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Well, kudos to NASA but also kudos to ISRO for taking the initiative in making satellite launches more cost effective.
I'm not sure where the India reference came from? The EU and Japan both operate smaller launchers. A couple of startups are getting close to their first launch, too.
Orbital ATK has been building and launching the Pegasus XL ( https://www.orbitalatk.com/flight-systems/space-launch-vehic... ) for a bit now. It is an extremely cheap platform that is launched from an airplane. What's neat is the User Manual is available online: https://www.orbitalatk.com/flight-systems/space-launch-vehic... [pdf]
Part of that is due to its extremely low launch rate -- this was the first launch since 2013 -- but still.
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It's a lot easier to get up to speed if you don't have to deal with cutting through a heavy chunk of atmosphere on the way up. Plus, rocket designs could vary, be less concerned about aerodynamics, if they were starting from a launch platform already in very thin air. A wider, shorter rocket might work better in thin air, for example, but that would be impractical launching from sea-level as is tradition.
I have this dream that someday we'll build a SR-710 that's 10x the size and carry a BIG payload. And then putting stuff into orbit will basically be strapping your thing to a "big" upper stage (but small relative to a whole rocket stack), loading it into the cargo bay and then some fancy flying. I know it'll never happen for a variety of reasons. But it's such a cool plane and when you think about cruising at mach 3…
Lifting a rocket that high before firing it carries another benefit besides the (small) altitude gain and lower fuel requirements due to drag: Max Q, the maximum dynamic pressure that has to be sustained by the rocket usually happens at a lower altitude than that (depending on the mission). This means your rocket has to sustain a far lower structural load, making it safer and lighter.
The thing is because all rockets follow the same trajectory to orbit, The gravity curve. So you hit similar speeds at similar altitudes. If you don't, you either aren't making it to orbit, or you're wasting fuel.
This is because the gravity curve is a straight line if you ask Einstein, just earth's gravity makes space-time look wibbly-wobbly.
Newton calls this the derivative of the balastic arc.
There isn't a magical trajectory to orbit that is cheaper.
Lifting a rocket that high before firing it carries another benefit besides the (small) altitude gain and lower fuel requirements due to drag: Max Q, the maximum dynamic pressure that has to be sustained by the rocket usually happens at a lower altitude than that (depending on the mission). This means your rocket has to sustain a far lower structural load, making it safer and lighter.
The overall benefits of the platform are questionable, at best, especially considering its absurd launch cost.
I worked on the software for the star trackers in these. Glad to hear they have already made contact. :-)
Can you tell us some more? What the software is, what language, what hardware they're based on, etc.?
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I can't get my head around how this thing works. Apart from the direct GPS signal it's able to also receive the part of it that was reflected by the ocean? How does the reflected signal tell anything about the wind speed? And btw what are star trackers used for? As a fallback for GPS?
IIRC, star trackers are used as both a position and an attitude reference. GPS gives you only position (though more sophisticated systems can be used to determine attitude). While a GPS outage is a minor inconvenience for most of us, it could be pretty catastrophic for spacecraft if they didn't have another position reference. EDIT: See below - I was off; they're just attitude, not position
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Can you tell us some more? What the software is, what language, what hardware they're based on, etc.?
It's a LEON CPU (SPARC architecture) with a FPGA for hardware acceleration. Languages are C, MATLAB, and VHDL. The function is to take a picture of stars and return where you are pointed in inertial space with lots of accuracy.
Lifting a rocket that high before firing it carries another benefit besides the (small) altitude gain and lower fuel requirements due to drag: Max Q, the maximum dynamic pressure that has to be sustained by the rocket usually happens at a lower altitude than that (depending on the mission). This means your rocket has to sustain a far lower structural load, making it safer and lighter.
Lighter? I'm not so sure. Most of the reduced mass has to be added back in again for Pegasus to have aerodynamic control during stage 1 flight. The overall benefits of the platform are questionable, at best, especially considering its absurd launch cost.