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A plane being developed by Paul Allen could lower the cost of launching to low-Earth orbit:
Rockets have been the way to get satellites into orbit since the dawn of the space age. But Microsoft co-founder Paul Allen hopes to shake that up with help from the world's biggest airplane.
"Stratolaunch" is a 500,000-pound beast with twin fuselages and a wingspan of 385 feet. Allen's Seattle-based company is developing it as a platform for lifting rockets into the stratosphere before launching them into space. It's seen as a cheaper, more reliable route to low-Earth orbit (LEO) — the sweet spot for many kinds of satellites.
The plane is still in development and has yet to fly, but last December it taxied out onto the runway at the Mojave Air & Space Port in Mojave, California. In another test last Sunday, it hit a new top taxi speed of 46 miles per hour [40 knots]. If all goes according to plan, the plane will take its first test flight next year. As to when Stratolaunch might begin commercial operations, no date has been given.
Twitter video of rollout.
Also at Flying Magazine.
Previously: Stratolaunch: The World's Largest Plane Rolls Out
(Score: 4, Informative) by frojack on Friday March 02 2018, @06:21PM (3 children)
Its not meant to add speed.
Its meant to cut that portion of the rocket fuel needed to lift the rocket (and it's fuel) to the height where they actually light up that rocket.
Is the fuel that expensive? No, not really. But without lifting all of that fuel, the whole rocket doesn't need to be so big.
The big parts can be built into the airplane.
You can launch above certain types of weather. You can launch at any azimuth and lattitude you want.
No, you are mistaken. I've always had this sig.
(Score: 3, Interesting) by bob_super on Friday March 02 2018, @06:53PM
On the other hand, a typical uncrewed mission launchpad explosion is pretty easy to deal with: Mop up, straighten up the bent parts, add concrete here and there, and repaint.
Here, you have serious danger for any crew (don't believe this is a drone, yet) from the time you fuel up on the ground to the time you've released and separated by at least a km. That's a long time, and the rocket could be subjected to significant accelerations in the wrong axis, requiring some over-designing.
It's not a new risk, since USAF has done it many times with B-52s. But in a commercial enterprise and with bigger rockets, it's not a trivial danger to the whole operation.
(Score: 4, Interesting) by deimtee on Friday March 02 2018, @07:08PM (1 child)
That's the same thing really. It all converts to delta v.
5% of delta v plus another few % for launching from preferred lattitude plus a few % saving a lot of low altitude drag.
Due to the rocket equation a 10% reduction in required delta v is significant.
One way to calculate how useful it would be is to find its altitude and speed at rocket launch (call it Rich's figure of 0.3 km/s and altitude of 20 km), and find out how much of its fuel a ground based rocket has used by that point. I don't know the answer, but I would not be surprised by something on the order of 20 to 30%.
Everything in rocketry is so close to the edge of feasibility that it might be enough that you could cut a stage from the vehicle. Even if the remaining stage(s) have to be slightly bigger/better there could still be major savings in that.
(Hmm. just worked out that 20 km of altitude is about 0.5 km/s of delta v. The savings from a plane launch could be quite significant.)
If you cough while drinking cheap red wine it really cleans out your sinuses.
(Score: 2) by c0lo on Friday March 02 2018, @11:32PM
Wake up the Kerbals, they will know.
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford