Rosseta awakening and more

Kiwi help in historic space hook-up

By Jamie Morton @Jamienzherald
5:00 AM Friday Aug 1, 2014

The Rosetta spacecraft's Philae robotic landing craft above comet 67P/Churyumov-Gerasimenko artist impression. Photo / Supplied


Kiwi-developed technology will assist a historic hook-up when a spacecraft makes its long-awaited date with a comet next week.

On Wednesday, the European Space Agency's probe Rosetta will reach the 3km-long 67P/Churyumov-Gerasimenko and begin planning an astonishing first in space exploration - landing on the surface of a comet.

Since its launch in 2004, Rosetta has travelled more than six billion kilometres to catch up with the rubber duck-shaped comet.

Once there, Rosetta will begin synchronising its orbit with the giant space rock, which is hurtling through the solar system at a speed of 400,000km/h.

Later in the year, the probe will drop its Philae lander to dock on to the comet's icy surface. The comet has almost no gravity so the probe will have to use harpoons and ice anchors to clamp on to the surface.

Following the mission closely are engineers at New Zealand-based tech company Rakon, whose special frequency-control technology is a crucial component of Rosetta's mission.

The world-renowned company's crystal oscillators and crystal filters are used in Rosetta's Comet Nucleus Sounding Experiment by Radiowave Transmission (CONSERT), which is designed to probe the comet's interior by using radio waves transmitted through the nucleus between the Philae lander and Rosetta orbiter.

"I guess it's the most out-there and exciting," said Rakon chief executive Brent Robinson, when asked how the mission compared with other space projects the company has been involved with.

"It's a world first, and Rakon is delighted to be involved in a project that will help us to understand our universe, and how it all came about."

The comet was selected because it followed orbital paths near the ecliptic plane, or path of the sun, making a rendezvous and landing easier to achieve, and also because its flight in the inner-solar system coincided with the mission timeline.

By studying the comet's dust and gas, Rosetta will help scientists learn more about the evolution of the solar system, of which comets are considered primitive building blocks.

As the comet comes into contact with heat and solar winds, scientists will also be able to observe how these giant bundles of rock and ice respond at relatively close distance to the sun.

Stardome astronomy educator David Britten said the landing as the comet rotated in its ultra-fast orbit was going to be tricky.

"As it gets closer, it will obviously be able to see the comet in much more detail, and it could just be a bit of rubble held together by ice."

Mr Britten said it was possible that learning more about this comet could help scientists better prepare for the threat of a comet on a collision course with Earth.

By Jamie Morton @Jamienzherald

- NZ Herald

Copyright ©2014, APN New Zealand Limited

http://www.esa.int/Our_Activities/Space_Science/Rosetta/Rosetta_takes_comet_s_temperature




ESA’s Rosetta spacecraft has made its first temperature measurements of its target comet, finding that it is too hot to be covered in ice and must instead have a dark, dusty crust.

The observations of comet 67P/Churyumov–Gerasimenko were made by Rosetta’s visible, infrared and thermal imaging spectrometer, VIRTIS, between 13 and 21 July, when Rosetta closed in from 14 000 km to the comet to just over 5000 km.

At these distances, the comet covered only a few pixels in the field of view and so it was not possible to determine the temperatures of individual features. But, using the sensor to collect infrared light emitted by the whole comet, scientists determined that its average surface temperature is about –70ºC.

The comet was roughly 555 million kilometres from the Sun at the time – more than three times further away than Earth, meaning that sunlight is only about a tenth as bright.

Although –70ºC may seem rather cold, importantly, it is some 20–30ºC warmer than predicted for a comet at that distance covered exclusively in ice.

“This result is very interesting, since it gives us the first clues on the composition and physical properties of the comet’s surface,” says VIRTIS principal investigator Fabrizio Capaccioni from INAF-IAPS, Rome, Italy.

http://blogs.esa.int/rosetta/2014/08/02/comet-at-1000-km/

COMET AT 1000 KM

Rosetta sees the comet just five days before arrival.


http://blogs.esa.int/rosetta/2014/08/01/how-rosetta-arrives-at-a-comet/
HOW ROSETTA ARRIVES AT A COMET

After travelling nearly 6.4 billion kilometres through the Solar System, ESA’s Rosetta is closing in on its target, but how does a spacecraft actually arrive at a comet?

The journey began on 2 March 2004 when Rosetta launched on an Ariane 5 G+ from Europe’s spaceport in Kourou. Since then, Rosetta has had to loop around the Sun five times, picking up speed through three essential gravity assist manoeuvres at Earth and one at Mars, to put the spacecraft on an orbit similar to its destination: comet 67P/Churyumov-Gerasimenko.

http://blogs.esa.int/rosetta/2014/08/04/whats-happening-in-rosetta-mission-control-today/

WHAT’S HAPPENING IN ROSETTA MISSION CONTROL TODAY

Yesterday’s orbit correction manoeuvre (OCM) – dubbed CATP for ‘Close Approach Trajectory – pre-Insertion’ – went off without problems, delivering the desired 3.2 m/s of speed decrease.

We now have just one final burn of around 1 m/s that will slow Rosetta and kick it onto the first of the comet orbit arcs (see video below). This will take place on Wednesday, which will also be celebrated as the official ‘arrival day’ at ESOC with a formal programme and media briefing (you can follow via webcast).

The Rosetta Flight Control Team (FCT) are very busy, as today marks the first day in a new weekly work cycle that will see thruster burns taking place on Wed/Sun well into 2015.

Rosetta will, follow, at least for now, a three-legged triangular orbit that requires a small thruster burn at each apex. The legs are about 100 km long and it will take Rosetta between three and four days to complete each one.

http://rosetta.esa.int/
WATCH ROSETTA RENDEVOUS LIVE
08:00 GMT on 6 Aug

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

Europe's Rosetta probe goes into orbit around distant comet

Europe's Rosetta probe has arrived at a comet after a 10-year chase.
In a first for space history, the spacecraft was manoeuvred alongside a speeding comet to begin mapping its surface in detail.
The spacecraft fired its thrusters for six and a half minutes to finally catch up with comet 67P/Churyumov-Gerasimenko.
"We're at the comet!" said Sylvain Lodiot of the European Space Agency (Esa) operations centre in Germany.

http://blogs.esa.int/rosetta/2014/08/18/whats-up-with-rosetta/

WHAT’S UP WITH ROSETTA?

Today: a quick recap of Rosetta orbital manoeuvres in the past fortnight since arrival at Comet 67P/C-G on 6 August. Today’s post is covers multiple manoeuvres, which means that the mission operations teams and flight dynamics experts at ESOC have been busy ensuring that everything is happening when it should!

First, before we go any further, a mandatory video! We say ‘mandatory’ because this animation explains in rather good detail what Rosetta has been doing and covers the current time frame up to the end of September. OK – lets watch:

Landing site selection: The race is on

http://blogs.esa.int/rosetta/2014/08/21/landing-site-selection-the-race-is-on/

LANDING SITE SELECTION: THE RACE IS ON

Rosetta has been at comet 67P/Churyumov-Gerasimenko for two weeks, collecting critical data that is now being used to identify candidate landing sites for Philae. This coming weekend up to five candidate landing sites will be proposed for further analysis (they will be announced on Monday), but what exactly goes into choosing a landing site, and who gets to decide?

Let’s start with the ‘who’: to summarise, responsibility for the selection of the candidate sites lies with the Landing Site Selection Group (LSSG), which comprises engineers and scientists from Philae's Science, Operations and Navigation Centre (SONC) at CNES, the Lander Control Centre (LCC) at DLR, scientists representing the Philae Lander instruments, and supported by the ESA Rosetta team, which includes representatives from science, operations and flight dynamics. The final Go/No Go decision for the primary landing site is given after a formal review by ESA, including the lander team, in mid-October.

Now for the ‘what’: in general terms, the landing site selection process will ultimately identify a safe and scientifically interesting landing site for Rosetta's lander, Philae. Very well, but what defines “safe” and what is “scientifically interesting”?

Landing site search narrows

http://www.esa.int/Our_Activities/Space_Science/Rosetta/Rosetta_Landing_site_search_narrows

Using detailed information collected by ESA’s Rosetta spacecraft during its first two weeks at Comet 67P/Churyumov-Gerasimenko, five locations have been identified as candidate sites to set down the Philae lander in November – the first time a landing on a comet has ever been attempted.

Before arrival, Comet 67P/Churyumov-Gerasimenko had never been seen close up and so the race to find a suitable landing site for the 100 kg lander could only begin when Rosetta rendezvoused with the comet on 6 August.

The landing is expected to take place in mid-November when the comet is about 450 million km from the Sun, before activity on the comet reaches levels that might jeopardise the safe and accurate deployment of Philae to the comet’s surface, and before surface material is modified by this activity.