HAPS: High-Altitude Pseudo Satellite

[JamD]

There is a lot of interest in High-Altitude Pseudo Satellite (HAPS) around the world. The idea behind HAPS is to have a high-flying, electric aircraft, that charges its batteries using solar panels. Since the power generated by solar panels is limited, HAPS need to be extremely efficient flyers. It is for this reason they have long, slender wings that are covered in solar panels. These wings need to be light, which means they are very flexible, which makes them challenging to fly safely.

The advantages of such a platform are that you get the capabilities of a low-Earth orbit satellite at a fraction of the launching and operating costs. Furthermore, HAPS can remain over an area indefinitely, as opposed to a satellite that orbits.

The main challenges of designing and operating HAPS are:

1. High-efficiency solar panels
2. High energy density batteries
3. Highly efficient electric motors
4. Propellors that are efficient over a wide range of operating conditions - sometimes different motor/prop sets are used at different regimes.
5. Lightweight and optimized airframe design and construction attempting to keep the airframe as stiff as possible without subjecting it to loads that will break it.
6. Flight control of highly flexible aircraft - this needs to minimize flutter (excitation of aeroelastic modes), excitatation of purely structural modes, and maintaining efficient trim conditions to maximize flight-time.
7. Optimization of altitudes and profiles to account for day-night cycles (sunlight, temperature variations) and shorter time-scale variations.
8. Safe launch and recovery for a such a flexible aircraft designed to fly at many 10s of thousands of feet.
9. Design of very lightweight payloads
10. Design of very lightweight communication equipment

Some of the HAPS programs becoming mature are:

Aurora’s Odysseus

• Carries a class-leading 140 lbs of payload to 60,000 ft and above
• Provides 900 watts maximum or continuous 250 watts of power
• Operable year-round between medium latitudes and 6 months at sub-arctic latitudes
• Autonomously maintains its position for months on end in any stratospheric condition
• Generates zero emissions and operates far above weather and other aircraft

Airbus Zephyr

• Zephyr is the world’s leading solar-electric stratospheric Unmanned Aerial System (UAS), with a wingspan of 25m and weighs less than 75kg.
• Having already taken to the stratosphere and breaking multiple world records, Zephyr is an innovative solution currently under development by Airbus.
• Zephyr will bring new See, Sense and Connect capabilities to commercial, institutional and military customers
• Zephyr relies on solar energy, with secondary batteries charged in daylight to power overnight flight. Thanks to this Zephyr’s flight time is carbon neutral.

AVIC Morning Star
Developer Aviation Industry Corporation of China (AVIC) announced that the unmanned aerial vehicle (UAV), which has a 20-metre (66-foot) wingspan, attained and cruised at an altitude of more than 20,000 metres (66,000 feet).

There is a single HAPS program being attempted by integrated dynamics in Pakistan:
Currently they have built a small-scale technology demonstrator the ID Solaris

This program can and should be pursued and expanded. Especially by the newly made Pakistan Space Command.

EDIT: Just to demonstrate how much of a baby step the ID effort is

	Payload	Wingspan	Payload/Span (sort of efficiency)
Aurora Odysseus	63.5 kg	25 m	2.54 kg/m
ID Solaris	5 kg	6 m	0.83 kg/m

Furthermore, the ID Solaris is so small (6m wingspan) that it doesn't have to deal with the challenges of flying a highly flexible aircraft like:

 

[Moon]

There is a lot of interest in High-Altitude Pseudo Satellite (HAPS) around the world. The idea behind HAPS is to have a high-flying, electric aircraft, that charges its batteries using solar panels. Since the power generated by solar panels is limited, HAPS need to be extremely efficient flyers. It is for this reason they have long, slender wings that are covered in solar panels. These wings need to be light, which means they are very flexible, which makes them challenging to fly safely.

The advantages of such a platform are that you get the capabilities of a low-Earth orbit satellite at a fraction of the launching and operating costs. Furthermore, HAPS can remain over an area indefinitely, as opposed to a satellite that orbits.

The main challenges of designing and operating HAPS are:

1. High-efficiency solar panels
2. High energy density batteries
3. Highly efficient electric motors
4. Propellors that are efficient over a wide range of operating conditions - sometimes different motor/prop sets are used at different regimes.
5. Lightweight and optimized airframe design and construction attempting to keep the airframe as stiff as possible without subjecting it to loads that will break it.
6. Flight control of highly flexible aircraft - this needs to minimize flutter (excitation of aeroelastic modes), excitatation of purely structural modes, and maintaining efficient trim conditions to maximize flight-time.
7. Optimization of altitudes and profiles to account for day-night cycles (sunlight, temperature variations) and shorter time-scale variations.
8. Safe launch and recovery for a such a flexible aircraft designed to fly at many 10s of thousands of feet.
9. Design of very lightweight payloads
10. Design of very lightweight communication equipment

Some of the HAPS programs becoming mature are:

Aurora’s Odysseus

• Carries a class-leading 140 lbs of payload to 60,000 ft and above
• Provides 900 watts maximum or continuous 250 watts of power
• Operable year-round between medium latitudes and 6 months at sub-arctic latitudes
• Autonomously maintains its position for months on end in any stratospheric condition
• Generates zero emissions and operates far above weather and other aircraft

View attachment 786183
View attachment 786184

Airbus Zephyr

• Zephyr is the world’s leading solar-electric stratospheric Unmanned Aerial System (UAS), with a wingspan of 25m and weighs less than 75kg.
• Having already taken to the stratosphere and breaking multiple world records, Zephyr is an innovative solution currently under development by Airbus.
• Zephyr will bring new See, Sense and Connect capabilities to commercial, institutional and military customers
• Zephyr relies on solar energy, with secondary batteries charged in daylight to power overnight flight. Thanks to this Zephyr’s flight time is carbon neutral.

View attachment 786185
View attachment 786186

AVIC Morning Star
Developer Aviation Industry Corporation of China (AVIC) announced that the unmanned aerial vehicle (UAV), which has a 20-metre (66-foot) wingspan, attained and cruised at an altitude of more than 20,000 metres (66,000 feet).
View attachment 786187
View attachment 786188




There is a single HAPS program being attempted by integrated dynamics in Pakistan:
Currently they have built a small-scale technology demonstrator the ID Solaris
View attachment 786189
View attachment 786190
This program can and should be pursued and expanded. Especially by the newly made Pakistan Space Command.

EDIT: Just to demonstrate how much of a baby step the ID effort is

	Payload	Wingspan	Payload/Span (sort of efficiency)
Aurora Odysseus	63.5 kg	25 m	2.54 kg/m
ID Solaris	5 kg	6 m	0.83 kg/m

Furthermore, the ID Solaris is so small (6m wingspan) that it doesn't have to deal with the challenges of flying a highly flexible aircraft like:
View attachment 786193

I've been obsessing over HAPS for quite some time now.

Their long endurance and wide area of operations make them an excellent asset for monitoring an area for long periods of time. Borders, terrorist hotspots etc.. by making use of EO/IR and SAR, they can easily monitor the "pattern of life" of an area and using that we can see abnormalities that might hint towards suspicious activity. Not to mention monitoring large swathes of oceans at a time, to look for suspicious vessels.

Not only that, they can play a critical role in providing encrypted and secure communication to soldiers and other military installations.

They can provide emergency communications to an area which has been struck by natural disasters (flood, earthquake etc...) Or to war torn areas like Syria, Afghanistan and Libya to allow easier access of information (or propaganda).

However, I'd say HAPS are "peacetime weapons". They won't fare well in a conventional war, against an enemy with proper AD and AF. Unless you've placed them deep inside your territory and are using the outer margins of their coverage for your ops.


Lastly, I'd say an array of HAPS play a huge part in maintaining global communications (Internet, GPS, Telecommunications etc...) After a Kessler Syndrome takes place, following some war where we blow up all our satellites.



As for their capabilities, in the late 90s to early 2000s, USA was planning on much more ambitious HAPS designs, with heavier payloads 200-500kg. I'd say the only thing limiting the progress in HAPS is interest and funding.

 

[JamD]

I've been obsessing over HAPS for quite some time now.

Their long endurance and wide area of operations make them an excellent asset for monitoring an area for long periods of time. Borders, terrorist hotspots etc.. by making use of EO/IR and SAR, they can easily monitor the "pattern of life" of an area and using that we can see abnormalities that might hint towards suspicious activity. Not to mention monitoring large swathes of oceans at a time, to look for suspicious vessels.

Not only that, they can play a critical role in providing encrypted and secure communication to soldiers and other military installations.

They can provide emergency communications to an area which has been struck by natural disasters (flood, earthquake etc...) Or to war torn areas like Syria, Afghanistan and Libya to allow easier access of information (or propaganda).

However, I'd say HAPS are "peacetime weapons". They won't fare well in a conventional war, against an enemy with proper AD and AF. Unless you've placed them deep inside your territory and are using the outer margins of their coverage for your ops.


Lastly, I'd say an array of HAPS play a huge part in maintaining global communications (Internet, GPS, Telecommunications etc...) After a Kessler Syndrome takes place, following some war where we blow up all our satellites.



As for their capabilities, in the late 90s to early 2000s, USA was planning on much more ambitious HAPS designs, with heavier payloads 200-500kg. I'd say the only thing limiting the progress in HAPS is interest and funding.

I agree. There are a LOT of peacetime application of HAPS and that is really where they can shine.

But of course they come with their own very unique challenges in structural and flight control design, which makes them difficult to design and build. They require lots of prolonged research. For example at the University of Michigan they have been running the X-HALE program for over a decade:

This is nothing that a Pakistani university cannot also do if given the right funding and incentives for long enough.

Perhaps ID is on to something and if they can fund themselves to a full-sized HAPS, they might become super profitable by serving the civilian market.

 

[Bilal Khan (Quwa)]

I agree. There are a LOT of peacetime application of HAPS and that is really where they can shine.

But of course they come with their own very unique challenges in structural and flight control design, which makes them difficult to design and build. They require lots of prolonged research. For example at the University of Michigan they have been running the X-HALE program for over a decade:
View attachment 786195
This is nothing that a Pakistani university cannot also do if given the right funding and incentives for long enough.

Perhaps ID is on to something and if they can fund themselves to a full-sized HAPS, they might become super profitable by serving the civilian market.

If someone could solve the energy requirements issue, HAPS could become a really interesting ECM system. Imagine a 'wall' of radar and communication jamming nodes at different altitudes. This might be doable for a very short amount of time using an attritable ECM decoy as the basis for the HAPS' ECM kit. Obviously, you might have at best a couple minutes of ECM coverage, but you never know, that short period could make the difference in some situations.

BriteCloud DRFM (Digital RF Memory) countermeasure

www.leonardocompany.com

 

[JamD]

If someone could solve the energy requirements issue, HAPS could become a really interesting ECM system. Imagine a 'wall' of radar and communication jamming nodes at different altitudes. This might be doable for a very short amount of time using an attritable ECM decoy as the basis for the HAPS' ECM kit. Obviously, you might have at best a couple minutes of ECM coverage, but you never know, that short period could make the difference in some situations.

BriteCloud DRFM (Digital RF Memory) countermeasure

www.leonardocompany.com

The 74 m wingspan Aurora Odysseus generates 250W of continuous power from which it has to find power to fly its 680 kg self. The fact that it can carry a 72 kg payload itself is amazing. For context, a plane with a wingspan bigger than a 747 can barely lift a person as payload. Well it does fly just on sunlight.

Not sure if deployable ECM solutions make sense. The whole point of a HAPS is persistency. Short term things can be done by short term mission aircraft.

For HAPS I see surveillance as the primary mission. Maybe communication repeater if it has enough power.

Solving the power issue will require some radical shift in design. We are basically hitting the theoretical maximum of solar panel efficiency and structural design strength. You would either need a radical new way to make the craft even lighter - carbon nanotubes or something I dont know. Or you'd need a different kind of power source. Perhaps nuclear. For example the multi-mission radioisotope thermoelectric generator (MMRTG) can generate 125 W of power and weighs 45kg. That still isn't a good enough power to mass ratio for most power hungry applications and you're creating a lot of risk and cost by having a radioactive device on an airplane that might crash or get shot down.

Maybe in 20 years. But you can't wait 20 years for all the tech to develop before you start working on your own HAPS. There are many other challenges that we can solve in the meantime.

 

[Moon]

I agree. There are a LOT of peacetime application of HAPS and that is really where they can shine.

But of course they come with their own very unique challenges in structural and flight control design, which makes them difficult to design and build. They require lots of prolonged research. For example at the University of Michigan they have been running the X-HALE program for over a decade:
View attachment 786195
This is nothing that a Pakistani university cannot also do if given the right funding and incentives for long enough.

Perhaps ID is on to something and if they can fund themselves to a full-sized HAPS, they might become super profitable by serving the civilian market.

The beauty of the concept of HAPS is, that to achieve the performance objectives, you can take multiple routes to do so.
There are designs that are far more robust and reliable present as of now.
One of these is the "balloon" form factor. :

The great thing about them is that the materials required to build one of these aren't as "sci-fi" like their aircraft counterparts and balloon platforms take far less stress as well, especially if they're operating at higher altitudes (admittedly they're more delicate).

They have a much longer endurance as well (months to years at a time).


Lastly, unlike the above illustrations, the balloons aren't as large as they're shown.

I believe Thales planned on building a 250kg payload airship, which will stay in the air for a whole year.

I think Pakistan can easily develop HAPS. They're excellent ISR assets to have, drastically reduce operational costs (during peacetime of course) and equipment wear and tear.

Imagine the Navy deploying these for ISR over the sea, instead of ATRs or even drones. Plus they're dirt cheap (relative to aircrafts).

 

[JamD]

The beauty of the concept of HAPS is, that to achieve the performance objectives, you can take multiple routes to do so.
There are designs that are far more robust and reliable present as of now.
One of these is the "balloon" form factor. :

The great thing about them is that the materials required to build one of these aren't as "sci-fi" like their aircraft counterparts and balloon platforms take far less stress as well, especially if they're operating at higher altitudes (admittedly they're more delicate).

They have a much longer endurance as well (months to years at a time).


Lastly, unlike the above illustrations, the balloons aren't as large as they're shown.

I believe Thales planned on building a 250kg payload airship, which will stay in the air for a whole year.

I think Pakistan can easily develop HAPS. They're excellent ISR assets to have, drastically reduce operational costs (during peacetime of course) and equipment wear and tear.

Imagine the Navy deploying these for ISR over the sea, instead of ATRs or even drones. Plus they're dirt cheap (relative to aircrafts).

These are certainly promising. I admit I don't know much about these. What are the challenges/downsides to these?

 

[Moon]

These are certainly promising. I admit I don't know much about these. What are the challenges/downsides to these?

The biggest downside they face is the inherent difficulty all blimps face, that is they are susceptible to adverse weather conditions (especially the climb to and descent from the stratosphere) almost all prototypes have crashed in this frame.
And by adverse, I mean anything less than ideal.

This leads to our second problem, the balloons aren't able to operate safely at lower altitudes (due to weather) this means the electronics you'll put in them will need to be designed for more higher altitudes, which in turn means you'll require more energy to power them, which means more batteries, which means more weight, which means a larger size (you get them point). There are small balloon HAPS, but they'll last you a 100 days at max (still better than a drone).

The third limitation is that unlike their plane counterparts, you cannot rapidly deploy these from one theatre to another, they'll take more than a week to go from one part of the country to another.

And I can't even begin to tell you the infrastructure it'll require us to keep this blimps afloat, from hangars to helium, to the industries required to manufacture them (talking about Pakistan).


My idea is to take the Aircraft HAPS and combine it with the Balloon HAPS. An inflatable flying-wing craft, having photovoltaic cells, as well as a helium cells.
The wings would be semirigid in nature, contributing to lift, both by aerodynamics and by the helium in them.
The craft would then ommit the need for development of super-light and flexible materials, due to these capabilities already present in polyester-neoprene combination used in modern blimps. It would instead be designed with "hinges" in its wings to allow for it to change it's shape at different altitudes.
I wish I could illustrate it, but it'd look something like a combination of this:

And this:

Obviously the shape of the wing would have to be optimized for that perfect volume to lift ratio, but that's all manageable, and we won't even need those "hinges" I was talking about.

I wish I could illustrate this better, but I suck at drawing let alone 3D modelling. Maybe you could take this as a little side project, who knows what'll come of it?.

 

[JamD]

The biggest downside they face is the inherent difficulty all blimps face, that is they are susceptible to adverse weather conditions (especially the climb to and descent from the stratosphere) almost all prototypes have crashed in this frame.
And by adverse, I mean anything less than ideal.

This leads to our second problem, the balloons aren't able to operate safely at lower altitudes (due to weather) this means the electronics you'll put in them will need to be designed for more higher altitudes, which in turn means you'll require more energy to power them, which means more batteries, which means more weight, which means a larger size (you get them point). There are small balloon HAPS, but they'll last you a 100 days at max (still better than a drone).

The third limitation is that unlike their plane counterparts, you cannot rapidly deploy these from one theatre to another, they'll take more than a week to go from one part of the country to another.

And I can't even begin to tell you the infrastructure it'll require us to keep this blimps afloat, from hangars to helium, to the industries required to manufacture them (talking about Pakistan).


My idea is to take the Aircraft HAPS and combine it with the Balloon HAPS. An inflatable flying-wing craft, having photovoltaic cells, as well as a helium cells.
The wings would be semirigid in nature, contributing to lift, both by aerodynamics and by the helium in them.
The craft would then ommit the need for development of super-light and flexible materials, due to these capabilities already present in polyester-neoprene combination used in modern blimps. It would instead be designed with "hinges" in its wings to allow for it to change it's shape at different altitudes.
I wish I could illustrate it, but it'd look something like a combination of this:

And this:

Obviously the shape of the wing would have to be optimized for that perfect volume to lift ratio, but that's all manageable, and we won't even need those "hinges" I was talking about.

I wish I could illustrate this better, but I suck at drawing let alone 3D modelling. Maybe you could take this as a little side project, who knows what'll come of it?.

Funny how I had started to think about a similar idea right after your original post on the blimps

 

[Moon]

@JamD
I'd like to add further to this thread with context of this development:

Lasers to Extend the Missions of Solar Powered Drones - Defense Update:

Laser beams are used for numerous applications and when associated with unmanned aerial systems are most likely used as drone killers. But under a new research supported by the US Defense Advanced Programs Research Agency (DARPA), lasers are used as a consistent power source for drones. DARPA...

defense-update.com

Basically, lasers based on the ground could effectively be used to charge the photovoltaic cells on the HAPs.
We could essentially increase the endurance of the craft many times over using this technique.
Having "charging" lasers on the ground to give the HAPs an extra boost, especially during emergency conditions. Meaning longer missions thus more capable. Furthermore, HAPs could carry a more energy hungry module for the same amount of time, by balancing it's charging and discharging times.

Secondly I was giving @Bilal Khan (Quwa) 's comments about using the HAPs as a means of dispensing ECMs.... Which has me thinking along the lines of Electronic Warfare, especially SIGINT is the context of terrorism... See, a HAPs equipped with a "listening" module can be flown, to detect anomalous radio frequencies, for eg: someone using a SATCOM phone from the middle of nowhere in Balochistan, that ought to raise eyebrows.... Or if the module can be powerful enough to listen to handheld radios, or GPS signals from mobile phones. If these signals can be correlated with their timings and locations, it'd be a major intelligence win.

 

[Bilal Khan (Quwa)]

@JamD
I'd like to add further to this thread with context of this development:

Lasers to Extend the Missions of Solar Powered Drones - Defense Update:

Laser beams are used for numerous applications and when associated with unmanned aerial systems are most likely used as drone killers. But under a new research supported by the US Defense Advanced Programs Research Agency (DARPA), lasers are used as a consistent power source for drones. DARPA...

defense-update.com

Basically, lasers based on the ground could effectively be used to charge the photovoltaic cells on the HAPs.
We could essentially increase the endurance of the craft many times over using this technique.
Having "charging" lasers on the ground to give the HAPs an extra boost, especially during emergency conditions. Meaning longer missions thus more capable. Furthermore, HAPs could carry a more energy hungry module for the same amount of time, by balancing it's charging and discharging times.

Secondly I was giving @Bilal Khan (Quwa) 's comments about using the HAPs as a means of dispensing ECMs.... Which has me thinking along the lines of Electronic Warfare, especially SIGINT is the context of terrorism... See, a HAPs equipped with a "listening" module can be flown, to detect anomalous radio frequencies, for eg: someone using a SATCOM phone from the middle of nowhere in Balochistan, that ought to raise eyebrows.... Or if the module can be powerful enough to listen to handheld radios, or GPS signals from mobile phones. If these signals can be correlated with their timings and locations, it'd be a major intelligence win.

That is an excellent idea IMO.

 

[JamD]

@JamD
I'd like to add further to this thread with context of this development:

Lasers to Extend the Missions of Solar Powered Drones - Defense Update:

Laser beams are used for numerous applications and when associated with unmanned aerial systems are most likely used as drone killers. But under a new research supported by the US Defense Advanced Programs Research Agency (DARPA), lasers are used as a consistent power source for drones. DARPA...

defense-update.com

Basically, lasers based on the ground could effectively be used to charge the photovoltaic cells on the HAPs.
We could essentially increase the endurance of the craft many times over using this technique.
Having "charging" lasers on the ground to give the HAPs an extra boost, especially during emergency conditions. Meaning longer missions thus more capable. Furthermore, HAPs could carry a more energy hungry module for the same amount of time, by balancing it's charging and discharging times.

Good idea. Most tech we end up discussing is somewhere at technology readiness level 2-4 so they need time and resources for development.

Perhaps a hybrid scheme (https://www.aerosociety.com/media/5962/3-hybrid-power-in-light-aircraft.pdf) might be feasible for some HAPS aircraft applications. One would have to do a design study to see if its even feasible or not. Might be a fun concept to explore and relatively low-tech (compared to ground or space based lasers).

@JamD
Secondly I was giving @Bilal Khan (Quwa) 's comments about using the HAPs as a means of dispensing ECMs.... Which has me thinking along the lines of Electronic Warfare, especially SIGINT is the context of terrorism... See, a HAPs equipped with a "listening" module can be flown, to detect anomalous radio frequencies, for eg: someone using a SATCOM phone from the middle of nowhere in Balochistan, that ought to raise eyebrows.... Or if the module can be powerful enough to listen to handheld radios, or GPS signals from mobile phones. If these signals can be correlated with their timings and locations, it'd be a major intelligence win.

Hmm...That is a good application. I wonder how power hungry passive systems like that are.