Swiss Space Systems - reusable air-launched vehicle

[RanulfC]

I wanted to point to the fact that launching from the top of an airplane brings less of a weight gain than launching from untherneath an airplane.

Got any cites for that? I ask because that's not what I've seen from any air-launch reports due to the need for larger wings on the top-mounted launch vehicle or some other method of ensuring positive separation. Or is that backwards since you seem to indicate such later?

There's almost certainly some military research to that effect. The main argument I've header is that is gentler on the carrier to drop something than release it and get out of the way.

Up to and including the last DARPA/NASA Air Launch study the "conclusion" was for a top mounted, liquid fueled "Super Pegasus" vehicle using Falcon-9 derived first stage, (single engine) and a RL10 powered Centaur "derived" upper stage with the carrier vehicle performing a high angle diving turn upon release.

Main (and about the only one listed) reason for top carry was the LVs were all to large to be carried under the airframe. Everything in the report gave the impression of reaching a pre-determined conclusion with details of the LV and carrier aircraft changed as needed to reach the "right" conclusion.

Seriously drop is easier AND safer by a huge margin but if you have certain "requirements" for the LV design then the it works out the "conclusion" for top carry and launch becomes the only "viable" option Almost none of the documented and known possible methods for allowing under-carry were addressed in the report such as over-filling the gear olios or using a T-LAD system and any type of 'non-single-stick' LV to name just a few.

There's also the SR-71/D-21 experience that separating a top-mounted aircraft at high speed is deadly.

Note that specifically that type of launch had been done before, successfully. The accident happened because the D21 control system malfunctioned and suddenly commanded a dive even before it had passed through the SR-71 mach-shock. The entire reason for launching that way was because the D-21 at that point in flight had a positive lift of its own so that separation would continue even if the ramjet stopped working and that the air flow above and aft of the SR-71 was very smooth. This condition was also the reason NASA did an extensive study for possibly launching large glide, ramjet, and rocket booster high-speed aerodynamic test vehicles from their SR-71s. Specifically citing the accident as the only one of it's type during the program and the exact cause of the failure they concluded that a more advanced and redundant flight control system, (the D21 had only a single control computer) would preclude any reoccurrence of the accident. (Which is what the flight safety review board concluded on the original accident but there was no budget, or really room to so upgrade the D-21 so M71 flights were canceled and the M21s reverted to SR-71s)

Top mounted launch IS in fact useful in some situations, however the standard "low-and-slow" subsonic launch is NOT one of those situations.

Randy

[RanulfC]

@RanulfC
In my post previous (#106) to the one you reacted to (#111), I wrote that my source are the Aldebaran studies, that were run by CNES between 2007 and 2010. I'll post two links: [1] and [2].

Thanks for those

This ones I could find fast, there are at least for presentations and document with about the same content. I want to point to page 23 of [2].
If you want to launch an 300kg satellite into a 300kg SSO orbit, what would be the takeoff weight of an launching system. With ground launch, the GLOW would be about 32mT. If you release from an balloon at 20km altitude the GLOW is decreased to 21mT. This is a 34% decrease. When you launch from the top of an airplane (Shuttle) the GLOW is 25% lower compared with ground launch. When launching after an airdrop from an plain (Pegasus) the GLOW is 35% lower. (I posted 20% vs 30% because I didn''t look up the numbers.)
So SOAR is for the same performance 10% heavier than SpaceShip Two.

That's actually why I was asking as your original statement was:

I wanted to point to the fact that launching from the top of an airplane brings less of a weight gain than launching from underneath an airplane.

Both according to the reports you cite and those I have a top-launched LV weighs more than one that is bottom mounted. (Hence the -25% for top mounted GLOW versus -35% for bottom. The former is heavier than the latter which is where I was confused by what you were stating )

I've a nit or two with some other assumptions in the study as well as they actually show the various factors relevant to air launch, (altitude, speed, and Angle-to-the-local-Horizon) but most of them are misrepresented in the comparisons. As an easy example the chart on page 23 the QuickReach launch vehicle is listed as "launched" at a 0-degree angle when it is fact launched at a 90-degree angle as stated on page 25, (and this being noted as a "problem" with no explanation as to why this would be) which according to the same chart on page 23 would indicate a significant "gain" n payload to orbit over the given launch angle of zero. And in fact this is so as the QuickReach, despite being a pressure fed, sub-optimal LV design due to constrained requirements lofts 150kg MORE than the baseline required "300kg". For (one of) the same reasons the last two carrier vehicles also show an increased payload in the fact the "launch angle" at engine ignition is over 70 degrees to the local horizon. This counts almost as much as added speed in an air launch scenario. The added speed at launch for those two carries adds about half again in GLOW reduction and payload to orbit.

I think designing a gliding suborbital vehicle is inherently more difficult, also operationally.

Historically the difficulty has been about the same with various factors highly dependent on operational and mission requirements as envisioned by the designers. (Which of course include significant bias' from those designers which effect the outcome of the trade studies )

Historically there is much more experience with gliding or powered landing like an aircraft and people are more comfortable with that method of landing. While the heating pulse of reentry is longer for a lifting vehicle it is most often lower as long as the vehicle has a good lift to mass factor. (The Shuttle Orbiter didn't have as good of one as it could have) Cross-range and landing options are easier to predict, understand and plan for with a lifting vehicle. Capsules on the other hand are very limited on ability to significantly adjust their landing area through internal control, however barring significant offset by some mechanism their flight profiles and trajectory are very easy to predict and understand. Capsules rely on deployed mechanisms for a safe landing where as lifting vehicles have inherent landing systems by design that are less prone to failure. (In general) Lastly in a situation like this (air launched, sub-orbital) the passengers in the lifting system remain pretty much at the same position throughout the flight where as the capsule occupants go from what amounts to a 'standing" upright position in their seats to one where they land on their back which can be annoying to do as well as to accommodate operationally.

Operationally, the capsule requires recovery, servicing,  and then re-mating to the booster section and then re-attachment to the carrier vehicle where as the lifting vehicle/crew cabin only requires servicing and then re-mating to the carrier vehicle. In most cases the winged vehicle can use it's own landing gear for towing from one place to another where as a capsule usually requires a dedicated pallet and transporter systems to move.

Now note that things change significantly once we go beyond simple sub-orbital and into orbital operations but overall for the lower requirements of sub-orbital operations the choice is not at all as clear as some think it is.

All the systems need a form of rocket propulsion this is a very expensive development. SOAR wants to use an Russian engine that already has been developed, but if they are allowed to buy the Russian engines remains to be seen. For the other vehicles new rocket engines have been developed.

SOAR according to what I read is using kerosene-lox and there's no obvious reason they HAVE to use Russian engines, the NK-33/39 is nice but you can work around it with other available or tested engine designs. Various designers have taken to designing and building specific rocket engines for perceived needs but really there are a lot of designs out there both legacy and prototyped that could be used as long as you don't bring to many bias' to the table in the first place.
 

With a capsule system you have two components the Rocket booster and the capsule. This rocket booster can relatively easily be used as first stage for a micro launch vehicle (Boeing & BO XS-1; Orbspace Infinity (nano) concept).
With a suborbital space plane (XCOR, Lynx / Airbus concept) in one system all the functions are packed, (takeoff, propulsive phase, pressurization and live support, reentry control and landing.)

Actually it's not at all that "easy" or simple as the stage has to handle both horizontal as well as vertical loading and transient stress' which they are not normally designed to handle at the sizes being discussed. The entire reason that the Pegasus is an all solid booster is they are more sturdy and capable of handling said stress' without extra reinforcement and support. The QuickReach booster was designed the way it was and had the support stand it does to reduce the amount of stress-points and shocks to the vehicle body in flight. Hanging (or mounting on top) a liquid fueled LV requires a great deal of attention to be paid to all the possible shock, loading, and transient loading factors which no vertically launched LV every sees or is designed to handle. Doing so significantly increases the difficulty in design and mass of the eventual LV. In a unitary design such as a 'spaceplane' the vehicle is already designed to handle both horizontal and vertical stress.
 

With an orbital released system; a modified airplane and a suborbital space plane are needed. Only the takeoff function is removed from the function requirements of the suborbital plane, and a release function is added. The airplane has the takeoff and the release function to cope with.

This is required for either system, unless you're talking avoiding air launch all together which isn't clear.
 

My intuition tells me that developing a rocket booster and a capsule is the simplest and thus cheapest, (the booster recovery ads a lot of development but makes the operations cheaper.) A space plane that does all the functions comes next I think. SOAR is next because they use an commercial airplane, and Virgin Galactic took the most expansive approach; develop a dedicated airplane and a sub-orbital space plane. They cut back on automation to save development cost.

Most of the concepts for suborbital travel are trying in various ways to reduce operational costs as much as possible and expand market applicability. In the case of Blue Origin they have their own dedicated launch site, but in VG and S3 they want to be able to embark passengers from a normal airport is at all possible to increase their ability to serve passengers. BO has an aggressive planned program but it's going to be limited by the turn-around time of the booster and capsule whereas VG and S3 for example are going to be limited by the turn around time of each spaceplane. With a highly reusable "booster" carrier aircraft they can (in theory) load another spaceplane within a few hours of the fist flight and fly again whereas BO has to have multiple boosters and capsules to do the same.

How well this will work out for each in actual practice is very much up for debate, specifically since a controlled area of flight (range) will be required for the actual suborbital flight and this will not be "near" the type of airports that VG and S3 are considering operating out of.

Note also that VG never "cut back" on automation as they have stated from the beginning that SS2 would be tested and flow in a similar manner to normal aircraft testing. BO on the other hand is not going that route but neither are they ever expecting to launch from anywhere but specialized locations. Launcher One, (should it ever actually fly) will be unmanned from the start as it's not a passenger launch vehicle of any type.

I agree that NS will not be piloted as will SOAR if Oli is right. I think it's the only safe approach, and you save about 100-200kg in system mass (one or two pilots)

SOAR is their nano-sat launcher so that's understandable, however it's ALSO supposed to be a prototype for a later manned sub-orbital launch vehicle which WILL require pilots.

To your comment of BO and not trusting their system. I think they want a safety level close to flying on an airplane. They have a system that is autonomous, so there is (rightly so) no requirement to carry a pilot on early flights. They might have a closed business case for suborbital payload flights, so they don't lose money on the dozens of unmanned flights. But they get the flight experience from all those flights. No competitor is around to steal from their potential client base. So I think it is a very wise and sensible decision to do looooooots of unmanned NS flight before manned testing takes place. They will know the cost of operating their system. And I expect that BO will only start selling rides after a (couple) successful manned flight.

I didn't say they didn't trust their system but that what they are doing has the appearance they don't Considering that the Blue Shepard vehicle has a proven abort system, working capsule, landing system and booster they have everything in place to start volunteer manned flights at any time. Considering how many people around here would volunteer to fly in a Dragon capsule WITHOUT an abort system I'm pretty sure they won't lack for volunteers willing to sign waivers to fly with very lax restrictions. But I don't expect that to happen because Bezo's has stated he wants a LARGE number of unmanned test flights first.
And no, they are not going to be at a safety level of an airplane, they can't, it's not one and it is in fact a Vertical Take Off, Vertical Landing, (parachute with rocket assist landing for the capsule) ROCKET launch vehicle. They are never going to be considered for, or given an aircraft flight safety certificate. VG and S3 in fact have stated that is what they were aiming or to arrive at "aircraft" levels of safety but in reality they won't be given such either, (though their "booster" carrier aircraft will in fact have them) despite testing as they are but that won't change their approach nor should it.

BO has a fully automated system and has never been planned to carry a "pilot" of any type as all functions are automatic other than a single on-board abort button. They believe they have a business case for suborbital flight, there is no way to know if they have one that actually works until they start flying paying passengers and commercial operations. In this they are no different than VG or any other suggested provider. Frankly I expect BO to probably fly passengers before VG does simply because of the highly different business models and plans. This was always VGs race to lose and many of the design and development choices show a distinct lack of flexibility and to question "common wisdom" handed to them. I would not be surprised to see VG fold if BO starts regular flights before they get going.

In S3s case they have a lot of assumptions that are not as solidly based as they seem to think and they are trying to claim cost advantages that are marginal at best. Again I'll be surprised if they go beyond the microgravity flight missions.

Randy

[Oli]

SOAR is their nano-sat launcher so that's understandable, however it's ALSO supposed to be a prototype for a later manned sub-orbital launch vehicle which WILL require pilots.

Smallsat launcher. The passenger version would have a pressurized module in the cargo bay instead of the upper stage. Why the requirement for a pilot?

[RanulfC]

SOAR is their nano-sat launcher so that's understandable, however it's ALSO supposed to be a prototype for a later manned sub-orbital launch vehicle which WILL require pilots.

Smallsat launcher. The passenger version would have a pressurized module in the cargo bay instead of the upper stage. Why the requirement for a pilot?

As I understood it the two would share basic design, but the passenger vehicle was going to be designed from the ground up AS a passenger vehicle. Pilot was included for safety and regulatory reasons. The wings-and-wheels vehicles all have pilots because they are working from the premise of appearing to follow airline/airplane safety and operations. They are not, but you (currently) can't have an unmanned "aircraft" taking off or landing at a regular airport. And in the end that is where the operators are seeing this going even if it's not going to happen.

Randy

[Oli]

SOAR is their nano-sat launcher so that's understandable, however it's ALSO supposed to be a prototype for a later manned sub-orbital launch vehicle which WILL require pilots.

Smallsat launcher. The passenger version would have a pressurized module in the cargo bay instead of the upper stage. Why the requirement for a pilot?

As I understood it the two would share basic design, but the passenger vehicle was going to be designed from the ground up AS a passenger vehicle. Pilot was included for safety and regulatory reasons. The wings-and-wheels vehicles all have pilots because they are working from the premise of appearing to follow airline/airplane safety and operations. They are not, but you (currently) can't have an unmanned "aircraft" taking off or landing at a regular airport. And in the end that is where the operators are seeing this going even if it's not going to happen.

Randy

It's from here:

http://spacenews.com/startup-spotlight-swiss-space-systems-s3/

“Instead of a third stage in the cargo bay, we implement a pressurized module we are developing with Thales Alenia Space,” Jaussi said. “As we will have covered the development costs of the shuttle with small satellites launches, the ticket price for the passengers will only have to cover the costs related to the shuttle modification and certification.”

[Borklund]

They appear to have a plane

[RonM]

S3 must be serious. An Airbus A340-300 is not cheap.

[Hauerg]

S3 must be serious. An Airbus A340-300 is not cheap.

It may be the cheapest option available, at least if they ordered before the Iranians ordered the stock of pre owned 340s.

[baldusi]

The A340 is a failed project that nobody wants due to the completely uncompetitive operating cost. Operators want B777 or, in the worst case, A330. I know because the corrupt laden prevous administration bought A340 and much was told regarding the competitiveness (or lack of there of).

[Lars-J]

The A340 is a failed project that nobody wants due to the completely uncompetitive operating cost. Operators want B777 or, in the worst case, A330. I know because the corrupt laden prevous administration bought A340 and much was told regarding the competitiveness (or lack of there of).

Wow, that's quite some exaggeration there... The A340 was eventually phased out from most airlines due to slightly higher cost than the 777 and A330, but it was never *that* un-competitive. The growing range of the A330 is what killed it, not disastrous economy. But A340 models have flown for two decades now and the many are still in service.

[Oli]

I'm sure acquisition cost is a lot more relevant for S3 than fuel consumption.

[Hobbes-22]

Up to and including the last DARPA/NASA Air Launch study the "conclusion" was for a top mounted, liquid fueled "Super Pegasus" vehicle using Falcon-9 derived first stage, (single engine) and a RL10 powered Centaur "derived" upper stage with the carrier vehicle performing a high angle diving turn upon release.

Main (and about the only one listed) reason for top carry was the LVs were all to large to be carried under the airframe. Everything in the report gave the impression of reaching a pre-determined conclusion with details of the LV and carrier aircraft changed as needed to reach the "right" conclusion.

Seriously drop is easier AND safer by a huge margin but if you have certain "requirements" for the LV design then the it works out the "conclusion" for top carry and launch becomes the only "viable" option Almost none of the documented and known possible methods for allowing under-carry were addressed in the report such as over-filling the gear olios or using a T-LAD system and any type of 'non-single-stick' LV to name just a few.

IIRC Orbital spent large amounts of money modifying their L-1011 to carry the tiny Pegasus. And the L-1011 has several factors in its favor: more ground clearance than e.g. the 747, and no keel down the middle of the fuselage so they could insert the slot for the Pegasus' top fin without major structural modification.
Despite this, Orbital was limited to a payload of about 400 kg to orbit. The Pegasus has a diameter of 1.2 m. There are no airliners with enough ground clearance to fit a Falcon 9-sized vehicle underneath (3.6 m diameter), and no amount of overfilling the gear oleos is going to get you there.
T-LAD does nothing to reduce the ground clearance needed.
The only aircraft that could possibly drop-launch a Falcon-sized vehicle are high-wing transports like the C-5 and the An-124. The last airliner to get close to 3 m ground clearance was the Tupolev 114.

[Kabloona]

IIRC Orbital spent large amounts of money modifying their L-1011 to carry the tiny Pegasus.

Since you mention it, here's the L-1011 story direct from Antonio Elias:

https://forum.nasaspaceflight.com/index.php?topic=3911.msg61342#msg61342

As for "large amounts of money," relative to what? IIRC, it was on the order of $5M-$10M, which was hardly a deal-breaker. The main challenge of the L-1011 was that the mods were done by Marshall Aerospace in England, and the coordination between them and the Pegasus team was rather painful and involved a lot of trans-Atlantic travel and some arm-twisting to get the project finished.

[Hobbes-22]

I may be misremembering things, the amount lodged in my memory is 10 times that.

[Kabloona]

I may be misremembering things, the amount lodged in my memory is 10 times that.

$50-$100 million for the L-1011 mods?? Oh, no. $50M was the entire Pegasus development budget, and the plane itself cost them only $10M.

[somepitch]

S3 must be serious. An Airbus A340-300 is not cheap.

I don't know if this is a -300 but it certainly seems like they're out there cheap. They would likely be fine with a high-time/high-cycle airframe given the relatively low usage rate of air launch (vs. airline ops).

http://www.controller.com/listings/aircraft/for-sale/1432897/1998-airbus-a340

[RanulfC]

IIRC Orbital spent large amounts of money modifying their L-1011 to carry the tiny Pegasus. And the L-1011 has several factors in its favor: more ground clearance than e.g. the 747, and no keel down the middle of the fuselage so they could insert the slot for the Pegasus' top fin without major structural modification.
Despite this, Orbital was limited to a payload of about 400 kg to orbit. The Pegasus has a diameter of 1.2 m. There are no airliners with enough ground clearance to fit a Falcon 9-sized vehicle underneath (3.6 m diameter), and no amount of overfilling the gear oleos is going to get you there.
T-LAD does nothing to reduce the ground clearance needed.
The only aircraft that could possibly drop-launch a Falcon-sized vehicle are high-wing transports like the C-5 and the An-124. The last airliner to get close to 3 m ground clearance was the Tupolev 114.

Falcon "derived" LV actually, as in "Falcon-1-ish" not an actual Falcon-9. See:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20130000446.pdf
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20120000791.pdf

t/LAD was not about reducing the ground clearance it was about getting the LV to a "proper" launch angle without using wings which significantly reduces the actual LV payload unless significantly integrated with the LV. (Which is technically is in the SSS system, but is not with Pegasus or the DARPA systems, part of the reason they don't have the same payload capacity)

A good list of the 'issues' with top-launch is here:
http://mae.engr.ucdavis.edu/faculty/sarigul/papers/AIAA-2008-7835.pdf

As noted the cost of modification for the L1011 wasn't that much but you might be thinking of the cost of modification cited in the above study for the 747, (@20 million) which has been quoted here before. Pretty much the more the LV weighs the more systems conversion costs, and the more existing 'infrastructure' you can use the more you save. (IIRC VG is using the 747's "Engine Ferry" hard-point near the wing root for the basis of the Launch One carry point which actually should help since the 747 is designed to carry something there in the first place)

In the end S3 is going to have to modify the A340 to carry a significant amount of mass in a position that it was never designed to carry there and reinforce the airframe to stand loading and stress it wasn't designed to handle on a regular basis. IF their LV can actually "glide" off the top in a similar manner to the earliest Shuttle drop tests, (before they removed the tail-cone covering the engines) that will help a lot but it's still going to cost quite a bit. More than the L1011 but probably a bit less than the t/LAD projection, maybe.

Randy

[Borklund]

They posted another Zero G/watch ad:



Still no sign of SOAR

[SwissCheese]

Sad news from S3, the CEO was attacked and severely wounded:

http://www.tdg.ch/suisse/suisse-romandepatron-s3-sauvagement-agresse/story/26698862 (in French)
http://www.thelocal.ch/20160905/swiss-space-firm-boss-left-badly-injured-in-violent-attack (summary in English)

Looks like it's directly related to S3 activities. This follows the malicious flooding of their servers last year. Very strange things going on there...

[Rocket Science]

Terrible news... My hopes and prayers for a best recovery...