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fork(2) [soylentnews.org] writes:

      Soylent News has carried articles about Juno, the NASA spacecraft headed for a rendezvous with Jupiter on July 4. Here [soylentnews.org], here [soylentnews.org], here [soylentnews.org], and here [soylentnews.org]. Among all the cool stuff about this, "as Juno nears Jupiter tonight, the giant planet's powerful gravity will accelerate the spacecraft to an estimated top speed of about 165,000 mph (265,000 km/h) relative to Earth, mission team members said."

      From Space.com [space.com],

"I don't think we've had any human[-made] object that's moved that fast, that's left the Earth," Juno principal investigator Scott Bolton, of the Southwest Research Institute in San Antonio, said during a news conference last week. [Juno's Plunge Into Jupiter Orbit Fraught With Danger (Video)] [space.com]

        The all-time speed record is currently held by NASA's Helios 1 and Helios 2 spacecraft, which launched in the mid-1970s to study the sun. Both probes reached top speeds of about 157,000 mph (253,000 km/h) at their points of closest approach to Earth's star.

      For perspective: Bullets cut through the air at about 1,700 mph (2,735 km/h), and the International Space Station zooms around Earth at 17,500 mph (28,160 mph).

      Indeed, Juno will be moving a bit too fast for its own good tonight. To slow down enough to be captured into Jupiter orbit, the probe must slam on the brakes, which it will do by firing its main engine for 35 minutes, beginning at 11:18 p.m. EDT (0318 GMT) tonight.

      Bolton said he's nervous about this make-or-break maneuver, which Juno will perform on autopilot.

      "If that doesn't all go just right, we fly past Jupiter," Bolton said. "Everything's riding on it."

      [...]

      If all goes according to plan tonight, Juno will enter into a 53.5-day orbit around Jupiter. The probe's handlers will then commission the probe's instruments and use them to study the giant planet over the next few months.

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