The International Ultraviolet Explorer (IUE) was a space mission which operated between 1978 and 1996. The final merged log of IUE observations, published in 2000, contains a vast collection of 110033 spectra, which are still of scientific value decades later.

A special operation was performed in 2000 at the Strasbourg astronomical data center (CDS) to provide links between astronomical objects from the SIMBAD database and the IUE Newly Extracted Spectra hosted at VILSPA by ESA. This resulted in 65872 spectra being linked from 7392 distinct SIMBAD objects.

Despite the considerable growth of the number of objects referenced in SIMBAD between 2000 and 2024 (from less than 3 to more than 18 millions), the links to the IUE archive remained unchanged. We therefore decided to attempt a significant update, trying to provide as many links as possible between SIMBAD objects and the IUE spectra.

We describe in this paper the challenges in trying to improve the discoverability of archival data several decades after the end of the mission. The most time-consuming part is the recovery of information hindered by the use of improper object identifiers, concealed implicit information, and human errors (typos).

Ultimately, we were able to link 99.7\% of the eligible IUE spectra to SIMBAD objects (calibration spectra, and spectra of solar-system objects are not relevant for SIMBAD), compared to only 67.7\% in the 2000 operation. We also generated the space-time coverage of the corresponding spectra using the ST-MOC IVOA standard.
Our work strongly advocates for the Best Practices for Data Publication in the Astronomical Literature (Chen et al., 2022), and also stresses the needs for extra care in the observer's proposal tools and metadata management, in order to facilitate the long-term use and optimal scientific return of astronomical observations.