Catch up on stories from the past week (and beyond) at the Slashdot story archive

 



Forgot your password?
typodupeerror
Earth Space Communications Technology

SpaceX Launches Super-Heavy Satellite Atop Falcon 9 Rocket (usatoday.com) 85

SpaceX has successfully launched a heavy commercial communications satellite atop one of its Falcon 9 rockets today. "Weighing in at nearly 13,500 pounds atop the rocket, the fourth Inmarsat-5 satellite was the heaviest load lofted by a Falcon 9 yet," reports USA Today. From the report: The 230-foot rocket delivered the spacecraft larger than a double-decker bus to an orbit more than 22,000 miles over the equator. As a result, SpaceX did not attempt to land the rocket's first stage either at Cape Canaveral or at sea, and the Falcon 9 booster was not equipped with landing legs. The Inmarsat-5 Flight 4 satellite, built by Boeing, completes Inmarsat's four-satellite Global Xpress constellation focused on delivering high-speed broadband data to mobile customers, including commercial aircraft and ships and the U.S. military.

SpaceX Launches Super-Heavy Satellite Atop Falcon 9 Rocket

Comments Filter:
  • by Anonymous Coward on Tuesday May 16, 2017 @02:05AM (#54424417)

    Heaviest to GTO, not heaviest overall. They've lofted bigger loads to low earth orbit. Iridium flight was over 9 tons. All Dragon missions to ISS (Dragon + Trunk + all the stuff inside and mounted in the trunk) are also heavier than this sat was.

    But different orbits, so this is legit heaviest satellite to this specific orbit.

  • The 230-foot rocket delivered the spacecraft larger than a double-decker bus to an orbit more than 22,000 miles over the equator.

    Could someone please convert that to football fields? ;)

    • by dbIII ( 701233 )
      Here you go:
      http://www.convertunits.com/fr... [convertunits.com]
      The joke has got so old that someone has knocked up a conversion script for miles to football fields.
      Also the payload is around the mass of seven and a half Volkswagen Beetles.
      Libraries of Congress? I've got nothing.
      • LoC/sec is a good BW measurement.

        Based on Boeing’s BSS-702HP satellite platform, each weighs in at around 6,100 Kilograms and hosts 89 Ka-Band transponders, supporting high user download speeds of 50Mbps and uplink of 5Mbps.

        and

        “A TB, or terabyte, is about 1.05 million MB. All the data in the American Library of Congress amounts to 15 TB.”

        So:
        download aggregate (50MB+89 transponders)/15TB == 0.000296666667 LoC/sec download and 1/10th that in upload.

    • Over in the UK we prefer to use El Reg Standard Units [theregister.co.uk], for length it's Linquine, Double-decker bus or Brontosaurus.

      So, 22,000 miles is the equivalent [theregister.co.uk] of 1.61 mega-brontosauruses, which I think everyone can agree is much simpler to envisage.

    • by feargal ( 99776 ) on Tuesday May 16, 2017 @04:16AM (#54424741) Homepage

      A football field is a unit of area, not distance. However, since we know a mile is eight furlongs, there's five furlongs to a kilometer, and approximately forty-five and a half brontosauruses per kilometer, we can quickly do the maths:

      22,000 * 8 / 5 * 45.5 gives us an approximate distance of 1,601,600 apatosauruses. And since we know five brontosauses can be laid along the length of a football field we can correct the sentence from the article.

      The 500-linguine rocket delivered the spacecraft larger than 237,000 grapefruits to an orbit higher than 320,320 football fields if they placed vertically end-to-end over the equator.

      • Shouldn't the football field be measured corner to opposite corner though? That's how all the cool kids measure screens
        • by feargal ( 99776 )

          You wouldn't be able to stack them vertically on that axis though, so it wouldn't be a useful measurement to give. You're right however, I should have at least specified that they were standard 340' football fields.

    • by wbr1 ( 2538558 )
      Football fields is an incompatible unit. Just request freedom units and let the neckbeards figure it out.
    • Did you want CFL or NFL? There's a big difference in the length between the two with the CFL field being longer.

  • I was just wondering it says that they wouldn't attempt recovery of the first stage because the payload was so heavy, 13,400 lbs and it was to GTO orbit. That sort of indicates that the Falcon 9 is maxed out at that weight. But then if you look at the Wikipedia page it says that the max weight to GTO is actually a lot more, 18,300 lb.
    So, what gives? Is Wikipedia wrong?

    • 18,300 lbs is the maximum payload it can deliver to GTO if they don't try a recovery. If they wan't to recover the 1st stage the maximum payload is 10,690 lbs.
    • Re:Why no recovery? (Score:5, Informative)

      by Ost99 ( 101831 ) on Tuesday May 16, 2017 @07:06AM (#54425117)
      The limit for recoverability for GTO missions depends on weight and the exact orbit.
      A 5300kg (~11600lbs) GTO payload mission has been flown with recovery, wikipedia lists 5500kg as max (perhaps a bit optimistic) for reusable and 8300kg for expendable.

      With the same ~33% penalty in payload weight for a recoverable mission, the 5300kg reusable mission could have been a 8000kg expendable mission.
      In other words, the 6070kg mission flown yesterday was in just a bit over reusable weight and the in the lower end of expandable mode.
      • Right, so they could have made their satellite a lot heavier with at extra cost

        • I mean, they could have made their satellite a lot heavier at no extra cost

          • by Ost99 ( 101831 )
            Probably.
            But the satellite was ordered in october 2013 and was built to the same specifications as the previous 3, ordered in 2010. It's not something they could or would change based on the improved performance of Falcon 9 (F9 1.2 FT).

            I think the satellite was booked on Falcon Heavy (FH), but the delay of FH and the improvements to F9 1.2 made it possible to launch as F9 expendable.
          • Not really. Although the bulk of the cost of launching is the cost of the Stages the cost of the fuel is not insignificant
  • That's 6123.5 kilograms for people who are thinking straight.
  • Regardless of the bit rate, there's considerable latency with a geosynchronous orbit. Radio waves travel around 186,000 miles/second, meaning a round trip to the satellite is 1/4 of a second. If you're typing in ssh, double that. Press a key, half a second later the letter appears. If you click a link that has to hit a server, same thing - 1/2 second of overhead. The way some web pages are made those half seconds are going to stack up.

    I know there are plenty of places where the latency won't matter, but

    • I know there are plenty of places where the latency won't matter, but geosynch satellites will never have widespread usage for internet.

      I could see a mode where geosynch does the heavy lifting while other low latency & low bandwidth methods do the SSH and other low latency stuff.

      Imagine browsing the Netflix list while on a LEO sat, and then when you click on the movie, the stream comes from a high-bandwidth, high latency GEO sat.

      If that happens, then geosynch satellites may have a very high usage for Internet, in terms of bits moved.

    • Radio waves travel around 186,000 miles/second, meaning a round trip to the satellite is 1/4 of a second. If you're typing in ssh, double that. Press a key, half a second later the letter appears. If you click a link that has to hit a server, same thing - 1/2 second of overhead

      So it's the world's highest Comcast simulator?

    • by Ranbot ( 2648297 )

      ...there's considerable latency with a geosynchronous orbit. ...The way some web pages are made those half seconds are going to stack up.... geosynch satellites will never have widespread usage for internet.

      Yes, but their commercial and military customers probably do not allow users surf the web like normal folks.

      The Inmarsat-5 Flight 4 satellite... focused on delivering high-speed broadband data to mobile customers, including commercial aircraft and ships and the U.S. military.

      And for those customers half second delays are probably really fast compared to the alternatives.

    • As the satellites are by coincident nearly exactly 1/10 of a light second away, the round trip is 2/10 of a second and not 1/4th. But well, that is close enough :D probably 1/4th is actually a tick closer than 2/10th, to lazy to do the correct math.

      • As the satellites are by coincident nearly exactly 1/10 of a light second away, the round trip is 2/10 of a second and not 1/4th. But well, that is close enough :D probably 1/4th is actually a tick closer than 2/10th, to lazy to do the correct math.

        Light travels at 186,000 miles per second. 22,000 x 2 = 44,000. 44,000 x 4 = 176,000. 44,000 / 186,000 = .236. It's closer to 1/4 than 2/10.

        That's the actual math.

        • I was more thinking about the fact that it seems people actually have to look up those numbers instead of simply memorizing the moon is roughly 1/3rd of a light second farer away than one second and a GSO is roughly 1/10th of a light second away from earth. I would be already happy if they would say the moon is about one light second away.
          And that has obviously nothing to do with metric versus imperial ...

  • "You can go anywhere in world, and you’re still our customer,” said Pearce. “And you can do it on the move.”

    wat

Life is difficult because it is non-linear.

Working...