Surrounded by a multitude of craters, this environmentally stable sector was chosen to host the now thriving Moongate Hub. With the subsequent construction of its very own cosmoport, the base has truly become a gateway to the stars and beyond.
Server-wide progression within this zone resulted in the development of new infrastructure, such as a fast travel system for quickly moving to different areas. In later stages, new areas to explore and new missions were unlocked. For the in-game development stages, see the above link.
While the first three stages are progressed rapidly to unlock the initial fast travel system (most servers completed them within hours of the release of patch 7.21), the subsequent stages require significantly more effort.
The following missions have time requirements (2 missions per crafter and gatherer). Each time window lasts for 2 hours Eorzea Time. Rank A EX+ mission availability for a given class is always 12 hours offset from its Rank A mission window. In addition, time-restricted EX+ missions require Development Log 8 to be unlocked in the world. The FSH EX+ mission requires Development Log 13 to be unlocked.
All time-restricted missions are prerequisites for certain sequential missions.
Certain missions in Sinus Ardorum appear in one of two specific weathers: Moon Dust or Umbral Wind. Each of these weathers is available 15% of the time (the remaining being the default Fair Skies weather), so there is a 30% chance of any weather-restricted missions being up.[1]
There is no skywatcher in the zone, but the weather and the corresponding missions that are available can be tracked using this site. This is made possible because the weather directly tracks with that in Ultima Thule: Umbral Wind in Ultima Thule means Umbral Wind in Sinus Ardorum, and Astromagnetic Storm in Ultima Thule means Moon Dust in Sinus Ardorum.
Weather-restricted missions are distinct from critical missions, which only spawn during Red Alerts and are specific per world.
There are four weather-restricted missions for each crafter, six each for miner/botanist, and five for fisher. In addition, some weather-restricted missions require two classes.
* Also requires Development Log 8 unlocked in the Infrastructure Index.
** Also requires Development Log 13 unlocked in the Infrastructure Index.
Sequential
Completing certain missions with a gold star rank are prerequisites for unlocking other missions. These sequential missions then become available with no time limit. The prerequisite mission needs to be completed with a gold rank each time the player would like to attempt a sequential mission. There are 2-3 missions in a given chain. Some prerequisite missions are time-restricted.
Sinus Ardorum is what we call this crater we occupy. Believe it or not, we've got a fairly stable living environment nestled in here. They say that Namingway dreamt up the name and its meaning. Fitting, considering he did the same for countless landmarks in Mare Lamentorum some thousand years ago. For a blessing, this place has ready access to stellar currents, making it an ideal port to harbor a starship! I'm told they're akin to the aetherial currents you might find back home.
Sinus Ardorum is Latin for Bay of Ardor as in passion. (The "fire" meaning is metaphorical. Literal fire would be Sinus Ignium.)
Historical Notes
A number of quality-of-life changes were made in Patch 7.3[2]. Many of these addressed player feedback received during the initial launch of Cosmic Exploration:
The option "Travel to Sinus Ardorum" was added to the aetheryte in Bestways Burrow. (Previously players needed to travel to Drivingway and speak with them in order to travel to Sinus Ardorum.)
Mounts can be summoned in Sinus Ardorum, although flight is unavailable. (Previously mounts were not allowed.)
A summoning bell was placed in Sinus Ardorum at (X:21.0, Y:21.8). (Previously players were unable to summon retainers while in this zone.)
The notation indicating difficulty of Class A missions has been adjusted, with "EX" and "EX+" indicating the second and third tiers of increased difficulty. (Previously the labels "A-1", "A-2", and "A-3" were used to indicate the tiers of difficulty in increasing order, but this was unclear to many players.)
The time allowed for most Stellar Missions was increased. The time allowed was not increased for EX+ missions that could be accepted by only one class. (Previously the time limits for many missions were very tight, with many of the most difficult missions being impossible to complete even with best-in-slot gear and buffs unless the players were extremely lucky with random procs during the missions.)
The sound effects played when starting and completing stellar missions were changed.
When completing a stellar mission, the amount of experience gained for bronze and silver ratings was increased such that all rating tiers granted the same amount of experience. (Previously the amount of experience gained was based on whether a player achieved a bronze, silver, or gold rating, with gold awarding the most.)
When completing missions that can be accepted by multiple classes, each class will earn points toward their cosmic class score. This applies to several missions which involve one part as a gatherer and another part as a crafter. (Previously only the class used when reporting the mission as complete earns cosmic class score.)
Players can confirm the relative distance to the site of stellar missions via the Stellar Missions window. (Previously there was no indicator, which caused issues for gatherers who may have initiated a mission that was on the opposite side of a large map with limited mission time and limited traversal options.)
When undertaking stellar missions, the objective and gold star rating requirements will be displayed. (Previously the gold star rating requirements were not displayed until the silver star rating was achieved. This made it difficult for players to plan appropriately for gold star ratings without using external resources.)
A notification marker indicating the availability of provisional missions will appear in the Stellar Missions window. (Previously no notification indicator displayed, so many players did not know when provisional missions became available to them.)
Notifications will be displayed when sequential missions become available. (Previously no indicator displayed. This was especially challenging for sequential missions, as many players did not know that sequential missions existed and became available upon the completion of a prerequisite mission.)
The time limit for accepting sequential missions after they appear was removed. (Previously sequential missions were available for only 5 minutes after the previous quest was reported. This caused issues for gatherer sequential missions, due to the GP replenishment issues at the time.)
When a Red Alert has been issued, the time remaining to accept critical missions will be displayed in the Stellar Missions window. (Previously only the time remaining to turn in critical missions was displayed. New critical missions could not be accepted within roughly the last two minutes of the Red Alert.)
When both Red Alert progress gauges are filled, periodic announcements will indicate that the alert is nearly resolved.
The Mission in Progress window will automatically display when reporting is the only remaining step to completing a mission. (Previously players needed to open the Mission in Progress window upon completing the objectives for the mission, a minor annoyance due to how frequently it happened.)
The Mission Log will indicate when further exploration is required to trigger a mission.
Upon completing gathering stellar missions, gatherers will recover GP equal to the total amount spent during the mission and the recast timer of GP recovery items such as cordials will be reset. (Previously gatherers needed to wait several minutes to replenish GP after a mission and for the recast timer of the cordial to complete.)
When stellar missions for botanists and miners are graded based on successive gathering chains or gatherer's boons, the evaluation criteria and scores will be displayed in the chat log. (Previously there was no clear communication to players how these were scored, so they may not have understood that longer chains provided substantially more points than shorter ones. As a result, these missions would have appeared impossible for those players, as chains of 4+ were required to get gold star ratings.)
When stellar missions for fishers are graded based on collectability, Collect must be activated to begin fishing. (Previously Collect was not required to start fishing, but players could not increase their score without Collect active.)
The time limit of both Mech Ops ("Directive: Destroy Corrupted Crystals" and "Directive: Clear Toxic Lunar Spongoi") was increased from 5 minutes to 10 minutes, and the amount by which ground support contributes to the progress gauge during the Mech Ops was increased. (Previously, if no pilots were active for the Mech Ops, it was impossible for ground support players to complete it within the time limit due to the low amount they contributed to the progress gauge.)
When a project has been completed, and progress advances to the next stage, "Announcement" will be displayed at the top of the screen if no new project is underway.
A notification window will automatically appear if there has been any progress in ongoing projects since your last visit to a cosmic exploration area.
Requirements for certain Stellar Successes were changed. (Previously players needed to "unlock" a particular class of missions to complete some Stellar Successes. The revised requirements are functionally the same, but are clearer for what the player needs to do to complete them. For example, one had the requirement "Unlock class C stellar missions for carpenter on the moon," a process which requires the player to complete three unique class D missions for carpenter. The revised text now says "Complete three unique class D missions for carpenter on the moon.")
• 
: 
A Cosmic Homecoming
A Cosmic Homecoming
Endwalker.
Cruisingway (X:20.6, Y:19.5) - travel to other Cosmic Exploration planets
Orbitingway (X:21.8, Y:21.1) - Cosmic Fortune
Researchingway (X:21.1, Y:21.8) - Cosmic Tools
Alerot (X:22.4, Y:20.3) - Mech Ops pilot tickets
Starward Standings Stela (X:21.2, Y:21.1) - view the seven most recent Star Contributors
Carpenter
Blacksmith
Armorer
Goldsmith
Leatherworker
Weaver
Alchemist
Culinarian
Miner
Botanist
Fisher
Moon Dust or 
Umbral Wind. Each of these weathers is available 15% of the time (the remaining being the default 
Fair Skies weather), so there is a 30% chance of any weather-restricted missions being up.[1]
Astromagnetic Storm
Meteor Showers
Sporing Mist
10 
10
Big Bang Ticket (Sinus Ardorum)
Vacuum Suit Identification Key
Stargazers
Carrots of Passion
Carrots of Happiness (Forge Ahead)
Hey, Cid!
Battle 1 from FINAL FANTASY IV
The Airship
Astromagnetic Storm Red Alert
Meteor Showers Red Alert
Sporing Mist Red Alert
Sinus Ardorum hub
work center
mech hangers
spaceport
interstation transport
travelling between stations
habitat module
Piercingway Tunnel Stage 1
Base Camp Gamma
energy and water storage
spaceport and hangar upgrade
Nadir Lift Stage 1
Nadir Lift complete
Lunar Nadir
Chlorophosvault
complete hub with dome
hub's core
celebratory photo shoot
Galactic Way on spaceport
Galactic Way side view
Galactic Way rear view
Collect must be activated to begin fishing. (Previously Collect was not required to start fishing, but players could not increase their score without Collect active.)
Abalathia's Spine
Gyr Abania
Norvrandt
The Northern Empty
Yok Tural