Author Topic: Starship Expendable Upper Stage?  (Read 44779 times)

Offline Robotbeat

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Re: Starship Expendable Upper Stage?
« Reply #100 on: 02/08/2023 09:12 pm »
*snip*
And all of this, including any expendable SS, leaves open the question: how many unitary payloads greater than 150 tonne are there?

Expendable starship does not necessarily assume a 150+ ton payload.

With an expendable Starship-derived upper stage you could maximum yeet a 10 ton probe on an outer planets mission, so it won't take 10 years to fly by the outer planets. For reference, Cassini (at launch, with Huygens probe) was 5 metric tons, the New Horizons probe to Pluto was less than 500 kg.
Yup, although starship even stripped down has high dry mass so would benefit from a third stage for small payloads, even like a solid kick motor or something.
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Online TheRadicalModerate

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Re: Starship Expendable Upper Stage?
« Reply #101 on: 02/08/2023 09:16 pm »
*snip*
And all of this, including any expendable SS, leaves open the question: how many unitary payloads greater than 150 tonne are there?

Expendable starship does not necessarily assume a 150+ ton payload.

With an expendable Starship-derived upper stage you could maximum yeet a 10 ton probe on an outer planets mission, so it won't take 10 years to fly by the outer planets. For reference, Cassini (at launch, with Huygens probe) was 5 metric tons, the New Horizons probe to Pluto was less than 500 kg.

Dan was looking explicitly at LEO payloads, but with a refueling so that a reusable Starship didn't have to hold back the landing residuals.  It makes a non-trivial difference.

Offline Robotbeat

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Re: Starship Expendable Upper Stage?
« Reply #102 on: 02/08/2023 09:27 pm »
That plus droneship landing could make a pretty big difference for Starship reusable performance.
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Offline baddux

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Re: Starship Expendable Upper Stage?
« Reply #103 on: 02/14/2023 12:00 am »
Maybe one option for expendable Starship would be cargo Mars lander, ship with maybe one Raptor and header tanks lands on Mars, the "usual" Starship stage with 3 vacuum Raptors just sends it to TMI. It would be shorter so easier to access the surface. Of course that would require redesign of the flaps, or maybe expendable heatshield on the bottom.

Offline Brigantine

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Re: Starship Expendable Upper Stage?
« Reply #104 on: 09/16/2023 10:09 am »
To flip this old thread on its head... I'm pondering Starship backloading as a way of recovering otherwise expendable upper stages from other launch vehicles.

You space-tug an empty Falcon 2nd stage or Centaur etc. to the future orbit of a Starship commercial payload launch, integrate into the payload bay in orbit, then extract it after landing.
(the concept is this is low cost as the the Starship needs to land anyway and there isn't much demand for down-mass)

Falcon 2nd stage is 13.8m high, Centaur V is 12.7m, Starship payload bay is 17m tall - so they would fit vertically.
Falcon 2nd stage is 3.7m diameter, Centaur III is 3.05m diameter. payload bay interior approx 8m ( ??)
Depending on the exact details of the payload bay you could fit 2 or 3. (or in theory 1 Falcon and 3 Centaurs - or 1 Centaur V)

I'm assuming the upper stages being recovered would be from GTO missions, so not directly competing with Starship and not from wildly different inclinations. The space tug side could be its own whole discussion, but this is about the Starship part.

Since the upper stages are empty, the mass is well within the down-mass Starship can land.


Q1) Does this seem feasible? (other than the space tug part)
Q2) What technical challenges? e.g. robotic loading & securing, pressurizing them before they get crushed...
Q3) How much potential value? is the marginal upper stage replacement cost much?
Q4) Would 3rd parties even pay a competitor for this service? Or would it be in-house only?
Q5) Or could you kill 2 birds with 1 stone and just re-fuel an old upper stage in orbit and re-use it as a kick stage? (I doubt it)
« Last Edit: 09/16/2023 10:27 am by Brigantine »

Offline TomH

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Re: Starship Expendable Upper Stage?
« Reply #105 on: 09/17/2023 01:37 am »
Q1) Does this seem feasible?

My WAG is that SX would have no interest in considering it simply because they intend to retire Falcon completely when SS is fully online. The investment required would soon be lost.
« Last Edit: 09/17/2023 02:07 am by TomH »

Offline whitelancer64

Re: Starship Expendable Upper Stage?
« Reply #106 on: 09/17/2023 01:54 am »
To flip this old thread on its head... I'm pondering Starship backloading as a way of recovering otherwise expendable upper stages from other launch vehicles.

You space-tug an empty Falcon 2nd stage or Centaur etc. to the future orbit of a Starship commercial payload launch, integrate into the payload bay in orbit, then extract it after landing.
(the concept is this is low cost as the the Starship needs to land anyway and there isn't much demand for down-mass)

Falcon 2nd stage is 13.8m high, Centaur V is 12.7m, Starship payload bay is 17m tall - so they would fit vertically.
Falcon 2nd stage is 3.7m diameter, Centaur III is 3.05m diameter. payload bay interior approx 8m ( ??)
Depending on the exact details of the payload bay you could fit 2 or 3. (or in theory 1 Falcon and 3 Centaurs - or 1 Centaur V)

I'm assuming the upper stages being recovered would be from GTO missions, so not directly competing with Starship and not from wildly different inclinations. The space tug side could be its own whole discussion, but this is about the Starship part.

Since the upper stages are empty, the mass is well within the down-mass Starship can land.


Q1) Does this seem feasible? (other than the space tug part)
Q2) What technical challenges? e.g. robotic loading & securing, pressurizing them before they get crushed...
Q3) How much potential value? is the marginal upper stage replacement cost much?
Q4) Would 3rd parties even pay a competitor for this service? Or would it be in-house only?
Q5) Or could you kill 2 birds with 1 stone and just re-fuel an old upper stage in orbit and re-use it as a kick stage? (I doubt it)

Starship's payload bay would need a robotic arm, and some highly specialized structures to support - any captured object - from the forces of reentry. They'd be unique to the object being captured. Whether the costs involved would make it worthwhile is something to look closer at. If hiring a Starship and paying for designing, building, testing, and installing a unique fixture costs $15 million to return $10 million of hardware, it's not going to be worth it.

ULA is already studying in-space refueling of a future long-duration Centaur V. A Starship tanker carrying hydrogen would make some sense.
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Offline DanClemmensen

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Re: Starship Expendable Upper Stage?
« Reply #107 on: 09/17/2023 01:57 am »
To flip this old thread on its head... I'm pondering Starship backloading as a way of recovering otherwise expendable upper stages from other launch vehicles.
 Q1) Does this seem feasible? (other than the space tug part)
My guess: no, it is not feasible. Existing upper stages are not designed to handle the lateral forces they would experience during the re-entry inside the SS cargo bay. SS re-enters in a belly-forward attitude and probably decelerates at 2 G or more, but existing upper stages are designed to withstand axial forces, not lateral forces. If you are going to design new upper stages, for this, I think the money is better spent on just flying on Starship in the first place.

Offline mikelepage

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Re: Starship Expendable Upper Stage?
« Reply #108 on: 09/17/2023 03:06 am »
To flip this old thread on its head... I'm pondering Starship backloading as a way of recovering otherwise expendable upper stages from other launch vehicles.

You space-tug an empty Falcon 2nd stage or Centaur etc. to the future orbit of a Starship commercial payload launch, integrate into the payload bay in orbit, then extract it after landing.
(the concept is this is low cost as the the Starship needs to land anyway and there isn't much demand for down-mass)

Falcon 2nd stage is 13.8m high, Centaur V is 12.7m, Starship payload bay is 17m tall - so they would fit vertically.
Falcon 2nd stage is 3.7m diameter, Centaur III is 3.05m diameter. payload bay interior approx 8m ( ??)
Depending on the exact details of the payload bay you could fit 2 or 3. (or in theory 1 Falcon and 3 Centaurs - or 1 Centaur V)

I'm assuming the upper stages being recovered would be from GTO missions, so not directly competing with Starship and not from wildly different inclinations. The space tug side could be its own whole discussion, but this is about the Starship part.

Since the upper stages are empty, the mass is well within the down-mass Starship can land.


Q1) Does this seem feasible? (other than the space tug part)
Q2) What technical challenges? e.g. robotic loading & securing, pressurizing them before they get crushed...
Q3) How much potential value? is the marginal upper stage replacement cost much?
Q4) Would 3rd parties even pay a competitor for this service? Or would it be in-house only?
Q5) Or could you kill 2 birds with 1 stone and just re-fuel an old upper stage in orbit and re-use it as a kick stage? (I doubt it)

I agree with other commenters that recovering spent upper stages still in orbit is probably a bridge too far for now, but having done a fair bit of study on the space debris issue, I'd say the low hanging fruit would be using the expendable upper stages to do controlled capture, de-orbit and disposals of 200+ spent rocket stages in excess of a ton. Seems kind of wasteful on first glance, but realistically, many of the rocket stages that cause the main risk aren't likely to be in any condition to be reused. Doing this alone would eliminate the main part of the risk of Kessler syndrome for the foreseeable future.

Offline Brigantine

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Re: Starship Expendable Upper Stage?
« Reply #109 on: 09/17/2023 03:17 am »
If they can support 150+ tonnes at 4(?) g axially (FH payload & fuel at MECO), but can't support their own empty mass of 4 tonnes at 2 g laterally even with the aid of "highly specialized structures"... that would be quite a result for a horizontally-integrated LV

---------
Whitelancer64 has some good points, even if it is feasible, the setup won't be cheap. You'd need to build a few cradles and fly them over and over, eventually recovering & re-using dozens of the same model of upper stage.

You'd need a continuing market for F9 and/or ULA launches for years in parallel with Starship, despite space tugs being in operation at least for specific uses.

---------
How quickly would Falcon and competitors really be retired?
(I don't have answers, only questions)

Supply:
Even if they shut the factory, SpaceX already have a fleet of boosters with a combined remaining life of *a lot* of launches. The same could be true of upper stages. If they write down the capital value of that fleet, they can operate profitably at reduced prices for many years. (at a fraction of 100 launches/year, TBF)

Demand:
- Are classified F9-sized defense payloads going to still want dedicated launches?
- When will Starships fly to polar orbits? Until then - depending on the state of space tugs - F9s will have demand (re-use, no recovery)
→ Lunar polar orbit doesn't count! Either SS flying from a launch site like Vandenberg, or else pay for orbital refueling and plane-change
- Express freight to GEO - How cost-effective will it be to bulk-carry to GEO on Starship? Can cut-price FH/F9/ULA still compete?
→ (Possibility that snail freight to GEO flies on Starship to LEO and electric space tug to GEO, so the express market is low volume)
→ "in-space refueling of a future long-duration Centaur V" might kill here, as an efficient LEO-GEO chemical/express space tug. Just add H2

--------
Clarification: The proposal here is to recover recently flown upper stages, which would include a space tug in their payload in lieu of de-orbiting.

Cleaning up old rocket bodies from past eras is a worthwhile but separate topic - though yes if it offers orbital stages a valuable terminal mission extension, then it reduces the value of my proposal.
« Last Edit: 09/17/2023 03:56 am by Brigantine »

Offline Vahe231991

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Re: Starship Expendable Upper Stage?
« Reply #110 on: 09/17/2023 03:45 am »
Given the weight of the Starship's upper stage, the scheme by SpaceX to fit the Starship Cargo version's upper stage with a large cargo door that opens to release payloads into orbit and closes upon reentry makes more sense than leaving the Starship upper stage in orbit because if SpaceX wishes to re-use the upper stage for a future Starship mission, repairs or other intricate fine-tuning of silica tiles on the upper stage could be easily made.

Offline TomH

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Re: Starship Expendable Upper Stage?
« Reply #111 on: 09/17/2023 04:55 am »
On Sept. 7, the GAO released (another) report stating that SLS costs are unsustainable. Of course, they've always said that.

If hot staging proves to be successful, and increases standard SS payload by 10 tons, I wonder how much it would increase payload for a stripped down expendable SS US. If you add in downrange drone ship landing for SH, you increase payload even further. (I acknowledge landing legs issue.)

If GAO and other budget watchdogs put serious cost reduction pressure on NASA re. Artemis, I really can see Orion atop a SS stack and the full National Team Lander (including transfer module) tucked below, a la Apollo, for a single launch architecture. I could also envision a tank stretch (Elon tweeted that full stack will grow 10%-20% in height) for the US, which might possibly eliminate the transfer module. Of course, there is also the possibility of remaining with a 2 launch architecture, but both are SS. One carries Orion and the other carries SS HLS.

I do not see NASA launching astronauts (from Earth) on SS (sans capsule with LAS) for a long time. I do not see F-9/Dragon ferrying them, nor do I see Dragon going to Luna. I can see NASA giving up SLS for a fully tested SS stack, but I just don't see them giving up Orion for a number of years. Of course, SS does have do show improvement in the coming months.

And I do think SX would go for this if they knew it meant the death of SLS.

GAO report on SLS: https://www.gao.gov/assets/gao-23-105609.pdf

« Last Edit: 09/18/2023 06:21 am by TomH »

Offline volker2020

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Re: Starship Expendable Upper Stage?
« Reply #112 on: 09/17/2023 01:10 pm »
On Sept. 7, the GAO released (another) report stating that SLS costs are unsustainable. Of course, they've always said that.

If hot staging proves to be successful, and increases standard SS payload by 10 tons, I wonder how much it would increase payload for a stripped down expendable SS US.
...

I don't think, that you can translate this to SS. The reason why Starship get's a higher payload, is that the ullage gas in the booster does not collapse, allowing it to use the spared fuel to boost starship further.

Since the first stage of SS is expandable, those effects play no role. All you get is a few seconds of gravitational lost.

Offline DanClemmensen

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Re: Starship Expendable Upper Stage?
« Reply #113 on: 09/17/2023 02:24 pm »

If hot staging proves to be successful, and increases standard SS payload by 10 tons, I wonder how much it would increase payload for a stripped down expendable SS US. If you add in downrange drone ship landing for SH, you increase payload even further. (I acknowledge landing legs issue.)

If you just want to replace SLS while retaining Orion and the rest of the Artemis architecture, then why bother with re-usability at all? Just fly an expendable SH and a custom expendable SS with an Orion stuck on top as you pictured. Since Orion only flies once a year, recovery has low ROI. SLS costs at least $2 B. An expendable SH will be a whole lot cheaper and even the custom SS should be fairly cheap: a wild guess would be the SH is less than $100 M and the custom SS is less than $100 M. SS cost is mostly the amortized development cost.

Any Orion-on-SS will require some customization of the launch tower to add a crew access arm. I assume the plan will be to stack the Orion atop the SS in the Megabay and then stack this mess atop the SH on the OLM using the chopsticks: this may be "interesting".


Offline Zed_Noir

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Re: Starship Expendable Upper Stage?
« Reply #114 on: 09/17/2023 10:31 pm »
<snip>
Any Orion-on-SS will require some customization of the launch tower to add a crew access arm. I assume the plan will be to stack the Orion atop the SS in the Megabay and then stack this mess atop the SH on the OLM using the chopsticks: this may be "interesting".

Think it is cheaper and easier to build a mobile service gantry with crew access than to modified the launch and integration tower.

It isn't a customized SS that is needed. Just an austere SS with a few extra ring segments with lifting attachments  above the propellant tanks and an adopter ring segment to the Orion stack. Don't think the chopsticks should have too much difficulties with the SS & Orion integrated stack.

Will also point out that the Orion capsule don't need the current launch escape system design to outrun the SRBs. Something less capable and much less in mass will do.

Offline DanClemmensen

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Re: Starship Expendable Upper Stage?
« Reply #115 on: 09/18/2023 12:01 am »
<snip>
Any Orion-on-SS will require some customization of the launch tower to add a crew access arm. I assume the plan will be to stack the Orion atop the SS in the Megabay and then stack this mess atop the SH on the OLM using the chopsticks: this may be "interesting".
Think it is cheaper and easier to build a mobile service gantry with crew access than to modified the launch and integration tower.
That would be a really tall gantry. I disagree with you, but I'm just guessing.
Quote
It isn't a customized SS that is needed. Just an austere SS with a few extra ring segments with lifting attachments  above the propellant tanks and an adopter ring segment to the Orion stack. Don't think the chopsticks should have too much difficulties with the SS & Orion integrated stack.
I consider that degree of modification to be "customization". Feel free to pick your own terminology.

Offline Vahe231991

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Re: Starship Expendable Upper Stage?
« Reply #116 on: 09/18/2023 01:01 am »

If hot staging proves to be successful, and increases standard SS payload by 10 tons, I wonder how much it would increase payload for a stripped down expendable SS US. If you add in downrange drone ship landing for SH, you increase payload even further. (I acknowledge landing legs issue.)

If you just want to replace SLS while retaining Orion and the rest of the Artemis architecture, then why bother with re-usability at all? Just fly an expendable SH and a custom expendable SS with an Orion stuck on top as you pictured. Since Orion only flies once a year, recovery has low ROI. SLS costs at least $2 B. An expendable SH will be a whole lot cheaper and even the custom SS should be fairly cheap: a wild guess would be the SH is less than $100 M and the custom SS is less than $100 M. SS cost is mostly the amortized development cost.

Any Orion-on-SS will require some customization of the launch tower to add a crew access arm. I assume the plan will be to stack the Orion atop the SS in the Megabay and then stack this mess atop the SH on the OLM using the chopsticks: this may be "interesting".
The Starship being designed to carry up to 100 people on long-duration, interplanetary flights begs one simple question: is a special access arm would be required for a large number of people to safely board the Starship stage?

Offline DanClemmensen

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Re: Starship Expendable Upper Stage?
« Reply #117 on: 09/18/2023 01:12 am »

If hot staging proves to be successful, and increases standard SS payload by 10 tons, I wonder how much it would increase payload for a stripped down expendable SS US. If you add in downrange drone ship landing for SH, you increase payload even further. (I acknowledge landing legs issue.)

If you just want to replace SLS while retaining Orion and the rest of the Artemis architecture, then why bother with re-usability at all? Just fly an expendable SH and a custom expendable SS with an Orion stuck on top as you pictured. Since Orion only flies once a year, recovery has low ROI. SLS costs at least $2 B. An expendable SH will be a whole lot cheaper and even the custom SS should be fairly cheap: a wild guess would be the SH is less than $100 M and the custom SS is less than $100 M. SS cost is mostly the amortized development cost.

Any Orion-on-SS will require some customization of the launch tower to add a crew access arm. I assume the plan will be to stack the Orion atop the SS in the Megabay and then stack this mess atop the SH on the OLM using the chopsticks: this may be "interesting".
The Starship being designed to carry up to 100 people on long-duration, interplanetary flights begs one simple question: is a special access arm would be required for a large number of people to safely board the Starship stage?
I see that as a completely separate application. I was just discussing the SLS replacement using and Orion atop a funny SH/SS. I have no idea how SpaceX intends to get 100 people onto an interplanetary SS. I see that as off-topic for the "expendable SS" thread.

Offline jimvela

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Re: Starship Expendable Upper Stage?
« Reply #118 on: 09/18/2023 02:44 am »
If NASA were to slightly delay Artemis 4 and 5, then a SH/SS version could be developed to not just carry the Orion but also use strap-on solid-fuel rocket boosters to allow it to fly past max-q velocity in a much shorter period of time than a basic SH/SS.

That's chatbot nonsense.

Offline Vahe231991

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Re: Starship Expendable Upper Stage?
« Reply #119 on: 09/18/2023 03:54 am »

If hot staging proves to be successful, and increases standard SS payload by 10 tons, I wonder how much it would increase payload for a stripped down expendable SS US. If you add in downrange drone ship landing for SH, you increase payload even further. (I acknowledge landing legs issue.)

Any Orion-on-SS will require some customization of the launch tower to add a crew access arm. I assume the plan will be to stack the Orion atop the SS in the Megabay and then stack this mess atop the SH on the OLM using the chopsticks: this may be "interesting".
How much would it cost for SpaceX to add a crew access arm to the launch tower for the Starship?

 

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