Feeds

Herschel and Planck off to meet Lagrange

European twin 'scope launch tomorrow

5 things you didn’t know about cloud backup

The European Space Agency's Herschel and Planck space telescopes look good to go tomorrow (Thursday 14 May) at 13:12 GMT from the ESA spaceport in French Guiana.

Herschel and Planck seen in the upper stage. Pic: ESASitting atop an Ariane 5 ECA (see graphic), the two vehicles are ultimately destined for "L2", the second Lagrangian point lying around 1.5m km from Earth "where all the gravitational forces acting between two objects cancel each other out and therefore can be used by spacecraft to 'hover'".

Once "hovering", Herschel will get down to the business of probing the cosmos with its infrared telescope capable of covering the entire spectrum from far-infrared to sub-millimetre wavelengths.

Planck, meanwhile, will be set to studying the Cosmic Microwave Background "with the highest accuracy ever achieved".

That's the plan, but there's the small matter of first getting the two spacecraft onto the right trajectory using a single lifter. Once off the launchpad, the Ariane 5 ditches its solid boosters after around two-and-a-half minutes. Upper stage separation and engine ignition are scheduled for around nine minutes, after which the upper stage accelerates to towards the 10 km/s at which it will offload its cargo.

First to go will be Herschel (seen in the pic nestled at the top of the upper stage), departing at around 26 minutes after launch. One-and-a-half minutes later, the support structure which supported Herschel and protected Planck will be jettisoned and the latter will follow shortly after, at just under 29 minutes into the mission.

ESA continues: "The launcher will set the satellites directly on the path to L2. This means that no injection manoeuvre will be necessary for Herschel; the satellite will be close to its orbit around L2 right from separation. One major manoeuvre is planned to fine-tune the orbit about 24 hours after launch.

"Planck will also be in orbit around L2 at separation, but since the amplitude of its orbit is half that of Herschel, engineers will execute manoeuvres to reduce its orbit to half that of the original. The first manoeuvre is planned about 30 hours after launch."

Ultimately, and assuming all goes according to plan, Herschel's final "quasi-halo orbit" will see it at an average distance of 800,000 km from L2. Planck will settle into a Lissajous orbit "with an amplitude of 400,000 km".

For those of you who've never adopted a Lissajous or quasi-halo orbit, the former is "the natural motion of a satellite around a collinear libration point in a two-body system" (more here). The latter, ESA helpfully explains, is "an orbit that resembles a halo orbit"*, but it's actually a variant of the Lissajous orbit. ®

Bootnote

*"Where the satellite follows a simple circular or elliptical path about the libration point."

Boost IT visibility and business value

More from The Register

next story
Boffins attempt to prove the UNIVERSE IS JUST A HOLOGRAM
Is this the real life? Is this just fantasy?
China building SUPERSONIC SUBMARINE that travels in a BUBBLE
Shanghai to San Fran in two hours would be a trick, though
Our LOHAN spaceplane ballocket Kickstarter climbs through £8000
Through 25 per cent but more is needed: Get your UNIQUE rewards!
Cutting cancer rates: Data, models and a happy ending?
How surgery might be making cancer prognoses worse
CRR-CRRRK, beep, beep: Mars space truck backs out of slippery sand trap
Curiosity finds new drilling target after course correction
SpaceX prototype rocket EXPLODES over Texas. 'Tricky' biz, says Elon Musk
No injuries or near injuries. Flight stayed in designated area
Galileo, Galileo! Galileo, Galileo! Galileo fit to go. Magnifico
I'm just a poor boy, nobody loves me. But at least I can find my way with ESA GPS by 2017
prev story

Whitepapers

Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Endpoint data privacy in the cloud is easier than you think
Innovations in encryption and storage resolve issues of data privacy and key requirements for companies to look for in a solution.
Scale data protection with your virtual environment
To scale at the rate of virtualization growth, data protection solutions need to adopt new capabilities and simplify current features.
Boost IT visibility and business value
How building a great service catalog relieves pressure points and demonstrates the value of IT service management.
High Performance for All
While HPC is not new, it has traditionally been seen as a specialist area – is it now geared up to meet more mainstream requirements?