Author Topic: Possible cost-reduction possibilities for the NASA portions of MSR  (Read 92231 times)

Offline vjkane

  • Full Member
  • ****
  • Posts: 1285
  • Liked: 626
  • Likes Given: 5
One of the reasons why the 2010 cost estimates were wrong is that the size of the orbiting sample has grown from 5kg to 11kg. The mass of the samples being returned from Mars has not gone up. NASA should figure out what has driven the mass growth. Are there dumb requirements that need to be eliminated? Why do we need 11kg of spacecraft to package 0.45kg of Martian sample?
Maybe there's been a lot more thought about what's needed in the orbital sample container? Do you have a list of design requirements from 2010 and today?

Offline Blackstar

  • Veteran
  • Senior Member
  • *****
  • Posts: 15384
  • Liked: 7949
  • Likes Given: 2
One of the reasons why the 2010 cost estimates were wrong is that the size of the orbiting sample has grown from 5kg to 11kg. The mass of the samples being returned from Mars has not gone up. NASA should figure out what has driven the mass growth. Are there dumb requirements that need to be eliminated? Why do we need 11kg of spacecraft to package 0.45kg of Martian sample?

Sigh.

Having worked on both the 2010 and 2021 decadal surveys, and having sat through many meetings on the CATE/TRACE process, it would take me a few hours with you in a room to explain how much you have wrong here. But the first is treating those dollar figures as estimates of the cost of an actual designed spacecraft. Those dollar figures are used to put a frame around a mission proposal so that the proposals can be binned--medium/large--and can aid in decision making when compared to other options in the decadal survey. Too many people take a DS "cost estimate" and then a final design and claim that the cost grew and that what this somehow indicates that the people involved either at the beginning or at the implementation stage were stupid.

Second, why assume the requirements were "dumb"? Does posting on the internet make you a genius?


Offline Don2

  • Full Member
  • ****
  • Posts: 541
  • Liked: 299
  • Likes Given: 0
One of the reasons why the 2010 cost estimates were wrong is that the size of the orbiting sample has grown from 5kg to 11kg. The mass of the samples being returned from Mars has not gone up. NASA should figure out what has driven the mass growth. Are there dumb requirements that need to be eliminated? Why do we need 11kg of spacecraft to package 0.45kg of Martian sample?
Maybe there's been a lot more thought about what's needed in the orbital sample container? Do you have a list of design requirements from 2010 and today?

That's probably what happened. They haven't built anything quite like the orbiting sample before. The 2010 number was an optimistic estimate. Then they found reasons it needed more mass when they did the detailed design.
This paper probably has some answers but I don't have any access to it.
https://ieeexplore.ieee.org/document/7943979

Second, why assume the requirements were "dumb"?

I'm referring to the first step of Elon Musk's 5 step design process:
1/ Make the requirements less dumb.
2/ Delete the part or process
etc.

I wonder if they could delete the orbiting sample and store the samples in the nosecone of the second stage. The Earth Return Orbiter could dock with that and then somehow transfer the sample to the Earth Entry Vehicle. That might reduce the MAV mass and the lander mass.

Offline Blackstar

  • Veteran
  • Senior Member
  • *****
  • Posts: 15384
  • Liked: 7949
  • Likes Given: 2
I'm referring to the first step of Elon Musk's 5 step design process:


Just stop right there. Science requirements are an entirely different thing than operational requirements.

There is a big difference between figuring out a better way to do something that has been done many times before and figuring out how to do something that has never been done before. So many people in the space enthusiast community have adopted this belief that Elon is a wizard and SpaceX is magic and all you have to do is apply SpaceX to any problem and expecto patronum!, it is fixed. That's not how things work.
« Last Edit: 11/07/2023 02:22 pm by Blackstar »

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 37507
  • Cape Canaveral Spaceport
  • Liked: 21564
  • Likes Given: 429

I wonder if they could delete the orbiting sample and store the samples in the nosecone of the second stage. The Earth Return Orbiter could dock with that and then somehow transfer the sample to the Earth Entry Vehicle. That might reduce the MAV mass and the lander mass.

That is what the orbiting sample is.   Just a spherical container with beacon.

Offline Don2

  • Full Member
  • ****
  • Posts: 541
  • Liked: 299
  • Likes Given: 0
https://www.colorado.edu/event/ippw2018/sites/default/files/attached-files/innersys_8_siddens_presid557_presslides_docid1030.pdf

This presentation shows how the nosecone of the booster (the aero-thermal structure) and the Orbiting sample are currently separate systems. Integrating the sample tube storage into the nosecone of the second stage and then capturing the whole thing with the Earth return orbiter would allow for parts and hopefully mass to be deleted from the MAV.

The downside to this is that you would then have to transfer individual tubes into the Earth Entry Vehicle rather than just transferring the Orbiting Sample. ( You might consider putting the entire second stage of the MAV inside the Earth Entry Vehicle to avoid this.)

Offline deadman1204

  • Full Member
  • ****
  • Posts: 1806
  • USA
  • Liked: 1481
  • Likes Given: 2544
The planetary society recently did an hour longer interview with Orlando Figueroa. He chaired the independent review board which released the recent report on MSR costs and timeline. Alot of interesting stuff in there.

https://www.planetary.org/planetary-radio/spe-what-went-wrong-with-msr

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 37507
  • Cape Canaveral Spaceport
  • Liked: 21564
  • Likes Given: 429
https://www.colorado.edu/event/ippw2018/sites/default/files/attached-files/innersys_8_siddens_presid557_presslides_docid1030.pdf

This presentation shows how the nosecone of the booster (the aero-thermal structure) and the Orbiting sample are currently separate systems. Integrating the sample tube storage into the nosecone of the second stage and then capturing the whole thing with the Earth return orbiter would allow for parts and hopefully mass to be deleted from the MAV.

The downside to this is that you would then have to transfer individual tubes into the Earth Entry Vehicle rather than just transferring the Orbiting Sample. ( You might consider putting the entire second stage of the MAV inside the Earth Entry Vehicle to avoid this.)


No.  You are looking at 5 year old charts. 
But still, you are wrong.
Putting anything but the orbiting sample "ball" into the Earth Entry Vehicle increases its complexity and mass.
Anything but a sphere makes capture and containment more complex
Launching sphere is the cheapest.   Capturing a sphere is the cheapest.

Offline Don2

  • Full Member
  • ****
  • Posts: 541
  • Liked: 299
  • Likes Given: 0
Putting anything but the orbiting sample "ball" into the Earth Entry Vehicle increases its complexity and mass.

Much cheaper to send mass to low Mars orbit than to the surface and back. A more massive Earth Entry vehicle may be a worthwhile price to pay for a less massive MAV.

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 37507
  • Cape Canaveral Spaceport
  • Liked: 21564
  • Likes Given: 429
Putting anything but the orbiting sample "ball" into the Earth Entry Vehicle increases its complexity and mass.

Much cheaper to send mass to low Mars orbit than to the surface and back. A more massive Earth Entry vehicle may be a worthwhile price to pay for a less massive MAV.

Your ideas make the MAV larger. 

Add "and MAV" to my statement.
« Last Edit: 11/09/2023 01:39 pm by Jim »

Offline Don2

  • Full Member
  • ****
  • Posts: 541
  • Liked: 299
  • Likes Given: 0
One way to get the cost of MSR down would be to shrink the landed payload to the point where the legacy Skycrane landing system could handle it. That requires getting the mass of the lander down to less than 1000kg. Many studies indicate that that is compatible with a 300kg MAV. One way to do that is to shrink the mass that the MAV has to put into orbit.

Another way is to increase MAV performance. Before the current solid rocket design was chosen, serious studies were done of a hybrid rocket fueled by wax with an oxidizer of nitrogen oxides or MON. However, this did not offer a huge performance advantage.

However, hybrid rockets can also be made to run on liquid or gaseous oxygen. And the mass of the oxygen is a substantial fraction of the mass of the whole system. For stoichoimetric combustion with long chain hydrocarbons, the oxygen will make up 77% of the mass of the propellant. If you can make the liquid oxygen on Mars, the mass of propellant that has to be landed goes down dramatically. That will be offset to some degree by the mass of the oxygen production system, but there is obviously potential for a dramatic reduction in landed mass. The MOXIE experiment on Perseverance has recently finished a highly successful demonstration of oxygen production. To make liquid oxygen you would need a refrigerator that is a bigger version of the cryocoolers used to cool sensors on infrared telescopes, and you would need an insulated tank to store it in.

This architecture was explored in this 2013 paper. I don't have access, but the abstract indicates that a 40% mass reduction is possible. That would reduce the lander from the current mass of 3375kg to 2025kg. The April 2010 concept study I referenced upthread had a Skycrane with a wet mass of 1,111kg landing a 1011kg payload for a total system mass of 2122kg. So the ISRU architecture should be just within the capabilities of the current Skycrane system.
https://arc.aiaa.org/doi/pdf/10.2514/6.2013-3899

I think it would be a good idea to wait to load the samples until the oxygen tank is full. If oxygen production fails, you still have the samples for another attempt. You should not launch the Earth Return Orbiter until the MAV has succeeded and the samples are safely in Mars orbit. If the MAV doesn't work, you can store the Earth Return Orbiter for a second attempt with backup samples.

It goes without saying that a demonstration of a rocket fueled by ISRU would be of high value. I think you could justify using technology development funding to pay for some of this.

***********
The following paper, available online, gives an idea of how the numbers work for a hybrid MAV. They show a two stage design, using a paraffin based fuel, and a mix of nitrous oxide (N2O) and oxygen as an oxidizer. They claim a design with a gross mass of 248kg could take a 36kg 'payload' to a 500km orbit. Most of the 'payload' is made up of systems including separation mechanisms, reaction control and avionics, with only 5kg allocated to the Orbiting Sample (OS).

Using numbers from the paper and ignoring some of the complexities, I estimate that this design has roughly 34kg of structure, 38kg of fuel and 141kg of oxidizer. Oxidizer is 57% of the total mass, so ISRU has a large potential benefit. If liquid oxygen was used then less mass of oxidizer would be needed and the Isp would be higher. 140kg seems a good estimate for the amount of liquid oxygen that would be needed to orbit a 5kg OS.

We need to allow for the fact that the OS size has grown and the current MAVs are about 50% bigger than the design in this paper. 210kg of LOX should cover the current requirements.

https://web.stanford.edu/~cantwell/Selected_Publications/Liquifying%20hybrid%20fuels,%20hybrid%20rocket%20design,%20small%20thrusters,%20propulsion%20designs%20for%20Mars/A%20two-stage,%20single%20port%20hybrid%20propulsion%20system%20for%20a%20Mars%20Ascent%20Vehicle%20AIAA%202010-6635.pdf

*********

How could we make 210kg of oxygen? MOXIE produced 10g per hour, so 876 days of production would be needed. MOXIE has a mass of 17kg and consumed 300W of power. MOXIE only produced a total of 0.122kg of oxygen, so a huge extension in lifetime would be needed for ISRU.
https://mars.nasa.gov/mars2020/spacecraft/instruments/moxie/

Additional power would be required for liquefaction of produced oxygen and tank boil-off. Power would be required day and night, so a large solar panel feeding a battery would be needed. Jezero has many dust devils, so Martian winds should keep the panel clean.

*********

Overall, I think that this is a promising approach that could avoid the need to design an expensive new lander. It also has great value as a technology demonstration. The downside is that it is more risky than the current approach to Mars Sample Return. Although MOXIE demonstrated oxygen production, it did not demonstrate liquid oxygen production and storage at the required scale. Although hybrid rocket designs were seriously considered for the MAV, they are considerably less mature than conventional solids. However,  if NASA can't afford the safe, conservative way to do MSR, they might want to try this adventurous concept.

Offline thespacecow

  • Full Member
  • *
  • Posts: 178
  • e/acc
  • Liked: 172
  • Likes Given: 38
I thought the business case would be obvious: It's the crewed Mars missions that NASA is hoping to do under Artemis.

This has been pointed out early in the thread: Just use a uncrewed version of your crewed Mars architecture to do MSR. You're going to have to do uncrewed test flight of this architecture anyway, so adding sample return is just a bonus. There are huge potential in terms of cost sharing, and it also helps that the current Artemis PoR is already funding one of these for lunar landing.

Planetary protection requirements at Mars.  Canít control spore counts on something as big and exposed as Starship.

PPIRB has standing recommendation to change PP requirements, might as well do it now, especially since you'll need it in about 5 to 10 years anyway, before MSR is even launched.



Just stop right there. Science requirements are an entirely different thing than operational requirements.

There is a big difference between figuring out a better way to do something that has been done many times before and figuring out how to do something that has never been done before. So many people in the space enthusiast community have adopted this belief that Elon is a wizard and SpaceX is magic and all you have to do is apply SpaceX to any problem and expecto patronum!, it is fixed. That's not how things work.

Right, performing supersonic retro-propulsion and landing an orbital class booster on a droneship has been done many times before SpaceX did it, launching a heavy lift launch vehicle 80 times and sending 1,000 ton to orbit in a year has also been done many times before SpaceX did it, launching a constellation of 5,000 satellite has also been done many times before SpaceX did it. SpaceX did literally nothing new, it's all been done many times before... /s

https://twitter.com/lrocket/status/1721996598929174774
« Last Edit: 11/10/2023 04:09 am by thespacecow »

Offline VSECOTSPE

  • Full Member
  • ****
  • Posts: 1494
  • Liked: 4733
  • Likes Given: 2
PPIRB has standing recommendation to change PP requirements, might as well do it now, especially since you'll need it in about 5 to 10 years anyway, before MSR is even launched.

Reviewed does not equal relaxed, especially around Jezero.  The requirements may become tougher.

Quote
Right, performing supersonic retro-propulsion

SX demonstrated it first, but itís important to recognize that supersonic retropropulsion work goes back decades, long before SX existed:

https://ssdl.gatech.edu/sites/default/files/ssdl-files/papers/conferencePapers/IEEE-2008-1246.pdf

Everything in aerospace builds on something else.  Nothing is developed de novo.  In the coming years, SX will probably also be the first org to demonstrate large-scale cryo storage and xfer in orbit.  But that work also goes back decades.

Will SX use supersonic retropropulsion to land on Mars, manufacture propellant from the Martian atmosphere, and relaunch back to Earth in the coming decades?  Itís not a slam dunk but probably.

But even setting aside the planetary protection issues with something as large and exposed as Starship, could a decision on a revised MSR architecture that needs to be made in the next handful of months bet the program that SX will achieve these multiple firsts over the next decade?  I wouldnít make that bet.  (And I started the COTS program that saved SX.)

Does SX have something to contribute that could help achieve MSR over the next decade?  Potentially, and the program should be talking to them and other suppliers.

Quote
and landing an orbital class booster on a droneship has been done many times before SpaceX did it, launching a heavy lift launch vehicle 80 times and sending 1,000 ton to orbit in a year has also been done many times before SpaceX did it, launching a constellation of 5,000 satellite has also been done many times before SpaceX did it.

These are not technical firsts in the same way that supersonic retropulsion was.  SX has done (and is doing) these things at new scales, but rocket landings, heavy lift, and satellite constellations have been demonstrated before.

Quote
https://twitter.com/lrocket/status/1721996598929174774

Iím a Tom Mueller fan, and heís understandably proud of SX achievements.  But that statement is demonstrably false.  SX and other orgs canít do anything just because they set a goal.  Dragon wasnít suppossed to land in water.  It does (for example).

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 37507
  • Cape Canaveral Spaceport
  • Liked: 21564
  • Likes Given: 429

Overall, I think that this is a promising approach that could avoid the need to design an expensive new lander.

?????, quite the opposite.  More risky and much more expensive.  Landers are known commodity.   LOX production on Mars is not.   Even to do it requires many times the power that has been used on previous landers/rovers.

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 37507
  • Cape Canaveral Spaceport
  • Liked: 21564
  • Likes Given: 429
launching a constellation of 5,000 satellite has also been done many times

That only requires money and not technology

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 37507
  • Cape Canaveral Spaceport
  • Liked: 21564
  • Likes Given: 429

I thought the business case would be obvious: It's the crewed Mars missions that NASA is hoping to do under Artemis.


Typical nonsense.  Again typical SpaceX can do anything and everything.
a.  Artemis is only moon
b.  Crew Mars missions are much further away than MSR.
« Last Edit: 11/10/2023 08:01 pm by Jim »

Offline Don2

  • Full Member
  • ****
  • Posts: 541
  • Liked: 299
  • Likes Given: 0
Your argument is based upon a 10-year-old paper that you don't even have access to and you've only read the abstract? Does that seem like rather thin data to you?

Do you have any idea how long it has taken to get to this point in the MSR debate and MSR technology? Decades.

It's not based on that single paper. There are three references and the results of several calculations in that post. I was investigating the idea and found out that somebody else had thought of it first. That paper provided a number for the mass reduction.

Do you have any criticisms of a technical nature?
« Last Edit: 11/11/2023 08:28 am by Don2 »

Offline Don2

  • Full Member
  • ****
  • Posts: 541
  • Liked: 299
  • Likes Given: 0
?????, quite the opposite.  More risky and much more expensive.  Landers are known commodity.   LOX production on Mars is not.   Even to do it requires many times the power that has been used on previous landers/rovers.

Thank you for your opinion. Why do you think this is much more expensive? Being able to use the existing landing system would save a lot over designing a new one. MOXIE was not hugely expensive. Liquefying the oxygen needs technology which is similar to the cryocoolers which keep IR sensors cold. Not expensive. The power supply will require a large solar panel, but they are not super expensive.

MOXIE has retired a lot of the risk. The technology works. The remaining question is if it will work for long enough to fill the oxygen tank. Also the hybrid rocket technology isn't as well proven as conventional solids. I think those are the main remaining risks.

Offline ccdengr

  • Full Member
  • ****
  • Posts: 670
  • Liked: 494
  • Likes Given: 74
MOXIE has retired a lot of the risk. The technology works.
MOXIE is a toy.  It generated about 125 grams of O2 over the whole course of its operation and discarded it to the environment with no storage.

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 37507
  • Cape Canaveral Spaceport
  • Liked: 21564
  • Likes Given: 429

Thank you for your opinion. Why do you think this is much more expensive? Being able to use the existing landing system would save a lot over designing a new one. MOXIE was not hugely expensive. Liquefying the oxygen needs technology which is similar to the cryocoolers which keep IR sensors cold. Not expensive. The power supply will require a large solar panel, but they are not super expensive.


Not an opinion.  Cheaper to design and build a new landing system than to design and build a Mars LOX plant (which is also going to weigh much more than any SRM MAV).  The MSL Descent stage is not going to be able to land a large solar panel

You are also forgetting a power hunger pressure pump for the O2.
« Last Edit: 11/12/2023 01:37 pm by Jim »

Tags:
 

Advertisement NovaTech
Advertisement Northrop Grumman
Advertisement
Advertisement Margaritaville Beach Resort South Padre Island
Advertisement Brady Kenniston
Advertisement NextSpaceflight
Advertisement Nathan Barker Photography
1