Cygwin is required by the Windows version of SDDAS. Cygwin is a UNIX
emulation layer for Windows. It is easy to install and offers all
the utilities of a UNIX system on the Windows platform.
On the Windows platform, you must also have an X Server. Many commercial ones are available, but if you want a decent free one, this is the only one
that works.
If you just want to look at Cluster or Mars Express data, but do not want to install SDDAS, the following websites might be exactly what you need: