Defense against Hypersonic Glide Vehicles

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Report to Congress on Hypersonic Missile Defense - USNI News

The following is the Jan. 24, 2023, Congressional Research Service In Focus report, Hypersonic Missile Defense: Issues for Congress. From the report The Missile Defense Agency (MDA) and Space Development Agency (SDA) are currently developing elements of a hypersonic missile defense system to...
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La Commission européenne envisage un second projet d'intercepteur d'armes hypersoniques, cette fois confié à MBDA - Zone Militaire

Chef de file du programme européen qui, financé par l'Union européenne au titre de la Coopération structurée permanente , vise à développer un système de
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The European Commission is considering a second hypersonic weapons interceptor project, this time entrusted to MBDA​

Leader of the European program [Timely Warning and Interception with Space-based Theater surveillance] which, financed by the European Union [EU] under the Permanent Structured Cooperation [CSP or PESCO], aims to develop a defense system against hypersonic missiles, MBDA France had all the cards in hand to be appointed coordinator of another related project, namely the European Hypersonic Defense Interceptor [EU HYDEF]. Especially since the industrialist had just launched his interceptor missile project, called AQUILA
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www.spacewar.com

Space Development Agency to launch 10 satellites

Washington DC (SPX) Mar 31, 2023 - SpaceX launched 10 Space Development Agency satellites into orbit from Vandenberg Space Force Base in California Sunday in the Tranche 0 mission.
www.spacewar.com

Following tomorrow's launch, those first ten satellites - eight of which are "transport layer" satellites and two of which are "tracking layer" satellites - will undergo calibration and their efficacy will also be evaluated with a series of tests.
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I’m impressed with how quickly they fielded this system (test satellites but still). There have been so many starts and stops with the early warning constellations over the past few decades. SDA seems to have determined a viable path forward.
 
"designed to shoot down hypersonic missiles before they begin the high-speed maneuvers that make them hard to engage, according to a senior MDA official."

"As the name suggests, the GPI program is aimed at knocking down hypersonic missiles during the glide phase of flight when the hypersonic warhead is skimming space before it reenters the atmosphere (wtf?) — the longest phase of flight between launch and “terminal” phase."

Well something doesn't add up. It's called GLIDE phase intercept but the target doesn't "glide" in space. Hell, it may never even reach space. The BGRV didn't. It flew 5000nm all well within the atmosphere.
 
sferrin said:
"designed to shoot down hypersonic missiles before they begin the high-speed maneuvers that make them hard to engage, according to a senior MDA official."

"As the name suggests, the GPI program is aimed at knocking down hypersonic missiles during the glide phase of flight when the hypersonic warhead is skimming space before it reenters the atmosphere (wtf?) — the longest phase of flight between launch and “terminal” phase."

Well something doesn't add up. It's called GLIDE phase intercept but the target doesn't "glide" in space. Hell, it may never even reach space. The BGRV didn't. It flew 5000nm all well within the atmosphere.
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It still has a boost phase though. Hit the booster before separation but you won't do that with an interceptor.

Not a lot of sense made because a non-glide phase interceptor can hit it in space.
 
I think it’s just poor phrasing on the writers part. I’m assuming that DoD thinks boost gliders will hold a steady course and speed because to do otherwise reduces the speed and range of the glider.
 
Josh_TN said:
I think it’s just poor phrasing on the writers part. I’m assuming that DoD thinks boost gliders will hold a steady course and speed because to do otherwise reduces the speed and range of the glider.
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The thing with these HGVs and MaRVs is that they don't necessarily know when to manoeuvre. A HGV doesn't necessarily know an interceptor is about to hit it unless it's kitted out with a full EW suite. Is that likely?
 
Forest Green said:
sferrin said:
"designed to shoot down hypersonic missiles before they begin the high-speed maneuvers that make them hard to engage, according to a senior MDA official."

"As the name suggests, the GPI program is aimed at knocking down hypersonic missiles during the glide phase of flight when the hypersonic warhead is skimming space before it reenters the atmosphere (wtf?) — the longest phase of flight between launch and “terminal” phase."

Well something doesn't add up. It's called GLIDE phase intercept but the target doesn't "glide" in space. Hell, it may never even reach space. The BGRV didn't. It flew 5000nm all well within the atmosphere.
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It still has a boost phase though. Hit the booster before separation but you won't do that with an interceptor.

Not a lot of sense made because a non-glide phase interceptor can hit it in space.
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BGRV PEAKED at 130,000ft. A glider never needs to go to space.


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sferrin said:
BGRV PEAKED at 130,000ft. A glider never needs to go to space.


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Have to say, the range surprises me, because Atlas had a range of <8000nm even on a minimum energy trajectory, but nonetheless the GPI article made no sense. With HGVs, more and more the solution seems to come back to lasers. You would need some space based assets plus some ground based assets as a back up, along with a relay mirror system in case an enemy tries to use their own ground-based laser to damage your space-based ones.
 
Forest Green said:
Josh_TN said:
I think it’s just poor phrasing on the writers part. I’m assuming that DoD thinks boost gliders will hold a steady course and speed because to do otherwise reduces the speed and range of the glider.
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The thing with these HGVs and MaRVs is that they don't necessarily know when to manoeuvre. A HGV doesn't necessarily know an interceptor is about to hit it unless it's kitted out with a full EW suite. Is that likely?
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Oh definitely, and moreover I assume the drag penalties for maneuvering earlier in flight increase in a non linear fashion. The glider would have to be preset to start taking evasive maneuvers while roughly maintaining a baseline course to the target to make GPI engagements more difficult-which is going to penalize range and speed. To some extent I think GPI is an effort to decrease range or force the incoming out of the hypersonic envelope for easier terminal engagement as much as actually achieve kills.

I read an article about the 2017 CPS test that indicated the glider traveled 2200 miles in under 30 minutes- though I can no longer find any source to quote for those numbers. When did the math I think that was roughly an average of Mach 6. Given the logarithmic rate of deceleration, that probably means a massive double digit Mach initial speed and quite possibly a merely highly supersonic (<mach5) terminal impact. Forcing gliders to maneuver early in flight could greatly reduce performance envelope to make other defenses much more effective. Also there might be upper limits to maneuvering at all during the earliest phases of flight, depending on the glider.
 
Forest Green said:
sferrin said:
BGRV PEAKED at 130,000ft. A glider never needs to go to space.


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Have to say, the range surprises me, because Atlas had a range of <8000nm even on a minimum energy trajectory, but nonetheless the GPI article made no sense. With HGVs, more and more the solution seems to come back to lasers. You would need some space based assets plus some ground based assets as a back up, along with a relay mirror system in case an enemy tries to use their own ground-based laser to damage your space-based ones.
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The RV Atlas achieved 8000nm+ with was likely lighter than BGRV also it was traveling in space with little to no friction. BGRV would have been fighting drag so much it would have been glowing the entire way. That takes energy.

As for relay mirrors they were an important consideration, even back in the SDI days, to reduce the number of required lasers. Not only could you bounce off the relay mirror it could be used to refocus the laser.

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www.daviddarling.info

RME

RME (Relay Mirror Experiment) was launched as a dual payload with LACE and carried defense experiments.
www.daviddarling.info
 
Yes, typically you would have a relay mirror in a very high orbit and targeting mirror in a low earth orbit.
 
Josh_TN said:
Oh definitely, and moreover I assume the drag penalties for maneuvering earlier in flight increase in a non linear fashion. The glider would have to be preset to start taking evasive maneuvers while roughly maintaining a baseline course to the target to make GPI engagements more difficult-which is going to penalize range and speed. To some extent I think GPI is an effort to decrease range or force the incoming out of the hypersonic envelope for easier terminal engagement as much as actually achieve kills.

I read an article about the 2017 CPS test that indicated the glider traveled 2200 miles in under 30 minutes- though I can no longer find any source to quote for those numbers. When did the math I think that was roughly an average of Mach 6. Given the logarithmic rate of deceleration, that probably means a massive double digit Mach initial speed and quite possibly a merely highly supersonic (<mach5) terminal impact. Forcing gliders to maneuver early in flight could greatly reduce performance envelope to make other defenses much more effective. Also there might be upper limits to maneuvering at all during the earliest phases of flight, depending on the glider.
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And, after a while of degrading its speed and hence performance, it becomes an easier target for interceptors.
 
DOD wanting to develop new X-band radars for domestic defense against hypersonic? cruise missiles.
Though X-band due to its shorter waveband gives better definition than the recent years overwhelming choice of the longer waveband S-band as in the Navy's Air and Missile Defense Radar SPY-6, Patriot's Lower Tier Air and Missile Defense Sensor, the BMD Alaskan Long Range Discrimination Radar and the SPY-7 radar for the two 20,000t Japanese Aegis destroyers, so surprised at choice of X-band.
The big plus of S-band is its much lower cost, long range X-band radars much more expensive as the THAAD radar the quarter $billion X-band TPY-2 said to use 25,344 transmit/receive modules to populate its 100 sq ft array whereas it would only require 600 the S-band transmit/receive modules to populate a 100 sq ft array as used in the SPY-6.
Question what was the driver that caused the change to pick a X-band radar with its higher discrimination to justify its much higher cost for the new radar.
https://insidedefense.com/daily-news/dod-seeking-fy-24-funding-develop-prototype-x-band-domestic-cruise-missile-defense-radar
 
Article (in German) with a bunch of detail on the Diehl IRIS-T derivative for the EU HYDEF projects. Interesting details include a multi-spectral (IR/RF) seeker and a possible air-breathing lower stage.
 

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edwest4 said:
So... there is a missile... uh, HGV defense gap which means hundreds of defensive warheads need to be built. Good news for Defense Contractors.

Regarding irrational actors, something along the lines of, "You do X and we blow up your country." should help.
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By definition, irrational actors are not deterred by that. They will do what they will do, and the consequences of those actions do not matter.

"Try it, and we destroy everything you value" just doesn't work when they don't care.
 
Forest Green said:
kocovgoce said:
and why don't they shoot down these hypersonic rockets in the final flight somewhere at a height of 10 km, something similar to using multiple rocket launchers in order to create a cloud of explosion and shrapnel?
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If it was possible to build a large, ground-based, solid-state phased array laser in the same form as many missile defence radars, then that would be an extremely effective terminal defence. It would need serious power, but being ground-based weight/size wouldn't be an issue.
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It's theoretically possible, but the problem is that a phased array requires emitter elements to be spaced 1/4 wavelength apart. And, I believe that's 1/4 wavelength center to center, not edge to edge, but I don't have enough references to figure that out.

With radio waves, even high frequencies like X-band, that's not hard to do. X-band has a wavelength of around 3cm, so the emitter elements are 0.75cm apart. Simple enough.

But light frequencies? 2400nm deep IR lasers means your emitters have to be 600nm apart. 0.0006 Millimeters. That is one hell of an engineering challenge! This only gets worse with less attenuated light frequencies like green (500-570nm, 125-142.5nm 1/4 wave distance) or blue (450-500nm, 112.5-125nm 1/4 wave distance).

Also, I don't know if it'd be possible to have emitters spaced X+0.25 wavelengths apart and the system still work. If it is, that would partially solve the packing issue, but very likely at a severe performance and efficiency penalty.

It may actually be better to take a step back in laser development and use a microwave phased array. That's a roughly 1cm wavelength and a 0.25cm array spacing. That would be trivial to make.

Edit: I stand corrected. While it is a pain in the butt to do, there is open literature of a DARPA team having made a functional phased array LIDAR chip! And it isn't severely hampered by larger spacing of emitters on the chip, either. Thank you, Forest Green
 
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Scott Kenny said:
It's theoretically possible, but the problem is that a phased array requires emitter elements to be spaced 1/4 wavelength apart. And, I believe that's 1/4 wavelength center to center, not edge to edge, but I don't have enough references to figure that out.

With radio waves, even high frequencies like X-band, that's not hard to do. X-band has a wavelength of around 3cm, so the emitter elements are 0.75cm apart. Simple enough.

But light frequencies? 2400nm deep IR lasers means your emitters have to be 600nm apart. 0.0006 Millimeters. That is one hell of an engineering challenge! This only gets worse with less attenuated light frequencies like green (500-570nm, 125-142.5nm 1/4 wave distance) or blue (450-500nm, 112.5-125nm 1/4 wave distance).

Also, I don't know if it'd be possible to have emitters spaced X+0.25 wavelengths apart and the system still work. If it is, that would partially solve the packing issue, but very likely at a severe performance and efficiency penalty.

It may actually be better to take a step back in laser development and use a microwave phased array. That's a roughly 1cm wavelength and a 0.25cm array spacing. That would be trivial to make.
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Forest Green said:
Scott Kenny said:
It's theoretically possible, but the problem is that a phased array requires emitter elements to be spaced 1/4 wavelength apart. And, I believe that's 1/4 wavelength center to center, not edge to edge, but I don't have enough references to figure that out.

With radio waves, even high frequencies like X-band, that's not hard to do. X-band has a wavelength of around 3cm, so the emitter elements are 0.75cm apart. Simple enough.

But light frequencies? 2400nm deep IR lasers means your emitters have to be 600nm apart. 0.0006 Millimeters. That is one hell of an engineering challenge! This only gets worse with less attenuated light frequencies like green (500-570nm, 125-142.5nm 1/4 wave distance) or blue (450-500nm, 112.5-125nm 1/4 wave distance).

Also, I don't know if it'd be possible to have emitters spaced X+0.25 wavelengths apart and the system still work. If it is, that would partially solve the packing issue, but very likely at a severe performance and efficiency penalty.

It may actually be better to take a step back in laser development and use a microwave phased array. That's a roughly 1cm wavelength and a 0.25cm array spacing. That would be trivial to make.
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PDF No Longer Available.
 
Scott Kenny said:
works, and holy cow they got a working phased array LIDAR!!!

I was not expecting that to be done yet.
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Yes, and now with phased array LIDAR, the high efficiencies of fibre lasers/metastable rare gas lasers and super lightweight nuclear reactors, like those of USNC, there is the opportunity for a game changing weapon as regards missile defence that also has many other uses.
 

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