Stratolaunch: General Company and Development Updates and Discussions

[edzieba]

They may just want the "biggest (by wingspan) aircraft to fly" record - replace Spruce Goose with Space Goose - before the program gets mothballed, with the hope that someone may figure out a use for it later.

[TrevorMonty]

Even if Stratolaunch had LVs to lift the business would be vunerable without backup Stratolaunch. If they lost Stratolaunch its years to replace. A launch pad can be rebuild in months. In case of Virgin LauncherOne a replacement 747 would only take months to modify.

Virgin could modify backup 747 and lease it out to airfrieght company, to be called on if needed. Not really option for Stratolaunch.

[jstrotha0975]

I know this sounds crazy, but what about resurrecting Falcon 1 to launch on the roc? SpaceX doesn't even have to do it, some other company could buy the rights to do it and buy the toolings and engines from SpaceX.

[niwax]

I know this sounds crazy, but what about resurrecting Falcon 1 to launch on the roc? SpaceX doesn't even have to do it, some other company could buy the rights to do it and buy the toolings and engines from SpaceX.

Putting Falcon 1 on there is a great illustration why air launching makes no sense. You're paying the same hardware cost on the rocket since it's not anywhere near enough to replace a first stage. All you did is replace a simple dirt launchpad in the middle of nowhere with an insanely expensive to build, fly and service plane. The only difference is a minor payload increase - well guess what, they planned a Falcon 1e with a slight tank stretch and engine uprating. The difference is some 10t in takeoff weight, a minor increase in fuel and fabrication costs compared to adding a plane.

[TrevorMonty]

I know this sounds crazy, but what about resurrecting Falcon 1 to launch on the roc? SpaceX doesn't even have to do it, some other company could buy the rights to do it and buy the toolings and engines from SpaceX.

Putting Falcon 1 on there is a great illustration why air launching makes no sense. You're paying the same hardware cost on the rocket since it's not anywhere near enough to replace a first stage. All you did is replace a simple dirt launchpad in the middle of nowhere with an insanely expensive to build, fly and service plane. The only difference is a minor payload increase - well guess what, they planned a Falcon 1e with a slight tank stretch and engine uprating. The difference is some 10t in takeoff weight, a minor increase in fuel and fabrication costs compared to adding a plane.

Biggest plus to air launch is the mobile launch pad. The ability to launch from anywhere and to any orbit from single runway. Thats means air traffic free airspace and fine weather areas.
Performance boost becomes significant with ability to launch from equator.

[Mardlamock]

I know this sounds crazy, but what about resurrecting Falcon 1 to launch on the roc? SpaceX doesn't even have to do it, some other company could buy the rights to do it and buy the toolings and engines from SpaceX.

Putting Falcon 1 on there is a great illustration why air launching makes no sense. You're paying the same hardware cost on the rocket since it's not anywhere near enough to replace a first stage. All you did is replace a simple dirt launchpad in the middle of nowhere with an insanely expensive to build, fly and service plane. The only difference is a minor payload increase - well guess what, they planned a Falcon 1e with a slight tank stretch and engine uprating. The difference is some 10t in takeoff weight, a minor increase in fuel and fabrication costs compared to adding a plane.

Biggest plus to air launch is the mobile launch pad. The ability to launch from anywhere and to any orbit from single runway. Thats means air traffic free airspace and fine weather areas.
Performance boost becomes significant with ability to launch from equator.

Do the numbers, air launch makes sense for certain rocket sizes and configurations.

[envy887]

I know this sounds crazy, but what about resurrecting Falcon 1 to launch on the roc? SpaceX doesn't even have to do it, some other company could buy the rights to do it and buy the toolings and engines from SpaceX.

Putting Falcon 1 on there is a great illustration why air launching makes no sense. You're paying the same hardware cost on the rocket since it's not anywhere near enough to replace a first stage. All you did is replace a simple dirt launchpad in the middle of nowhere with an insanely expensive to build, fly and service plane. The only difference is a minor payload increase - well guess what, they planned a Falcon 1e with a slight tank stretch and engine uprating. The difference is some 10t in takeoff weight, a minor increase in fuel and fabrication costs compared to adding a plane.

Biggest plus to air launch is the mobile launch pad. The ability to launch from anywhere and to any orbit from single runway. Thats means air traffic free airspace and fine weather areas.
Performance boost becomes significant with ability to launch from equator.

Do the numbers, air launch makes sense for certain rocket sizes and configurations.

Perhaps is theory, but it has yet to manifest in practice. Electron's $/kg is about the same as LauncherOne. And Pegasus is ridiculously expensive for a tiny payload.

[Mardlamock]

I know this sounds crazy, but what about resurrecting Falcon 1 to launch on the roc? SpaceX doesn't even have to do it, some other company could buy the rights to do it and buy the toolings and engines from SpaceX.

Putting Falcon 1 on there is a great illustration why air launching makes no sense. You're paying the same hardware cost on the rocket since it's not anywhere near enough to replace a first stage. All you did is replace a simple dirt launchpad in the middle of nowhere with an insanely expensive to build, fly and service plane. The only difference is a minor payload increase - well guess what, they planned a Falcon 1e with a slight tank stretch and engine uprating. The difference is some 10t in takeoff weight, a minor increase in fuel and fabrication costs compared to adding a plane.

Biggest plus to air launch is the mobile launch pad. The ability to launch from anywhere and to any orbit from single runway. Thats means air traffic free airspace and fine weather areas.
Performance boost becomes significant with ability to launch from equator.

Do the numbers, air launch makes sense for certain rocket sizes and configurations.

Perhaps is theory, but it has yet to manifest in practice. Electron's $/kg is about the same as LauncherOne. And Pegasus is ridiculously expensive for a tiny payload.

Rockets are exponential, highly-coupled creatures. LauncherOne has nearly the exact same technical decisions as Electron, but even worse. It's leaving out all most multi-disciplinary advantages of air-launch by putting turbopumps on the rocket, targeting way too large a market, and w/ other penalties I won't discuss. Pegasus is a non-sequitur; developed far before any of the real commercial launchers, and using leftover SRMs.

[novak]

Do the numbers, air launch makes sense for certain rocket sizes and configurations.

Perhaps is theory, but it has yet to manifest in practice. Electron's $/kg is about the same as LauncherOne. And Pegasus is ridiculously expensive for a tiny payload.

My take on this is that there are two reasons airlaunch doesn't work as well in practice as it does on paper.  First, building the infrastructure needed to support a rocket launch is hard enough without trying to make the infrastructure fly.  On LauncherOne, rather than deal with that they just load propellants on the ground and deal with boiloff.  There's no way that's good for your launch window or payload fraction.

Second, there's actually a lot of extra load on an airlaunched rocket, which tends to translate into a lot of extra structural mass.  You're hanging the rocket off of a single (often heavy) hardpoint, and then it has to do a hard pull-up maneuver after you drop it, which usually means the whole vehicle has to be stiffer/heavier.

I suspect that the combination of how tricky these problems are to analyze combined with the tendency for their solutions to slightly decrease performance is why you don't usually see big benefits from airlaunch.  I'll grant that in theory, a heavily invested player could probably do the required work to get at least some performance benefit- but it's not at all clear to me that this is going to happen in practice. 

I'd much rather launch off of an Antanov or 747 than strato though, because you could buy the airplane and decide how to operate it.  Working with an outside company, like Stratolaunch, you're going to have to do all of your complex rocket operations within whatever guidelines they give you- which again, are unlikely to benefit performance.

[Lars-J]

Do the numbers, air launch makes sense for certain rocket sizes and configurations.

Perhaps is theory, but it has yet to manifest in practice. Electron's $/kg is about the same as LauncherOne. And Pegasus is ridiculously expensive for a tiny payload.

Rockets are exponential, highly-coupled creatures. LauncherOne has nearly the exact same technical decisions as Electron, but even worse. It's leaving out all most multi-disciplinary advantages of air-launch by putting turbopumps on the rocket, targeting way too large a market, and w/ other penalties I won't discuss. Pegasus is a non-sequitur; developed far before any of the real commercial launchers, and using leftover SRMs.

So you agree with him then? Air launch has theoretical benefits, but none of them outweigh the practical drawbacks you list. (and that's only a subset of them)

VO is giving it a go, and they may find a niche, but that niche may only exist because of a temporary under capacity in the payload capability range.

[Mardlamock]

Do the numbers, air launch makes sense for certain rocket sizes and configurations.

Perhaps is theory, but it has yet to manifest in practice. Electron's $/kg is about the same as LauncherOne. And Pegasus is ridiculously expensive for a tiny payload.

Rockets are exponential, highly-coupled creatures. LauncherOne has nearly the exact same technical decisions as Electron, but even worse. It's leaving out all most multi-disciplinary advantages of air-launch by putting turbopumps on the rocket, targeting way too large a market, and w/ other penalties I won't discuss. Pegasus is a non-sequitur; developed far before any of the real commercial launchers, and using leftover SRMs.

So you agree with him then? Air launch has theoretical benefits, but none of them outweigh the practical drawbacks you list. (and that's only a subset of them)

VO is giving it a go, and they may find a niche, but that niche may only exist because of a temporary under capacity in the payload capability range.

Yes and no. I agree in the sense that without a certain set of technical decisions to accompany it, air-launching provides moderate to no performance improvement. However, that doesn't mean all air-launched rockets are a fad, and in no way does it mean it doesn't decrease size. Just look at the delta-v reductions you get by using it for rockets smaller than VO's; do some quick math (with mass-fraction penalties if you like), and you'll see air-launch can be extremely favourable in some configurations.

[Patchouli]

Yes and no. I agree in the sense that without a certain set of technical decisions to accompany it, air-launching provides moderate to no performance improvement. However, that doesn't mean all air-launched rockets are a fad, and in no way does it mean it doesn't decrease size. Just look at the delta-v reductions you get by using it for rockets smaller than VO's; do some quick math (with mass-fraction penalties if you like), and you'll see air-launch can be extremely favourable in some configurations.

Small rockets tend to benefit more from air launching than large ones since drag is a bigger issue for them.

[Steven Pietrobon]

Pegasus is a non-sequitur; developed far before any of the real commercial launchers, and using leftover SRMs.

Pegasus was the first real commercial launch vehicle. Its Orion motors were specifically developed for Pegasus by ATK.

"The Orion family of motors was originally designed for the three stages of the Pegasus launch vehicle."

https://web.archive.org/web/20100415145936/http://www.ltas-vis.ulg.ac.be/cmsms/uploads/File/DataSheetSolidATK.pdf

[meekGee]

Do the numbers, air launch makes sense for certain rocket sizes and configurations.

Perhaps is theory, but it has yet to manifest in practice. Electron's $/kg is about the same as LauncherOne. And Pegasus is ridiculously expensive for a tiny payload.

Rockets are exponential, highly-coupled creatures. LauncherOne has nearly the exact same technical decisions as Electron, but even worse. It's leaving out all most multi-disciplinary advantages of air-launch by putting turbopumps on the rocket, targeting way too large a market, and w/ other penalties I won't discuss. Pegasus is a non-sequitur; developed far before any of the real commercial launchers, and using leftover SRMs.

So you agree with him then? Air launch has theoretical benefits, but none of them outweigh the practical drawbacks you list. (and that's only a subset of them)

VO is giving it a go, and they may find a niche, but that niche may only exist because of a temporary under capacity in the payload capability range.

Yes and no. I agree in the sense that without a certain set of technical decisions to accompany it, air-launching provides moderate to no performance improvement. However, that doesn't mean all air-launched rockets are a fad, and in no way does it mean it doesn't decrease size. Just look at the delta-v reductions you get by using it for rockets smaller than VO's; do some quick math (with mass-fraction penalties if you like), and you'll see air-launch can be extremely favourable in some configurations.

Can you show the math?  I'm curious to compare that airborne delta-V benefit to an increase in first stage size that provides the same.

[TrevorMonty]

I know this sounds crazy, but what about resurrecting Falcon 1 to launch on the roc? SpaceX doesn't even have to do it, some other company could buy the rights to do it and buy the toolings and engines from SpaceX.

Putting Falcon 1 on there is a great illustration why air launching makes no sense. You're paying the same hardware cost on the rocket since it's not anywhere near enough to replace a first stage. All you did is replace a simple dirt launchpad in the middle of nowhere with an insanely expensive to build, fly and service plane. The only difference is a minor payload increase - well guess what, they planned a Falcon 1e with a slight tank stretch and engine uprating. The difference is some 10t in takeoff weight, a minor increase in fuel and fabrication costs compared to adding a plane.

Biggest plus to air launch is the mobile launch pad. The ability to launch from anywhere and to any orbit from single runway. Thats means air traffic free airspace and fine weather areas.
Performance boost becomes significant with ability to launch from equator.

Do the numbers, air launch makes sense for certain rocket sizes and configurations.

Thats problem with Stratolaunch is its built for rocket size that doesn't exist, around 6t to LEO size. To small for GEO market while to expensive to compete with F9R and NG for bulk LEO constellation deployment. To big for smallsat and cubesat market.

[libra]

If Stratolaunch provides 1100 m/s of "bonus" on the way to Earth orbit 9 km/s, then there is a way to get a "simple" rocket for it.
According to Space Launch Report
https://www.spacelaunchreport.com/taurus2.html

Antares 200 stage 1 weights 260 mt for 240 mt of props, so 20 mt empty.

PMF: 1-(20/260) = 0.923

ISP: 337

then...

9.81*337*ln(260/20)= 8479 m/s - minus the Stratolaunch boost of 1100 m/s = 9579 m/s total.

Which mean that Earth orbit is possible, with some payload. And just one single stage, not two or three. Plus the ISP could be improved, since Antares launches from the ground.

[Kryten]

If Stratolaunch provides 1100 m/s of "bonus" on the way to Earth orbit 9 km/s, then there is a way to get a "simple" rocket for it.
According to Space Launch Report
https://www.spacelaunchreport.com/taurus2.html

Antares 200 stage 1 weights 260 mt for 240 mt of props, so 20 mt empty.

PMF: 1-(20/260) = 0.923

ISP: 337

then...

9.81*337*ln(260/20)= 8479 m/s - minus the Stratolaunch boost of 1100 m/s = 9579 m/s total.

Which mean that Earth orbit is possible, with some payload. And just one single stage, not two or three. Plus the ISP could be improved, since Antares launches from the ground.

The Stratolaunch rocket architecture did seem to be single-stage, given they were testing the large booster engine and never showed or mentioned any kind of upper stage engine.

[Archibald]

Do you mean the late FGA thing derived from the SSME ? I was thinking about the earlier solid fuel booster (Thunderbolt ) which was multistage - solid and solid and Centaur.
With one LH2 lox stage (think a 250 mt S-IVB look alike) max payload could be 18 mt. Lower energy stage either kerolox or storable are barely 6 mt - single stage again.
Of course there is that slosh issue that could be annoying. Solids just don't care but performance is too low for single booster.

[Zed_Noir]

Do you mean the late FGA thing derived from the SSME ? I was thinking about the earlier solid fuel booster (Thunderbolt ) which was multistage - solid and solid and Centaur.
With one LH2 lox stage (think a 250 mt S-IVB look alike) max payload could be 18 mt. Lower energy stage either kerolox or storable are barely 6 mt - single stage again.
Of course there is that slosh issue that could be annoying. Solids just don't care but performance is too low for single booster.

Think you meant the PGA thing.

Thinking about it. Could you build a SSTO core with a gross mass of of around 250 tonnes powered by a single J-2X launching from the Roc? Of course you need some method of replacing the boiled off propellants in-flight during the transit to the launch point.

[libra]

PGA yes. FGA is Fighter Ground Attack, as in Hawker Hunter FGA :p

18 mt of payload - somebody did the math at another forum. SSTO empty mass has to be below 18 mt, or burst - zero payload to orbit.

https://www.secretprojects.co.uk/forum/index.php/topic,14179.msg344871.html#msg344871

Of course you need some method of replacing the boiled off propellants in-flight during the transit to the launch point.

See the following discussion. Air dropping such a monster from Roc would be a little hair-rising.