News Stratolaunch

[C3PO]

Depends on how severe a dog-leg you fly.

Try it.

 

[T.Neo]

Try it.

Depends on how severe a dog-leg you fly.

From what launch site? To what orbit? With what vehicle? At what point in the flightpath?

 

[C3PO]

Depends on how severe a dog-leg you fly.

From what launch site? To what orbit? With what vehicle? At what point in the flightpath?

Your choice, any site, any target, any vehicle. Just try launching out of plane.

 

[T.Neo]

Just try launching out of plane.

Are you trying to be facetious? :shifty:

If you are so desperate to prove that it is impossible, show it yourself.

 

[C3PO]

If you are so desperate to prove that it is impossible, show it yourself.

Progress --> ISS

Worst case would be a 22.5° plane change, so let's use ~50% of that: 11°

DV: 1380 m/s

Extra fuel for plane change: 3618 kg

Max payload 2350 kg

Payload reduction: 154%

The calculations include negative mass for payload, so you would have to add larger fuel tanks to make it to ISS.

Then you need to include the increased gross mass to all the orbital maneuvers, so I'm guessing the final number would be closer to 200% payload reduction.

 

[T.Neo]

Worst case would be a 22.5° plane change, so let's use ~50% of that: 11°

DV: 1380 m/s

Extra fuel for plane change: 3618 kg

Max payload 2350 kg

Payload reduction: 154%

The calculations include negative mass for payload, so you would have to add larger fuel tanks to make it to ISS.

Then you need to include the increased gross mass to all the orbital maneuvers, so I'm guessing the final number would be closer to 200% payload reduction.

Wait, you're talking about a plane-change on orbit, done by the propulsion onboard the spacecraft itself?

I'm talking about flying the launch vehicle sideways to change inclination as was performed on some Shuttle and Delta II flights.

 

[C3PO]

An aggressive rendezvous has nothing to do with launch location but rather the amount of dV expended in orbit. And it is a trade-off: do you want a shortened rendezvous time, if it results in even a 50% payload reduction?

Wait, you're talking about a plane-change on orbit, done by the propulsion onboard the spacecraft itself?

I'm talking about flying the launch vehicle sideways to change inclination as was performed on some Shuttle and Delta II flights.

Can you please make up your mind?

 

[T.Neo]

Can you please make up your mind?

I made my mind up a long time ago, but I didn't clarify that my envisioning of an "aggressive rendezvous" assumed that the spacecraft and its target were more or less in the same plane.

 

[C3PO]

Calculating dog-leg during ascent is a bit too complex for me. (for this discussion anyway) But I doubt that any existing launcher will make it into orbit, even without payload, if the target plane is more than a few degrees off.

.... assumed that the spacecraft and its target were more or less in the same plane

That is the way we do things now using launch sites. But the target may be in the wrong position for a direct ascent by the time the launch site is in-plane.

By using a plane as a first stage it's possible to fly out to the location where you're in-plane at the same as the target is at the optimal TrA.

A winged first stage does this kind of maneuver much more efficiently than a ballistic one.

 

[zerofay32]

While I don't have hard numbers yet, in order for the shuttle to perform a 'dog-leg' maneuver, NASA was planning to utilize five segment SRBs or Liquid boosters (all the way up to STS-107 when the 5-seg SRB was finally nixed from the SSP). This would have allowed acceptable payload to a south-north polar orbit or 20,000 lb more payload to an ISS-inclination orbit. I haven't found any info on if the shuttle would be able to perform the maneuver empty but what is the point of an empty space shuttle? :lol:

My opinion is, there are too many unknowns in the system to make a definitive conclusion. Personally I like the idea of air launching an orbit bound payload. But the advantages and disadvantages have yet to be explored in real world conditions yet. I'll wait until they produce some hardware :thumbup:

 

[C3PO]

My opinion is, there are too many unknowns in the system to make a definitive conclusion. Personally I like the idea of air launching an orbit bound payload. But the advantages and disadvantages have yet to be explored in real world conditions yet. I'll wait until they produce some hardware :thumbup:

That's exactly why I'm excited about this project. :thumbup:

 

[Napalm42]

- I can't be the only one thinking "go around, go around" on that landing video--way too high and fast, and they ate up a ton of runway in the roundout and flare...

I was nearly screaming :lol:

 

[T.Neo]

That is the way we do things now using launch sites. But the target may be in the wrong position for a direct ascent by the time the launch site is in-plane.

I never suggested doing a direct ascent, rather doing a 'traditional' ascent with more 'dV expensive' manuvers to catch up to the target in a reduced period of time.

 

[Sky Captain]

I guess if the huge carrier aircraft could be used to also carry oversized air cargo then the concept might be finnancially viable. An 225 is used quite often to carry heavy machinery to remote regions. If a runway can handle the An 225 then it also should be able to handle this plane since the weight is quite similar.
That way they could avoid the poblem of spending hundreds of millions of $ on a new aircraft that is used only few times per year.

 

[orb]

Parabolic Arc: Stratolaunch Extends Northrop Grumman’s Commercial Space Portfolio:

NGC PR — REDONDO BEACH, Calif., Dec. 22, 2011 — Northrop Grumman Corporation expanded its commercial space portfolio with Stratolaunch Systems’ recent selection of Scaled Composites, a Northrop Grumman subsidiary, to build the largest aircraft ever constructed. This is the latest example of the company’s innovative solutions to challenging problems. Scaled Composites is developing an air-launch system for Stratolaunch Systems, which is a Paul G. Allen project that will revolutionize space transportation by providing orbital access to space at lower costs, greater safety and increased flexibility.

“This private spaceflight initiative represents a significant leap forward in defining technologies today which will open doors tomorrow for affordable commercial space transportation,” said Paul Meyer, vice president and general manager of advanced programs and technologies for Northrop Grumman Aerospace Systems. “Whether it be manned and unmanned aircraft, space systems or advanced technologies, we are focused on developing innovative solutions that enable the growth of the aerospace industry.”

{...}

 

[C3PO]

I never suggested doing a direct ascent, rather doing a 'traditional' ascent with more 'dV expensive' manuvers to catch up to the target in a reduced period of time.

Then what are the dog-leg maneuver you're talking about? They're not done during the ascent, neither during orbital operations. Is there another period that I'm not aware of?

The point is that a winged first stage makes it much easier to do a direct ascent. Or an ascent with fewer phasing orbits. Or with awkward launch azimuths.

There is no "wrong" or "right" way to launch. It all depends on the mission, hardware, [________] etc.

Your continued statements that you're much smarter than most participants in the COTS programme, without any reasonable argument or example or calculation, simply doesn't impress me at all.

 

[T.Neo]

Then what are the dog-leg maneuver you're talking about?

The dog-leg maneuver is a dog-leg maneuver, don't confuse it with anything else.

The point is that a winged first stage makes it much easier to do a direct ascent.

And have several other disadvantages.

But where is this requirement for a direct ascent? You don't need a 2-hour transit time to get an acceptable market for space tourism (for example), millions of people take trips to places that last for half a day or more.

The prohibitative factor is the price of the trip, and if you halve that you'll see far more increased interest than if you halved the time to docking.

Your continued statements that you're much smarter than most participants in the COTS programme, without any reasonable argument or example or calculation, simply doesn't impress me at all.

I am sorry about that, because;

1. Stratolaunch is not connected to COTS/CCDev except for the involvement of SpaceX, which is a contractor.

2. I never stated I was smarter, but rather detailed scenarios where an assumed (or their stated) business case could fail or their technical decisions could be disadvantageous.

3. Groups of smart, experienced people can come together with good intentions and work hard, and still be wrong.

 

[C3PO]

You don't answer any questions, do you?
When exactly do you propose that dog-leg maneuver to occur? And how much of an advantage will you gain by that method?

What does direct ascent have to do with space tourism? Is this particular project even supposed to be manned? I thought it was about flexibility.

How does "being a contractor" translate to: "not connected"?

So you don't say you're smarter, but you've spotted a flaw in a plan made by "Groups of smart, experienced people". I think I'll let people make up their own mind about those statements.

 

[T.Neo]

When exactly do you propose that dog-leg maneuver to occur?

During launch, just like the dog-leg manuvers done by STS, Delta and Atlas.

And how much of an advantage will you gain by that method?

I don't know, I just suggested it as an option to launch slightly out of plane of the target orbit.

What does direct ascent have to do with space tourism?

The idea that it would be useful due to a reduced travel time to the space station or 'orbital hotel', which would make it more attractive from a customer standpoint.

Is this particular project even supposed to be manned?

I think it is implied, for example by the animations/graphics depicting Stratolaunch lifting what looks like a Dragon capsule.

I thought it was about flexibility.

Well, flexibility can be a nice buzzword. You can also achieve flexibility by being able to launch 400 tons of payload to the ISS, but such a capability would be totally meaningless.

In the US exist two launch sites that can cover pretty much all demanded orbits, and limitations by the Earth's rotation (i.e. being able to launch to the ISS only once a day) are more or less matched by the rate at which the vehicle can be prepared or 'recycled' for launch.

How does "being a contractor" translate to: "not connected"?

If Bob sells apples to Applemart, and also sells apples to Alice (who makes apple juice), it does not mean that Alice sells anything to Applemart.

So you don't say you're smarter, but you've spotted a flaw in a plan made by "Groups of smart, experienced people".

Er... no. I've explained ways I think the plan could be flawed. I haven't said whether it is flawed or not, I have no idea.

 

[orb]

Parabolic Arc: Stratolaunch Breaks Ground on Mojave Production Facility

SPACE.com: Construction of Giant Hangar for Rocket-Launching Monster Jet Begins