Rosetta burns... and burns...
Rosetta's next orbital correction manoeuvre (OCM) is taking place tonight. The thruster burn began at 17:59 CET (spacecraft time) and will run until shortly after midnight (371 mins total). The planned change in speed is 274 m/s with respect to the Sun. Like last night, the Rosetta teams at ESOC will be on shift until late!
Some bits of info collected from around ESOC earlier today on the Rosetta burn last night:
First - An update from the Rosetta flight control team: yesterday's burn went according to plan! The team noted a very slight over performance - meaning that the thrusters provided more of a boost than planned but still well within the expected range (more on that below). For the flight control & flight dynamics teams, the last shift ended at 04:30 CET this morning (just after the burn ended).
Next - the detailed burn schedule is posted below (click on the 'Full story' link), sent in by Roberto Porta, one of the Rosetta Spacecraft Operations Engineers at ESOC. Note that we'll wait to do any further blog updates until we get the final results after the last slot, now booked for 23 January.
Finally - we received a note from Trevor Morley, the team lead for flight dynamics support for Rosetta. Trevor wrote:
Preliminary assessment of last night's manoeuvre based on Doppler data indicates that the velocity change was about 1 m/s more than the planned 300 m/s. Such an error is well within the expected performance accuracy and the accumulation of such errors over the first four legs of the manoeuvre will be compensated for by an eventual re-optimisation of the 5th and final leg (an 'orbit trim'). This re-optimisation will be based upon an accurate reconstruction of the orbit for which purpose both ESA and NASA delta-DOR measurements will be made in addition to routine Doppler and range measurements.
'Delta-DOR' refers to the ultra-accurate position determination technique used by both ESA and NASA. Delta-DOR uses two widely separated antennas to simultaneously track a transmitting probe in order to measure the time difference ('delay time') between signals arriving at the two stations. The technique of measuring this delay is named Differential One-way Range (DOR). More details via the ESTRACK pages in the ESA web site
. -- Daniel
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ESOC teams at work tonight
Some nice photos just sent in from ESA/ESOC where the flight dynamics team and the flight control team are watching closely this evening as Rosetta conducts an important thruster burn to help line up the spacecraft for her rendezvous with a comet in 2014. Scroll down for details!
Rosetta Spacecraft Operations Engineer Roberto Porta
on console in the Rosetta dedicated control room
Members of the flight dynamics team on shift to monitor tonight's manouevres
And here's what Rosetta Spacecraft Operations Manager Andrea Accomazzo is seeing on his screen: a display based on telemetry received from Rosetta showing the jump in thruster temperature as the burn got underway about an hour ago at 20:03 CET.
Rosetta flight control team in crucial manoeuvre tonight
A quick update from ESA/ESOC: one of the most important trajectory correction manoeuvres (TCM) as Rosetta line-ups for her encounter with Comet 67P/Churyumov-Gerasimenko in 2014 is now taking place.
Tonight's burn, which began at 19:03 UTC (20:03 CET) spacecraft event time (meaning the time at Rosetta, which is now over 629 mn km from earth), is expected to produce a 'delta-v' - or change in velocity with respect to the Sun - of 300 m/second. The burn is part of a series in the coming days that should produce an overall change of 778 m/second - one of the longest-running burns conducted to date by any of the Agency's deep-space missions.
This series of burns are crucial in that they are necessary to help Rosetta line up for her final approach to 67P/Churyumov-Gerasimenko.
ESA's first deep-space ground station at New Norcia (Western Australia) - now communicating with Rosetta.
Rosetta Spacecraft Operations Manager Andrea Accomazzo and members of the flight control team are watching progress closely from the Rosetta Dedicated Control Room at ESOC; he sent in a mail a few minutes ago to report that they are monitoring evolution of propellant pressure and making sure that everything is working as expected on board the spacecraft.
Signals from Rosetta are being received on Earth via ESA's giant 35m deep-space tracking station at New Norcia, Australia.
We'll check with the team tomorrow and provide more details here in the blog. -- Daniel