Stratolaunch: General Company and Development Updates and Discussions

[Jim]

A rocket can not be cleansed.  It is what ITAR is restricting.

[go4mars]

Once you've paid for the launch aircraft using it one more time should be quite inexpensive. Ground launching the rocket sounds like a great way to add additional development costs and reduce payload to orbit for no obvious compensating benefit. Why on earth would SpaceX want to do that when they can either air-launch the Falcon 5 as it's designed ...What's the benefit?

For some launches, F5 from the ground might be capable enough.  The ground infrastructure for F5 is almost the same as for F9 (2-level strongback needed).  I assume F5 would have the same thrust structure and mostly common plumbing with F9. 
The benefit is that SpaceX might eventually make more $ doing the whole show with F9 (or F5) from their launch pads than by selling a F5 to stratolaunch. 
Also, the new Vandy pad will presumably have some vertical integration capability (IIRC, which I'm iffy on here).  If vertical integration is preferable for a smallish load, then maybe a ground F5 would be preferable to F9 and stratolaunch. 

[fatjohn1408]

To bad itīs a subsonic plane. Again.
Making assisted launch efficient will in my view require supersonic assist capabilities. The XCOR lynx Mark III is a far more superior concept in my view. If Allen had put his money in a greater and slightly faster lynx (i'm officialy coining the names leopard and lion for the follow ups) then it could even assist a single stage kerolox launcher to Leo. The small dimensions of such a kerolox stage could prove beneficial when trying to make it reusable.

But I digress. Stratolaunch is cool and exiting but it will only marginally survive in the market. Too slow, too low.

[yg1968]

Could the Falcon 5 on the Stratolaunch be reusable and still have enough fuel to lift a crewed Dragon to space? I think that they said that initially reusability was not planned for the Falcon 5. But I am wondering if it could be added later on.

[Garrett]

Do you mean a giant suborbital tourist "spacecraft" like a big spaceship 2?  Seating 100 instead of 6?  Or something like that?

Just jumping in here.
Has it been discussed yet about the possibility that Stratolaunch may be a prototype for an intercontinental suborbital passenger plane? From the announcement I thought I picked up on something along those lines.

[go4mars]

That would certainly fit with Elon's mention of advancing transportation by 3 or 4 generations and be a tremendous-sized market.  There's a thread in advanced concepts that discusses a lot of that (which started a bit side-tracked assuming batteries were a necessary condition).  Some very interesting thoughts on that thread though that would tie in with your idea.  The question then becomes "would it be horizontal landed?  Or vertically landed.  Pros and cons to either but I think vertical for a few reasons that are on that thread.  I'd elaborate now but I'm swamped at work.

[Zed_Noir]

What I'm asking is, if the falcon is a placeholder, then removing the placeholder and reverting to the original spaceship1, spaceship2 concept, what a 3rd stage launched from a merlin powered spaceship3 (sized to the stratolaunch carrier), might be able to get to orbit?

The Falcon-based rocket isn't a placeholder (though the particular design of the wing may be), but rather the first and simplest of several potential vehicles which could be launched from the carrier aircraft. These other vehicles would only likely happen after the winged Falcon has successfully flown.

Since any first stage launched from the aircraft has to have wings, it's a logical assumption to have a runway-landing recoverable first stage. However, it's not a simple conversion, and the result first stage would be an almost completely new design. At that point, it would make sense to move to LH2, which would provide much more performance per take-off mass. Plus, you could leverage Scaled's SS2 experience to build it primarily from composites.

Thus, IMHO, a flyback first stage with one or two SSMEs would be an appropriate future upgrade. But there's long way to go before they'd even consider that.

I doubt anyone will consider using LH2 on an air-launched LV core stage anytime soon. The main issue with LH2 is it's a low density cryogenic fuel resulting in a bigger tank and vehicle as compared to a similar kerolox design.

The acquisition & operating costs of a Merlin compare to a SSME is quite low. Also the current SSME flavor (RS-25E) is not currently in production or anytime before 2018.

[Robotbeat]

Could the Falcon 5 on the Stratolaunch be reusable and still have enough fuel to lift a crewed Dragon to space? I think that they said that initially reusability was not planned for the Falcon 5. But I am wondering if it could be added later on.

Possibly. It'd be a lot easier if they can get a higher Isp upper stage on it (whether staged combustion or, maybe less likely, another propellant like methane, propane, or something). Airlaunch offers a nice benefit in that you can "boost-forward" by launching up range of your stage landing point instead of having to cancel out and reverse your stage's velocity.

Second stage reusability is another matter.

Either way, it'll be interesting to see what happens with Grasshopper in 2012 (when we should see a first, short flight).

Stratolaunch opens up the trade space quite a bit. But we must keep in mind that this is NOT a SpaceX project. SpaceX is just a subcontractor (doesn't mean that wouldn't change in the future), so SpaceX isn't likely to base a huge investment in reusability on someone else's project unless they're getting paid for it.

[yg1968]

Could the Falcon 5 on the Stratolaunch be reusable and still have enough fuel to lift a crewed Dragon to space? I think that they said that initially reusability was not planned for the Falcon 5. But I am wondering if it could be added later on.

Second stage reusability is another matter.

How so?

[Tcommon]

I doubt anyone will consider using LH2 on an air-launched LV core stage anytime soon. The main issue with LH2 is it's a low density cryogenic fuel resulting in a bigger tank and vehicle as compared to a similar kerolox design.

It's also difficult to work with - the Shuttle had lots of delays due to hydrogen leaks for a program costing $200 million per month. I think the extra cost of using LH2 was around $1 billion based on that.

[Robotbeat]

Could the Falcon 5 on the Stratolaunch be reusable and still have enough fuel to lift a crewed Dragon to space? I think that they said that initially reusability was not planned for the Falcon 5. But I am wondering if it could be added later on.

Second stage reusability is another matter.

How so?

The heaviness of the reusability systems on a second stage eats more directly into the payload, of course. Not saying it's impossible, just more difficult. Also, reusability for a second stage doesn't gain as much from airlaunch compared to first stage reusability.

[deltaV]

Starting one of the rocket engines on the ground sounds like a serious operational inconvenience and a non-trivial safety hazard. What's the benefit?

JATO.

Of course, the runway requirements are not seriously unreasonable as matters stand, so it might be superfluous.

Is it easier to get permission to use a 12,000 foot runway for launch of an inert rocket or a roughly 9,000 foot runway for launch of an operating rocket? I have no idea, but as you say long runways are available so JATO is likely unnecessary.

[mrmandias]

Do you mean a giant suborbital tourist "spacecraft" like a big spaceship 2?  Seating 100 instead of 6?  Or something like that?

Just jumping in here.
Has it been discussed yet about the possibility that Stratolaunch may be a prototype for an intercontinental suborbital passenger plane? From the announcement I thought I picked up on something along those lines.

That might be enough of an upside payoff that it makes the funding worthwhile.  Intercontinental suborbital is *almost* as tough as orbital, but not quite.  Add that difference in delta-v to the extra delta-v that the carrier airplane buys you and a single-stage suborbital might just be possible.

[Jim]

I doubt anyone will consider using LH2 on an air-launched LV core stage anytime soon. The main issue with LH2 is it's a low density cryogenic fuel resulting in a bigger tank and vehicle as compared to a similar kerolox design.

It's also difficult to work with - the Shuttle had lots of delays due to hydrogen leaks for a program costing $200 million per month. I think the extra cost of using LH2 was around $1 billion based on that.

Wrong, not a valid comparison
a.  Delta IV or Atlas V use it without major issues
b.  The shuttle did not have "a lot" of leaks
c.  it did not cost "extra"

[Jim]

I doubt anyone will consider using LH2 on an air-launched LV core stage anytime soon. The main issue with LH2 is it's a low density cryogenic fuel resulting in a bigger tank and vehicle as compared to a similar kerolox design.

Actually, it is the opposite.  LH2 is more suited for airlaunch and provides more benefits since it is less dense and therefore the vehicle weighs less.

[Jim]

a. they aren't airlaunched
b. wrong
c. Incorrect

All wrong again. 

A. Launch methodhas no bearing on the subject.
b.  number of google hits is meaningless statistic.  there weren't "a lot"
c.  Whether there was a leak or not, shuttle ops still cost the same.  It did not add more costs. 

[Tcommon]

c.  Whether there was a leak or not, shuttle ops still cost the same.  It did not add more costs.

Ok, then it reduced the number of possible launches, if that's the way you want to look at it, all the while costing $200 million per month. Or, if you prefer,  it increased the cost of each launch. That $200 million per month went somewhere.

[Chris Bergin]

Hey, calm it down. Tcommon, you've lost a post and you'll lose more if you can't be civil.

[kfsorensen]

I doubt anyone will consider using LH2 on an air-launched LV core stage anytime soon. The main issue with LH2 is it's a low density cryogenic fuel resulting in a bigger tank and vehicle as compared to a similar kerolox design.

Actually, it is the opposite.  LH2 is more suited for airlaunch and provides more benefits since it is less dense and therefore the vehicle weighs less.

Jim is right, for an air-launched vehicle there's got to be a pretty strong argument AGAINST LH2 not to use it.

[Tcommon]

c.  Whether there was a leak or not, shuttle ops still cost the same.  It did not add more costs.

Ok, then it reduced the number of possible launches, if that's the way you want to look at it, all the while costing $200 million per month. Or, if you prefer,  it increased the cost of each launch. That $200 million per month went somewhere.

Wrong again.  Know something before posting.

this applies to you

http://forum.nasaspaceflight.com/index.php?topic=27520.msg840823#msg840823

Ha Ha. I'm right and you know it. The only way months and months of delays due to Shuttle hydrogen leaks didn't cost money is if you think of the $200 million per month as an entitlement.

Hey, calm it down. Tcommon, you've lost a post and you'll lose more if you can't be civil.

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