So basically, somebody at DARPA read Dale Brown's 'Skymasters' a dozen years ago, and is no trying to implement the idea.

Need to convert exec jets, other to carry rockets into skies for launch, otherwise Minimum cost, awesome idea. radical.

Nice idea, but the landing gear has to be able to retract and come out again, somehow overlooked in the artistic video.

Ummm no. All we need is a guy with a small plane and someday every orbiting sat will be toast.

Wings and under carriage are still being debated, even as the space shuttle era proved its capabilities.
The operational X 37B has wings that allow better cross range, not to mention quick adjustments during final approach.
Wings + powered approach is an unbeatable concept.
Great idea to be able to land on existing infrastructure around the world.

Nice concept but 100 lbs is extremely light. Swiss are developing a system to launch from an A300 and a mini shuttle (returnable) on board. They are claiming 551 lbs payload capability.

Wow, that F-15 was contracted in 1932, or are we going to start buying them in 2032?

The Pegasus rocket built by Orbital Sciences Corp. launches satellites into Earth orbit after it is dropped from a conventional aircraft. It's been doing that since 1990. http://en.wikipedia.org/wiki/Pegasus_(rocket)
The ALASA appears to be a smaller implementation of that existing technology.

"The initial launch price offered was US$6 million, without options or a HAPS (Hydrazine Auxiliary Propulsion System) maneuvering stage. With the enlargement to Pegasus XL, prices increased. At the same time, many improvements were made in the wake of early launch failures, requiring more money. In addition, customers usually purchase additional services, such as extra testing, design and analysis, and launch-site support. A launch package is then approximately US$30 million in total. Some customers also have OSC provide mission hardware, up to a fully functional spacecraft such as a Microstar. Such packages can be much higher in cost."
Mass: 18,500 kg (Pegasus), 23,130 kg (Pegasus XL) Length: 16.9 m (Pegasus), 17.6 m (Pegasus XL) Diameter: 1.27 m Wing span: 6.7 m Payload: 443 kg (1.18 m diameter, 2.13 m length)
Aimed at reducing costs to US$1 million per launch, its (ALASA) designed to be ready to launch at 24 hours' notice and carry payloads of up to 100-lb (45-kg) into orbit.
"We’ve made good progress so far toward ALASA’s ambitious goal of propelling 100-pound satellites into low Earth orbit (LEO) within 24 hours of call-up, all for less than $1 million per launch,” says Tousley.
~1/8 the payload at 1/30 the cost.

For those of you saying this will never work, this was essentially done over 30 years ago, during the anti-satellite program the Air Force was testing before Congress killed it. Back then, the goal was to get a kinetic kill warhead into space to destroy satellites, and initial tests were successful. Now DARPA wants to launch satellites instead of destroying them. Essentially the same technology with the same target altitude. Both ideas even use the F-15 for the launch vehicle since it's one of the few aircraft that can go supersonic almost straight up.
And for those trying to be snarky about the landing gear, the F-15 main gear pivot forward, not inward toward the centerline. ALASA isn't much bigger than a standard F-15 center-mounted external fuel tank.