General Space Mission Thread

[r.soleofsalford]

18 hours surely?

think Damocles is using dog years

 

[Damocles]

18 hours surely?

It does, one of those stupid mistakes that happens when you're doing a couple of sums at the same time on different objects. 14 months was the communications time to the edge of the Oort Cloud but I'm, starting to think I better recheck that now

 

[Damocles]

http://www.dlr.de/dlr/en/desktopdefault.aspx/tabid-10081/151_read-14019/#/gallery/311

Contact with Philae still irregular and unstable

Despite a new trajectory for Rosetta and a reduction of the distance between the orbiter and Comet 67P/Churyumov-Gerasimenko from 200 to 180 kilometres, contact with the Philae lander remains irregular and short. After the initial contact on 13 June 2015, Philae has reported to the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) Lander Control Center (LCC) in Cologne a total of six times. However, for the last three possibilities calculated for establishing a connection with Philae, no data could be received. "Right now, we are playing with the geometry between the Rosetta orbiter and the Philae lander," says DLR's Philae Project Manager, Stephan Ulamec. "The most recent contact – on 24 June 2015 – lasted 20 minutes; then, the line went dead again." Now, the DLR and ESA mission teams are analysing which measures will make better contact with Philae possible.

Communication needs sunlight

Comet 67P/Churyumov-Gerasimenko has a rotation period of 12.4 hours, so a contact should be possible approximately twice per Earth day during an overflight by the Rosetta orbiter. But several conditions must be met before Philae can communicate with Rosetta and its control room in Darmstadt, and then with the LCC. Firstly, Philae must be in operation, and this can only happen when there is sufficient solar illumination for its solar panels to generate the necessary power. In addition, the antennas on the lander and the orbiter must be aligned. The performance of Philae’s antennas is partially affected by objects in the nearby and fairly harsh environment. Also, the Rosetta orbiter needs to align its antenna as closely as possible towards the comet.

Caution on active comets

The Rosetta team has to take other factors into consideration during their flight planning. The increasingly active Comet 67P/Churyumov-Gerasimenko ejects gas and dust particles into space. This already caused a problem in March 2015, when the star trackers on the orbiter incorrectly interpreted dust particles as stars and was unable to determine the orientation of the orbiter. At that time, Rosetta automatically transitioned into 'safe mode' and moved away from the comet; only then could it be controlled by commands from the ground again. For this reason, a closer approach to 67P/Churyumov-Gerasimenko has to take place gradually and under constant observation to confirm whether the orbiter remains unaffected. The trajectory of the orbiter is currently considered to be in a non-hazardous environment for comet outgassing. Rosetta is flying a 'terminator orbit' along the day-night boundary of the comet and passes over Philae in the comet's early morning; at this time, the lander is on – but only just. "At this point, the lander is not optimally illuminated by the Sun," says Ulamec. Overflights at other times on the comet have not been carried out since Philae awoke from hibernation.

Intermittent contacts

Having the orbiter move 20 kilometres closer to the comet does not seem to have improved matters. "There have been multiple contacts during which Philae has sent us information about its status, but these connections were unstable," explains Ulamec. On 19 June, the LCC in Cologne received two two-minute-long connections within 19 minutes. On 20 June, there were again two connections, each of which lasted about one minute. On 23 June, Philae made a 20-second transmission but did not send any data. During the most recent contact on 24 June, the connection lasted 20 minutes but was not stable, so Philae sent a total of 80 data packets. Between contacts, there have been multiple calculated contact times when no connection has been established. Even during the last three overflights by Rosetta – at an altitude of 180 kilometres – there was no contact.

On Saturday, ESA will begin new manoeuvres, which will move the Rosetta orbiter 20 kilometres closer to the comet's surface and Philae by 30 June 2015. The team at the DLR control centre hopes that contact with Philae at a distance of 160 kilometres will then be regular and stable. The next few days will show whether changes in the geometry between the lander and orbiter improves communication with Philae.

Dependent on long and predictable contacts

One possible reason for the lander's current silence could be a failure of Philae's communications equipment caused by poor conditions during hibernation. Analysis of the data received so far by the team at DLR has shown that while one of the communications units is compromised, the other unit has worked thus far without problems. "To continue conducting scientific work with Philae, we rely on long and predictable contact times," says Ulamec. Once Philae can receive and execute extensive command sequences safely, store the measurement data and send it to the ground team, its 10 instruments will be operated again.

The mission

Rosetta is an ESA mission with contributions from its Member States and NASA. Rosetta's Philae lander is contributed by a consortium led by DLR, MPS, CNES and ASI.

Unfortunate news regarding Philae from the DLR.

For the more techie out there, Philae's data packets have a size of about 140 16-bit WORDs so even for 20 of them we're talking about 6kb of data. That's about the size of a decent length forum post. The last transfer said:

TCM_MUPUS_DD 24.06.2015 17:38:43 -46.63°C TCM_PB_H4 7.05°C

Which are just the current operating temps for MUPUS and the Thermal Control Module Power Board. It has ~8000 stored up waiting to send, mostly housekeeping but also scientific data from the comet and getting that precious data off is now the top priority. Poor Philae.

With that said, I saw a few days ago that the Rosetta mission had received extra funding for another year after the increased visibility over other missions so hopefully they will work it out.

 

[Damocles]

OSIRIS-REx just had its first instrument successful installed which is a bit of a milestone for that team. Osiris is a mission launching 2017 (?) by NASA to be the first time they are going to land on an asteroid, mine some samples then bring them back to Earth so that they can be experimented on in labs.

Not the awe inspiring fun of Philae or New Horizons but it's extremely important in the space industry as there is literally trillions of pounds at stake for the first people to start mining asteroids, so the very vague first steps in that direction and the lessons that people will learn more from the mission in general could kickstart many commercial enterprises.

Mine is an exaggeration really, more that they are blowing up a bit of the surface then collecting the fragments by sucking them in. Video of the TAGSAM equipment here

http://www.asteroidmission.org/videos/acquisition_sim.webm

 

[Damocles]

SpaceX wasting millions of dollars of essential equipment there. SpaceX are a private company founded by PayPal founder Elon Musk and have a contract from NASA to build rockets and deliver cargo to the ISS. They've done alright so far.

Rocket was unmanned

 

[Damocles]

 

[allan harper]

The coast looks clear for a NASA spacecraft's historic Pluto flyby less than two weeks from now.

The New Horizons probe has spotted no signs of rings or additional moons in the Pluto system, so the spacecraft will remain on its original trajectory when it zooms past the dwarf planet on July 14, NASA officials announced Wednesday (July 2).

"Not finding new moons or rings present is a bit of a scientific surprise to most of us," New Horizons principal investigator Alan Stern, of the Southwest Research Institute in Boulder, Colorado, said in a statement

But as a result, no engine burn is needed to steer clear of potential hazards," Stern added. "We presented these data to NASA for review and received approval to proceed on course and plan. We are 'go' for the best of our planned Pluto encounter trajectories.

 

[aguero93:20]

Now what we really need is to have a lab that assembles these satellites in Low Earth Orbit like the ISS then we'd not really be too bothered about a single launch cost and could spread it over many trips.

Money's not there for it I'm afraid. Times are hard and cuts have to be made.

*drives away in Rolls Royce*

 

[Damocles]

Money's not there for it I'm afraid. Times are hard and cuts have to be made.

*drives away in Rolls Royce*

This video puts an emotional but rather convincing case for people who suggest there isn't enough money in the US system (or any system) for space funding.

 

[1.618034]

5 Million Miles from Pluto

Image Credit: NASA, Johns Hopkins Univ./APL, Southwest Research Inst.

Explanation: An image snapped on July 7 by the New Horizons spacecraft while just under 5 million miles (8 million kilometers) from Pluto is combined with color data in this most detailed view yet of the Solar System's most famous world about to be explored. The region imaged includes the tip of an elongated dark area along Pluto's equator already dubbed "the whale". A bright heart-shaped region on the right is about 1,200 miles (2,000) kilometers across, possibly covered with a frost of frozen methane, nitrogen, and/or carbon monoxide. The view is centered near the area that will be seen during New Horizons much anticipated July 14 closest approach to a distance of about 7,750 miles (12,500 kilometers).