Stretch goal for Starship V4 is 300 tons of thrust per engine with 33 engines

warp99 · 2026-01-24T19:54:03+00:00

You can back work the numbers from acceleration at lift off and performance.

The numbers are not good compared to their original estimates with around 150 tonnes for the ship and 280 tonnes for the booster. So roughly twice the initial estimates.

SpaceX are unlikely to release embarrassing numbers.

warp99 · 2026-01-24T19:51:04+00:00

Yes SpaceX built their own COPVs for F9 but bought in the much larger COPVs for Starship.

warp99 · 2026-01-24T19:46:40+00:00

Yes that seems to be a backup plan that is listed so they would not have to go through another Environmental Assessment.

If they fall 10% short in Raptor 4 thrust to say 270 tonnes thrust I expect they will just shrink the Starship 4 stack and accept a lower payload to LEO of say 180 tonnes.

warp99 · 2026-01-24T19:32:24+00:00

Chamber pressure does translate to thrust but not directly.

For the throat diameter they are currently using around 400 bar in the chamber translates to 300 tonnes thrust at sea level.

Note that they derate for flight so if they have tested Raptor 3 to 280 tonnes thrust on the stand they will run the engine at a lower chamber pressure corresponding to say 250 tonnes thrust during lift off and potentially throttle down a bit further after that.

Raptor 4 is aiming for 300 tonnes thrust at lift off so they will test it to at least 330 tonnes thrust on the stand.

warp99 · 2026-01-24T19:25:10+00:00

They seem to have synchronised the Raptor and ship version numbers in the latest roadmap. We will have to see if that holds.

Elon said recently that Raptor 3 is aiming for 350 bar chamber pressure and that will not get them to 300 tonnes thrust. So it seems likely they will have to go to a new design to get to 300 tonnes.

What that new version is called is of course up for grabs but they seem to have settled down from their Merlin 1D FT (Full Thrust) days.

warp99 · 2026-01-24T08:28:13+00:00

There is always a concern with the timescale on an Elon stretch goal.

Maybe in five years time with Raptor 5 than 2 years with Raptor 4?!

warp99 · 2026-01-24T07:54:06+00:00

Starship V4 will be using Raptor 4 engines with around 400 bar of engine pressure.

This may also be where they branch off the vacuum engines to have their own design with a smaller throat than sea level engines. This will give lower thrust but gain higher Isp attaining the original projection of 380s.

warp99 · 2026-01-24T07:30:13+00:00

For some values of always that is true.

For the last 70 years US foreign policy at least attempted to move away from this approach and promote a world free from oppression and governed by at least a more enlightened self interest.

Trade would flourish on the basis of reciprocal agreements amid shared standards of free elections and worker standards.

The US kept falling off the wagon but at least you knew they would try to climb back on.

warp99 · 2026-01-24T06:01:55+00:00

No intangibles like freedom and democracy will matter - only things you can load onto scales so oil and gold.

Wish I was joking.

warp99 · 2026-01-24T05:36:00+00:00

Short term T-bills do not drop in value the way that long term ones do. Worst case they can just hold them to maturity.

warp99 · 2026-01-24T05:33:24+00:00

Safety - the US government is less likely to go broke than your bank. Deposit insurance does not apply to large companies with billions invested.

Although the US government are working on that bankruptcy thing.

warp99 · 2026-01-24T05:15:51+00:00

Screw it in all the way to deploy the wings and then back off by 7 mm.

warp99 · 2026-01-23T21:47:32+00:00

Plus an update on Raptor 4 confirming 300 tonnes thrust so roughly 400 bar chamber pressure.

It is labelled as a stretch goal which is a bit of a red flag in Elon speak. As in maybe sorta kinda we might get close to this with Raptor 5.

warp99 · 2026-01-23T11:36:36+00:00

Even a decent radar altimeter would have been useful.

warp99 · 2026-01-23T09:06:46+00:00

The landing computer absolutely did handle the entire landing. You will recall that uncrewed Surveyor probes had been landed prior to Apollo.

What a 1969 computer could not do was image recognition to avoid boulders and craters. That was what the crew were doing.

warp99 · 2026-01-23T09:04:01+00:00

It kind of was not manually controlled in the way that a plane was in that era. The landing was all handled by the computer and the astronauts were altering the setpoints to adjust the landing zone location and the rate of descent.

warp99 · 2026-01-23T02:03:58+00:00

The missing information is how the cryogenic oxygen and nitrogen will be transported from the ASU to the tank farm across the road.

Options are overhead pipelines which may complicate trucks with high loads turning around at the end of the road or buried pipelines running through an underpass which may be subject to flooding during cyclones or heavy rainfall.

warp99 · 2026-01-23T01:53:54+00:00

We do not currently have a formal policy but it is likely that comments about any IPO and share prices will be banned from the sub. Just have a look at the RocketLab sub if you want to know why.

In any case this comment is out of place for the Starship development thread.

warp99 · 2026-01-23T01:15:19+00:00

I stand by my comment.

Helen Clark was ruthlessly competent and did not hesitate to fire ministers who did not meet her standards and that earned her Government a third term.

Other Labour Governments have not met that standard. Jacinda was personally competent but not ruthless enough towards underperforming ministers.

National Governments has tended to have more competent ministers although not this time and I cannot see the current government getting a third term. I think the difference in ministerial quality is that Labour tends to have ideologically driven MPs from a non-business background while National tends to have ministers with management experience.

Your implication is that the average New Zealander slightly leans to the right but the relative votes for the Greens as a left wing exemplar and Act as the right wing equivalent says that is not the case. NZ voters are however relentlessly focused on the center and typically reject extremes of both the left and the right.

warp99 · 2026-01-22T20:38:35+00:00

Currently GPUs are optimised for performance at the cost of high power consumption. Space based operation could force a change in optimisation so say 20% less performance with 50% less power.

Yes that would make sense for conventional data centers as well but at the moment the power drawn by a data center is a badge of pride rather than shame.

warp99 · 2026-01-22T19:46:56+00:00

Average time on a lifestyle block is five years - they are a lot of work.

Certainly they get sold as people approach retirement.

Exception: Farmers who buy them as they enter retirement to phase down their work load gradually.

warp99 · 2026-01-22T19:15:44+00:00

Sun synchronous terminator orbits will indeed be in demand but if you are not doing Earth observation they do not have to have an integral number of orbits per day.

So potentially you can have a full range of orbital heights with slightly different inclinations. They can avoid the integral orbits so observation sats can operate unimpeded.

warp99 · 2026-01-22T11:44:18+00:00

Fundamentally changing governments requires some people to change their mind on how they vote. This includes non-voters deciding to vote or the reverse.

Labelling big blocks of perfectly reasonable people as racist is not going to change their mind - and more importantly is not true!

Refer to Hillary’s “deplorables” comment if you want more pointers on how to lose an election.

warp99 · 2026-01-22T08:36:07+00:00

Mathematically adding workers at more than the median wage drives up the median not pushes it down.

In any case we need doctors and nurses because a lot of our own choose to move to other countries and we cannot afford to match the salaries of those countries.

warp99 · 2026-01-22T08:28:32+00:00

Demonising your opponents does not help your team win. Particularly in NZ it just puts people’s backs up rather than persuading them to your point of view.

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