Category Archives: Space

Cassini’s last images have been taken

Cassini took its last pictures, including a stirring set of images showing Enceladus off the limb of Saturn, and has been downlinking them to Earth.  JPL is putting them up as quickly as possible.  The main communications currently are still through the big Mars antenna at Goldstone, but the big dish at Canberra has started to pick up the carrier signal and will soon take over the task of talking to Cassini; that dish will be dedicated to Cassini for the remainder of the mission.  Around midnight here in Central Daylight Time, Cassini will pass the orbit of Enceladus and begin moving once more into the domain of the ring system.  Finally, at 5:32 CDT, Cassini is expected to lose its lock on Earth due to excessive aerodynamic forces, and at 6:55 CDT, the signal received on Earth will cut off.  It will be over.

But it will not be soon forgotten.


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Cassini: just a little over a day left

The Cassini spacecraft has just one day and eight hours left to live, and after thirteen years in Saturn orbit, it’s hard not to feel a little choked up thinking about it.  I just rewatched this animation, and I gotta admit . . . it got awfully dusty in here . . . .

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The next crew is on its way to the ISS!

Soyuz MS-06 launched today!  And actually, by the time I’m writing this, they’re at the ISS, docked and preparing to board.  Here’s the spectacular nighttime launch from Baikonur Cosmodrome:

On board are Alexander Misurkin, Mark Vande Hei, Joe Acaba.  They are expected to stay in space until late February.

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Cassini’s “Goodbye Kiss” of Titan is complete

One step closer to the bittersweet end of a magnificent mission….  Cassini said goodbye to Titan today, where its companion, the Huygens probe, rests permanently.  There was a final sequence of images taken, which have now been downlinked to Earth.  Here’s one of the raw images in the sequence, this one taken through the CL1 and CB3 filters, which allows it to peer a bit through the smog to make out a hazy glimpse of Titan’s surface features:

Goodbye, Titan….I hope we visit again soon.  😉

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Proton-M places Amazonas-5 into orbit for Hispasat

A Proton-M made by Khrunichev and sold by International Launch Services placed the Amazonas-5 communications satellite into geosynchronous transfer orbit.   The flight originated at Baikonur Cosmodrome, which won’t have time to relax; they’re pressing towards the launch of Soyuz MS-06 with the next ISS crew late tomorrow/early Wednesday.

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Cassini’s on the home stretch — the last periapse is complete

Cassini’s final orbit is underway.  Yesterday, Cassini made its final (survivable) dip into Saturn’s atmosphere, completing its final periapse.    Sixteen hours from now, it will encounter Titan for one last time.  This will not be a close flyby, but it will be close enough to feel Titan’s gravity, which is the point of the exercise — Titan’s gravity will give the spacecraft a little nudge, transforming the next close approach into a kamikaze plunge.  Here’s a brief timeline of Cassini’s last few days, from the mission website (times given in UTC, which is used for spacecraft time, and in PDT, since the mission is run out of JPL in California):

September 11, 12:04 PM PDT (19:04 UTC) – the “goodbye kiss”, as Cassini passes 119,049 km from Titan

September 11, 10:27 PM PDT (September 12, 05:27 UTC) – final apoapsis, 1.3 million km from Saturn

September 12, 4:56 PM PDT (23:56 UTC) – final Titan data downlink begins

September 12, 6:19 PM PDT (September 13, 01:19 UTC) – signal from Titan data downlink reaches Earth

September 14, 12:38 PM PDT (18:38 UTC) – Cassini takes its last picture

September 14, 1:22 PM PDT (20:22 UTC) – Cassini slews its main antenna to Earth to begin the final downlink of data from its recorder; this data stream will be continuous until the end of the mission

September 14, 2:45 PM PDT (21:45 UTC) – signal from the final transmission begins reaching Earth

September 14, 8:15 PM PDT (September 15, 03:15 UTC) – Canberra, one of the three Deep Space Network sites, begins receiving the signal; Canberra will be the last station to receive signals from Cassini

September 14, 10:08 PM PDT (September 15, 05:15 UTC) – Cassini passes the orbit of Enceladus for the last time

September 15, 12:14 AM PDT (07:15 UTC) – Cassini rolls to allow its instruments to allow its INMS instrument to sample particles.  Spacecraft also configures itself for real-time data transmission; no more data will be stored in the recorder

September 15, 12:22 am PDT (07:22 UTC) – Cassini passes the distance of the F-ring for the last time

September 15, 1:37 AM PDT (08:37 UTC) – Cassini’s real-time data stream begins to reach Earth

September 15, 3:31 AM PDT (10:31 UTC) – Cassini begins to enter the atmosphere, with thrusters firing at 10% to maintain signal lock on Earth

September 15, 3:32 AM PDT (10:32 UTC) – Cassini will increase thruster firing to maintain lock until 100% capacity is reached; at that point, it will no longer be able to maintain the lock, and signal will be lost

September 15, 4:54 AM PDT (11:54 UTC) – Canberra receives the signals indicating that Cassini has reached the atmosphere and is firing its thrusters

September 15, 4:55 AM PDT (11:55 UTC) – Cassini’s signal stops being received; end of mission.

At this point, Cassini will have spent nearly 20 years in space, and conducted an impressive 293 orbits of Saturn.  It’s one of the most impressive and capable space probes we’ve ever sent out into the cosmos.  It’s bittersweet to think of its demise in this way, but nothing lasts forever, and at least Cassini is getting to go out with a bang, collecting some priceless data that could not be obtained any other way.

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X-37 dodges Hurricane Irma aboard a Falcon 9

Today was the scheduled liftoff day for the fifth X-37 mission (OTV-5), and the first aboard a Falcon 9.  (X-37 was designed from the start to be compatible with almost any launch vehicle, including the Space Shuttle, but its first four launches were all aboard the Atlas V.)  As a bonus, since SpaceX is still unable to use their original Florida launchpad, Cape Canaveral Air Station’s SLC-40, this launch used the pad they’re adapting for Falcon Heavy, Kennedy Space Center’s venerable LC-39A.  So LC-39A got to launch another spaceplane after all.  😉  (LC-39A’s last spaceplane launch was STS-135, the final flight of the Space Shuttle program, just over six years ago.)

Coverage of the ascent stops with first stage separation, as normal for classified flights*, but since this was Falcon 9, we got to see coverage of the first stage continue all the way to touchdown back at the Cape.  Now, SpaceX gets to scramble to safe it and stash it safely in a hangar in advance of Hurricane Irma.

*X-37 is not a classified spacecraft, but its missions are generally classified.  This one does carry one unclassified payload, the Advanced Structurally Embedded Thermal Spreader, for the Air Force Research Laboratory.  It will “test experimental electronics and oscillating heat pipe technologies in the long duration space environment”.  Satellites already use heat pipe technology to draw waste heat away from sensitive electronic components (since obviously fans don’t work for cooling a spacecraft computer), but this new technology will be lighter and cheaper.  All the other payloads, as well as their quantity and the target orbit and any planned maneuvers, remain classified.  But they are probably also experimental technologies, since X-37 offers a unique opportunity to test equipment for a long duration in space and recover it for extensive engineering analysis afterwards.

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