Can Cubesats Make Existing Anti-Satellite Systems Obsolete?

[Jonfliesgoats]

As image and other processing improves along with propulsion we can get more capabilities into smaller satellites.  It seems a nation or company can launch swarms of cubesats to have redundant reconnaisance and communications capabilities.  Meanwhile anti-satellite systems remain expensive.

More satellites can be launched than can be knocked out, so, at best, existing anti-satellite systems can offer only a marginal degradation in a nation's's sensing capabilities.

Does this new era in low cost, miniature satellites require a paradigm shift in anti-satellite approaches?

Do we need to launch formations of cheap, defensive satellites whose sole purpose is to disable other satellites?  

Do we need orbital lasers, like SDI?

Questions regarding cubesat propulsion and maneuvering capability arise in this scenario.  What options exist for packing enough Delta v into those wee satellites?

Imagine lots of these things aimed at Earth rather than Alpha Centauri.

http://www.space.com/34340-project-blue-alpha-centauri-earthlike-alien-planet.html

Of course, it may be easier to mass produce missiles than satellites, so perhaps my math is out of whack?

History of ASAT capabilities:

http://www.globalsecurity.org/space/systems/asat-overview.htm

http://www.ucsusa.org/nuclear-weapons/space-security/a-history-of-anti-satellite-programs#.WFvc2bROKhA

Edited December 22, 2016 by Jonfliesgoats

[Nibb31]

Imaging relies on optics, and you can't beat the laws of physics when it comes to focal length and aperture. You simply can't fit decent optics into a cubesat. 

The same is pretty much true for power and antennas. Miniature satellites can only carry limited power,  which limits transmission capabilities. 

 

[Jonfliesgoats]

Yeah, I am aware of the issues regarding optics.  There are certainly limits imposed based on wavelength and photons.  Still you can also be surprised by the powers of miniaturization and creativity.  One program I was on developed a sensor array for airplanes that fit in a fairing about the size of a canoe.  It was so big, we had to move a separate, optical sensor to a different location on the plane.  It became a hassle, but the new sensor could get a lot more information faster with more accuracy.  A year later, ingenious modification to the antennae allowed the same sensor to fit into blister the size of a shoe box.  Antennae, for example, don't have to be rigid.  A small inflatable or reel can allow a LOT of antenna geometry and size to get loaded into a very small package.  We can spitball ideas on solving these engineering challenges in another thread, because that actually sounds kind of fun!

While knocking out larger objects would certainly degrade information resolution (be it IMINT or SIGINT) enough baseline reconnaissance capability can be pulled from cubesats to justify their use.  

How do you knock down swarms of satellites?

 

All I can think of are directed energy weapons or swarms countering swarms.

Directed energy weapons need to be solid state, if they are orbital or surface/airborne chemical lasers.

Swarms need a lot of Delta v packed into small packages.  Perhaps electromotive tethers?

[Elthy]

Just with MIRVs (and additional decoys) it will be cheaper to lauch new cubesats up than to shoot them down. But, as stated by Nibb31 cubesats arent that usefull for military applications, so there isnt much reason to even try it.

[Jonfliesgoats]

The alpha Centauri thing is .5meters.  I brought it up as an example of miniaturization coming and promptly mixed it up with cubesat telescope missions in my head.  I am announcing my error there.

You know, I was just looking at some cubesat telescope missions.  I think those will have military applications in the  near future.  Here's an example of one: 

http://www.jpl.nasa.gov/cubesat/missions/asteria.php

There is another proposal for two cubesats in formation to address focal length issues.

[kerbiloid]

1. And then 20 Mt bursts in ionosphere, and all souvenir sats burn out, as they can't be protected. And communication is lost with survivors.

2. Plane optics range is 10-100 km. Satelite orbit is at least 200. Visible detail size limit ~ distance * wavelength / optics diameter. Tens meters for cubesat.

3. The more nodes in sat network - the more effort to coordinate them (at least because light delay, and also due to the Earth shadowing at least a half of network).

Spoiler

Unless you mean

 

 

Edited December 22, 2016 by kerbiloid

[_Augustus_]

On 12/22/2016 at 9:18 AM, Nibb31 said:

you can't beat the laws of physics when it comes to focal length

Ever heard of a Cassegrain?

[YNM]

1 hour ago, _Augustus_ said:

On 12/22/2016 at 9:18 PM, Nibb31 said:

Imaging relies on optics, and you can't beat the laws of physics when it comes to focal length and aperture.

Ever heard of a Cassegrain?

Resolving power depends purely on apperture, there's no way to fold that one. (Also, Cassegrain and such suffers from less collecting area - hence slightly less sensitivity. Unless we're talking about Ritchey-Cheretien, which is a witch.)

[Jonfliesgoats]

Speaking of which I think one of the KSP players here lives near this Ritchey Cheretien (sic) telescope:

https://en.m.wikipedia.org/wiki/Gran_Telescopio_Canarias

Edited December 28, 2016 by Jonfliesgoats

[_Augustus_]

10 hours ago, YNM said:

Resolving power depends purely on apperture, there's no way to fold that one. (Also, Cassegrain and such suffers from less collecting area - hence slightly less sensitivity. Unless we're talking about Ritchey-Cheretien, which is a witch.)

Ritchey-Chretien is actually worse in terms of central obstruction - a typical Cass has around 35% central obstruction, RCs have 40-50% sometimes.

[YNM]

I suppose they can actually get the whole focus distance changed or something ? Maybe... the light geometry could be changed with mirrors with different eccentricity ? (definitely I have no idea about what I'm talking here, I haven't get it for hyperbolic mirrors.)

[Green Baron]

13 hours ago, Jonfliesgoats said:

Speaking of which I think one of the KSP players here lives near this Ritchey Cheretien (sic) telescope:

https://en.m.wikipedia.org/wiki/Gran_Telescopio_Canarias

I do :-) Anyone else ? *curiouslylookingaround*

RC is simply a type (one of the Cassegrain-types, that are those who reflect the rays back through the main mirror instead of out at the side like Nasmyths or Newtonians) where two curved mirrors are combined in a way to reduce coma and aberrations in the picture's field, that is away from the optical axis.

Most of the large telescopes are RCs because they combine an easy handling of the weight involved and offer a basically corrected field. Most have several focus points (2*Nasmyth, 1 Cassegrain-style) for a whole lot of different instruments, cameras, spectrometers, sensor phalanx, that sort of things :-)).

Of course one wants to have as little optical elements as possible, the usual way of building long focal ratios is by folding the rays multiple times. I don't know how many mirrors the GTC has (at least three) to get to its focal length of 170m. Diameter of the central obstruction is a construction element. It makes the image a little darker, but it must obstruct 50% to cost one focal ratio unit ....

Oh, btw., the new E-ELT will have a focal ration of 0.9. I don't know about the TMT, but probably something alike ...

 

Edited December 28, 2016 by Green Baron