Engineers at the European Space Agency (ESA) are getting ready for a Windows 98 upgrade on an orbiter circling Mars. The Mars Express spacecraft has been operating for more than 19 years, and the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) instrument onboard has been using software built using Windows 98. Thankfully for humanity and the Red Planet’s sake, the ESA isn’t upgrading its systems to Windows ME.

The MARSIS instrument on ESA’s Mars Express was key to the discovery of a huge underground aquifer of liquid water on the Red Planet in 2018. This major new software upgrade “will allow it to see beneath the surfaces of Mars and its moon Phobos in more detail than ever before,” according to the ESA. The agency originally launched the Mars Express into space in 2003 as its first mission to the Red Planet, and it has spent nearly two decades exploring the planet’s surface.

MARSIS uses low-frequency radio waves that bounce off the surface of Mars to search for water and study the Red Planet’s atmosphere. The instrument’s 130-foot antenna is capable of searching around three miles below the surface of Mars, and the software upgrades will enhance the signal reception and onboard data processing to improve the quality of data that’s sent back to Earth.

Image: ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO

“We faced a number of challenges to improve the performance of MARSIS,” explains Carlo Nenna, a software engineer at Enginium who is helping ESA with the upgrade. “Not least because the MARSIS software was originally designed over 20 years ago, using a development environment based on Microsoft Windows 98!”

The ESA and operators at the National Institute for Astrophysics (INAF) have relied on a technique to store lots of high-resolution data on the MARSIS instrument, but it fills up the onboard memory quickly. “By discarding data that we don’t need, the new software allows us to switch MARSIS on for five times as long and explore a much larger area with each pass,” says Andrea Cicchetti, a MARSIS operation manager at INAF. “The new software will help us more quickly and extensively study these regions in high resolution and confirm whether they are home to new sources of water on Mars. It really is like having a brand new instrument on board Mars Express almost 20 years after launch.”

The ESA hasn’t detailed the exact software that the MARSIS is being upgraded to, but it’s unlikely the team has upgraded its CPU and enabled TPM 2.0 in the BIOS to get Windows 11 installed. Right?