Curiosity Blog Sols 4804-4811: Kicking Off the Final Phase of Boxwork Exploration

Written by Abigail Fraeman, Curiosity Deputy Project Scientist

Date of the earthworks plan: Friday February 13, 2026

Curiosity spent this week at Gale Crater completing final activities associated with the “Nevado Sajama 2” drill before launching our final phase of the boxwork exploration campaign. As we explored the boxwork region, the scientific team divided our activities into four phases:

• Phase 1: First approach (sols 4534-4570 / May to June 2025) — This phase focused on initial observations of the caisson unit, which resulted in the team’s decision to drill at the Altadena site.
• Phase 2: Establish regional context (sols 4571-4599 / June to July 2025) — During this period, we collected additional observations of the caisson unit between the Altadena borehole location and arrival at the “main” caisson zone. This included a stop at the distinctive “Volcán Peña Blanca”.
• Phase 3: Exploration of the best expressed caisson structures (sols 4600-4805 / July 2025 to February 2026) — This period was the heart of the caisson campaign. During Phase 3, we collected numerous observations of the most well-defined ridges and troughs within the caisson unit, and we used what we learned to select locations where we wanted to drill a trough and ridge. We selected targets named “Valle de la Luna” and “Nevado Sajama” respectively.
• Phase 4: Our Final Look (Soils 4805- ??? / February 2026 and beyond) — We are now launching this phase which will focus on some final crest and trough measurements as well as an exploration of contacts between the caisson unit and adjacent geologic units to the east and south. Once this is completed, we will complete and continue our ascent of Mount Sharp through the new “Valle Grande”.

Our first ride from the Nevado Sajama drill took Curiosity northeast along one of the broad ridges. From near this location we have a good view of the ridges and troughs to the east. We’re particularly interested in getting a better look at a trough that, in orbital data, appears to have interesting-looking bedrock on its bottom, as well as a particularly narrow ridge with many small ridges branching off from it, which the team has dubbed “Los Flamencos.” These images will help us see if we want to drive to one or both items, and they will help us plan the exact places to drive next week. While we’re here, Curiosity will also collect lots of data on the bedrock in front of the rover, with APXS and MAHLI observations planned for targets named “Mollecita” and “Monte Cielo.”

We’ve gotten so much wonderful data on drilling activity over the past few weeks, and it feels really good to be back on the Martian boxwork road to begin this final phase of our boxwork unit campaign.