Rosetta comet chaser completes "big burn"

MeteoritesEire

http://www.bbc.com/news/science-environment-27517090

Rosetta comet-chaser completes 'big burn'
By Jonathan Amos
BBC News
May 22, 2014

Europe's comet-chaser Rosetta has taken a big step towards making its
historic rendezvous with a 4km-wide ball of ice and rock in early August.

Controllers confirm the spacecraft conducted a major orbit manoeuvre on
Wednesday without incident.

The near-eight-hour thruster burn was designed to slow the satellite's
speed relative to Comet 67P/C-G.

More adjustments are required, but the operation was a significant event
in ensuring Rosetta meets its target.

The pair are roughly 500 million km from Earth and separated by about
a million km, and closing.

Wednesday's big burn was initiated at 15:23 GMT (16:23 BST; 17:23 CEST).
It was intended to take out a big chunk (almost 300m/s) of the velocity
Rosetta had (755m/s) with respect to 67P/Churyumov-Gerasimenko.

Engineers at the European Space Agency's (Esa) "mission control" in Darmstadt,
Germany, will have to examine in detail the telemetry they received from
the satellite but confirmed on Thursday that the manoeuvre was "completed
nominally".

"The thrusters and propulsion system overall performed very well, and
we had a nominal completion of the burn at 22:39 UTC (00:39 CEST Thursday),"
said Rosetta Spacecraft Operations Manager Sylvain Lodiot.

"It will take a few days for the flight dynamics team to analyse data
and determine the final actual change in speed, but it won't be too far
from what we planned," he told the mission blog.

There had been some concern prior to the burn that a leak in the system
used to pressurise the propellant tanks might result in uneven combustion,
but Paolo Ferri, who heads up the European Spacecraft Operations Centre
(Esoc), described Rosetta as having "very stable performance".

Comet 67P/C-G is travelling around the Sun on a big loop that takes it
out beyond the orbit of Jupiter and then back in to just inside the orbit
of Mars.

Rosetta is attempting to target its rendezvous at the start of the inward
curve, before our star can warm the icy object to trigger large jets of
gas and dust from its surface.

The mission goal is to orbit the comet, starting on 6 August, and then
follow the body in its orbit.

In November, an attempt will be made to put a small lander, called Philae,
on 67P's surface.

If all goes well, the mission should return some remarkable insights on
the behaviour and chemical make-up of its icy quarry.

Eight further burns are required to get Rosetta into position. The next
two, on 4 June and 18 June, are somewhat smaller than Wednesday's manoeuvre.

Yogosan

An Irish company had a part to play in this mission.

"McKenna-Lawlor, who studied experimental physics at University College Dublin and is a Professor Emeritus at NUI Maynooth, has been director of the company Space Technology Ireland Ltd (STIL) since it was set up in 1986. Since then STIL has built instrumentation launched by ESA, NASA and the Chinese, Indian and Russian Space Agencies.

For Rosetta, the company designed, constructed and tested the onboard Electrical Support System (ESS) processor unit, she explains, and when the Lander is on the comet, this system will play a key role in passing the streams of commands and data between the Rosetta spacecraft and the instruments on the Lander. "Since the success of the Lander depends on the successful acquisition of scientific data from the comet nucleus, the ESS is defined to be mission critical hardware," says McKenna-Lawlor."

MeteoritesEire

June 10, 2014

NASA Instruments Begin Science on European Spacecraft Set to Land on Comet

Three NASA science instruments aboard the European Space Agency's (ESA)
Rosetta spacecraft, which is set to become the first to orbit a comet and
land a probe on its nucleus, are beginning observations and sending science
data back to Earth.

Launched in March 2004, Rosetta was reactivated January 2014 after a record
957 days in hibernation. Composed of an orbiter and lander, Rosetta's
objective is to arrive at comet 67P/Churyumov-Gerasimenko in August to study
the celestial object up close in unprecedented detail and prepare for landing
a probe on the comet's nucleus in November.

Rosetta's lander will obtain the first images taken from a comet's
surface and will provide the first analysis of a comet's composition by
drilling into the surface. Rosetta also will be the first spacecraft to
witness at close proximity how a comet changes as it is subjected to the
increasing intensity of the sun's radiation. Observations will help
scientists learn more about the origin and evolution of our solar system and
the role comets may have played in seeding Earth with water, and perhaps even
life.

"We are happy to be seeing some real zeroes and ones coming down from our
instruments, and cannot wait to figure out what they are telling us," said
Claudia Alexander, Rosetta's U.S. project scientist at NASA's Jet Propulsion
Laboratory (JPL) in Pasadena, California. "Never before has a spacecraft
pulled up and parked next to a comet. That is what Rosetta will do, and we
are delighted to play a part in such a historic mission of exploration."

Rosetta currently is approaching the main asteroid belt located between
Jupiter and Mars,. The spacecraft is still about 300,000 miles (500,000
kilometers) from the comet, but in August the instruments will begin to map
its surface.

The three U.S. instruments aboard the spacecraft are the Microwave Instrument
for Rosetta Orbiter (MIRO), an ultraviolet spectrometer called Alice, and the
Ion and Electron Sensor (IES). They are part of a suite of 11 science
instruments aboard the Rosetta orbiter.

MIRO is designed to provide data on how gas and dust leave the surface of the
nucleus to form the coma and tail that gives comets their intrinsic beauty.
Studying the surface temperature and evolution of the coma and tail provides
information on how the comet evolves as it approaches and leaves the vicinity
of the sun.

Alice will analyze gases in the comet's coma, which is the bright envelope of
gas around the nucleus of the comet developed as a comet approaches the sun.
Alice also will measure the rate at which the comet produces water, carbon
monoxide and carbon dioxide. These measurements will provide valuable
information about the surface composition of the nucleus.

The instrument also will measure the amount of argon present, an important
clue about the temperature of the solar system at the time the comet's
nucleus originally formed more than 4.6 billion years ago.

IES is part of a suite of five instruments to analyze the plasma environment
of the comet, particularly the coma. The instrument will measure the charged
particles in the sun's outer atmosphere, or solar wind, as they interact with
the gas flowing out from the comet while Rosetta is drawing nearer to the
comet's nucleus.

NASA also provided part of the electronics package for the Double Focusing
Mass Spectrometer, which is part of the Swiss-built Rosetta Orbiter
Spectrometer for Ion and Neutral Analysis (ROSINA) instrument. ROSINA will be
the first instrument in space with sufficient resolution to be able to
distinguish between molecular nitrogen and carbon monoxide, two molecules
with approximately the same mass. Clear identification of nitrogen will help
scientists understand conditions at the time the solar system was formed.

U.S. scientists are partnering on several non-U.S. instruments and are
involved in seven of the mission's 21 instrument collaborations. NASA's Deep
Space Network (DSN) is supporting ESA's Ground Station Network for spacecraft
tracking and navigation.

Rosetta is an ESA mission with contributions from its member states and NASA.
Rosetta's Philae lander is provided by a consortium led by the German
Aerospace Center, Cologne; Max Planck Institute for Solar System Research,
Gottingen; French National Space Agency, Paris; and the Italian Space
Agency, Rome. JPL manages the U.S. contribution of the Rosetta mission for
NASA's Science Mission Directorate in Washington. JPL also built the MIRO and
hosts its principal investigator, Samuel Gulkis. The Southwest Research
Institute (San Antonio and Boulder), developed the Rosetta orbiter's IES and
Alice instruments, and hosts their principal investigators, James Burch (IES)
and Alan Stern (Alice).

For more information on the U.S. instruments aboard Rosetta, visit:

http://rosetta.jpl.nasa.gov

More information about Rosetta is available at:

http://www.esa.int/rosetta

For more information on the DSN, visit:

http://deepspace.jpl.nasa.gov/dsn

-end-

Dwayne Brown
Headquarters, Washington
202-358-1726
dwayne.c.br...@nasa.gov

DC Agle
Jet Propulsion Laboratory, Pasadena, Calif.
818-393-9011
a...@jpl.nasa.gov

Markus Bauer
European Space Agency, Noordwijk, Netherlands
011-31-71-565-6799
markus.ba...@esa.int

MeteoritesEire

http://blogs.esa.int/rosetta/2014/06/17/the-big-burns-part-3/

Rosetta
The Big Burns Part 3
June 17, 2014

It's burn week in space again!

On Wednesday, 18 June, Rosetta will conduct the third in a series of
three "Big Burns", which are themselves part of the ten-burn series of
orbit correction manoeuvres (OCMs) that are taking us to arrival at
comet 67P/C-G on 6 August.

We've dubbed these three the "Big Burns" because, well, they're big.

The first two, on 21 May and 4 June, used 218 kg and 190 kg of
propellant, respectively, and delivered a delta-v (change in velocity)
of 289.9 and 269.5 m/s, respectively.

Both delivered results to within just a few percent of the planed
delta-v, indicating that, so far, everything is working nominally with
the spacecraft's propulsion system, even though it is working well
outside its design range.

"The series of ten OCMs during May to August has to deliver a total of
about 775 m/s delta-v, and we've already achieved about three-quarters
of that," says Sylvain Lodiot, Rosetta Spacecraft Operations Manager.
"We continue monitoring all the OCMs very closely."

Thruster commands will execute automatically

The burn tomorrow is set to achieve a delta-v of 88.7 m/s and should run
for 136 mins: 41 secs; it gets under way at 15:17 CEST (13:17 UTC). The
burn will be commanded automatically by a series of commands that will
be uploaded on 17 June.

The manoeuvre will be conducted with ground station coverage provided by
ESA's 35m deep space station at New Norcia, Australia

Telemetry (status information from Rosetta's systems) will be monitored
in real-time; the radio signals must travel 24 min:22 sec to cover the
enormous distance from Rosetta, currently about 2.9 AU (434 million km)
from Earth.

[Graphic]
Rosetta OCM plan as of 17 June 2014. Note that future OCMs will be
adjusted based on the actual performance of past burns.

As with past OCMs, the rest of the series will be adjusted based on the
actual performance of the previous burn and the continuous improvement
of our knowledge of the comet's orbit; the comet's trajectory is being
regularly refined by analysing images taken with the OSIRIS camera
<http://blogs.esa.int/rosetta/2014/05/15/comet-67pc-g-is-becoming-active/>
and the navigation camera.

The rest of the spacecraft's systems - including power, thermal,
attitude and orbit control, data handling and communications - are
operating as expected.

ESA's Heavy Metal tracking station

It's interesting to note what happens at the New Norcia ground station
to get ready for Rosetta tracking passes, lining up the 580-tonne
moveable antenna and support structure to point at the spacecraft.

"There are 45 minutes of preparation required at the ground station
prior to each pass," says Gabriela Ravera, the Ground Operations Manager
supporting the Rosetta mission.

"This includes configuring the station to support Rosetta [setting the
uplink and downlink frequency -- Ed.], confirming the Spacecraft
Trajectory Data Message, commanding the massive 35m dish antenna to
point to the correct point in the sky, configuring the station's front
and back end, warming up the amplifiers, calibrating the ranging signal
and then reporting readiness for the track."

These activities are coordinated and implemented by the Estrack Control
Centre at ESOC, where operators are on shift 24 hrs/day year-round.

Gabriela says ESA deep-space stations have a redundant "hot-backup"
chain of hardware connected to the antenna so as to minimise the chance
that any telemetry or data would be lost.

The station sends commands to Rosetta at 2 kbps , and transmits with 10
kW of power.

Capt'n Midnight

http://www.bbc.co.uk/news/science-environment-28351234

Comet 67P/Churyumov-Gerasimenko is far more irregular in shape than anyone imagined.

It has already been dubbed the "rubber duck" in space.

The latest pictures were acquired by the approaching Rosetta probe from a distance of about 12,000km.

expectationlost

august 6th

this true ? European Space Agency gives in to demands to release pictures of Rosetta spacecraft's decade-long hunt for comet http://www.independent.co.uk/news/science/european-space-agency-gives-in-to-demands-to-release-pictures-of-rosetta-spacecrafts-decadelong-hunt-for-comet-9645202.html

ESA wanted to withhold all images and only released this one when another was leaked http://blogs.esa.int/rosetta/2014/08/03/cometwatch-2-august/

Rucking_Fetard

Rosetta's rendezvous

degrassinoel

they should be broadcasting pretty soon here

Standman

Some great detailed pics coming in:



EDIT: More here

MeteoritesEire

just jaw dropping pics.

I see the remnants of an ancient planet or planetisimal that got pummeled to smithereens.

maybe one day we will know its' story

expectationlost

i found this useful http://space.io9.com/how-big-is-rosettas-comet-1617103535

Capt'n Midnight

expectationlost wrote: »

i found this useful http://space.io9.com/how-big-is-rosettas-comet-1617103535

From http://www.bbc.co.uk/news/science-environment-28659783

MeteoritesEire

to think that objects that big and bigger have slammed and will continue to slam into the earth at 30 to 40,000 mph is staggering.The whole planet must shake.Thankfully it's only every 100,000 years or so at this moment in time.We are overdue a big one though eek

MeteoritesEire

http://www.jpl.nasa.gov/news/news.php?release=2014-289

Rosetta: Landing Site Search Narrows
Jet Propulsion Laboratory
August 25, 2014

The European Space Agency's Rosetta mission has chosen five candidate
landing sites on comet 67P/Churyumov-Gerasimenko for its Philae lander.
Philae's descent to the comet's nucleus, scheduled for this November,
will be the first such landing ever attempted. Rosetta is an
international mission spearheaded by the European Space Agency with
support and instruments provided by NASA.

Choosing the right landing site is a complex process. It must balance
the technical needs of the orbiter and lander during all phases of the
separation, descent and landing, and during operations on the surface,
with the scientific requirements of the 10 instruments on board Philae.
A key issue is that uncertainties in navigating the orbiter close to the
comet mean that it is possible to specify any given landing zone only in
terms of an ellipse - covering up to six-tenths of a square mile (one
square kilometer) - within which Philae might land.

"This is the first time landing sites on a comet have been considered,"
said Stephan Ulamec, Philae Lander Manager at the German Aerospace
Center, Cologne, Germany. "The candidate sites that we want to follow up
for further analysis are thought to be technically feasible on the basis
of a preliminary analysis of flight dynamics and other key issues - for
example, they all provide at least six hours of daylight per comet
rotation and offer some flat terrain. Of course, every site has the
potential for unique scientific discoveries."

For each possible zone, important questions must be asked: Will the
lander be able to maintain regular communications with Rosetta? How
common are surface hazards such as large boulders, deep crevasses or
steep slopes? Is there sufficient illumination for scientific operations
and enough sunlight to recharge the lander's batteries beyond its
initial 64-hour lifetime without causing overheating?

The potential landing sites were assigned a letter from an original
pre-selection of 10 possible sites, which does not signify any ranking.
Three sites (B, I and J) are located on the smaller of the two lobes of
the comet and two sites (A and C) are located on the larger lobe.

"The process of selecting a landing site is extremely complex and
dynamic; as we get closer to the comet, we will see more and more
details, which will influence the final decision on where and when we
can land," said Fred Jansen, Rosetta's mission manager from the European
Space Agency's Science and Technology Centre in Noordwijk, The
Netherlands. "We had to complete our preliminary analysis on candidate
sites very quickly after arriving at the comet, and now we have just a
few more weeks to determine the primary site. The clock is ticking and
we now have to meet the challenge to pick the best possible landing site."

The next step in preparation for landing operations is a comprehensive
analysis of each of the candidate sites, to determine possible orbital
and operational strategies that could be used for Rosetta to deliver the
lander to any of them. At the same time, Rosetta will move to within 31
miles (50 kilometers) of the comet, allowing a more detailed study of
the proposed landing sites. By September 14, the five candidate sites
will have been assessed and ranked, leading to the selection of a
primary landing site. A fully detailed strategy for the landing
operations at the selected site will be developed, along with a backup.

The landing of Philae is expected to take place in mid-November when the
comet is about 280 million miles (450 million kilometers) from the sun.
This will be before activity on the comet reaches levels that might
jeopardize the safe and accurate deployment of Philae to the comet's
surface, and before surface material is modified by this cometary activity.

Launched in March 2004, Rosetta was reactivated in January 2014 after a
record 957 days in hibernation. Composed of an orbiter and lander,
Rosetta's objectives since arriving at comet 67P/Churyumov-Gerasimenko
earlier this month are to study the celestial object up close in
unprecedented detail, prepare for landing a probe on the comet's nucleus
in November, and track its changes through 2015, as it sweeps past the sun.

Comets are time capsules containing primitive material left over from
the epoch when the sun and its planets formed. Rosetta's lander will
obtain the first images taken from a comet's surface and will provide
comprehensive analysis of the comet's possible primordial composition by
drilling into the surface. Rosetta also will be the first spacecraft to
witness at close proximity how a comet changes as it is subjected to the
increasing intensity of the sun's radiation. Observations will help
scientists learn more about the origin and evolution of our solar system
and the role comets may have played in seeding Earth with water, and
perhaps even life.

The scientific imaging system, OSIRIS, was built by a consortium led by
the Max Planck Institute for Solar System Research (Germany) in
collaboration with Center of Studies and Activities for Space,
University of Padua (Italy), the Astrophysical Laboratory of Marseille
(France), the Institute of Astrophysics of Andalusia, CSIC (Spain), the
Scientific Support Office of the European Space Agency (Netherlands),
the National Institute for Aerospace Technology (Spain), the Technical
University of Madrid (Spain), the Department of Physics and Astronomy of
Uppsala University (Sweden) and the Institute of Computer and Network
Engineering of the TU Braunschweig (Germany). OSIRIS was financially
supported by the national funding agencies of Germany (DLR), France
(CNES), Italy (ASI), Spain, and Sweden and the ESA Technical Directorate.

Rosetta is an ESA mission with contributions from its member states and
NASA. Rosetta's Philae lander is provided by a consortium led by the
German Aerospace Center, Cologne; Max Planck Institute for Solar System
Research, Gottingen; French National Space Agency, Paris; and the
Italian Space Agency, Rome. NASA's Jet Propulsion Laboratory in
Pasadena, California, a division of the California Institute of
Technology, manages the U.S. participation in the Rosetta mission for
NASA's Science Mission Directorate in Washington.

For more information on the U.S. instruments aboard Rosetta, visit:

http://rosetta.jpl.nasa.gov

More information about Rosetta is available at:

http://www.esa.int/rosetta

Rucking_Fetard

Who Owns Asteroid Rights?

Congress is back in session and getting right down to work on pressing science and technology issues like education funding, Net neutrality and ... oh wait. Actually, the House is holding a hearing on Wednesday to discuss a new law to manage resource mining in space: the ASTEROIDS Act (PDF).

No one seems to be asserting that managing mineral claims on asteroids is a pressing issue at the moment. But as Adam Minter reports today for Bloomberg, establishing a legal framework for it would probably help spur more entrepreneurial interest in the sector. James Cameron, Eric Schmidt, and Larry Page are among the investors in Washington State-based Planetary Resources, which plans to survey the “low-hanging fruit of the Solar System” using its Arkyd series of robotic spacecraft. Planetary Resources is also behind the Asteroid Zoo project, which exploits enables students, citizen scientists and other interested amateurs to hunt for undiscovered asteroids.

Texas-based Deep Space Industries last year announced plans to survey, prospect, harvest and process water and rare earth metals via a number of CubeSat-derived space probes called (...wait for it...) “Fireflies.” Shiny!

The proposed legislation, dubbed ASTEROIDS (for American Space Technology for Exploring Resource Opportunities In Deep Space), would work with the existing legal rubric of the 1967 Outer Space Treaty, which prohibits national claims on celestial territories as well as claims by private sector entities within signatory nations. The proposed legislation would give U.S. companies ownership of any materials they mine from asteroids, although not ownership of the asteroid itself. Minter notes that it's an approach similar to current laws around claims to marine resources.

The ASTERIODS Act will need tweaks, however, to create a solid foundation for space mining once firms from different nations get into the act. There's a precedent for this too, Minter notes, “in U.S. law related to mining of the deep-sea bed (also a field that’s more speculative than real at the moment).”

Rather than accept an international authority to regulate such activity (under the United Nations Convention on the Law of the Sea, or UNCLOS), U.S. law since the early 1980s has made provision for reciprocal recognition of deep-sea claims. In the mid-1980s, the U.S. extended reciprocity to the U.K., Japan, France and several other countries with similar laws.

As applied to space, these agreements would not only offer long-term property assurances to space prospectors (and perhaps attract a broader range of international investors) but also represent a small but important step forward in building trust and perhaps even encouraging global collaboration in space ventures.

The ASTEROIDS Act is co-sponsored by Representatives Bill Posey (R-Fla.) and Dered Kilmer (D-Wash.). The Sept. 10 hearing before the Space Subcommittee of the House Science, Space, and Technology Committee begins at 10:00 am ET.

MeteoritesEire

just now reading "2312" by Kim Stanley Robinson and his imagination concerning the mining and terraforming of asteroids is very interesting.He has obviously done some research into meteorites and their possible parent bodies.

Standman

This is the stuff of science fiction :eek:



On a closer look the landing sites aren't as smooth as they thought:



It so amazing to get such a close up look at a comet. Can't wait 'til the get the lander down there.

shedweller

Am i right in saying that philae will still be working while the comet starts spraying stuff out into space?
It should have started by now i suppose...

Rucking_Fetard

shedweller wrote: »

Am i right in saying that philae will still be working while the comet starts spraying stuff out into space?
It should have started by now i suppose...

From the Sun heating it up you mean? Yup, but they expect it to overheat in March, Rosetta will be able to follow for up to a year.

Landing spot chosen (2 spots if you include the backup), 11 Nov all going to plan.




How it's gonna land, what's the plans etc

Be a miracle if it goes right.

MeteoritesEire

very exciting times-so hoping the lander touches down successfully

shedweller

Does Philae have the ability to adjust its landing trajectory like the Chineese lander recently? It would suck to high heaven if it is unable to divert to miss a large boulder eh?

Rucking_Fetard

Comet from 39 Miles away.

http://www.aliveuniverseimages.com/speciale-missioni/missioni-nel-sistema-solare/rosetta/930-esa-rosetta-i-primi-dati-di-alice,-cosima,-osiris-e-virtis


Colourised here (with lots more) but can't seem to embed them. Down near the bottom.

From here.

Capt'n Midnight

shedweller wrote: »

Does Philae have the ability to adjust its landing trajectory like the Chineese lander recently? It would suck to high heaven if it is unable to divert to miss a large boulder eh?

AFAIK it doesn't

Rucking_Fetard

Capt'n Midnight wrote: »

AFAIK it doesn't

It takes days for any adjustment to be made. Think its 3 days after they press the button to land before it happens. So any boulders and its goodnight.

On phone so didnt check this but dont think i mixed it up with something else.

Rucking_Fetard

2 Weeks later, 30 Mile closer and less than a Month till touch down on the 12th.



Just shy of 10 Miles off, she's spitting Gas.

http://www.bbc.co.uk/news/science-environment-29620127

shedweller

Rucking_Fetard wrote: »

2 Weeks later, 30 Mile closer and less than a Month till touch down on the 12th.

http://news.bbcimg.co.uk/media/images/78214000/jpg/_78214682_78214681.jpg

Just shy of 10 Miles off, she's spitting Gas.

http://www.bbc.co.uk/news/science-environment-29620127

Getting exciting now eh?!
We'll hardly get a video of the descent like MSL will we?

Capt'n Midnight

Rosetta mission: Comet landing gets green light

http://www.bbc.co.uk/news/science-environment-29633734

The decision to try to land a robot on Comet 67P/Churyumov-Gerasimenko on 12 November has been confirmed.
...
The Rosetta probe will eject the Philae robot shortly after 08:30 GMT on the day of landing.

The shove will be imparted at a distance of about 20km from the surface of 67P.

The descent to the 4km-wide comet is expected to take about seven hours. Success or failure will be known roughly 30 minutes after that.

Rucking_Fetard

Rucking_Fetard wrote: »

Just shy of 10 Miles off, she's spitting Gas.

And she's a stinker!! Rotten Eggs and Cat Piss.

Latest Pic from the 20th at just 4.6 Miles from the Surface, 18 Days to go.

shedweller

As Gene Cernan once said "we is go and we is down among 'em!"

Rucking_Fetard

I wonder why it has to bail all the way back out to 13 Miles to release the little fella?

shedweller

http://www.esa.int/esatv/Television
They have a login code on the page as well.
Starting coverage at 19:00 this evening. Landing at 11:00 tomorrow i think??

GO PHILAE GO!!!

mickmackey1

shedweller wrote: »

Landing at 11:00 tomorrow i think??

Separation at 0903, touch down at 1602.

shedweller

mickmackey1 wrote: »

Separation at 0903, touch down at 1602.

I must have read conflicting info then. Thanks!

Akrasia

shedweller wrote: »

I must have read conflicting info then. Thanks!

one of Philae's thrusters isn't working adding extra drama to the manoeuvre. the top thruster was designed to give downward pressure to Philae to reduce the risk of it bouncing off the surface on landing and to hold it in place while the attachment screws are deployed.

The landing will still take place but its more risky now

shedweller

Well that sucks!

Akrasia

shedweller wrote: »

Well that sucks!

They still have the harpoons to tether it to the comet so it's not all lost. It's gonna be trickier, and more nerve racking for the team, but I still think they can do it

Akrasia

The ESA should confirm successful seperation at about 9 this morning, and the landing should be complete by about 4pm (GMT - which is currently irish time for the winter until the clocks change again in spring)

http://spaceflightnow.com/2014/11/12/comet-landing-is-a-go-despite-thruster-problem/

namloc1980

Separation confirmed!

Akrasia

namloc1980 wrote: »

Separation confirmed!

Man I am so gonna play a sh1t load of KSP tonight

shedweller

Im on the esa website trying to watch it live but its jammed up. Also getting redirected to the play store to download livestream but that wont save to my sd card. I thought they went to the phone instead of the card??

Edit: watching it on the desktop is far simpler!

Alun

I can watch the live stream on my phone (either via Chrome browser or the LiveStream app) or PC but for some reason it's refusing to cast to my Chromecast which is a PITA.

barry181091

I am in work (Not working might I add!) covering this. This is so exciting! I would love to know what are the chances they have calculated for successful touchdown and tethering. Maybe ~15%?

josip

I read somewhere on the BBC site that they believe the site chosen gives them a 75% chance of successful tethering.
I expect that 75% is lower now without a thruster

Ay suggestions for how to pass the time until 10:53? (Philly-Rosy radio connection)

shedweller

the harpoon, in fairness, is a serious piece of kit. It was tested in a box full of insulation granules and boy were they light. It pulled a bit as the barbs extended but then held fast. I presume they used the same winch with the same forces.
The loss of the top thruster is a kick in the goolies though so heres hoping all will go well. It'll be taking pictures during the descent too so we'll know more this time tomorrow regardless of the outcome today!
My kids are gone to school armed with links and data! Science baby!!:pac:

shedweller

josip

shedweller wrote: »

the harpoon, in fairness, is a serious piece of kit. It was tested in a box full of insulation granules and boy were they light. It pulled a bit as the barbs extended but then held fast. I presume they used the same winch with the same forces.
The loss of the top thruster is a kick in the goolies though so heres hoping all will go well. It'll be taking pictures during the descent too so we'll know more this time tomorrow regardless of the outcome today!
My kids are gone to school armed with links and data! Science baby!!:pac:

Anyone any idea if/how they mitigate the momentum in the opposite direction when the harpoon is fired towards the surface.
Its mass is undoubtedly considerably less than Philae, but its velocity is probably high?
So on a low gravity comet, would Philae jump up a bit when it fired the harpoon?

Javan

josip wrote: »

Anyone any idea if/how they mitigate the momentum in the opposite direction when the harpoon is fired towards the surface.
Its mass is undoubtedly considerably less than Philae, but its velocity is probably high?
So on a low gravity comet, would Philae jump up a bit when it fired the harpoon?

The top thruster was intended to counteract that force. At least; the harpoons firing will product a brief but significant impulse upwards but the top thruster would more than compensate for the delta-v produced by that impulse. Without that thruster the lander will be more dependent on the harpoons catching in the surface so the lander can pull itself down on the tethers.

(AFIAK, IANARS, etc.)

shedweller

Some difference to, say, the chinese lander that paused descent to analyse and go to the best spot! It's amazing what difference a few years makes.

shedweller

First pics after the seperation should be coming in in the next 10 to 15 mins.
:cool:

shedweller

Live now. Waiting for info from philae!

barry181091

Come on little guy, don't fail us now!!

EDIT: WOOOO!