Stories
Slash Boxes
Comments

SoylentNews is people

posted by martyb on Friday March 02 2018, @09:32AM   Printer-friendly

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


Original Submission

 
This discussion has been archived. No new comments can be posted.
Display Options Threshold/Breakthrough Mark All as Read Mark All as Unread
The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
  • (Score: 2) by Rich on Friday March 02 2018, @04:40PM (7 children)

    by Rich (945) on Friday March 02 2018, @04:40PM (#646460) Journal

    LEO required speed is 7 to 8 km/s. The plane's speed will be at most 0.3 km/s, probably less with a rocket loaded. So we're talking about less than 5% improvement (including altitude, which iirc is pretty negligible in that context), which is why many don't think a plane launch is worth the effort. If they launch near the equator, they gain about another 0.5 km/s. Which is especially welcome if they don't have a spaceport there, like Arianespace does. Probably a more convincing argument than the gains vs. extra technical overhead.

    Sidenote: As this is Paul Allen, he might, starting small, rehearse a bit by adding the airplane/rocketcraft pairs "G4M with MXY7" and "B-29 with X-1" to his Flying Heritage Collection. Airworthy, of course. Warbird nerds would marvel at them :)

    Starting Score:    1  point
    Karma-Bonus Modifier   +1  

    Total Score:   2  
  • (Score: 1, Interesting) by Anonymous Coward on Friday March 02 2018, @05:44PM (2 children)

    by Anonymous Coward on Friday March 02 2018, @05:44PM (#646496)

    In a vacuum, yes, the additional speed and altitude are not significant. But it's not in a vacuum, literally. The atmospheric drag is a problem and this gets you over most of it.

    It also allows you to launch from exactly the right latitude, the equator is good for some things, other satellites want orbits where it's more convenient to launch from other latitudes.

    You might also launch from international over-water airspace to avoid pesky regulators and fees or possibly just to ensure that expended rocket debris lands where you want.

    Is it valuable enough to outweigh the additional cost and complexity of having the airplane? Well obviously not so far because no one has done it, but no one was landing expended first stages on the launch pad until recently either. So it's worth a shot.

    • (Score: 3, Informative) by frojack on Friday March 02 2018, @06:24PM (1 child)

      by frojack (1554) on Friday March 02 2018, @06:24PM (#646520) Journal

      Well obviously not so far because no one has done it,

      Seriously? No wonder you post AC.
      https://en.wikipedia.org/wiki/Scaled_Composites_White_Knight_Two [wikipedia.org]

      --
      No, you are mistaken. I've always had this sig.
      • (Score: 0) by Anonymous Coward on Saturday March 03 2018, @07:01AM

        by Anonymous Coward on Saturday March 03 2018, @07:01AM (#646910)

        Nobody has done it, orbital. Much, much harder than suborbital.

  • (Score: 4, Informative) by frojack on Friday March 02 2018, @06:21PM (3 children)

    by frojack (1554) on Friday March 02 2018, @06:21PM (#646516) Journal

    So we're talking about less than 5% improvement

    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

      by bob_super (1357) on Friday March 02 2018, @06:53PM (#646539)

      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)

      by deimtee (3272) on Friday March 02 2018, @07:08PM (#646550) Journal

      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

        by c0lo (156) Subscriber Badge on Friday March 02 2018, @11:32PM (#646700) Journal

        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%.

        Wake up the Kerbals, they will know.

        --
        https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford