STEREO

RAL involvement: HI instrument - Heliospheric Imager

Principal Investigator: Prof Richard Harrison
Project Manager: Dr Chris Eyles
Project Scientist: Dr Chris Davis

Launch:

STEREO, onboard a Delta ll rocket, launched at 1:52am BST on 26th October 2006 from Cape Canaveral Air Force Station.

Mission:

It is the third mission in NASA's Solar Terrestrial Probes program, with the aim of providing the first ever stereoscopic (3D) measurements to study the Sun and the nature of its coronal mass ejections. RAL leads the UK consortium which developed the Heliospheric Imager (HI) on STEREO. For more information on STEREO, and coverage of the launch, visit the UK STEREO website.

We asked Doctor Chris Davis about Coronal Mass Ejections (CMEs), which the HI onboard STEREO will be examining:

How can CMEs potentially affect the Earth?

Each CME contains the equivalent energy of 100 times the world's nuclear arsenal travelling at a million miles an hour. If one of these clouds reaches the Earth, this energy has the potential to damage Earth-orbiting spacecraft, disrupt navigation systems and cause power surges on the ground. We need to understand the extremes of this 'space weather' if we are to manufacture spacecraft that will survive this harsh environment and also to provide a warning system if mankind is to travel to the Moon and beyond where humans are outside the Earth's magnetic field and protective atmosphere.

HINODE (Solar-B)

RAL involvement: EIS Instrument - Extreme ultraviolet Imaging Spectrometer

Project Co-Investigator: Dr Peter Young

Launch:

At 10:36pm on Friday 22nd September 2006, Solar-B launched successfully from Uchinoura Space Center, Japan. Santiago Station tracked SOLAR-B satellite, and confirmed satellite separation and solar panel deployment. SOLAR-B was given a nickname of "HINODE" (meaning "sunrise").

Mission:

Solar-B will study the sun in great depth. The Extreme ultraviolet Imaging Spectrometer (EIS) is a UK-led instrument on Solar-B that accurately measures the energy processes taking place before and during solar flares, which will allow us to identify the precise mechanism involved. RAL 's contributions to the EIS instrument include instrument assembly activities, calibration, software design and thermal analysis work, and will include participation in operations and in-flight calibration. Our Solar Physics group have world-leading expertise in the analysis of ultraviolet data and will exploit the Solar-B data in collaboration with other UK Solar Physics groups.

See recent data and images received from Hinode.

We asked Doctor Peter Young about the mission:

Why are so many different satellites and observatories needed to study the Sun?

SOHO was launched in 1995 to give a complete view of the Sun's behaviour, from its deep interior out to the tenuous gas flowing past SOHO in the solar wind. It continues to observe the Sun for 24 hours each day with 12 different instruments and has been a huge success, revolutionizing our view of our closest star. These new data have raised many new questions for scientists, and the recently-launched Japanese satellite, Hinode (previously called Solar-B), will study in particular the most spectacular of all solar events: solar flares. What causes them? How do they release so much energy? Hinode uses the improved technology we have today to answer these questions.

The purpose of the most recently launched solar mission, STEREO, is to study the Sun in a new kind of view, in three dimensions. Rather than sitting in between the Sun and Earth looking directly at the star, the twin satellites of STEREO will be able to view both the Sun and distance in between from a position following the Earth in its orbit, not in front of it.

The future mission planned to study the Sun is the 'Solar Orbiter' currently due for launch in 2015. This mission will also be different in its approach - this time the satellite will attempt to view the Sun from a far closer range. Using a tilted elliptical orbit the observatory will hopefully be able to give us much improved detail of the surface of the Sun as well as views of the Sun's polar regions - the satellite being outside the plane of our solar system for some of its orbit.

SOHO

RAL involvement: CDS Instrument - Coronal Diagnostic Spectrometer

Principal Investigator: Dr Andrzej Fludra

Launch:

SOHO was launched from Cape Canaveral Air Station, Florida, atop an Atlas IIAS rocket, at 08:08 UT on Saturday 2 December 1995. The 1.6 tonne observatory was released into its transfer orbit from the rocket's Centaur upper stage about two hours after launch.

Mission:

This European Space Agency (ESA) cornerstone mission is a joint venture with the National Aeronautics and Space Administration (NASA), to study the Sun, from its deep interior, through its atmosphere, out to the heliosphere, including the solar wind and its interaction with the interstellar breeze.

Visit our SOHO webpage to find out more...

We asked Professor Richard Harrison, a former project leader, about the mission:

How much interaction and collaboration with other space agencies, universities and industry was required for the SOHO mission?

Space instruments are at the cutting edge of technology and the expertise for different aspects of that technology will reside in different organisations.

Although RAL led the design and build of the UK instrument on SOHO, and still leads the operation of that instrument, we did that by including a variety of groups from the UK, Norway, the USA and Germany. Thus, a space instrument consortium often includes five or more hardware groups. As the lead team, we also act as the principal interface to ESA and NASA, which includes the discussion and design of interfaces between the instrument and the spacecraft and, later on, all operational aspects.

Was this in keeping with most missions in your experience?

SOHO was typical in terms of the consortium structure and the interfaces to ESA and NASA. What is not typical is the fact that we now have daily hands-on operations. We actually control our own instrument using daily commands and we coordinate that we a group of active scientific groups from around the world, running scientific operations planning through a series of monthly, weekly and daily planning sessions. In that sense, this is exciting stuff - you are not usually allowed to get your hands so dirty!