Will a Starship go to Mars in the 2026 launch window?

[meekGee]

How cool would it be if the mars ship opens a door and drops payloads from its height?

Imagine basically a non-0-g pez-like dispenser and door, but each payload package has a rapelling lanyard?   Hopefully cylindrical, but the pile at the bottom would be hilarious.

I'm assuming the last ones are robots in order to start unpiling them...  Or the first ones, in order to move each successive package.

I'm just thinking like whoever it was that invented the Falcon Starlink deployment concept. Probably his name was Chuck.

Idea being less things to develop for 2026...No external elevators, in-ship conveyance is solved already, and robots get to demonstrate agility...

[daedalus1]

So a setback already. The orbital launch mount has stopped work to convert it back, and it is being made a Starship testing mount again.

T - 17 months

[meekGee]

So a setback already. The orbital launch mount has stopped work to convert it back, and it is being made a Starship testing mount again.

T - 17 months

You're embarrassing yourself.

[daedalus1]

So a setback already. The orbital launch mount has stopped work to convert it back, and it is being made a Starship testing mount again.

T - 17 months

You're embarrassing yourself.

I know you are not interested in facts.

[envy887]

Like they may run late, and there won't be dedicated Mars vehicles, they'll just chuck something in the general direction...

That's my thought.  Just do something.  Throw mass in the general direction of Mars, and if it blows up on the way there, well we learned more than we did before.

Yeah.

I think the chance of a Mars landing in 2027 (launched in 2026) is incredibly low.

An interplanetary cruise test (does the fuel boil off, can Raptors restart after months, etc.) pointed in the general direction of Mars (TMI, but no EDL) might be possible. Whether that fits this thread's criteria *shrug*. I meant "to Mars" to be that broad (going through TMI counts even if it doesn't make orbit or landing) but others might disagree.

I think an interplanetary cruise test like that might be possible in 17 months IF

1) V3 comes into service fairly smoothly (no more than one explosive failure setting back from what had previously been achieved)

2) they get FAA permission to do full-orbits by spring of next year (demonstrating relight with either the last couple v2 or the first or second v2)

3) propellant transfer test is demonstrated successfully by summer of next year (August or so)

Those imply 4) no major GSE destruction costing multiple months to repair

--

I don't think Ship reuse is actually necessary for this. They could demonstrate relight with Ships already built (37 or 38). One or two v3 flights to demonstrate v3 also works, a couple Starlink launches, two Ships for propellant transfer test, add two or three more for further destructive mishaps, five or so for the actual cruise test (1 + 4 tankers)... That's only 16 Ships or thereabouts (the first one already built), so I think they could build that in 17 months

That does require NASA letting them delay the HLS test until early 2027, or building even more Ships, though.

4 tankers is highly pessimistic. Getting a ship to TMI with a minimal payload is probably feasible with 0 tankers and 1 expended booster, or 1 tanker with booster recovery. Maybe 2 tankers, if you really want a lot of margin or performance of the next Starship version ends up being very low.

[Lee Jay]

Getting a ship to TMI with a minimal payload is probably feasible with 0 tankers and 1 expended booster, ...

I seriously doubt that.

[envy887]

Getting a ship to TMI with a minimal payload is probably feasible with 0 tankers and 1 expended booster, ...

I seriously doubt that.

The Silverbird calculator says they can reach C3=8.7 with payload if they hit 6.5% dry mass on the booster and 7.7% on the upper stage, with the "Version 2" / "Next Gen" prop mass numbers. That's a 250 t booster and 120 t ship. I think that's probably feasible, especially if they take off a few EDL parts they don't need like TPS, flaps, and fins.

I think SpaceX would much rather recover the booster and try for refueling, but a expended shot isn't outside the realm of possibility.

[crandles57]

Getting a ship to TMI with a minimal payload is probably feasible with 0 tankers and 1 expended booster, ...

I seriously doubt that.

The Silverbird calculator says they can reach C3=8.7 with payload if they hit 6.5% dry mass on the booster and 7.7% on the upper stage, with the "Version 2" / "Next Gen" prop mass numbers. That's a 250 t booster and 120 t ship. I think that's probably feasible, especially if they take off a few EDL parts they don't need like TPS, flaps, and fins.

I think SpaceX would much rather recover the booster and try for refueling, but a expended shot isn't outside the realm of possibility.

No fuel left after TMI and boil off would mean no aerocapture attempt and the mission is just a PR, Optimus wave as Mars goes by.

If that is all they can do then I am certainly not ruling it out. If that is what it is then no TPS or front flaps is needed on ship but a last minute decision to go for this and removal may not save as much mass as not installing in the first place? Do fins on ship have fire suppression gasses that are still needed? Besides removing grid fins on booster is there much else that could be removed from a booster that is changed to being expended mission booster with just a months notice?

PR, Optimus wave mission seems to be of minimal use? Long cold soak engine relight test is possibly one use but could be done orbiting la grange point and this offers more timing flexibility.
   
The bigger gains I think SpaceX will want to aim for include some of:

Aerocapture at mars data
Reaching Mars orbit
Deploying marslink satellites
Attempting ED for data
Attempting EDL for data
Successfully landing
Unloading Starship
Pics of Optimus walking on Mars

I think SpaceX will try to hold on to deploying marslink satellites as long as it is remotely possible.

For Marslink deploy, what is needed?

1. Single use heat shield (flight 6 plus improvements since then may be sufficient for Mars aerocapture to orbit?)
2. Refuelling (from expended tanker ok, if they only need 1 2 or 3 tankers? Maybe 3 or more is getting to point where heat shield refurbishment and tanker ship reuse is needed?)
3. Fuel boil off minimisation
4. Solar panels and any deployment thereof for power on journey
5. Engine relight after long cold soak (maybe this can be first launch which tests this? A later launch might also test it out with a shorter length prior to time relight is needed by mars ship?)

What else?
Also will all those be in development in parallel with each other?
If there is something in development, would they tend to throw it on and pray, even if it is inadequately tested? Or would it not get passed COSPAR if it is inadequately tested?

[Norm38]

Aerocapture at mars data

6-9 months of coast is a long time for a very short duration test with a high risk of failure and may need significant iteration.
Is there an Earth orbit, or an Earth-Moon orbit that skims through the high atmosphere that would match the expected dynamic forces and heating of a Mars entry?

I would want to see that be successful a dozen times in a row before sending a ship to Mars to try it.  If that pushes a Mars trip to 2028, so be it.  Better to be successful 2 years later with actual flight data under the belt than to just wing it.  That might sound like a contradiction from what I said yesterday, but I'd rather get data faster in Earth orbit.

I suppose they could launch a ship to Mars and then spend the 6 months doing Earth tests to inform the flight profile, but that doesn't allow any changes to hardware.

[envy887]

No fuel left after TMI and boil off would mean no aerocapture attempt and the mission is just a PR, Optimus wave as Mars goes by.

It would verify that Starship can do a good injection, and test GNC and comms function across interplanetary distances. With a couple tons of payload they could also do some boiloff and maybe even Raptor restart tests.

A picture of Starship flying past Mars would make the whole project "real" for a lot of people, inside and outside of SpaceX. That's not just PR, it's a very tangible step towards SpaceX's main goal as a company. Sure, it's not on the surface, but it's there, at Mars.

Aerocapture at mars data
Reaching Mars orbit
Deploying marslink satellites
Attempting ED for data
Attempting EDL for data
Successfully landing
Unloading Starship
Pics of Optimus walking on Mars

Aerocapture to orbit has never been attempted. Trying it on Starship's first deep space mission seems ambitious.

I think the performance needed to try all the things on your list would require at least 1 refueling, perhaps two. Can they get to the point where they can do that in the next 15 months? Almost everything would have to go right, which it usually doesn't.

[TheRadicalModerate]

The Silverbird calculator says they can reach C3=8.7 with payload if they hit 6.5% dry mass on the booster and 7.7% on the upper stage, with the "Version 2" / "Next Gen" prop mass numbers. That's a 250 t booster and 120 t ship. I think that's probably feasible, especially if they take off a few EDL parts they don't need like TPS, flaps, and fins.

According to my slightly-hacked version of the late lamented EasyPorkchop, the minimum C3 for Mars in the 2026 window is 9.2km²/s².

ε=6.5% for the booster isn't completely unreasonable, but it's awfully aggressive for a program whose first priority has to be launching stuff reliably for refueling tests.  ε=7.7% for the Ship I could believe if you stripped off the TPS, flaps, and header tanks.  But then you really can't do anything other than a flyby, and your restart-after-cold-soak Raptor tests probably don't happen.  And any kind of aerocapture test really can't happen with no TPS or nose ballast.

[envy887]

The Silverbird calculator says they can reach C3=8.7 with payload if they hit 6.5% dry mass on the booster and 7.7% on the upper stage, with the "Version 2" / "Next Gen" prop mass numbers. That's a 250 t booster and 120 t ship. I think that's probably feasible, especially if they take off a few EDL parts they don't need like TPS, flaps, and fins.

According to my slightly-hacked version of the late lamented EasyPorkchop, the minimum C3 for Mars in the 2026 window is 9.2km²/s².

ε=6.5% for the booster isn't completely unreasonable, but it's awfully aggressive for a program whose first priority has to be launching stuff reliably for refueling tests.  ε=7.7% for the Ship I could believe if you stripped off the TPS, flaps, and header tanks.  But then you really can't do anything other than a flyby, and your restart-after-cold-soak Raptor tests probably don't happen.  And any kind of aerocapture test really can't happen with no TPS or nose ballast.

The NASA Ames trajectory browser returns these when asked for the lowest velocity injections in 2026:

[crandles57]

Aerocapture at mars data

6-9 months of coast is a long time for a very short duration test with a high risk of failure and may need significant iteration.
Is there an Earth orbit, or an Earth-Moon orbit that skims through the high atmosphere that would match the expected dynamic forces and heating of a Mars entry?

I would want to see that be successful a dozen times in a row before sending a ship to Mars to try it.  If that pushes a Mars trip to 2028, so be it.  Better to be successful 2 years later with actual flight data under the belt than to just wing it.  That might sound like a contradiction from what I said yesterday, but I'd rather get data faster in Earth orbit.

I suppose they could launch a ship to Mars and then spend the 6 months doing Earth tests to inform the flight profile, but that doesn't allow any changes to hardware.

>a dozen times in a row
They won't have time to do that.

If the only opportunity for mars aerocapture data before a proper attempt in 2028 is launched is a Dec 2026 launch then SpaceX will want to try it if they possibly can. If it isn't adequately tested prior to launch who cares? (Well COSPAR probably) but as far as SpaceX is concerned just Fail fast, Fail forwards if they possibly can. 

[sdsds]

The NASA Ames trajectory browser returns these when asked for the lowest velocity injections in 2026:

Oh, tricky! If you launch early enough in 2026 and allow 2+ years to get there it can be done with < 4000 m/s of depature vInf. I hacked my porkchop plotter and got the attached result.

Arrival window: 28-05-01 - 28-06-29
Departure window: 26-04-01 - 26-05-30
Departure vinf Limit: 4000.0
Grid Size: 400 x 400
Latest available departure:
Departs: 26-05-30
Arrives: 28-06-01
Transit duration: 732.65 days

[TheRadicalModerate]

The NASA Ames trajectory browser returns these when asked for the lowest velocity injections in 2026:

The 10/26/26 departure is the one that EasyPorkchop had at v∞ = 3.03km/s.  I'd trust an Ames calculator more than the one I'm using.  The ones before that are more than 360º orbits.

Note:  "Delta-v" is really v∞ here.  The "other delta-v" value is the arrival v∞.

[sdsds]

The 10/26/26 departure is the one that EasyPorkchop had at v∞ = 3.03km/s.  I'd trust an Ames calculator more than the one I'm using.  The ones before that are more than 360º orbits.

I wonder about the granularity of the search used to generate the Ames table. Do they claim each of those is a local optimum?

As for the multi-revolution trajectories, the lobe of the pork chop that extends up and to the right apparently goes for some way.

Arrival window: 28-05-01 - 28-09-27
Departure window: 26-03-01 - 26-07-28
Departure vinf Limit: 4000.0
Grid Size: 600 x 600
Latest available departure:
Departs: 26-07-15
Arrives: 28-08-27
Transit duration: 774.0 days

[catdlr]

Elon Musk@elonmusk

Slight chance of Starship flight to Mars crewed by Optimus in Nov/Dec next year. A lot needs to go right for that.

More likely, first flight without humans in ~3.5 years, next flight ~5.5 years with humans.

Mars city self-sustaining in 20 to 30 years.

https://x.com/elonmusk/status/1953028261044187204

[envy887]

The 10/26/26 departure is the one that EasyPorkchop had at v∞ = 3.03km/s.  I'd trust an Ames calculator more than the one I'm using.  The ones before that are more than 360º orbits.

I wonder about the granularity of the search used to generate the Ames table. Do they claim each of those is a local optimum?

They have a user guide but it doesn't seem to answer that question: https://trajbrowser.arc.nasa.gov/user_guide.php

The NASA Ames trajectory browser returns these when asked for the lowest velocity injections in 2026:

The 10/26/26 departure is the one that EasyPorkchop had at v∞ = 3.03km/s.  I'd trust an Ames calculator more than the one I'm using.  The ones before that are more than 360º orbits.

Note:  "Delta-v" is really v∞ here.  The "other delta-v" value is the arrival v∞.

You're showing a slightly shorter time of flight, which probably explains at least part of your higher c3.

[meekGee]

Elon Musk@elonmusk

Slight chance of Starship flight to Mars crewed by Optimus in Nov/Dec next year. A lot needs to go right for that.

More likely, first flight without humans in ~3.5 years, next flight ~5.5 years with humans.

Mars city self-sustaining in 20 to 30 years.

https://x.com/elonmusk/status/1953028261044187204

Slight, hmmm

[catdlr]

Elon Musk@elonmusk

Slight chance of Starship flight to Mars crewed by Optimus in Nov/Dec next year. A lot needs to go right for that.

More likely, first flight without humans in ~3.5 years, next flight ~5.5 years with humans.

Mars city self-sustaining in 20 to 30 years.

https://x.com/elonmusk/status/1953028261044187204

Slight, hmmm

My initial thoughts are:
1) He is attempting to launch outside the optimal launch window, but
2) he wants to use Robots that can be turned off during the longer transit time, less lifesupport weight,
3) his "Slight chance " means 2027