3,393LY below the galactic plane and back - the Great Escape from Trieneou AA-A h2

On 12 May 3305, the starship Endurance reached Trieneou AA-A h2, 3,393LY below the galactic plane. Less than 20 minutes later - barely 7 minutes before the return journey became impossible - she escaped the system, making the rendezvous with her support tanker with less than 400kg of fuel remaining onboard.

This discovery has been nearly a year in the making, and is very much a community achievement. I will put full details in the second post, but before I go further I would like to give due credit to those Commanders who made the voyage possible:
  • Taen - developer of the innovative ‘pre-fuelling’ technique needed to carry enough fuel, and first visitor to the system, providing intra-system distances essential to planning the return trip
  • BooT CZ - support tanking for the flight and the two test runs
  • NotableOregon13 - support tanking for the second test run
  • Dystopia - outfitting advice for an extreme range Anaconda
  • Iain666 - correcting my assumptions for the maths behind the Guardian FSD booster with fuel log data and a new hyperspace fuel equation correction factor
The Trieneou sector lies just north-east of Colonia, far below the galactic plane. The existence of AA-A h2 has been known for some time now; it was first visited by CMDR Taen on 9 July 3304. The only route down is via DL-Y g3, which is 332.38LY away - very close to maximum range, even for a range-maxed Anaconda. At the time it was not possible to carry sufficient fuel for the jump back, and as AA-A h2 has no fuel star only a one-way trip could be made. I was able to make the return journey thanks to several factors:
  • Discovery scanners (FSS and DSS) are now massless
  • The new G5 lightweight life support blueprint
  • My exceptional legacy lightweight sensors (11.58T)
  • Taen’s clever ‘pre-fuelling’ technique, providing an extra 1T of fuel to a ship as it jumps away. This idea was a stroke of genius without which the return trip would not have been possible; all the previous factors combined still cannot give an Anaconda enough fuel to get back.
Even with all of the above I calculated the fuel remaining upon returning to DL-Y g3 at just 400kg. The matter is complicated further by the location of the neutron star at AA-A h2, which is over 357,000LS from the system entry point, requiring around 16 minutes of supercruising to reach. Both main and reserve fuel tanks must be fuelled precisely - almost to the kilogram - to ensure that the ship is light enough to make the jump there, has enough fuel in the main tank for the jump back, and enough fuel in the reserve tank for the long supercruise flight to the neutron star.

The last of those three requirements is what made this trip particularly nerve-wracking. If the reserve tank depleted before I could supercharge and escape, it would draw 1.07T from the main tank to refill - leaving me stranded without enough fuel for the jump back. Once I arrived it was a race against time to reach the neutron star! I had balanced the tanks to give myself around 27 minutes of total flying time at AA-A h2. After carefully supercharging (the neutron jet cones were tiny) I spent a couple of minutes taking pictures before using the last of my main tank fuel to jump back. This was my fuel gauge when I reached BooT:


There isn't very much to see down there - but here are a few pictures I snapped. I do have video footage so I may make a little montage.

Racing to the neutron star
Made it!
Heading home
Safe at last


The long version

This discovery is the result of a comprehensive effort (by Taen and me) to map the upper and lower reaches of the galaxy, searching for record-breaking places to visit. On 8 September 3303 I flew the Endurance to 3,381LY below the galactic plane, returning via the now-defunct double neutron supercharge. That system - Vahsel Point (Kyli Flyuae AA-A h4) - marked a record new lowest system visited, and also a record furthest distance from the galactic plane in either direction. But, records are made to be broken…

Fast forward several months and we were given Engineers 3.0 and the Guardian FSD booster. These combined to push jump ranges up by about 50LY - but a record-breaking return trip would now require a neutron star in the destination system. I set about scouring the galaxy map for potential new record-breakers. Independently, CMDR Taen was doing likewise - although we were not aware of each other’s efforts initially.

Systems lower than -3381LY, or higher than +3354LY (the double-supercharged height record) were few and far between. Of these, only a handful had neutron stars, and only one could actually be reached - Trieneou AA-A h2. I thought I was onto a winner until I arrived at the jump-off system (DL-Y g3) and saw the massive distance to AA-A h2. Some maths confirmed my suspicions that even a range-maxed Anaconda could not carry enough fuel for a return journey; the galaxy map showed no fuel stars down there, so I moved on and continued my search.

Shortly afterwards I saw CMDR Taen had visited AA-A h2 on a one-way trip; we got discussing and realised we were attempting the same thing. Taen had developed an innovative ‘pre-fuelling’ technique, whereby a ship could receive fuel from a support tanker during the 4-second hyperspace countdown. However, 1T of extra fuel did not provide enough extra fuel to make the return trip viable - even for a ship carrying no discovery sensors. It was not clear if the technique could provide more than 1T (I was working on the assumption that it could not; it may in fact be possible).

I subsequently made one-way trips to -3397LY and -3433LY, whilst Taen reached +3450LY one-way to set new records for the highest system visited and furthest distance from the plane. But a return trip that surpassed Vahsel Point continued to elude us.

The big exploration update made discovery sensors massless. The return trip was still not viable - but it was agonisingly close, with less than 1T extra fuel needed. Etienne Dorn duly obliged by developing the G5 lightweight life support blueprint, saving another 800kg. The return trip was now theoretically possible. However, the margin was tiny - just 400kg - and that was with my god-rolled legacy lightweight sensors (11.58T - saving 1.22T compared to the new G5 blueprint). Then I looked up the system on EDSM to check the distance to the neutron star (possible thanks to Taen’s visit) to find it was just over 357,000LS from the system entry point. This meant both main and reserve fuel tanks would need to be balanced perfectly. Too much in either and the ship would be too heavy for the jump down. Too little in the main and there wouldn’t be enough for the jump back. Too little in the reserve and it would deplete before I could reach the neutron star - and take just over 1T from the main tank to refill, again leaving me without enough to jump back. Even if all this could be worked out, there would be no time for sightseeing - it would be a race against time to supercharge and escape before the reserve fuel ran out.

To complicate matters even further, there are no fuel stars along the route, and the neutron star in DL-Y g3 is also a considerable distance (around 112,000LS) from the system entry point. The practicalities of pulling this off looked decidedly far-fetched…but maybe not impossible. Upon my return from Distant Worlds 2 I set about building the extreme range monster and planning a serious attempt at the return trip. The route is as follows (all systems Trieneou sector):
  • TO-Q e5-0 (class A)
  • TO-Q e5-4 (neutron star)
  • DL-Y g3 (black hole and neutron star) - including a supercruise of ~112,000LS
  • AA-A h2 (two black holes and a neutron star) - including a supercruise of ~357,000LS
Here is an overview of my flight plan:

Preparations included:
  • Finding a system with two stars 357,000LS apart, and supercruising between them to determine the time it would take.
  • Making the supercruise flight to the neutron star at DL-Y g3 to time that.
  • Measuring the speed at which the FSD would engage so I knew how fast to fly for the pre-fuelling manoeuvre.
  • Determining the exact distance I needed to be from the fuel star at TO-Q e5-0 so the fuel scoop would immediately work at maximum rate when I powered it up. This was so I could calculate exactly how much fuel I was taking onboard by timing the scooping period; I used a 2A fuel scoop (75kg/s) to achieve the necessary precision.
  • Measuring the fuel consumption of all modules needed for the flight and determining for each phase which of them would need to be powered up.
  • Obtaining the exact distances between the systems in the route - then creating a replica course with the exact same distances near Colonia so that I could test the flight plan.
At this point I reached out to my Distant Worlds 2 buddies to ask for willing fuel tankers. BooT CZ and NotableOregon13 were kind enough to volunteer, and we conducted two test runs, to practice Taen’s pre-fuelling manoeuvre and test my fuel calculations. The ship’s jump range at each stage of both tests was almost exactly as predicted. At the end of the second test I used a neutron star to return to the simulated jump-off system and rendezvous with my wingmen, after waiting in supercruise for 16 minutes to represent the long flight I would have to make to the neutron star at Trieneou. Crucially, my estimate of the remaining supercruise flying time was also accurate. We had proved the return flight was possible.

On 12 May 3305 BooT and I descended to the Trieneou sector and winged up at TO-Q e5-0 to confirm instancing. BooT then headed for the neutron star at DL-Y g3, whilst I began the 11 minute reserve fuel burn needed at the start of the flight. This was actually the most nerve-wracking part of the trip as I had nothing to do but sit and wait. After the flight began, the practice paid off and everything ran like clockwork, scooping fuel for just the right amount of time before heading off to join BooT. We rendezvoused successfully, 3,214LY below the galactic plane, and BooT formed up astern as I set course for AA-A h2. Speed was set - 115m/s. FSD - charged and ready. The limpet latched on - I gave it one second before pushing the throttle to the stops. The fuel transfer completed and I was on my way.

Arriving, I zoomed past the black hole and honked the FSS, immediately setting course for the neutron star. But what was my jump range? I checked to see if all the maths was right - 84.27LY! There was enough in the main tank to get back. I shutdown the Guardian FSD booster and sensors to conserve fuel. The one other thing I was worried about was other bodies in the system being in my way, slowing me down with their gravity wells - but there is only one, a second black hole that is in a close orbit with the neutron star.

After all the excitement, I then had nothing to do for around quarter of an hour. My reserve fuel calculations proved accurate - I reached the neutron star with just over 10 minutes of flying time remaining. After supercharging and setting course back to DL-Y g3, I grabbed a couple of pictures - and then got out of there PDQ. In the meantime, BooT had supercruised back to the black hole at the entry point of DL-Y g3 to meet me on my return and replenish my fuel. I had calculated 230kg remaining in the main tank and 170kg in the reserve tank. Shortly thereafter we met again back at the start of the route, before returning to Colonia (rather slowly in my case, owing to the tiny 2A scoop) to register the discovery.

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Amazing. Just amazing. Congratulations.

It is a shame the jump range does not update in real time while you are watching the ship info since 3.3 (should we raise a ticket?).
If you want to check how close you were to the death, in the logs you should be able to find the exact amount of fuel you had left in the FSDJump event.
Excellent and well done! This will get noted in the GMP as a terrific new job.

Taen had hinted to me about a new fuel trick, and I had guessed it was fuel-limpets while jump-charging. Good to know I guessed right!
I congratulate and envy at the same time since I'm a big fan of highs and lows of the Galaxy. Now trying to break +3 kylies from the plane so I feel like a little puppy in comparison... ;)
Great! :)
This would have been kind of boring with the double-charge bug/exploit/feature, you have to admit ;)
A priori, the return journey was theoretically possible even without the recent mass reductions and Taen’s pre-fuelling trick. DL-Y g7 is scoopable and close enough to AA-A h2 that it could be reached without much fuel. From there one can jump to DL-Y g2 - but no further; the nearest star above it is about 190LY away, which is too far for a synthesis boost (neither g2 nor g7 has a neutron star). I spent many hours scouring the galaxy map for such a route back, to no avail. If the double supercharge was still possible, one could use it when departing AA-A h2 for DL-Y g7; after refuelling, the second supercharge would have easily provided enough range to complete the return leg.

However, I am glad that I never got the chance to try this, because the AA-A h2 neutron star has the thinnest wispy little jets I have ever seen. I didn’t hang around to check their orientation, but the double supercharge would most likely have failed!
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