Re-purposing SpaceX hardware for mid term exploration of Mars

[Slarty1080]

This is a follow on thread from Russel's thread here:https://forum.nasaspaceflight.com/index.php?topic=46888.0

Assumptions and restrictions:
- NASA will abandon further development of SLS in favour of commercial tender
- SpaceX will continue the development of Starship/Superheavy, but will be forced to focus on completing Starlink constellation first so the initial Starship is a giant sat dispenser circa 2024.
- Crewed Mars ship landing by 2030
- Limited launch cadence for Starship / Superheavy from KSC due to limited numbers, congestion at KSC and turn around teething problems. So 1 Starship to Mars per synod + FH/F9 as required.

What is the best way to get to Mars with primarily SpaceX kit and which organisations will be running the show or involved in the mission?

What are the pressing development priorities?

[Russel]

Is this a good explanation of Starship/Starlink?

https://www.nextbigfuture.com/2018/11/spacex-super-heavy-spaceship-makes-starlink-satellite-network-cheap.html

Do I take it that Starship is a stripped down version of BFS. Its just a container, correct?
Is it capable of being pressurised?
Have there been any serious third party estimates of its development cost?
Is it intended to sit on top of a BFR? Or just a scaled up version of FH?

[kevinof]

Starship IS BFS. Just a new name for it. There is/was talk of a cargo version (the chomper) as well but that will come later. Both sit on top of BFR.

Is this a good explanation of Starship/Starlink?

https://www.nextbigfuture.com/2018/11/spacex-super-heavy-spaceship-makes-starlink-satellite-network-cheap.html

Do I take it that Starship is a stripped down version of BFS. Its just a container, correct?
Is it capable of being pressurised?
Have there been any serious third party estimates of its development cost?
Is it intended to sit on top of a BFR? Or just a scaled up version of FH?

[Russel]

Starship IS BFS. Just a new name for it. There is/was talk of a cargo version (the chomper) as well but that will come later. Both sit on top of BFR.

Is this a good explanation of Starship/Starlink?

https://www.nextbigfuture.com/2018/11/spacex-super-heavy-spaceship-makes-starlink-satellite-network-cheap.html

Do I take it that Starship is a stripped down version of BFS. Its just a container, correct?
Is it capable of being pressurised?
Have there been any serious third party estimates of its development cost?
Is it intended to sit on top of a BFR? Or just a scaled up version of FH?

Which is cheaper. The "chomper" which is a cargo version, and BFS which presumably is fit for human habitation?

[kevinof]

We assume Chomper. No life support, shielding and internals needed for crew.

Starship IS BFS. Just a new name for it. There is/was talk of a cargo version (the chomper) as well but that will come later. Both sit on top of BFR.

Is this a good explanation of Starship/Starlink?

https://www.nextbigfuture.com/2018/11/spacex-super-heavy-spaceship-makes-starlink-satellite-network-cheap.html

Do I take it that Starship is a stripped down version of BFS. Its just a container, correct?
Is it capable of being pressurised?
Have there been any serious third party estimates of its development cost?
Is it intended to sit on top of a BFR? Or just a scaled up version of FH?

Which is cheaper. The "chomper" which is a cargo version, and BFS which presumably is fit for human habitation?

[rakaydos]

We assume Chomper. No life support, shielding and internals needed for crew.

Starship IS BFS. Just a new name for it. There is/was talk of a cargo version (the chomper) as well but that will come later. Both sit on top of BFR.

Is this a good explanation of Starship/Starlink?

https://www.nextbigfuture.com/2018/11/spacex-super-heavy-spaceship-makes-starlink-satellite-network-cheap.html

Do I take it that Starship is a stripped down version of BFS. Its just a container, correct?
Is it capable of being pressurised?
Have there been any serious third party estimates of its development cost?
Is it intended to sit on top of a BFR? Or just a scaled up version of FH?

Which is cheaper. The "chomper" which is a cargo version, and BFS which presumably is fit for human habitation?

all those things are factory extras for Starship. The planned 2022 landings, for instance, won't need them. The earliest planned mission that requires them is #dearmoon, in 2023, followed by the crewed Mars mission in 2024.

My prediction is that, like Vac nozzles on the upper stage, the chomper is an improvement being put off for later- focusing at the start on the hull design that has missions planned already.

[Tulse]

My prediction is that, like Vac nozzles on the upper stage, the chomper is an improvement being put off for later- focusing at the start on the hull design that has missions planned already.

If the missions are deploying Starlink, which has to happen relatively soon, it makes more sense to build the cargo/non-crewed version of Starship first.  It also allows SpaceX to get multiple launches of the basic stack under their belt before launching people.

[rakaydos]

My prediction is that, like Vac nozzles on the upper stage, the chomper is an improvement being put off for later- focusing at the start on the hull design that has missions planned already.

If the missions are deploying Starlink, which has to happen relatively soon, it makes more sense to build the cargo/non-crewed version of Starship first.  It also allows SpaceX to get multiple launches of the basic stack under their belt before launching people.

as I said, "crew version"  only means adding ELCSS. The side door version of Starship can launch any payload on the market right now, without needing crew capability.

[mikelepage]

In this scenario I could see the Starship remaining "cargo-only" for a number of years.  Even to the point of having a human-rated payload module that could be transported on cargo Starship.  Doing this would push back the dates for Mars exploration admittedly, but as long as the module fits into the same payload bay and adaptors that SpaceX is building for Starlink, you could start doing P2P Earth transport much sooner.  More $$ => more leeway when you do set off for Mars.

Imagine if that human-rated payload module was actually transported out to Starship Super Heavy on the same boat that picks people up from the local city and takes them out to the sea launch platform.  It needs to be at least an hour out to sea anyway.  People can take their time finding their seat and getting strapped in.  Then, arriving at the platform, a single crane picks up the module and deposits it directly into a fully fuelled Cargo Starship.  Close the payload bays and then launch.  Do the reverse at the landing site.  Anywhere on Earth in 3 hours or so.

[rakaydos]

In this scenario I could see the Starship remaining "cargo-only" for a number of years.  Even to the point of having a human-rated payload module that could be transported on cargo Starship.  Doing this would push back the dates for Mars exploration admittedly, but as long as the module fits into the same payload bay and adaptors that SpaceX is building for Starlink, you could start doing P2P Earth transport much sooner.  More $$ => more leeway when you do set off for Mars.

Imagine if that human-rated payload module was actually transported out to Starship Super Heavy on the same boat that picks people up from the local city and takes them out to the sea launch platform.  It needs to be at least an hour out to sea anyway.  People can take their time finding their seat and getting strapped in.  Then, arriving at the platform, a single crane picks up the module and deposits it directly into a fully fuelled Cargo Starship.  Close the payload bays and then launch.  Do the reverse at the landing site.  Anywhere on Earth in 3 hours or so.

The poison pill in that plan is "would push back the dates for Mars exploration admittedly..." given that Elon has improved his odds of personally going to mars in his lifetime.

[Slarty1080]

My prediction is that, like Vac nozzles on the upper stage, the chomper is an improvement being put off for later- focusing at the start on the hull design that has missions planned already.

If the missions are deploying Starlink, which has to happen relatively soon, it makes more sense to build the cargo/non-crewed version of Starship first.  It also allows SpaceX to get multiple launches of the basic stack under their belt before launching people.

as I said, "crew version"  only means adding ELCSS. The side door version of Starship can launch any payload on the market right now, without needing crew capability.

I would totally agree. IMO they would get the basic version flying and use the cargo bay door to eject Starlink sats as you suggest.

Seems to me that the hard bits of Starship / Superheavy are the main structural components, the flippers, the heat shield and getting all the new raptor engines working together. The contents of the "bit at the top" are not fixed or hard to change after the construction of any single SS/SH.

 All (or most) decks and fittings could be left out entirely to save weight. All they would need would be a Starlink "magazine" sat dispenser.

Once that basic version is up and running dispensing Starlink it will gain SpaceX a lot of valuable experience in operation and the ability to refine and improve the whole system. After a few years it should be possible to build a Starship with the same exterior / frame / flippers / heatshield / engines but with all the internal decks, fittings and ECLSS for a crewed flight.

Next thing would be to practice orbital refuelling and increase launch cadence leading eventually to DearMoon and missions to Mars.

[KelvinZero]

The poison pill in that plan is "would push back the dates for Mars exploration admittedly..." given that Elon has improved his odds of personally going to mars in his lifetime.

We brainstormed some nice ideas to allow a BFS to deliver monolithic cargo items to the surface, even without any crane infrastructure. In that case this could actually make mars colonisation easier. Send multiple BFS. return only one with its crew module. Leave others on surface.

[rakaydos]

The poison pill in that plan is "would push back the dates for Mars exploration admittedly..." given that Elon has improved his odds of personally going to mars in his lifetime.

We brainstormed some nice ideas to allow a BFS to deliver monolithic cargo items to the surface, even without any crane infrastructure. In that case this could actually make mars colonisation easier. Send multiple BFS. return only one with its crew module. Leave others on surface.

It's still a different design. The idea is to get boots on ground ASAP, by focusing entirely on the critical path. Once we're comitted to supplying a mars base, THEN we diversify into chompers and RVacs, and let the delays fall where they may.

[mikelepage]

In this scenario I could see the Starship remaining "cargo-only" for a number of years.  Even to the point of having a human-rated payload module that could be transported on cargo Starship.  Doing this would push back the dates for Mars exploration admittedly, but as long as the module fits into the same payload bay and adaptors that SpaceX is building for Starlink, you could start doing P2P Earth transport much sooner.  More $$ => more leeway when you do set off for Mars.

The poison pill in that plan is "would push back the dates for Mars exploration admittedly..." given that Elon has improved his odds of personally going to mars in his lifetime.

Elon is nothing if not pragmatic in pursuit of his goals, and I think if the choice ends up being between his personal ambition to go to Mars, and what he thinks is good for humanity, I think he would choose humanity without hesitation.  Obviously he wants to have his cake and eat it too, but the point of going to Mars according to him is to "make humanity a multiplanetary species", or if you want to dial it back further, to "back up" human civilisation by taking us to space.

What he/SpaceX has done so far is give themselves a very good shot at building a fully reusable two stage rocket, that is capable of being refuelled in LEO, or anywhere else where CO₂, H₂O and energy is available. (i.e. the solar system)

That in itself would be such a staggering achievement, that by comparison, putting human civilisation on Mars is a relatively minor footnote - since it's just one of many places humanity will settle.  Whatever will pay for the dev costs of Starship Superheavy, is IMO is something he'll consider far more important than whether we get to Mars fast enough for him personally to go. 

[rakaydos]

In this scenario I could see the Starship remaining "cargo-only" for a number of years.  Even to the point of having a human-rated payload module that could be transported on cargo Starship.  Doing this would push back the dates for Mars exploration admittedly, but as long as the module fits into the same payload bay and adaptors that SpaceX is building for Starlink, you could start doing P2P Earth transport much sooner.  More $$ => more leeway when you do set off for Mars.

The poison pill in that plan is "would push back the dates for Mars exploration admittedly..." given that Elon has improved his odds of personally going to mars in his lifetime.

Elon is nothing if not pragmatic in pursuit of his goals, and I think if the choice ends up being between his personal ambition to go to Mars, and what he thinks is good for humanity, I think he would choose humanity without hesitation.  Obviously he wants to have his cake and eat it too, but the point of going to Mars according to him is to "make humanity a multiplanetary species", or if you want to dial it back further, to "back up" human civilisation by taking us to space.

Something happened in the latest update that made him feel he was MORE llikely to personally go. Even assuming you're right, that signals that he feels he HAS a way to have his cake and eat it too.

[Russel]

I went back to do a little research on Elon's plans and to be honest I found it rather confusing.

What I am certain of is that at one stage there was a reusable rocket called a BFR.
Then there were was a reusable upper stage capable of landing aerodynamically on Mars and originally named ITS.
That then (so far as I can tell) got renamed to BFS.

Can someone help me out with the dimensions/masses for these so I have a baseline?

Now, up until relatively recently, the media I had seen showed a reusable upper stage for a F9. A "mini" BFS.
Here is where I first saw it

So my understanding of this until relatively recently was that SpaceX was going to test BFS type technology at smaller scale.
Now after I saw this there was also the publicity given Yusaku Maezawa agreeing to partly fund a round the moon trip.
What I was not sure of (and still am not) is which specific vehicle would be involved. Feel free to help me out there.
I just got the impression that it would not be a full scale BFS. Full scale as in capable of 100 passengers. Feel free to correct me.

It was only recently that I'd ever heard of Starlink and Chomper (what an awful name).
My first impression was that Elon had decided to find a plausible market for a large cargo delivery vehicle in order to get somewhere towards the development costs of BFS. Now huge satellite constellations have a chequered history so I'm not going to get too excited about this. I've no doubt about Elon's ability to drum up enough business and enough money to construct a large cargo delivery vehicle and in the process further test BFS related technology

Now, if I'm wrong tell me. But my impression at this point is that Elon will at some stage test some of the technologies related to BFS. At least all of those needed for cargo.

I remain highly skeptical about the BFS in its originally envisioned form. 100 passengers, cargo, human rated, fully developed and tested and in every respect ready for a real Mars mission.

I'm perfectly happy to include BFS related technology as part of a pragmatic near term Mars exploration mission.

I confess to liking a "flying" Mars lander however...

It would be a lot smaller than a BFS - capable of landing 4-6 people and it would be crew only.
It would land in 3 stages. First aerodynamic orbital capture. Second aerobraking into low orbit. Third landing.
It would use ISRU oxygen but it would land with methane already on board.
It would ascend to Mars orbit, dock with a larger vehicle and then return to Earth.

Can anyone explain to me why you would use a 100 person vehicle for an exploratory mission to Mars?

[Slarty1080]

I went back to do a little research on Elon's plans and to be honest I found it rather confusing.

What I am certain of is that at one stage there was a reusable rocket called a BFR.
Then there were was a reusable upper stage capable of landing aerodynamically on Mars and originally named ITS.
That then (so far as I can tell) got renamed to BFS.

Can someone help me out with the dimensions/masses for these so I have a baseline?

Now, up until relatively recently, the media I had seen showed a reusable upper stage for a F9. A "mini" BFS.
Here is where I first saw it

So my understanding of this until relatively recently was that SpaceX was going to test BFS type technology at smaller scale.
Now after I saw this there was also the publicity given Yusaku Maezawa agreeing to partly fund a round the moon trip.
What I was not sure of (and still am not) is which specific vehicle would be involved. Feel free to help me out there.
I just got the impression that it would not be a full scale BFS. Full scale as in capable of 100 passengers. Feel free to correct me.

It was only recently that I'd ever heard of Starlink and Chomper (what an awful name).
My first impression was that Elon had decided to find a plausible market for a large cargo delivery vehicle in order to get somewhere towards the development costs of BFS. Now huge satellite constellations have a chequered history so I'm not going to get too excited about this. I've no doubt about Elon's ability to drum up enough business and enough money to construct a large cargo delivery vehicle and in the process further test BFS related technology

Now, if I'm wrong tell me. But my impression at this point is that Elon will at some stage test some of the technologies related to BFS. At least all of those needed for cargo.

I remain highly skeptical about the BFS in its originally envisioned form. 100 passengers, cargo, human rated, fully developed and tested and in every respect ready for a real Mars mission.

I'm perfectly happy to include BFS related technology as part of a pragmatic near term Mars exploration mission.

I confess to liking a "flying" Mars lander however...

It would be a lot smaller than a BFS - capable of landing 4-6 people and it would be crew only.
It would land in 3 stages. First aerodynamic orbital capture. Second aerobraking into low orbit. Third landing.
It would use ISRU oxygen but it would land with methane already on board.
It would ascend to Mars orbit, dock with a larger vehicle and then return to Earth.

Can anyone explain to me why you would use a 100 person vehicle for an exploratory mission to Mars?

The real problem here is the huge cost of development. BFR / Starship is not ideal, it’s a compromise. Musk does not have enough time or money to develop all of the efficient specialised kit that will eventually be used, he’s in a hurry and he wants something that will work for a lot of different tasks – a jack of all trades - that is what the Starship is. Once it's functional the first task will be launching Starlink, then perhaps phasing out F9/FH and flying DearMoon (and similar) then Mars exploration then Mars base. Each of these will have different requirements and be kitted out differently and each new Starship will iterate the design. The 100 person BFR is the ultimate end point BFR used as a ferry. I doubt we will see that many people on a BFR, but who knows in the fullness of time…
 
So to answer the question why would you use a 100 person vehicle for an exploratory mission to Mars? Answer you would not use the 100 person variant. You would use the same basic vehicle but instead of taking 100 people and their supplies you would use it to take the multitude of miscellaneous gear that would be needed for the first crewed Mars mission.

Be in no doubt that the 100tons (or whatever they can get) will be used to capacity and there will be arguments over what can't be sent. Rover(s), a very large solar array and/or solar electric generators and caballing/batteries, crane, scientific and laboratory kit, drills, tools, space suits (more than one each), ISRU unit to extract water from the atmosphere, more spare parts than you can shake a stick at, medical kit probably bigger than that on the ISS given the circumstances and that IIRC that is well over 100kg, communications equipment, decks, partitions, tables, beds, toilets, showers, radiation protection, 3 years of food, water, oxygen, clothes and consumables for a 4-6 person crew. And the rest…

[rakaydos]

I went back to do a little research on Elon's plans and to be honest I found it rather confusing.

The BFR has a bit of a history. SpaceX used the software "Agile" approach to design, which basically means nothing is sacred, and if something objectively better comes along, to hell with sunk costs. I reccomend the following article, which was compiled shortly before the #dearmoon version was made public:
https://www.nasaspaceflight.com/2018/08/evolution-big-falcon-rocket/

The key feature of BFR/ITS/BFS/starship, is that it can throw mass at any problem and still be better than any other launcher on the market right now. At the same time, it's less than twice as powerful as a Block 5 Falcon Heavy expendable- there really isnt any reason, from a rocket stable point of view, to make it smaller. Upper stage reuse allowes it to be cheaper to launch than the parts of rockets that other designs throw away, meaning this bigger rocket can also be cheaper than the falcon family, but if falcon-sized masses were all they were going to launch, they could just use a falcon.

Now after I saw this there was also the publicity given Yusaku Maezawa agreeing to partly fund a round the moon trip.
What I was not sure of (and still am not) is which specific vehicle would be involved. Feel free to help me out there.
I just got the impression that it would not be a full scale BFS. Full scale as in capable of 100 passengers. Feel free to correct me.

The hull is the same one intended to later be a 100 passanger transporter. But 2023 is going to be really early in Starship development, so they likely intend to manage crew saftey with throwing mass at redundant systems- say, 2-3 off the shelf Dragon2 ELCSS, enough canned air and CO2 filters for the entire flight, and possibly even a pair of actual dragon 2s as lifeboats/escape pods. These excessive redundancies are inefficencies that are needed before they have confidence in their systems, but will have to go away before you can put 100 people in. It's plenty for 12-14 people for a week, though. They can improve the capacity slowly, like they improved the Falcon 9 up to Block 5.

It was only recently that I'd ever heard of Starlink and Chomper (what an awful name).
My first impression was that Elon had decided to find a plausible market for a large cargo delivery vehicle in order to get somewhere towards the development costs of BFS. Now huge satellite constellations have a chequered history so I'm not going to get too excited about this. I've no doubt about Elon's ability to drum up enough business and enough money to construct a large cargo delivery vehicle and in the process further test BFS related technology

Starlink was actually a gift from Google. As in, a google employee brought the idea to his boss, there was a call made, and now that employee works at SpaceX. The idea being that you didnt need a satelite to sit out at geosynch, if you had enough satelites that another would come into view as the one you were using left. Because they're closer in, you dont need as strong signal and lightspeed limits arnt as much of a problem (it's a shorter trip). The biggest problem is that you need more sats than have ever been launched in human history.

But to the SpaceX BFR/ITS/Starship/whatever it's called this year, you say "more sats than have ever been launched in human history", and it only hears "throw mass at the problem" and says "I'm your rocket".

Starlink simotaniusly supports big bank investers by providing data transfer faster than a direct fiber optic link, for any distance longer than a thousand KM or so, (speed of light in glass vs speed of light in vacuum) while also opening up rural internet access to people who have only had a single internet provider monopoly for years... if they even had one. There's a market big enough to maintain the network, pay all spaceX's upkeep, and have enough left over to create a mars colony, easilly.

Now, if I'm wrong tell me. But my impression at this point is that Elon will at some stage test some of the technologies related to BFS. At least all of those needed for cargo.

I remain highly skeptical about the BFS in its originally envisioned form. 100 passengers, cargo, human rated, fully developed and tested and in every respect ready for a real Mars mission.

Test hops are supposed to start next year, and they've got FCC paperwork for comunicating for those tests- 3 short hops a week, followed by 1 suborbital flight a week, for the duration of testing.

Can anyone explain to me why you would use a 100 person vehicle for an exploratory mission to Mars?

because you can leave people back on earth and fit in more stuff.

[ccdengr]

Starlink was actually a gift from Google. As in, a google employee brought the idea to his boss, there was a call made, and now that employee works at SpaceX. The idea being that you didnt need a satelite to sit out at geosynch...

Is Starlink different in principle from any of the previous big-LEO constellations that were proposed in the 90s, e.g., Teledesic?

https://www.its.bldrdoc.gov/media/30335/red_s.pdf

[rakaydos]

Starlink was actually a gift from Google. As in, a google employee brought the idea to his boss, there was a call made, and now that employee works at SpaceX. The idea being that you didnt need a satelite to sit out at geosynch...

Is Starlink different in principle from any of the previous big-LEO constellations that were proposed in the 90s, e.g., Teledesic?

https://www.its.bldrdoc.gov/media/30335/red_s.pdf

That DOES look awfuly familiar, doesnt it.

Slide 21 shows their cost saving measures, though.