Author Topic: Pegasus II  (Read 16048 times)

Offline Kabloona

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Pegasus II
« on: 08/13/2013 07:39 PM »
Thanks to Chris for this informative article on plans for Pegasus II.

http://www.nasaspaceflight.com/2013/08/orbital-atk-solid-partnership-stratolaunch-alv/

Let the discussion begin!

Offline Chris Bergin

Re: Pegasus II
« Reply #1 on: 08/13/2013 08:02 PM »
Thanks! But the larger version covering more of the vehicle is this one:
http://www.nasaspaceflight.com/2013/05/stratolaunch-orbital-air-launch/

Offline Kabloona

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Re: Pegasus II
« Reply #2 on: 08/13/2013 08:10 PM »
Thanks again, Chris.

I am puzzled, though, by an apparent contradiction between the text and the artist's concept showing the wing and fin locations. The article says,

"The wing will be located on the top of the first stage, while the inverted-V tails share a commonality with Pegasus, albeit at a different angle, so as not to be blanketed by the wings during high angles of attack."

But the artist's concept shows the wing on the *underside* of Stage 1, with a V-tail that is *not* inverted, but upright.

So the artist's concept shows the exact opposite of what the text describes. If the vehicle shown in the concept were rolled 180 degrees, then it would seem to match the text description, with wing on top and V-tails inverted.

Chris, do you have any insight into this apparent discrepancy?

« Last Edit: 08/13/2013 08:22 PM by Kabloona »

Online robertross

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Re: Pegasus II
« Reply #3 on: 08/13/2013 08:16 PM »
Great stuff Chris!

For a moment there I thought ATK was using my recipe for Pistachio ice cream!  ;)
Remembering those who made the ultimate sacrifice for our rights & freedoms, and for those injured, visible or otherwise, in that fight.

Offline Kabloona

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Re: Pegasus II
« Reply #4 on: 08/13/2013 08:26 PM »
Great stuff Chris!

For a moment there I thought ATK was using my recipe for Pistachio ice cream!  ;)

Yeah, that greenish cast is strange. I suspect it's just a color balance issue with the digital camera, as fluorescent lighting will make things look green if the color balance option on a digital camera isn't set correctly. Normally solid propellants in that condition look grayish due to the aluminum powder, and I doubt it was St Patrick's day at ATK when the photo was taken. ;-)
« Last Edit: 08/13/2013 08:30 PM by Kabloona »

Offline Chris Bergin

Re: Pegasus II
« Reply #5 on: 08/13/2013 09:28 PM »
Thanks again, Chris.

I am puzzled, though, by an apparent contradiction between the text and the artist's concept showing the wing and fin locations. The article says,

"The wing will be located on the top of the first stage, while the inverted-V tails share a commonality with Pegasus, albeit at a different angle, so as not to be blanketed by the wings during high angles of attack."

But the artist's concept shows the wing on the *underside* of Stage 1, with a V-tail that is *not* inverted, but upright.

So the artist's concept shows the exact opposite of what the text describes. If the vehicle shown in the concept were rolled 180 degrees, then it would seem to match the text description, with wing on top and V-tails inverted.

Chris, do you have any insight into this apparent discrepancy?



Yeah! :)

The info is bang up to date (per the first article), but the graphics are not. Makes sense as it probably took them a long time to create that video the slides are taken from.

Offline Kabloona

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Re: Pegasus II
« Reply #6 on: 08/13/2013 09:42 PM »
Thanks again, Chris.

I am puzzled, though, by an apparent contradiction between the text and the artist's concept showing the wing and fin locations. The article says,

"The wing will be located on the top of the first stage, while the inverted-V tails share a commonality with Pegasus, albeit at a different angle, so as not to be blanketed by the wings during high angles of attack."

But the artist's concept shows the wing on the *underside* of Stage 1, with a V-tail that is *not* inverted, but upright.

So the artist's concept shows the exact opposite of what the text describes. If the vehicle shown in the concept were rolled 180 degrees, then it would seem to match the text description, with wing on top and V-tails inverted.

Chris, do you have any insight into this apparent discrepancy?



Yeah! :)

The info is bang up to date (per the first article), but the graphics are not. Makes sense as it probably took them a long time to create that video the slides are taken from.

OK, thanks. Maybe they figured out after the artwork was done that the V-tail would work better inverted, where it would be in a "clean" airstream when pitching up. I guess that's what your text is saying.
« Last Edit: 08/13/2013 09:56 PM by Kabloona »

Offline Calphor

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Re: Pegasus II
« Reply #7 on: 08/14/2013 04:19 AM »
Great stuff Chris!

For a moment there I thought ATK was using my recipe for Pistachio ice cream!  ;)

Yeah, that greenish cast is strange. I suspect it's just a color balance issue with the digital camera, as fluorescent lighting will make things look green if the color balance option on a digital camera isn't set correctly. Normally solid propellants in that condition look grayish due to the aluminum powder, and I doubt it was St Patrick's day at ATK when the photo was taken. ;-)

You'd be surprised then, that color is accurate. Shuttle propellant is actually red-brown. It all depends on the ingredients.

Offline Kabloona

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Re: Pegasus II
« Reply #8 on: 08/14/2013 01:14 PM »
Great stuff Chris!

For a moment there I thought ATK was using my recipe for Pistachio ice cream!  ;)

Yeah, that greenish cast is strange. I suspect it's just a color balance issue with the digital camera, as fluorescent lighting will make things look green if the color balance option on a digital camera isn't set correctly. Normally solid propellants in that condition look grayish due to the aluminum powder, and I doubt it was St Patrick's day at ATK when the photo was taken. ;-)

You'd be surprised then, that color is accurate. Shuttle propellant is actually red-brown. It all depends on the ingredients.

What is the green ingredient? I worked with solid propellants for ten years (in the nineties) and saw colors range from black to gray to reddish (iron oxide burn rate catalyst) but never green.

Online robertross

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Re: Pegasus II
« Reply #9 on: 08/14/2013 03:09 PM »
Great stuff Chris!

For a moment there I thought ATK was using my recipe for Pistachio ice cream!  ;)

Yeah, that greenish cast is strange. I suspect it's just a color balance issue with the digital camera, as fluorescent lighting will make things look green if the color balance option on a digital camera isn't set correctly. Normally solid propellants in that condition look grayish due to the aluminum powder, and I doubt it was St Patrick's day at ATK when the photo was taken. ;-)

You'd be surprised then, that color is accurate. Shuttle propellant is actually red-brown. It all depends on the ingredients.

What is the green ingredient? I worked with solid propellants for ten years (in the nineties) and saw colors range from black to gray to reddish (iron oxide burn rate catalyst) but never green.

likely the binding agent has caused this colour cast?
Remembering those who made the ultimate sacrifice for our rights & freedoms, and for those injured, visible or otherwise, in that fight.

Offline Kabloona

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Re: Pegasus II
« Reply #10 on: 08/14/2013 03:22 PM »
Great stuff Chris!

For a moment there I thought ATK was using my recipe for Pistachio ice cream!  ;)

Yeah, that greenish cast is strange. I suspect it's just a color balance issue with the digital camera, as fluorescent lighting will make things look green if the color balance option on a digital camera isn't set correctly. Normally solid propellants in that condition look grayish due to the aluminum powder, and I doubt it was St Patrick's day at ATK when the photo was taken. ;-)

You'd be surprised then, that color is accurate. Shuttle propellant is actually red-brown. It all depends on the ingredients.

What is the green ingredient? I worked with solid propellants for ten years (in the nineties) and saw colors range from black to gray to reddish (iron oxide burn rate catalyst) but never green.

likely the binding agent has caused this colour cast?

Conventional binders (HTPB, PBAN) are not green, and IMO it's highly unlikely ATK would use a different binder given the extensive industry experience with HTPB and PBAN. More likely an oxidizer or some sort of energetic ingredient.

Offline Lee Jay

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Re: Pegasus II
« Reply #11 on: 08/14/2013 03:43 PM »
I'm trying to figure out where this vehicle sits given Antares.  Is this designed to replace Antares if the Antares first stage has to be retired when the engines run out and they can't find a suitable substitute?  Is there another reason to do this of which I am unaware?

Offline baldusi

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Re: Pegasus II
« Reply #12 on: 08/14/2013 04:35 PM »
First, remember that this is a Stratolauncher vehicle, were OSC is prime contractor. This means that the IP most probably belongs to Stratolaunch. Also, it's a lot easier to do a solid air launched first stage than a liquid. Else you start to get into issues of boil off, stability and abort complications.
Then, it might happen that the Zenit tooling doesn't lends itself to the sort of efforts that a hanging configuration has. In fact a the Soviet air launched concepts were from the top of a plane. So it's quite probable that the minimum investment design was going with solids. Specially since OSC has the Pegasus experience that they have.
Just doing an H2 US for this vehicle will be a problem big enough.

Online Robotbeat

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Re: Pegasus II
« Reply #13 on: 08/14/2013 05:10 PM »
I'm trying to figure out where this vehicle sits given Antares.  Is this designed to replace Antares if the Antares first stage has to be retired when the engines run out and they can't find a suitable substitute?  Is there another reason to do this of which I am unaware?
Because you can make the biggest airplane evar? ;)

Antares exists to fill the vacuum of Delta II that Orbital needs to launch their own birds domestically. Orbital has to pay for Antares. This Pegasus II, it seems, is being financed by Stratolaunch, which is /paying/ Orbital (from what I can tell). This is a better deal for Orbital than Antares is!

Launch vehicles and the infrastructure required is expensive. Here, you have an airplane that can allow efficient launches with basically all-domestic components to any inclination without having to build multiple launch sites. For Orbital, a great deal. For Paul Allen, this is a cheap way of getting the concept off the ground (heh) and launching stuff. They can always upgrade the concept at a later time. A better/cheaper upper stage, a higher performance liquid first stage (hydrolox is best, fueled in-flight), recoverable stages, etc.

And good for them. Now we just need to expand the launch demand somehow.
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Online yg1968

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Re: Pegasus II
« Reply #14 on: 08/14/2013 06:20 PM »
I'm trying to figure out where this vehicle sits given Antares.  Is this designed to replace Antares if the Antares first stage has to be retired when the engines run out and they can't find a suitable substitute?  Is there another reason to do this of which I am unaware?

I don't think that it's a replacement. My understanding is that Stratolaunch owns the IP rights related to Pegasus II. So Orbital cannot decide to transform Pegasus II into a competing rocket.

Online Robotbeat

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Re: Pegasus II
« Reply #15 on: 08/14/2013 07:06 PM »
I asked this on an L2 thread, but this is a better place:

What about a kerolox first stage filled via aerial refueling (assuming we can make Stratolaunch and the rocket use the same fuel)? By also allowing the Stratolaunch aircraft to launch nearly dry, this could allow a significantly greater payload to orbit.
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Offline Zed_Noir

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Re: Pegasus II
« Reply #16 on: 08/14/2013 08:53 PM »
I asked this on an L2 thread, but this is a better place:

What about a kerolox first stage filled via aerial refueling (assuming we can make Stratolaunch and the rocket use the same fuel)? By also allowing the Stratolaunch aircraft to launch nearly dry, this could allow a significantly greater payload to orbit.

First someone have to set up a fleet of Jumbo jet size tankers and test if you can get Birdzilla & Jumbo to do close proximity formation flying. Smaller size aerial tankers might have turbulence issues along with excessive link ups and total connection time.

Don't see a need to have common kero for the Stratolaunch aircraft and the LV. There should be enough volume to have two set of kero tankage.

Maybe a LOX pod on top of the middle of the wing can top up the LV before launch.

Online Robotbeat

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Re: Pegasus II
« Reply #17 on: 08/14/2013 09:06 PM »
I asked this on an L2 thread, but this is a better place:

What about a kerolox first stage filled via aerial refueling (assuming we can make Stratolaunch and the rocket use the same fuel)? By also allowing the Stratolaunch aircraft to launch nearly dry, this could allow a significantly greater payload to orbit.

First someone have to set up a fleet of Jumbo jet size tankers and test if you can get Birdzilla & Jumbo to do close proximity formation flying. Smaller size aerial tankers might have turbulence issues along with excessive link ups and total connection time.

Don't see a need to have common kero for the Stratolaunch aircraft and the LV. There should be enough volume to have two set of kero tankage.

Maybe a LOX pod on top of the middle of the wing can top up the LV before launch.
Common kero because it means fewer connections, mostly. Unfortunately, most of the weight of a liquid launch vehicle is actually LOx, not kerosene...

EDIT: Again, it's noting that the KC-10 has enough kerosene capacity (160mT) to totally fill up an Atlas V, though it would take a while (over half an hour, I think). KC-10s can refuel very large aircraft, so I see no fundamental reason why it couldn't refuel the Stratolauncher (which could in turn fuel up a kerolox rocket). It's more complication, sure, but it is one way to improve the payload capability without needing a bigger airplane.

And Air Force-1 is aerial-refuelable while also being 747-based (like Stratolaunch). Doesn't mean it's going to be easy. There is also a civil aerial refueling company (http://www.omegaairrefueling.com/) that does some of this, though their planes don't have the same capacity (more like 80mT) and use drogues instead of a boom like you'd want. It's estimated that aerial refueling costs about $20-50/gallon (including capitalization) for the military, so it's still a tiny fraction of the cost of the launch.
« Last Edit: 08/14/2013 09:46 PM by Robotbeat »
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Offline Proponent

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Re: Pegasus II
« Reply #18 on: 08/14/2013 09:08 PM »
Conventional binders (HTPB, PBAN) are not green, and IMO it's highly unlikely ATK would use a different binder given the extensive industry experience with HTPB and PBAN. More likely an oxidizer or some sort of energetic ingredient.

Maybe it's just dyed green, so it can be advertised as a "green" propellant. :)

Offline Calphor

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Re: Pegasus II
« Reply #19 on: 08/15/2013 12:03 PM »
Great stuff Chris!

For a moment there I thought ATK was using my recipe for Pistachio ice cream!  ;)

Yeah, that greenish cast is strange. I suspect it's just a color balance issue with the digital camera, as fluorescent lighting will make things look green if the color balance option on a digital camera isn't set correctly. Normally solid propellants in that condition look grayish due to the aluminum powder, and I doubt it was St Patrick's day at ATK when the photo was taken. ;-)

You'd be surprised then, that color is accurate. Shuttle propellant is actually red-brown. It all depends on the ingredients.

What is the green ingredient? I worked with solid propellants for ten years (in the nineties) and saw colors range from black to gray to reddish (iron oxide burn rate catalyst) but never green.

likely the binding agent has caused this colour cast?

Conventional binders (HTPB, PBAN) are not green, and IMO it's highly unlikely ATK would use a different binder given the extensive industry experience with HTPB and PBAN. More likely an oxidizer or some sort of energetic ingredient.

I don't know if it as been released in the open literature, but I can say that it is neither PBAN or HTPB.

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