Herschel satellite weighed and fuelled

Apr 22, 2009
Herschel being weighed before fuelling. The measurements taken will serve as the baseline from which the final spacecraft mass will be derived after fuelling. The expected mass at launch is about 3400 Kg. Credits: ESA

(PhysOrg.com) -- About two weeks ago, Herschel was weighed to record its dry mass before the satellite was fuelled with 256 kg of liquid hydrazine. After switching it on to confirm normal function, engineers integrated the fuelled satellite with the Ariane 5 adapter.

On 26 March, the satellite’s weight was measured with reference to calibrated masses for maximum accuracy. After this it was moved to another building on the launch site to begin fuelling operations.

Herschel will use its thrusters, propelled by liquid hydrazine, for any manoeuvres once in orbit. This is a volatile and toxic substance, commonly used as rocket fuel. This is why the critical fuelling operation required plenty of preparation, including safety training exercises for the fuelling team, and was executed with great care.

The operation was carried out from 10 to 11 April in a special room at the launch site. The personnel involved were dressed in protective clothing known as ‘scape suits’.

Before fuelling, the satellite’s two propellant tanks were pressurised to the end-of-life pressure with nitrogen and then the hydrazine was loaded. The tanks were filled with 128 kg of liquid hydrazine each. This amount of hydrazine is calculated to be enough for six years in orbit, and includes a safety margin.

Once fuelling was completed, engineers thoroughly decontaminated the equipment, ensuring that it was hydrazine-free, to 0.1 part per million.

After fuelling was completed, engineers switched Herschel on to ensure that the satellite worked normally. Herschel was then integrated with the adapter on 11 April.

Herschel, ESA's cutting-edge space observatory, will carry the largest, most powerful ever flown in space. A pioneering mission to study the origin and evolution of stars and galaxies, it will help understand how the Universe came to be what it is today.

Provided by European Space Agency (news : web)

Explore further: DNA survives critical entry into Earth's atmosphere

add to favorites email to friend print save as pdf

Related Stories

Planck spacecraft follows Herschel to launch site

Feb 20, 2009

(PhysOrg.com) -- Planck, ESA’s microwave observatory that will study the relic radiation of the Big Bang, was shipped from Ličge, Belgium, to Europe’s Spaceport in Kourou, French Guiana, on 18 February. ...

Russian fuel flows in Jules Verne's veins

Jan 14, 2008

Fuelling of the Jules Verne Automated Transfer Vehicle has started at Europe’s Spaceport. ATV is being loaded with Russian refuelling propellant destined for the International Space Station. After a month ...

Herschel and Planck to lift off on 6 May

Apr 08, 2009

(PhysOrg.com) -- With the additional checks related to the flight worthiness of the Herschel telescope now completed, ESA and Arianespace have set the launch date of Herschel and Planck for 6 May 2009.

Crew oxygen for ISS loaded on Jules Verne

Jan 28, 2008

Three weeks into delicate fuelling operations, Jules Verne Automated Transfer Vehicle has also been successfully loaded with oxygen. In orbit this will be transferred to the International Space Station's atmosphere ...

Herschel spacecraft assembly complete

Apr 23, 2008

The mirror of the Herschel telescope has now been assembled with the payload and service module, completing the spacecraft structure - an important milestone in the days following through to launch.

Herschel and Planck missions ready to move to launch site

Feb 09, 2009

(PhysOrg.com) -- ESA’s Herschel and Planck missions that will study the formation of stars and galaxies and the relic radiation from the Big Bang, respectively, have successfully completed their test campaigns ...

Recommended for you

DNA survives critical entry into Earth's atmosphere

17 hours ago

The genetic material DNA can survive a flight through space and re-entry into the earth's atmosphere—and still pass on genetic information. A team of scientists from UZH obtained these astonishing results ...

Team develops cognitive test battery for spaceflight

17 hours ago

Space is one of the most demanding and unforgiving environments. Human exploration of space requires astronauts to maintain consistently high levels of cognitive performance to ensure mission safety and success, and prevent ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.