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DARPA's ALASA Could Pave Way For Cheaper, Faster Satellite Launches
hypnosec writes DARPA is all set to take its Airborne Launch Assist Space Access module (ALASA) program to the next level after the program has shown promising results toward its mission of sending 100-pound satellites into low Earth orbit (LEO) for just $1 million per launch."
ALASA is a new program that seeks to streamline production and encourage re-usability and interchangeability in satellite systems.
From your link:
Failures of the 21-meter wingspan, multi-lobe composite material fuel cells during pressure testing ultimately led to its cancellation as a federal program in 2001. Lockheed Martin has conducted unrelated testing, and has had a single success after a string of failures as recently as 2009 using a 2 meter scale model
A 2-meter scale model of a suborbital craft doesn't sound like we're close to SSTO at all.
The F-18 has a big advantage because it can go a lot faster. Besides, it makes sense to first solve the problems on a smaller and cheaper platform.
First, it is an F-15E, not a F-18. The primary reason for the choice is the fact that there are no modifications needed to be used in this role (not even software - the rocket will use the same protocols that the typically mounted weapons systems use). This means that the aircraft can continue to be used in their primary role instead of having to be specialized just for this role.
As for why this project is not looking a larger launch platform - the project is specifically trying to make it easier to get small satellites into orbit (normally today these type of satellites are launched piggybacked onto larger launches - meaning they have to wait for one to be launching in an area that is useful for them). Many launch platforms today are actually cheaper per lb in getting things into orbit - but because they have to have much bigger payloads to reach those efficiencies you can wind up having to wait for a scheduled launch that may mean waiting as much as a year to get a satellite launched (compared to a possible 24 hour turn-around with this system)
I don't understand why the idea is being implemented in such a modest manner. The animation has the rocket stage carried aloft for ignition at high altitude by what looks like an F-18. While I don't doubt the performance of the Hornet's engines, wouldn't it make more sense to extend the payload capacity with a larger carrier craft? Say something on the order of the 747-based shuttle carriers?
Absolute ceiling on a Boeing 747 is ~51,000 feet. That's about the service ceiling for most military jets, and their absolute ceiling is much hgher than that. The SR-71 Blackbird had a service ceiling of ~92,000 feet; its absolute ceiling remains classified.
That's 5,000 feet under the service ceiling of the F-14; A Mig-25 on a ballistic arc (after its air-breathing engines were no longer functioning, it was ballistic until it reentered the atmosphere) is recorded to have hit 123,000 feet in 1977. The ballistic arc on an F-18 should be substantially better than that, but I suspect if you want actual numbers, they are classified.
The point is that the first part of getting up there is the hardest, and military and military-grade airgraft are substantially better at getting up higher because they can reach a higher altitude, and can be going multiple Mach at the time they go ballistic (think "muzzle velocity").
So no, a commercial jet is a bad idea.
> You are aware that mentally ill people and drug addicts are always going to spend whatever cash they are given
You have obviously no clue.
The single biggest reason is can you see some rich person buying a used one, like John Travolta bought a used 707, and deciding to take a planeload of ceramic coated rebar to orbit and drop it on peoples heads at 22,000 MPH?
Someone could do a lot more damage just by crashing the 707. For that matter, a 1 meter length of #8 rebar is about 4 kilograms, so, at 22,000 MPH would have about 193 MJ of kinetic energy, if it actually reached the ground with the same amount of energy it had before de-orbiting (which would be ridiculous). That's about 8% more than the equivalent mass of gasoline (and, once again, by the time it reaches the surface, it would be a lot less). Of course, gasoline gets to cheat on the energy density factor by using oxygen. You could argue that it's only fair to compare it to something where the energy is entirely self-contained. That's not really valid since the final destination is inside the atmosphere, but we'll give you that one anyway. We'll consider methane, which requires twice its mass in oxygen to combust. That ends up giving it 38.26% of the theoretical maximum of your de-orbiting rebar pieces by mass.
In other words, someone could do a lot more damage just by dropping various sorts of conventional bombs from a 707. Or from a smaller plane for that matter. Or going on foot. Heck, probably just by running around and beating random people with a piece of rebar considering how unlikely it is for the orbitally delivered rebar to both retain significant energy and actually hit a target.
The "rods from god" concept (usually considered with a much larger projectile of the densest practical materials rather than relatively light projectiles prone to tremendous drag like pieces of rebar) is easily shown to be not worthwhile (if you're launching the projectiles from earth with chemical rockets anyway) compared to just about any method of blowing things up. Any physicist or decent engineer with a napkin and a ball point pen can demonstrate it pretty easily. For some reason, the idea keeps coming up.
You are aware that mentally ill people and drug addicts are always going to spend whatever cash they are given, and remain homeless, right?
You are aware that you're both mischaracterizing what was said and that you're spouting nonsense, right? The GP didn't say "throw money at mentally ill and drug-addicted homeless people".
Ad you realize that poverty is defined as a certain percentage of the population at the bottom end of the bell curve, right?
Not legally it's not. Economics... life in general, in fact, isn't the kind of zero-sum game you seem to be implying it is. Poverty is defined by a number of guidelines. There are a number of factors. Whether the subject actually has adequate nutrition is an important one. Under those guidelines, 16% of Americans and 20% of American children live in poverty.
And you're aware that basic health care is already fixed, and was before the ACA, sincethe hospitals are legally required to treat you if you present at the ER, right?
What idiot/liar keeps spreading this load of nonsense around? Hospitals are legally required to _stabilize_ you! That means that, if you show up dying of something acute, they have to take you in, but can kick you out the door the moment you're not in critical condition anymore. If you show up, for example, with a terminal case of cancer, they don't have to treat, or even diagnose your cancer. If you have immediate, life-threatening symptoms, they have to provide some treatment for those symptoms. In a practical sense, it pretty much just means that they have to provide a bed for you to die in when you're ready to drop. I'm not sure they're even legally required to provide painkillers for someone dying in excruciating pain. The laws you're talking about are basically just to stop people dropping dead in the ER, and they don't even manage to stop that from happening sometimes.
What exactly makes you think that a F18, designed to go 1.5 Mach, would be able to go higher than a Mach 3 Mig25, designed to counter the SR-71?
Much like for the pentagon's ASAT missilefrom the 80's, the best available US platform would be an F15.
Democracy is a sheep and two wolves deciding what to have for lunch. Freedom is a well armed sheep contesting the issue
This doesn't make a dent in cost effectiveness of Falcon 9 or PSLV.
Let us calculate per pound LEO costs for these vehicles:
ALASA: $1M / 100 lb = $10,000 / lb
Falcon 9: $61.2M / 28,991 lb = $2,111 / lb
PSLV: $20M / 7170 lb = $2,789 / lb
Tiny satellites at 100lb can easily tag along with bigger launches on these vehicles. Costs may be even cheaper for such secondary payloads or may even free in some cases. If SpaceX succeeds in first stage reuse, or ISRO per chance succeeds in RLV-TD plans, costs may come further down.
So ALASA sounds like a costly option for small satellites today and in future. But the technology as such may have potential if handled by a better managed private company that works on it as a commercial venture.
Hey, we have all this hardware and software laying idle, why not do a cost reduction exercise and sell the effing thingie in the commercial market?
Seriously tough, I have to wonder if the Chinese, Russians and all the other minions (Iran, North Korea) are not thinking this is a brilliant disguise to be able to deploy an extensive Anti Satellite system.
"If a boss demands loyalty, give him integrity. But if he demands integrity, give him loyalty." (John Boyd, 1927-1997)