ESA Venus Express: ESOC have lost contact with Spacecraft

Artist's impression of Venus Express 

Credit: ESA (Image by AOES Medialab)

On 28 November 2014, the flight control team at ESOC reported loss of contact with Venus Express (VEX).

It is possible that the remaining fuel on board VEX was exhausted during the recent periapsis-raising manoeuvres and that the spacecraft is no longer in a stable attitude (the spacecraft’s high-gain antenna must be kept pointed toward Earth to ensure reliable radio contact).

Repeated attempts to re-establish contact using ESA and NASA deep-space tracking stations have been made since then, and there has been some limited success in the period since 3 December.

Although a stable telemetry link is not available, some telemetry packets were successfully downlinked.

These confirm that the spacecraft is oriented with its solar arrays pointing toward the Sun, and is rotating slowly.

The operations team is currently attempting to downlink the table of critical events that is stored in protected memory on board, which may give details of the sequence of events which occurred over the past few days.

The root cause of the anomaly (fuel situation or otherwise) remains to be established.

ESA will provide an update as soon as something more concrete is known.

ESA Rosetta: 67P/Churyumov–Gerasimenko - Comet-chaser initiates 'big burn'

Comet 67P/Churyumov–Gerasimenko already shows signs of a developing halo, or coma, around its nucleus

Europe's Rosetta spacecraft is in the midst of another critical moment in its mission to rendezvous with a comet.

The satellite has lit its thrusters for a near-eight-hour burn that should put it on just the right path to meet up with 67P/C-G in August.

Although eight further manoeuvres will be required to complete the task, Wednesday's is the big one.

Rosetta, which was launched from Earth 10 years ago, plans to orbit the comet and put a small lander on its surface.

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

Rosetta's automated systems initiated the thruster firing at 15:23 GMT (16:23 BST; 17:23 CEST).

'Fundamental' burn
Engineers at the European Space Agency's (ESA) ESOC "mission control" in Darmstadt, Germany, received confirmation some 28 minutes later.

The delay was down to the time it takes for signals to travel 500 million km - the current distance between Rosetta and Earth.

"BigBurn has started! Rosetta team at ESOC seeing good telemetry," the control room's Twitter feed reported.

"@ESA_Rosetta mission control seeing thruster temperatures rise as they heat up, 500mln km away #BigBurn," it added.

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 4km-wide body and trigger large jets of gas and dust from its surface.

At the moment, the separation between the pair is about one million km, and closing.

Wednesday's burn is designed to slow Rosetta's velocity relative to the comet and thus keep it on a trajectory to arrive just in front of the object in 11 weeks' time.

The idea by then is to have reduced the relative velocity from the present 755m/s down to just 1m/s, with a separation under 200km.

Relative to the Sun, of course, their speed will not be "walking pace" - rather, the duo will be hurtling through space at more than 13km/s as they fall deeper and deeper into our star's gravity well.

Even though engineers conducted a small test burn two weeks ago, there was a little nervousness at the European Space Operations Centre ahead of Wednesday's manoeuvre.

 That was because Rosetta has a leak in the system it uses to pressurise its propulsion tanks.

ESA astronaut Alexander Gerst testing his Russian Sokol spacesuit

ESA astronaut Alexander Gerst testing his Russian Sokol spacesuit for the last time before his launch to the International Space Station in May 2014. 

Alexander has been training for his mission since 2011 after he was selected as an ESA astronaut in 2009. 

Based at ESA's ESOC, European Astronaut Centre in Cologne, Germany, his space adventure has taken him to Canada, USA, Japan and Russia for training with robots, spacecraft, hypergravity and survival techniques. 

Image courtesy GCTC.

The clock is ticking: in 100 days ESA astronaut Alexander Gerst will be launched to the International Space Station with NASA astronaut Reid Wiseman and cosmonaut commander Maxim Suraev.

Strapped on top of 274 tonnes of rocket propellants, they will be boosted to 28 000 km/h to arrive at the orbital outpost in less than seven hours.

The launch will mark the start of Alexander's Blue Dot mission as part of Space Station Expedition 40/41, staying for six months on the ISS, the world's only permanently staffed orbital laboratory.

ESA Rosetta Mission: Waking up from Hibernation

Philae landing on comet

Next year, on 20 January, after 957 days of hibernation in deep space, ESA’s comet-chasing Rosetta spacecraft is set to wake up automatically en route to the destination it has been travelling towards for nearly a decade.

In preparation for the critical activation and the challenges that lie ahead for Rosetta, members of the media are invited to a briefing by ESA’s science and mission control experts and partners on Tuesday, 10 December, 10:00–12:30 CET, at ESA’s European Space Operations Centre (ESOC) in Darmstadt, Germany.

The 20 January milestone will mark the start of an intensive year as Rosetta draws steadily closer to comet Churyumov–Gerasimenko ahead of rendezvous in August.

After extensively mapping the comet’s surface, it will dispatch the lander Philae in November for close-up study of the nucleus.

Rosetta will then follow the comet on its journey through the inner Solar System, monitoring the ever-changing conditions as it warms up heading towards its closest approach to the Sun, in August 2015.

Rosetta’s main objective is to help understand the origin and evolution of the Solar System, in particular investigating the role that comets may have played in seeding Earth with water, and perhaps even life.

ESA MetOp-B: Europe's next weather satellite - Launch Simulation

Next ESA MetOpB launch simulation at ESA's ESOC set for Fri, to practise payload activation. 

Credit: ESA

ESA welcomes new friend at Mars

ESOC Control Room

"Congratulations to our NASA colleagues on a hugely successful landing,” said Paolo Ferri, ESA’s Head of Solar and Planetary Mission Operations. “The Mars Express team welcomes a new friend in the neighbourhood."

Mars Express picked up MSL signals about 10 minutes before it entered the atmosphere, travelling at 21 000 km/h, for its critical descent and landing phase.
 
“We tracked MSL for about 28 minutes then lost contact as expected just a few moments before Curiosity’s touchdown in Gale Crater,” said Michel Denis, Mars Express Spacecraft Operations Manager.

“NASA now have this valuable data and everyone here is delighted to have helped support Curiosity’s arrival at Mars.”

The signal recordings made by Mars Express and New Norcia station include information on MSL’s velocity and direction. They record the sequential critical events during descent, including parachute deployment, heat shield separation and rover separation.

They will prove valuable to scientists as they reconstruct MSL’s descent profile, helping to improve and refine models of the martian atmosphere and assess landing accuracy.

The signals recorded by Mars Express will be automatically downloaded two more times later today via New Norcia and ESA’s Cebreros station, in Spain, to ensure redundancy.