NASA suggests Mars Sample Return to cost $4 billion and 10 years. Not really.

[Exoscientist]

 

 

 NASA has collected its first Mars sample. But it needs $4 billion, 10 years, and new technology to bring the rock to Earth.   
https://www.businessinsider.in/science/news/nasa-has-collected-its-first-mars-sample-but-it-needs-4-billion-10-years-and-new-technology-to-bring-the-rock-to-earth-/articleshow/86051685.cms

 Take a look at the delta-v map above. It takes about 10.2 km/s total delta-v each way to go to and from Mars. The Falcon Heavy can get about 16.8 tons to Trans Mars Injection, where TMI is the propulsion step to head towards an encounter with Mars, that is, meet it in its orbit about the Sun. Then I estimate with a smaller 10 ton payload the Falcon Heavy’s upper stage could land a 10 ton payload on the surface of Mars by using  aerocapture , which minimizes the propellant required to do the landing.  

 This then allows a wide variety of combinations of existing solid rocket motors, 3 stages, such as from the Star series to make up the 10.2 km/s required delta-v to return from Mars. 

 All these are existing elements so could be mounted, like, tomorrow, and at a few hundred million dollar cost.

  Robert Clark

 

[mikegarrison]

Landing on Mars is one of the most difficult engineering feats humans have ever accomplished, and you think it can be done with a repurposed Falcon upper stage? I don't think that's credible.

[cubinator]

5 minutes ago, mikegarrison said:

Landing on Mars is one of the most difficult engineering feats humans have ever accomplished, and you think it can be done with a repurposed Falcon upper stage? I don't think that's credible.

Certainly not, however it can perhaps be done in fewer than 10 years. I think the current plan is a Rube Goldberg machine that will come to fruition at the same time as Starship performs the same task.

Edited September 10, 2021 by cubinator

[StopIteration]

5 minutes ago, cubinator said:

I think the current plan is a Rube Goldberg machine

I mean it's not all that much more Rube Goldberg than Apollo was.

[mikegarrison]

5 minutes ago, cubinator said:

Certainly not, however it can perhaps be done in fewer than 10 years. I think the current plan is a Rube Goldberg machine that will come to fruition at the same time as Starship performs the same task.

That's possible. I don't think *likely*, but possible.

It would be kind of ironic if the way that we pick up these core samples Perseverance is stashing is by lifting them by hand into the cargo space of a rover.

2 minutes ago, StopIteration said:

I mean it's not all that much more Rube Goldberg than Apollo was.

Well, there was the Stardust mission where we sort of waved high tech flypaper around a comet and then took it back to Earth to find out what had stuck to it.

[magnemoe]

You describe the canceled red dragon program landing an dragon 2 capsule on Mars. Have it house an small rover for grabbing the sample and an couple ton return rocket.

Now if you leave the return stage and earth landing capsule in orbit you can get away with an much smaller orbital rocket, think guided anti tank missile size. 
Downside is that you will need this mini rocket to dock with the transfer stage in mars orbit so the samples can be transferred to the earth landing capsule who then closes and you launch the return module towards earth then its an window. 
So yes the same procedure as Apollo did with an cubesat sized upper stage. And yes you need to load the sample into the orbital rocket but that is relatively easy. 

[Exoscientist]

On 9/9/2021 at 10:49 PM, mikegarrison said:

Landing on Mars is one of the most difficult engineering feats humans have ever accomplished, and you think it can be done with a repurposed Falcon upper stage? I don't think that's credible.

 

  ‘Red Dragon’ can also do it launched atop the Falcon Heavy:

'Red Dragon' Mars Sample-Return Mission Could Launch by 2022

By Mike Wall September 10, 2015

https://www.space.com/30504-spacex-red-dragon-mars-sample-return.html

 It would use though both aerobraking and propulsive landing.

 This article claims ‘Red Dragon’ was cancelled only for political reasons:

https://news.ycombinator.com/item?id=26274117

 

 By the way, looking at that delta-v map again, it looks like for a fully aerocapture approach to landing at both Mars and Earth, you could get greater mass to Mars. I was considering a 10.2 km/s delta-v each way to Mars and back, but part of this is for propulsive burns when arriving at Mars, or returning to Earth.

 If you do a fully aerocapture descent, i.e., aerodynamic slow down, with parachutes when sufficiently slowed, then you just need to do a Trans Mars Injection burn and this only takes ca. 3.8 km/s. And the Falcon Heavy can launch 16.8 tons to Mars on this trajectory. This would then make a direct descent to the Mars surface. Note the higher mass means we could add additional aerodynamic surfaces to assist with the slowdown on arrival at Mars.

 Also, for return to Earth, if this is fully aerodynamic, the delta-v for this is only around 6.3 km/s. So a larger mass could be returned from the Mars to Earth.

  Robert Clark

On 9/9/2021 at 11:01 PM, StopIteration said:

I mean it's not all that much more Rube Goldberg than Apollo was.

 Part of the reason why Apollo was multi-billion. For instance for the current sample return plan they want the Mars Ascent Vehicle to rendezvous with an orbiting spacecraft and then be launched by a another stage to Earth.

 Far simpler and cheaper to launch directly from Mars surface towards Earth.

 

  Robert Clark

Edited September 12, 2021 by Exoscientist

[kerbiloid]

SpaceX should send a methane plant, refuel the rocket and get back, like they anyway are going to do with humans.

[mikegarrison]

SpaceX stopped developing "Red Dragon" about the time that 2015 article was written.

[StopIteration]

2 hours ago, Exoscientist said:

Part of the reason why Apollo was multi-billion

Wait, you think direct ascent would have been cheaper than doing lunar orbit rendezvous for Apollo?  Because I've always heard the opposite.

3 hours ago, Exoscientist said:

few hundred million dollar cost

A few hundred million dollars is how much SpaceX would charge for the Falcon heavy launch vehicle itself.  But the only thing you're really saving by getting a bigger payload to Mars is the Mars orbit rendezvous part.  All the rest of the stuff that makes the mission difficult you still have to do.  And then you have the added challenge of landing such a huge payload on Mars, especially if you're trying to aerocapture it (which I'm pretty sure is a lot harder in real life than in KSP).  The engineering costs would still be very high.

 

Edited September 10, 2021 by StopIteration

[tater]

4 hours ago, Exoscientist said:

 Take a look at the delta-v map above. It takes about 10.2 km/s total delta-v each way to go to and from Mars. The Falcon Heavy can get about 16.8 tons to Trans Mars Injection, where TMI is the propulsion step to head towards an encounter with Mars, that is, meet it in its orbit about the Sun. Then I estimate with a smaller 10 ton payload the Falcon Heavy’s upper stage could land a 10 ton payload on the surface of Mars by using  aerocapture , which minimizes the propellant required to do the landing.  

You're saying that of the 16.8t, it could land 10 of payload, using the remaining 6.8t as parachutes/landing props?

Seems plausible, I suppose you could look at the relative mass of the aeroshell, chutes and landing props for other landers. The whole thing fitting under the fairing.

No need for "Red Dragon" in fact that would waste too much mass. I seem to recall seeing that after aerodynamics strips most of the velocity off, you need under a few hundred m/s for landing. The current SpaceX plan is obviously Starship, but NASA also looked at many ideas, including biconics that fly similar entries to Starship.

I suppose instead of dumping the Falcon fairing, you could keep half of it as an aeroshell. It is thought to mass 1900 kg, so half with added TPS might eat up...1200 kg of the 16.8t to TMI?

Send lander with 1/2 a fairing (TPS added) to TMI. Shed transfer velocity with aeroshell, jettison it. Chute or not, land propulsively, and maybe a sideways lander (a bunch of the NASA biconic ideas I have seen do this). The Earth return vehicle is then on its side, obviously. Upside is that it is easier for a rover to deposit the samples, down side is that the return vehicle needs to be erected before launch. Of course if the thing lands upright, launch is simpler—but now you need hardware to get the sample to the very top, so I think sideways wins here.

[tater]

NASA is talking about a return vehicle that masses only 400 kg. 16.8t to TMI gives loads of margin for something like that.

 

[kerbiloid]

They could use a bellow tank. The less fuel is rest, the flatter the tank gets.

When it's completely empty and flat, they can use it as an improvised heatshield instead of real one.

On landing they could inflate it again and use as a Mercury-style landing airbag.

Such a multi-purpose thing...

[Nuke]

does it have to return the samples directly to earth? what if they deliver them to the iss and then they can be returned to earth during a routine dragon flight. then you just need a small srb to get it off mars and a small second stage with a hall thruster. you can also save weight if the lander can manufacture fuel from the mars atmosphere. thus you can demonstrate isru and remote refueling on the same mission. 

though i dont know who came up with the idea of dropping samples as the rover moved on, now you just suddenly have a need for a second rover (or helicopter) with an apparatus to grapple the tube. seemed it would have been smarter to put the tubes into a carousel and drop that off as one piece. and the whole thing could be picked up and put in the rocket. 

Edited September 11, 2021 by Nuke

[Beccab]

2 minutes ago, Nuke said:

does it have to return the samples directly to earth? what if they deliver them to the iss

It is much, much easier to send it to earth than it is to make it enter LEO somehow, align with the ISS orbital plane, set up a rendezvous then berth and dock, as well as needing less fuel and less mass

[tater]

3 minutes ago, Nuke said:

does it have to return the samples directly to earth? what if they deliver them to the iss and then they can be returned to earth during a routine dragon flight. then you just need a small srb to get it off mars and a small second stage with a hall thruster. you can also save weight if the lander can manufacture fuel from the mars atmosphere. thus you can demonstrate isru and remote refueling on the same mission. 

ISS would be much harder dv wise. The dv requirement assumes a direct entry from TEI.

Any aerobraking involves adding TPS mass, and the difference between direct entry TPS mass and deep aerocapture TPS mass is probably not substantial.

So the math here would be is a propulsive LEO orbit from TEI more or less mas expensive than the hardware required for EDL at Earth (TPS, chutes, etc).

Any ISS capture version would also need RCS, etc to get close enough for capture by the SSRMS.

[mikegarrison]

Let's face it. The whole idea of "hey, we can collect samples and bring them back later" is probably just wishful thinking.

[Nuke]

1 hour ago, mikegarrison said:

Let's face it. The whole idea of "hey, we can collect samples and bring them back later" is probably just wishful thinking.

especially if you account for the fact that mars has dust storms. if enough dust can accumulate on a solar panel to shut down a rover, then enough can bury the sample tubes, then any retrieval system would have to dig it out. granted you would only need either a high rpm fan or compressed gas blower. the whole retrieval process would involve re-tracing the route of the current rover, so very little new ground would be covered. picking up a carousel would have allowed a path crossing route and could have actually done more science. i dont know how "maybe we can pick them up later" got the nasa stamp of approval. 

Edited September 11, 2021 by Nuke

[mikegarrison]

50 minutes ago, Nuke said:

i dont know how "maybe we can pick them up later" got the nasa stamp of approval. 

I presume it went like this:

1. Let's get a sample return onto Mars 2020!
2. We're not ready for a sample return
3. But we've got a drill!
4. But we're not ready for a sample return
5. Maybe we can gather samples and ... I don't know ... bring them back later?
6. Yeah, OK, let's try

Edited September 12, 2021 by mikegarrison

[tater]

^^^ Yeah, it was a way to push forward the idea of sample return without having to do it, secure the larger funding, etc.

I'd assume it would be far less complex to land something with a return stage, scoop up some Mars right there, and leave.

[Exoscientist]

On 9/10/2021 at 1:56 AM, mikegarrison said:

SpaceX stopped developing "Red Dragon" about the time that 2015 article was written.

 According to this article, NASA support for the mission was cancelled for political reasons:

https://news.ycombinator.com/item?id=26274117
 

  Robert Clark

[kerbiloid]

From Mars? Pathetic...

Roscosmos is wanting to get them from Venus.

https://translate.google.com/translate?hl=&sl=ru&tl=en&u=https%3A%2F%2F3dnews.ru%2F1036100%2Frossiya-namerena-dostavit-na-zemlyu-obraztsi-grunta-s-veneri

https://translate.google.com/translate?hl=&sl=ru&tl=en&u=https%3A%2F%2Fnplus1.ru%2Fblog%2F2020%2F09%2F16%2Fsemifantastic&sandbox=1

Spoiler

 

(The blue cigar is a telescopic hard envelope, to lift it and then to fill a soft balloon envelope. Then a rocket starts.)

Btw repeats my old idea with pistonned tanks for venus lander.

[Exoscientist]

On 9/10/2021 at 2:30 AM, tater said:

You're saying that of the 16.8t, it could land 10 of payload, using the remaining 6.8t as parachutes/landing props?

Seems plausible, I suppose you could look at the relative mass of the aeroshell, chutes and landing props for other landers. The whole thing fitting under the fairing.

 Actually, I was basing the 10 tons estimate on how much propellant I had once estimated would be left over in the FH upper stage if it only had to get a smaller payload mass to TMI. I then imagined doing a propulsive landing on Mars.

 But that’s really not the aerocapture method I was thinking of here.  Perhaps someone could do a Kerbal Realism Overhaul of a Falcon Heavy upper stage propulsive landing on Mars.

  Robert Clark

[tater]

15 minutes ago, Exoscientist said:

 Actually, I was basing the 10 tons estimate on how much propellant I had once estimated would be left over in the FH upper stage if it only had to get a smaller payload mass to TMI. I then imagined doing a propulsive landing on Mars.

 But that’s really not the aerocapture method I was thinking of here.  Perhaps someone could do a Kerbal Realism Overhaul of a Falcon Heavy upper stage propulsive landing on Mars.

  Robert Clark

You're thinking of a smaller craft as payload, and the added TMI mass is residuals in S2? So a kerolox landing with the S2  Mvac?

I suppose it saves the mass of the additional engine.

[monophonic]

On 9/12/2021 at 2:22 AM, Nuke said:

especially if you account for the fact that mars has dust storms. if enough dust can accumulate on a solar panel to shut down a rover, then enough can bury the sample tubes, then any retrieval system would have to dig it out. granted you would only need either a high rpm fan or compressed gas blower. the whole retrieval process would involve re-tracing the route of the current rover, so very little new ground would be covered. picking up a carousel would have allowed a path crossing route and could have actually done more science. i dont know how "maybe we can pick them up later" got the nasa stamp of approval. 

On the other hand if the rover broke down before you dropped the carousel you would lose all the samples. Just goes to show how unrealistic the entire "sample now, collect later" strategy is, I guess.