European Rosetta Space Craft About To Rendezvous With Comet

Taco Cowboy (5327) writes After a long 10-year journey spanning some four (4) billion kilometers, Rosetta, an interplanetary space craft from the ESA (European Space Agency), is on its final approach to comet Comet 67P (or comet Churyumov-Gerasimenko). The last in a series of 10 thruster firings over the past few months has slowed Rosetta to the pace of a person walking, about two miles per hour relative to the speed of its target at a distance of about 60 miles. Photographs have already revealed a surprisingly irregular shape for the 2.5-mile-wide comet, possibly an amalgamation of two icy bodies or a result of uneven weathering during previous flybys. From a distance, the blurry blob initially looked somewhat like a rubber duck. As the details came into the focus, it now more resembles a knob of ginger flying through space. Wednesday marks a big moment for space exploration: After a few thruster rockets fire for a little over six minutes, Rosetta will be in position to make the first-ever rendezvous with that comet nickname 'Rubber Duck.' 'This burn, expected to start at 11 a.m. central European time, will tip Rosetta into the first leg of a series of triangular paths around the comet, according to the Paris-based European Space Agency, or ESA, which oversees the mission. Each leg will be about 100 kilometers (62 miles) long, and it will take Rosetta between three to four days to complete each leg. There will be a live streaming webcast of Rosetta's Aug. 6 orbital arrival starting at 8 a.m. GMT via a transmission from ESA's spacecraft operations centre in Darmstadt, Germany. Also at the BBC.

Comments

Be sure to watch the live event

[Trapezium Artist]

Our live webcast will be at www.esa.int starting at 10:00 CEST / 08:00 UT. Should be some cool new pictures of the comet to see.

(Disclaimer: I'll be one of the speakers :-)

Re:Be sure to watch the live event

[PolygamousRanchKid]

(Disclaimer: I'll be one of the speakers :-)

. . . will you be speaking live, from the spacecraft?

That would surely impress the finicky crowd here. And make us all jealous!

Re:Be sure to watch the live event

[Trapezium Artist]

Ha ;-) From the live event at ESA's mission control centre in Darmstadt.

That said, there are some colleagues I tried to have volunteer to go ...

Re:Be sure to watch the live event

[Sockatume]

That was great! I didn't realise that there was an AFM on the probe to actually image sample particles. And the 3D printed model was a fantastic visual aid. Do you think that the 3D printer instructions for the comet will be shared?

Re:Be sure to watch the live event

[gstoddart]

(Disclaimer: I'll be one of the speakers :-)

Then, on behalf of the rest of us, thanks for the continuing awesomeness of space exploration. :-P

Hope the Kerbals are safe

[able1234au]

Two miles per hour is much slower than i can get my Kerbal space ships. Of course, in that you are flying by the seat of your pants and another space ship is just a few clicks away. Still, it gives you a bit of an appreciation of what they have achieved with Rosetta.

The ESA video stream URL is

[atom1c]

The URL is http://www.livestream.com/euro...

I'm actually surprised that the post/summary doesn't include it (except for the incidental embedded version in the one article linked).

Re:The ESA video stream URL is

[Sockatume]

Also at http://rosetta.esa.int/

Why aren't space pictures better?

[Bryan Ischo]

I have always wondered why the photographs that come back from space are so grainy/blurry and have poor color reproduction. Why aren't the images clearer? Why don't we get to see movies instead of just crummy looking stills?

There *must* be a reason that they can't make photos that come from space exploration better or include full color videos so that we can see what these things would look like if we were really there.

I can only posit that either the radiation hardening necessary for space exploration somehow precludes the use of large CCD/CMOS sensors, or the bandwidth limitation of sending data from that far out makes anything other than tiny images with low resolution possible, and makes video impossible.

But still I can't help wondering why, if they can spend tens of millions to put these things up there, they can't produce better images for whatever millions are left over for on board equipment.

Re:Why aren't space pictures better?

[ghighi]

I imagine that, given the price of sending any payload to space, fitting a real color, high res sensor of little scientific value must not be a priority. That being said we had some pretty bad ass shot from curiosity havn't we?

Re:Why aren't space pictures better?

[Calinous]

There are severe limits on sending antenna size and power use on the craft. They use a 2.2 meters diameter dish (seven feet), with 850W electric power from solar panels to transmit from a distance about one hundred thousand times greater than geostationary TV satellites.
      It's like the difference between whispering at someone's ear (half and inch away) and shouting for someone a mile away. I can't think of a car analogy on five orders of magnitude, but I'm sure someone will be more inspired

Re:Why aren't space pictures better?

[Anonymous Coward]

In Rosetta's case, the OSIRIS cameras (one narrow angle, one wide angle) have a resolution 2048x2048. You have to remember Rosetta was launched in 2004, and I would guess the spacecraft hardware was finalized sometime before 2000. 4MP is actually a pretty good resolution for a digital camera from that era - for example the first consumer 4MP camera was the SONY DSC-S85 from 2001. OSIRIS has a whole load of filters it can use (see http://www.planetary.org/explore/resource-library/data/rosetta-osiris.html) which are mostly designed for science (e.g. looking for specific molecules), but do include separate RGB filters on the narrow angle camera, so colour images should be possible.

Re:Why aren't space pictures better?

[bruce_the_loon]

Also, in addition to the bandwidth and generation of equipment involved, consider the range from Rosetta to the comet when the photos were taken.

One of the photos includes a |---2km---| scale marker. That means the camera is a bit further out than a studio photographer and distance reduces both the image size and amount of light reaching the camera.

Also, the amount of light at the comet location is lower than in a photographic studio, so longer exposures are needed which increase the effect of craft shake and sensor noise.

Re:Why aren't space pictures better?

[allcoolnameswheretak]

It's like the difference between silently swearing at the idiot in the car right in front of you and honking in a traffic jam at some idiot a mile away.

Re:Why aren't space pictures better?

[iktos]

If we were really there, the comet would look black, black, black and more black. And the shadows would be slightly, but probably imperceptibly, darker. The images are extremely enhanced to exagerrate the tiny variations of deep black.

The question of colour is interesting. Space probe cameras don't have RGB sensors, they're monochrome with lots and lots of switchable filters for specific purposes, like seeing seeing specific gases like nitrogen monohydride or a mineral like orthopyroxene, and many are in UV or IR. It's a bonus if the science lets you make more or less true colour images too.

The resolution will be much better when the probe gets close to the nucleus as the narrow field camera won't be able to see all of it at once. What I've seen so far seems to be only part of the full frame.

Science presentations 11:00 UTC

[coastwalker]

The live broadcast has been fairly interesting so far, they actually allowed a scientist pointing at a water spectrum graph to be broadcast. This is almost like being back in the 70's when they treated the audience as if they had done high school and were actually interested.

I do hope they put some of this up on Youtube

Where is Rosetta?

[skastrik]

Here it is ... http://sci.esa.int/where_is_ro...
Roughly 23 light minutes away.