing a one way trip or a round trip?

The idea is for it to be a one-way trip, but the colonists will have the option of returning, as the ITS will fly back to Earth anyway.

 

On the topic of LES: I used to be a stickler about having one, but now my view is starting to come around.  Colonizing Mars has a huge amount of risk, and anyone going (myself included) will have made peace with the fact that you could die.  A LES becomes harder and harder on large designs because it more severely impacts the performance of the spacecraft, and it adds much more complexity, resulting in more points of failure.The people willing to go live on Mars are not the kind of people who won't go for a lack of LES.  

[Montieth]

30 minutes ago, tater said:

Launching 20 Dragons to load the ship up would eliminate any cost reduction of making a large craft.

The ITS isn't disposable. When they return from Mars do they hang out in orbit and get prepped for the next mission or do you bring them back to earth? I would think the former. If that's the case, you've got to get crew and materials up to them. Do they go up on the tankers in penny packets with the cargo loads? 

Edited September 28, 2016 by Montieth

[tater]

Just now, Montieth said:

The ITS isn't disposable. When they return from Mars do they hang out in orbit and get prepped for the next mission or do you bring them back to earth? I would think the former. If that's the case, you've got to get crew and materials up to them. Do they go up on the tankers in penny packets with the cargo loads? 

I think it does a direct EDL from Mars, it doesn't have the dv to blow on an orbital insertion.

[Montieth]

Aerobrake to conserve the ∆V budget? 

Regardless, the craft are going to hang out in orbit for some time. Over what time it'll be is a question. I can't see them boosting the ITS spacecraft with full crew and passengers only to have them sit waiting for the next transfer window..

Edited September 28, 2016 by Montieth