Saturn V to Mars

RobertDyck · 2016-01-04 06:02:51

Here is a silly exercise. Could-a would-a should-a. One idea that could have gone to Mars.

Apollo used a Saturn V to go to the Moon. A minor upgrade to Saturn V to send Apollo on a fly-by to Mars and back. Using Apollo era hardware, but some modern knowledge.

Now image Saturn V first stage with F-1A engines. Each engine 20% more powerful, but that means they burn through propellant faster. Same second stage. Then a third stage based on the smaller S-IV stage of Saturn 1, which used 6 RL-10 engines instead of a single J-2 engine. However, the liquid hydrogen tank of the S-IV stage has a cone shaped top; upper diameter matched the Apollo service module. Imagine a modified S-IV stage that has a cylinder LH2 tank, like S-IVB. And expanded diameter: 6.6m diameter like S-IVB, instead of 5.49m diameter of S-IV. And since this will be stacked on an S-II stage, it will require the same interstage as Saturn V.

Then stacked on top a 4th stage, a modified S-IVB stage. This S-IVB stage would have an LH2 tank with the cone top of S-IV. Yes, that's swapping. But the volume of the LH2 tank would be the same as S-IVB. And yes, still 6.6m diameter, so the top of the LH2 tank would be an even more pronounced cone. The purpose is so an Apollo CSM can be mounted on top of this stage. It would use the same cylindrical interstage (payload adapter) that connected Apollo CSM to Saturn 1.

When Apollo launched to the Moon, the third stage (S-IVB) had two jobs: circularize orbit, and TLI. I suggest this smaller third stage would have one job only: circularize orbit. That would leave the 4th stage fully fuelled. The 4th stage would be TMI: Trans-Mars Injection.

The Skylab workshop was originally designed to launch wet. The reason the ceiling and floors of the living space were open mesh metal grids was to permit LH2 to flow through during launch. And that ceiling and floor, along with walls, would act as anti-vortex baffles and anti-slosh baffles. This new stage would launch wet. This would provide a Skylab-based living space during the trip to Mars and back.

This would not have an airlock. The CSM would turn around and dock the same way it did to the LM when going to the Moon. But in this case it would dock to the workshop. Obviously the top of the workshop would be smaller, so Locker stowage would not be cylindrical, that part would be a cone. And the workshop would require the same solar panel wings as the Skylab workshop. But ensure it doesn't rip off during launch this time.

The Command Module would have a PICA heat shield instead of AVCOAT, developed specifically as an upgrade to allow it to return from Mars.

This would be a fly-by mission, using a free-return trajectory. This trajectory was proposed in 2013 for Inspiration Mars.

Skylab era life support would have been almost good enough. Skylab was occupied for 171 days, NASA calculated crew would need 1,166 kg (2,565 lbs.) water for that duration. Skylab was launched with 2,700 kg (6,000 lbs.) water. Based on 5 pounds water per person per day, 3 crew would last 400 days. At launch oxygen weighed 2,240 kg (4,930 lbs.) and the nitrogen weighed 600 kg (1,320 lbs.). Assuming 0.84 kg (1.84 lb) oxygen per person per day, that would provide 3 crew 888.89 days. Subtract a substantial quantity of oxygen to pressurize the workshop, it should last 501 days. Skylab launched with 670 kg. (1,470 lbs.) of food. Assuming 0.62 kg (1.36 lb) food solids plus 1.15 kg (2.54 lb) water in food per person per day, that works out to 125.64 days. Skylab operated for 171 days, so they obviously used some dehydrated food. These figures could be adjusted for a Mars mission: more water and food, less equipment. So even without modern life support, it would have worked.

Last edited by RobertDyck (2016-01-05 05:05:44)

RobertDyck · 2016-01-04 16:35:47

The reason I thought of a small 3rd stage, was that NERVA was designed as a TMI stage to send humans to Mars. It was launched cold, with the reactor never turned on. That meant the reactor would have just uranium, embedded within solid ceramic fuel elements. There would be no fission fragments during launch, so no highly radioactive isotopes. Uranium itself is mildly radioactive, safe to handle with nothing but the loose plastic gloves you get with oven cleaner. Launching the NERVA engine cold was a deliberate safety measure, in case of rocket failure. The stage was for TMI, so would depart Earth orbit and never come back. The issue is Saturn V used its 3rd stage (S-IVB) for two jobs: circularization in Earth orbit, and TLI. But a NERVA stage cannot be used for circularization, because it shouldn't be turned on until *AFTER* it has been safely parked in orbit. So I thought of a stage smaller than S-IVB that could circularize. That led me to think of the smaller S-IV stage.

That would require a habitat for additional space, and extended life support. This wouldn't have a Lunar Module, so a hab instead. This lead me to think of Skylab. It was originally designed to launch wet as the upper stage of a Saturn 1B. So what if we use a Skylab workshop instead of the NERVA stage? Using full propellant for TMI instead of splitting propellant with circularization. Apollo had the S-IVB stage attached to the Apollo CSM and LM stack through TLI, so the stage was inserted into Trans-Lunar trajectory along with it. This would insert an Apollo CSM without the LM into Trans-Mars trajectory. It would have Skylab workshop stuff attached instead of the LM. And the Saturn I spacecraft adapter was much smaller than the adapter for Saturn 1B or Saturn V. So should have sufficient delta-V for TMI. And this also reminded me of NASA's 1965 study using an Apollo CSM and Skylab module for a Mars fly-by. However, this one would pass Mars and head directly back to Earth, not swing out into the asteroid belt, so a lot safer.

Note: PICA heat shield was developed in 1970 as an upgrade to the Apollo Command Module specifically so it could return from Mars. Dragon uses PICA-X, but Orion uses AVCOAT.

Also NERVA was originally conceived to send humans to the Moon. After Apollo 11 the Russians considered trumping that achievement by going directly to Mars. That's when NASA developed PICA. NASA also brushed off plans for NERVA and finished it. Specifically as the TMI engine for a human mission to Mars.

Last edited by RobertDyck (2016-01-04 20:41:42)

louis · 2016-01-04 20:01:08

Thanks Robert - all very interesting.

SpaceNut · 2016-01-04 20:53:59

Which means with SLS, we could if we did what these pages indicate do the mission with a degree of safety now compared to what would have been a possible disaster back then.

RobertDyck · 2016-01-04 23:35:31

My point was we could have gone to Mars a long time ago. I said NASA promised to go in the early 1980s. I thought it was 1981, because that was the date the Shuttle flew. We got a Shuttle instead of a Mars mission. The Shuttle was nice and all, but doesn't hold a candle to a Mars mission. But GW Johnson reminded us all that NASA actually promised a Mars mission for 1983. Well, close enough. Part of my point is we could have gone. Initially just a fly-by, but could have gone. Today NASA is saying we aren't ready. Twenty years ago they said it would be 20 years before we're ready. Now they're saying another 20 years. And 20 years from now it will be another 20 years. At one point NASA was saying it would be 2060 before we're ready. At their current pace, that's more likely. But we saw with Sputnik and Yuri Gagarin that American government can respond to a swift kick between the legs. Too bad it takes that.

Look at further technical documents, NASA had started development of Phenolic Impregnated Carbon Ablator (PICA) in the 1970s, as an upgrade to the Apollo Command Module to return from Mars. However, just to make it more complicated, it wasn't flight ready until 1990. DoD was working on Carbon Phenolic Ablator in the 1960s and 1970s, but it was considered too heavy. A light weight, reliable PICA was developed for Stardust.

Could they have gone to Mars? I think so. PICA was heavier in the 1970s, 3 times as heavy as AVCOAT. PICA-15 developed in 1990 was lighter. The Dragon spacecraft by SpaceX today uses PICA-X. But it would have allowed Apollo to return from Mars. Could we have gone in the 1990s with Mars Direct? Absolutely!

Last edited by RobertDyck (2016-03-14 10:31:48)

Tom Kalbfus · 2016-01-05 09:48:38

Sounds like the book Voyage by Stephen Baxter.
https://en.wikipedia.org/wiki/Voyage_(novel)

Voyage is a 1996 hard science fiction novel by British author Stephen Baxter. The book depicts a manned mission to Mars as it might have been in another timeline, one where John F. Kennedy survived the assassination attempt on him on November 22, 1963. Voyage won a Sidewise Award for Alternate History, and was nominated for the Arthur C. Clarke Award in 1997.
In 1999, it was adapted as a radio serial for BBC Radio 4 by Dirk Maggs.
Plot summary
The book tells the story in flashbacks during the actual Mars mission of the chronicalised history until the mission's beginning. The point of divergence for this alternate timeline happens on November 22, 1963, where John F. Kennedy survived the assassination (Jacqueline Kennedy was killed, hence the renaming of the Kennedy Space Center as the Jacqueline B. Kennedy Space Center), but was crippled and thus incapacitated, as Lyndon B. Johnson is still sworn in. On July 20, 1969, astronauts Neil Armstrong and Joe Muldoon walk on the moon, and Nixon's "most historic phone call" is joined by a call from former President Kennedy, committing the United States to send a manned mission to Mars, which Nixon backs as part of his fateful decision to decide the future of manned spaceflight, instead of deciding on the Space Shuttle program as he did in our timeline.
Preparations for this new goal include slashing the number of moon landings so funding and leftover Apollo spacecraft hardware can go towards the efforts of the manned Mars mission. Apollo 12 still lands, Apollo 13 still suffers its disaster, but Apollo 14 is crewed by the astronauts of the cancelled Apollo 15 mission to carry out the scientific experiments on the lunar surface, and is the last manned moon landing. At the same time, the NERVA program is revived to become the chosen Mars spacecraft development, with larger tests in Nevada, but without containment and plagued with engineering problems.
The book centers around chronicling the lives of the future Mars mission astronauts, NASA and contractor personnel all involved in making the mission become a reality, and the shifts within NASA's astronaut and management hierarchy throughout the mission's preparations, including female geologist Natalie York's quest to become an astronaut, and her stormy relationships with fellow astronaut Ben Priest and NERVA engineer Mike Conlig. Other astronauts include Ralph Gershon, a former fighter-bomber pilot involved in illegal bombing missions in Cambodia during the Vietnam War whose dream is to be the first black man in space, and Phil Stone, a veteran Air Force test pilot-turned-astronaut who has flown in a long-term stay on a lunar orbital station before the Mars mission.
In the 1970s, the Skylab Space Station is launched, but apparently as a wet workshop design that is based on the Saturn IB S-IVB upper stage called Skylab A. The Saturn V that might have launched Skylab in our timeline instead launches Skylab B, a lunar orbit space station unofficially named "Moonlab", also a wet workshop based on the S-IVB. The Apollo-Soyuz Test Project is instead a series of visits by the Apollo Command/Service Module to Salyut space stations, and Soyuz missions to both Skylab and Moonlab. To facilitate the latter, the Soviets finally finish work on their N-1. The Skylab/Moonlab programs lead to improvements in the design of the Apollo Command/Service Module. A Block III CSM is produced using battery power in place of fuel cells, followed by the Block IV and V, which have a degree of reusability (modular construction and resistance to salt water corrosion). Also chronicled is the development of the experimental 'Mars Excursion Module' by small aerospace firm Columbia Aviation as it struggles against larger rival contractors of NASA and its engineers working painstakingly against the technical challenges of a working and reliable Mars lander.
A test of the NERVA, called Apollo-N, is finally launched atop the modified Saturn VN, but suffers from pogo oscillations in the S-IC first stage. This damages the NERVA upper stage, which catastrophically fails once fired in orbit; despite returning to Earth safely, the entire crew (including Ben Priest) is killed by radiation poisoning, and the space program nearly collapses from hostile political and public opinion against the use of nuclear power in space, and the seemingly unnecessary risks and reasons of a Mars mission.
In the aftermath, a new Mars mission plan dubbed Ares is drawn up, utilising the upgraded Saturn VB, which has numerous improvements, including the use of solid rocket boosters to double its payload. Ares also uses on-orbit assembly of a different long duration Mars-ship using wet-workshop Saturn rocket components as the propulsion systems as well as a Skylab habitat module and external tanks to hold extra fuel. Ares performs a Venus flyby reminiscent of the Manned Venus Flyby NASA planned in the aftermath of the original Apollo program, but done in this timeline for gravitational assistance, and finally lands at Mangala Valles on March 27, 1986.
However, as a side effect, a number of unmanned probes – including the Viking program, Pioneer Venus project, Mariner 10, Pioneers 10 and 11, and the Voyager program – are cancelled so that their funding can be redirected to the manned Mars mission, although another Mariner orbiter is sent to Mars to help prepare for the manned landing. As a result, although humans walk on Mars, their knowledge of the solar system, including Mars itself, is far less than in reality.

Last edited by Tom Kalbfus (2016-01-05 09:54:43)

RobertDyck · 2016-01-05 12:08:40

Yesterday Robert Zubrin sent a Facebook link to this. He doesn't post here, but looks like he does read our stuff once in a while.

Mars Society Announces International Gemini Mars Design Competition

Students to propose design concepts mission to open the path to the Red Planet
...
The requirement is to design a two-person Mars flyby mission that can be launched no later than 2024 as cheaply, safely and simply as possible. All other design variables are open.
Alumni, professors and other university staff may participate as well, but the teams must be predominantly composed of and led by university students. All competition presentations must be completed exclusively by students. Teams will be required to submit their design reports in writing by March 15, 2016. From there, a down-select will occur with the top 10 finalist teams invited to present and defend their designs before a panel of six judges chosen (three each) by the Mars Society and NASA. The presentations will take place during a public event at the International Mars Society Convention in Washington DC in September 2016.

RobertDyck · 2016-01-05 13:43:46

Tom Kalbfus wrote:

Sounds like the book Voyage by Stephen Baxter.

The space program produced a lot of fans. For example: us. A lot of people looked at what NASA did, and said "what if". Your description sounds like what I'm talking about, because that's what NASA was working on.

A test of the NERVA, called Apollo-N, is finally launched atop the modified Saturn VN, but suffers from pogo oscillations in the S-IC first stage. This damages the NERVA upper stage, which catastrophically fails once fired in orbit; despite returning to Earth safely, the entire crew (including Ben Priest) is killed by radiation poisoning, and the space program nearly collapses from hostile political and public opinion against the use of nuclear power in space, and the seemingly unnecessary risks and reasons of a Mars mission.

Ooh! Ohh! Someone said the "N" word! You have to walk in circles 3 times, and self-flagellate with holly branches!

I take exception to Hollywood depictions of nuclear power in space. Movies, TV shows, computer games, all start with "nuclear accident killing all crew". That's about as realistic as 1970s TV shows that depict a car exploding just a few seconds after a crash. In reality gasoline does not explode. Gasoline must be atomized by a carburetor or fuel injector, and the fuel/air mixture has to be the perfect ratio. Cars don't explode. If they did what 1970s TV shows depicted, then cars wouldn't be allowed on the road. But they don't. Likewise nuclear reactors don't do what Hollywood claims. You have to show nuclear power respect, but that's the same as showing a car respect. If you drive a car into someone's house as 100 miles per hour, you will do great damage to yourself and anyone in that home. Nuclear reactors also require respect, but they aren't Chernobyl waiting to happen.

NERVA had many safety features built in. One was that the reactor wouldn't be turned on until after safely in orbit. So if the launch vehicle failed, the pieces of reactor would be so safe to handle that you could pick up pieces with the same loose plastic gloves you get with oven cleaner. You could use heavier gloves, but they would be unnecessary, something like a rubber gloves used for house cleaning, or winter gloves, or leather work gloves. But anything porous that touches the uranium would have to be surrendered with the uranium, so you want something cheap. You could use BBQ tongs; they would have to be scrubbed before giving back.

If an accident occurred in space, the fact the engine is at the back-end of the rocket while astronauts are at the front gives them some protection. Liquid hydrogen is the perfect shielding, so until the propellant tank is empty you have shielding between the reactor and you. Once the tank is empty, a NERVA stage would be discarded in space, not left attached to the spacecraft. So none of the problems described in this article would happen.

However, as a side effect, a number of unmanned probes – including the Viking program, Pioneer Venus project, Mariner 10, Pioneers 10 and 11, and the Voyager program – are cancelled so that their funding can be redirected to the manned Mars mission, although another Mariner orbiter is sent to Mars to help prepare for the manned landing. As a result, although humans walk on Mars, their knowledge of the solar system, including Mars itself, is far less than in reality.

More hyperbole. Human missions are bad, we need to send unmanned explorers. There are people at NASA who believe this. JPL has done great work, but there are things only humans can do. For example: Curiosity is doing great work now, but if Mars Direct was actually approved when Robert Zubrin and his partner first proposed it in 1990, then expect an unmanned test of equipment to be launched to Mars in 1997, and the first human mission in 1999. That first human mission would have been able to do everything Curiosity is doing today and more.

SpaceNut · 2016-01-05 17:35:37

During that era the "N" word (Nukes) was just a fear of repurcusion from having seen the fall out effects....the exposure to the radiational contanimation....
I think that its not longer the case and we can move on with it if we use partners in the task to build it so that any fear will be dispelled......

Tom Kalbfus · 2016-01-06 14:03:53

The NIMBY folks aren't consistently NIMBY when it comes to immigration, and selling nuclear material and technology to and dropping sanctions on countries likely to make nuclear bombs out of it. I have trouble believing people, who are not afraid of terrorism nuclear or otherwise, and want to cut defense spending, express their concerns about a nuclear accident!

kbd512 · 2016-01-08 21:35:33

There's no doubt in my mind that three Saturn V launches could have thrown enough tonnage to mount a proper mission to Mars. The real question is what they would realistically have been able to do when they arrived.

There were some advantages to the golden age. NASA was willing to take risks and try new things. NASA has become so risk averse today that a Mars mission is simply out of the question for the foreseeable future.

By the time the Mars mission hardware was ready, F-1A would have been available. NERVA would have been fully developed by the early 1980's. That's a major win for lift capability.

Now for the substantial downsides to late 70's era hardware.

CL-ECLSS (or something close to it) was merely a concept paper thought up to reduce consumable requirements for space stations. There's an actual piece of hardware that's in testing as we speak. I can't recall whether or not ISRU was even mentioned, let alone seriously considered as a viable means to obtain what humans required for surface sustainment. That means you have to truck a lot of heavy water and oxygen to the surface of Mars. The landing technology of the time was storable hypergolics, so tonnage available for scientific cargo would have been poor.

Every feasible measure to remove weight from the LEM was used. The Mars lander would need to be substantially more robust.

The computers of the time that could be stuffed into a lander were about as powerful as a pocket calculator and nowhere near as reliable as a modern pocket calculator.

The radios were simply poor by modern standards, in terms of data transmission rate and signal quality. The communications equipment was sufficient for the job, but that's all you can say about it.

The general reliability of unimportant things like ECLSS and space suits could best be described as marginal. There were a number of problems with those must-have items during the Apollo and Skylab programs. The results of the failures weren't fatal because the proximity to Earth allowed for quick communications to devise acceptable temporary solutions and a substantial amount of dumb luck.

SPE's were fairly well understood at that time, but accurate space weather warnings with substantial lead times didn't come until many years later. The crew would have had little prior warning of an inbound SPE.

I tend to think that any 1980's Mars mission would have been an opposition class flags-and-footprints endeavor. Still, it would have been far more preferable than 30 years of circling the Earth in an oversized cargo carrier. I choose to look at what happened before, during, and after Apollo as the learning experience required for us to get to where we are today.

Last edited by kbd512 (2016-01-08 21:37:54)

RobertDyck · 2016-01-08 23:53:26

People today do not understand what NASA did. They went from nothing to men on the Moon in ridiculous time. Sputnik launched 4 October 1957. Yuri Gagarin orbited the Earth on 12 April 1961. NASA started with a pressure suit the US Air Force used for high altitude pilots, converted that to the first Mercury spacesuit, which evolved to the Apollo suit. And that evolved to the EMU that NASA uses today. Apollo 11 launched 16 July 1969, landed on the Moon 20 July 1969. Neil Armstrong walked on the Moon 6 hours later.

The mission I just described includes a Skylab workshop. It doesn't include any modern life support, just the same as Skylab. That's crude by today's standards, no recycling. It's just bottled water, bottled oxygen, and lithium hydroxide to absorb CO2 from cabin air. It would have worked because Skylab is so big.

Could NASA have developed something by the 1980? Certainly! Depends which date. Remember that Dr. Robert Zubrin and his partner David Baker started development of Mars Direct in late 1989. It was presented at a NASA conference in June 1990. Mars Direct included recycling life support that existed at that time.

One of Robert Zubrin's arguments was to use life support that existed then. In his book "The Case for Mars", he complained that NASA wanted life support with 95% recycling efficiency before going to Mars. He argued to use what existed at that time. Just do it! He argued that if we waited until a 95% efficient system was available, it would be the 21st century before we're ready to go! Oops! It is the 21 century now. We've pissed away so much time that the 21 century is upon us. I've been saying this since 2001. Today is 2016. The system on ISS today is 93% efficient. I've pointed out a few simple improvements using technology that NASA already has; these improvements would improve efficiency even further.

GW Johnson · 2016-01-09 11:15:47

Using the "Skylab spacious idea" as a travel habitat to Mars and back makes a lot of sense. But you won't be able to land a thing that big. It has to stay in LMO. Why not recreate a space that big from Bigelow inflatables docked together, and fitted with the life support from ISS, plus whatever stores are needed to more-than-make-up for what cannot be recycled? Same idea, modern tinkertoys with which to build it.

Put this hab on one end of a string of docked propellant modules, with the engines and any nuclear electricity source at the other. The spin the damned thing head-over-heels like a baton for 1 full gee artificial gravity in the hab. Use it to transfer from LEO to LMO, and back again. What could be simpler? And there's nothing that we couldn't launch using today's rockets.

What's needed is a landing craft to reach the surface. There's more than one way to do this. But in any design, the lander's engines can be used to push it and some supplies to LMO, where the manned vehicle can rendezvous with it. You are not restricted to only one of these landers, either.

If you can solve the problem of landing accuracy, then you can pre-land stuff at your site or sites that you want to visit. Although close-up observation from LMO by the astronauts might identify better site choices. That's just something to think about before the mission design and vehicle designs "freeze". My guess is that we need some GPS satellites around Mars to solve the accuracy problem. You have to, if you wish to land multiple vehicles at one site.

When you look at things like Skylab, and recreate them with the tinkertoys available today, you find out that, yes, we could have sent men to Mars decades ago with the Saturn-5 technologies we had then. We can do this anytime we want to.

The two key impacts to any mission design today are what they didn't understand well enough in the 1970's: microgravity diseases, and surviving massive solar flare events. We have known how to deal with those since the 1990's.

GW

Last edited by GW Johnson (2016-01-09 11:20:23)

RobertDyck · 2016-01-09 13:19:09

Actually, what I described here, Apollo CSM + Skylab workshop, would only be a flyby. It would not be able to land on Mars, and would not even be able to enter Mars orbit. But could have been done in the last 1970s.

I also described a flyby using modern equipment here: Mars Society Announces International Gemini Mars Design Competition
This one uses a Dragon spacecraft, plus Pressurized Cargo Module from Cygnus, and one Bigelow BEAM. That's Cygnus without its service module, and filled with life support equipment the same as ISS. It would have a tunnel just barely large enough for one man, with Dragon at one end and BEAM at the other. Again, it would only be a flyby. But it could be launched by a single Falcon Heavy.

As for Mars GPS: do you realize NASA and ESA started on that? All orbiters starting with MGS have a Mars antenna. That can communicate to a Mars lander or rover, so the orbiter can be a communication relay. The Mars antenna can determine range. Then with multiple samples from different positions in orbit, it can use intersecting spheres to determine position. That requires multiple orbits. Or using multiple orbiters, you can do it with a single pass. It isn't quick, it doesn't give the instantaneous result that Earth's modern GPS does, and precision is pretty poor, but it is something.

RobertDyck · 2016-01-09 13:40:21

GW Johnson wrote:

The two key impacts to any mission design today are what they didn't understand well enough in the 1970's: microgravity diseases, and surviving massive solar flare events. We have known how to deal with those since the 1990's.

They did have a good idea back then. Not quite as much as today, but mostly. They just lived with microgravity stuff. Skylab actually had several experiments designed to mitigate microgravity issues. The lower body negative pressure device was supposed to suck the blood from the upper body back down. It didn't help; as mitigation for microgravity, it didn't work. They also had a exercise equipment, which did work. Equipment on ISS today is based on that equipment first developed for Skylab.

And they did know about solar flares. Their solution was watch the Sun, send a mission when there isn't a flare. And cross your fingers and hope it doesn't happen while astronauts are in space. For Skylab, they had mission control on the ground keep an eye on the Sun. If a solar flare happened, astronauts would be ordered to get into their Apollo CSM and come back home. You can do that from LEO, you can't on Mars.

If you want real solutions to these issues, then we're talking Mars Direct. Or some mission derived from Mars Direct. That would have artificial gravity during transit to Mars, and radiation shelter.

Tom Kalbfus · 2016-01-11 17:37:45

RobertDyck wrote:

Actually, what I described here, Apollo CSM + Skylab workshop, would only be a flyby. It would not be able to land on Mars, and would not even be able to enter Mars orbit. But could have been done in the last 1970s.
I also described a flyby using modern equipment here: Mars Society Announces International Gemini Mars Design Competition
This one uses a Dragon spacecraft, plus Pressurized Cargo Module from Cygnus, and one Bigelow BEAM. That's Cygnus without its service module, and filled with life support equipment the same as ISS. It would have a tunnel just barely large enough for one man, with Dragon at one end and BEAM at the other. Again, it would only be a flyby. But it could be launched by a single Falcon Heavy.
As for Mars GPS: do you realize NASA and ESA started on that? All orbiters starting with MGS have a Mars antenna. That can communicate to a Mars lander or rover, so the orbiter can be a communication relay. The Mars antenna can determine range. Then with multiple samples from different positions in orbit, it can use intersecting spheres to determine position. That requires multiple orbits. Or using multiple orbiters, you can do it with a single pass. It isn't quick, it doesn't give the instantaneous result that Earth's modern GPS does, and precision is pretty poor, but it is something.

What would be the point of a manned flyby? the astronauts would risk their lives spending 18 months in space without even the "paydirt" of collecting rock samples from Mars.

Tom Kalbfus · 2016-01-11 17:42:13

RobertDyck wrote:

Actually, what I described here, Apollo CSM + Skylab workshop, would only be a flyby. It would not be able to land on Mars, and would not even be able to enter Mars orbit. But could have been done in the last 1970s.
I also described a flyby using modern equipment here: Mars Society Announces International Gemini Mars Design Competition
This one uses a Dragon spacecraft, plus Pressurized Cargo Module from Cygnus, and one Bigelow BEAM. That's Cygnus without its service module, and filled with life support equipment the same as ISS. It would have a tunnel just barely large enough for one man, with Dragon at one end and BEAM at the other. Again, it would only be a flyby. But it could be launched by a single Falcon Heavy.
As for Mars GPS: do you realize NASA and ESA started on that? All orbiters starting with MGS have a Mars antenna. That can communicate to a Mars lander or rover, so the orbiter can be a communication relay. The Mars antenna can determine range. Then with multiple samples from different positions in orbit, it can use intersecting spheres to determine position. That requires multiple orbits. Or using multiple orbiters, you can do it with a single pass. It isn't quick, it doesn't give the instantaneous result that Earth's modern GPS does, and precision is pretty poor, but it is something.

Phobos and Deimos make good GPS satellites as well. If you know the two moons positions relative to one another, and you know the time, and you can determine their position in the sky you can determine longitude.

And by sighting this star with your astrolabe at night, you can determine latitude.

Last edited by Tom Kalbfus (2016-01-11 17:42:37)

RobertDyck · 2016-01-11 23:17:43

Tom Kalbfus wrote:

What would be the point of a manned flyby? the astronauts would risk their lives spending 18 months in space without even the "paydirt" of collecting rock samples from Mars.

I started trying to figure out what NASA could have done with 1970s equipment. They had a PICA heat shield to return an Apollo CM to Earth. And they had NERVA as TMI stage. You would need a circularization stage to park the NERVA stage in Earth orbit. So what I describe, but instead of a Skylab workshop, an S-IVB stage with the bulkhead removed so the entire tank is LH2, and the J-2 engine replaced with a single NERVA. If this is after 1974, it's NERVA 2. You would want additional living space, so say a habitation module the same diameter as an S-IVB stage. That would be the same diameter as the NERVA stage. Make it the same height as living compartment (lower compartment) of Skylab workshop. You could make the ceiling and floor flat by making internal partition walls load bearing. In a wooden house, load bearing walls hold the roof or upper floor up; in this case they hold the ceiling and floor together. This is beginning to look like a Mars Direct habitat, aka tuna can.

Landing and taking off again would be an issue. It would require Mars Direct, and that's early 1990 technology. Would this stack be able to enter Mars orbit and return to Earth? That would require the NERVA stage to have enough propellant for 3 burns: TMI, Mars orbit capture, and TEI.

Life support would also be an issue. The flyby mission described above would just bring bottled O2, water, and LiOH canisters to scrub CO2. That's not recycling at all. It's only possible by bringing an entire Skylab workshop and reducing mission time. Entering Mars orbit and doing so with a smaller hab would require recycling life support. NASA was thinking about that, but I don't know the state in 1970s.

To carry LH2 for that duration would probably require active refrigeration. Allow some LH2 to boil off into a gas capture tank. Then a refrigeration pump would re-liquefy it, returning to the main propellant tank. Power the pump by solar arrays. This has been proposed, but hasn't even been demonstrated today.

NERVA developed in 1974: Unfuelled mass 11,860kg, thrust (vacuum) 867.40kN (88450kg force), Isp (vacuum) 825s
NERVA design study in 1991, revised in detail 2005: Loaded/empty mass 158,400/27,000kg, Thrust 333.00kN (33956.5kg force), Isp (vacuum) 925s
Note the 2005 design has much higher empty engine mass, and lower thrust, although higher Isp. I believe one reason is the newer design had integrated ability to use the nuclear reactor for power generation. The 1974 design was propulsion only.

Do you really want me to calculate propellant required to do this?

Last edited by RobertDyck (2016-01-12 12:29:37)

Tom Kalbfus · 2016-01-12 12:16:31

One could always send additional supplies ahead of the manned ship. The crew would be consuming supplies on the way out to Mars, you could ship more bottled oxygen into Mars orbit in an unmanned craft, also food, and a lander. the astronauts when they arrived in Mars orbit would dock with the unmanned craft, and use the lander attached to it to explore the surface of Mars, then go back to Earth in either the manned craft or the previously unmanned one.

RobertDyck · 2016-01-12 12:53:19

Conjunction class example showed above has 545 day surface stay. And I argued to reduce surface stay to 425 days, so astronauts for the first mission would land back on Earth before the second mission departs. Opposition class example shows return takes 308 days, looping more than one full orbit around the Sun. There's got be a better way, a more direct path to Earth.

Engine mass of NERVA was very high. Timberwind was designed as single use, non-restartable. However, engine mass was dramatically reduced. Getting consistent data is an issue; again engine mass is unfuelled. I haven't found loaded mass.
Timberwind 45: Unfuelled mass: 1,500kg, thrust (vacuum) 441.30 kN (45,000kg force), Isp (vacuum) 1,000s

But Timberwind was developed 1992. It wasn't available in the 1970s.

::Edit:: I found another reference that said Timberwind 45 had unfuelled mass 7,500kg, gross mass 28,000kg. Heavier, but still much lower engine mass than NERVA.

Last edited by RobertDyck (2016-01-19 19:57:42)

SpaceNut · 2016-01-12 22:58:21

Located a few documents for mission type...

Considerations for Designing a Human Mission to the Martian Moons

http://spacese.spacegrant.org/uploads/H … -clean.pdf

Trades Between Opposition and Conjunction Class Trajectories for Early Human Missions to Mars

http://www.marsjournal.org/contents/200 … 7_0002.pdf

Trajectory Options for Human Mars Missions

Trajectories for Human Missions to Mars, Part 1: Impulsive Transfers

RobertDyck · 2016-04-05 07:33:36

Would be interesting to work out details of a mission that could land on Mars. Again using Saturn V and technology available in late 1970s. The point is NASA currently claims Mars is still decades away, but after Apollo 11 NASA promised Mars would be the next destination. I remember a date in the early 1980s, GW Johnson said they promised a manned mission to Mars would depart in 1983. So how?

I recently posted a link to a YouTube video explaining NERVA to the public. That video was produced in 1968. As the caption states, plans at that time were to send a manned mission to Mars in 1978. Ok. Screen captures from that video. First the 3rd stage of a Saturn V, stage S-IVB with Apollo attached...

Now a NERVA stage, with some unspecified payload...

The narrator said the 3rd stage of Saturn V would be replaced with this stage. Note: the diameter is the same as S-IVB, but it's longer. I assume total stage launch mass will be the same. Engine mass will be substantially higher, because of the reactor in NERVA. However, LH2 has much lower density than LOX. This stage would have one big LH2 tank, and no LOX. So this gives a size for the stage.

Again, NERVA was supposed to be launched cold. The reactor would only be started to propel the stack out of Earth orbit, it wouldn't be activated while launching into Earth orbit. So the modified S-IV stage that I described above would be used to circularize the stack. The NERVA stage would be entirely payload until ready to depart Earth orbit. Again, this makes Saturn V a 4 stage rocket. The first stage would use F-1A engines instead of the standard F-1, which provides 20% more thrust. That means propellant will be consumed that much faster, but it provides extra lift to launch an extra stage.

For a Mars landing, the NERVA stage would have to be used 3 times: TMI, Mars Orbit Insertion, TEI. Would the one stage have enough propellant to do all 3 jobs?

The habitat would be shrunk. Above I described a Skylab workshop launched wet as the TMI stage. That justifies a large workshop, but if it's launched dry, the habitat must be substantially shrunk. I suggest the aft compartment of the Skylab workshop. Just the aft compartment, so diameter is the same as an S-IVB stage, or more to the point the same as the NERVA stage, but height will be that of a single deck. The Skylab workshop used the bulkhead between tanks as it's lower/aft pressure floor, which was domed with the edges down. Working floor for the aft compartment was an open mesh metal grid to allow propellant to flow through during launch. For this deep space habitat, the floor will have to be flat. The ceiling of Skylab was a dome, but this ceiling will have to be flat as well. Interior partition walls will be load bearing, in tension, holding the floor to the ceiling. All food, water, and life support equipment and supplies will have to be in this one deck. We can't use the upper dome of the LH2 tank as a bulkhead between living compartment and propellant tank, because LH2 is cryogenic cold. A bulkhead works for a launch stage because the bulkhead separates a LH2 tank from LOX tank, both cryogenic. There is some insulation because LOX isn't as cold, but a little heat transfer is Ok. However, a habitat is substantially warmer. We will need vacuum to separate the LH2 tank from the habitat for temperature control.

This vehicle will still need solar arrays for power. The best way to do that would be the same solar arrays as the Skylab workshop, mounted to the sides of the NERVA stage. There were designs in 1990 to modify the NERVA engine to provide power during flight, but they didn't exist in the 1970s, and that complicates the engine. You're better off with a nuclear reactor that has just one job.

Again I'm thinking no multiple docking adapter or airlock. We need this craft to be lean. If an EVA is necessary, use the Apollo command module as the airlock. Apollo 9 did that. It was the only time the side hatch was opened in space.

For return, use Apollo with 4 astronauts, and PICA heat shield instead of AVCOAT. Marshal Spaceflight Centre did a study in 1965, came up with a modification of the Apollo CM for 4 astronauts. In 1970 they realized they would need PICA. The 1970 version of PICA was 3 times as much mass as an AVCOAT heat shield, but any attempt to use AVCOAT would kill the crew. The rescue Apollo for Skylab had 5 seats, but this one would have a heavier heat shield, so 4 seats. Apollo for the Moon carried food and life support supplies for 3 astronauts, but a Mars mission one would have that in the deep space habitat. So again, 4 seats.

So this raises the question of the Mars lander. Apollo left the CSM in lunar orbit, this mission would leave it in Mars orbit. And how to we attach it all? I suggest a spacecraft adapter on the NERVA stage to carry the Mars lander. Then the deep space habitat on top of that, with the Mars lander docked to a floor hatch in the habitat. A ceiling hatch in the habitat would allow the Apollo CSM to turn around and dock the same way it did with for the LM. But this means the deep space habitat will be between the CSM and lander. The spacecraft adapter around the lander would support the DSH. But wait, that means the DSH is cut free when the lander separates from the NERVA stage. And if the NERVA stage is used for MOI and TMI, then does Apollo need a SM at all? If we mount the DSH on bottom, then the lander propulsion stage is between lander crew compartment and DSH. For the Moon, the Apollo SM was used for LOI and TEI, but for Mars an SM would not be large enough for TEI, especially considering a DSH would be attached. If the DSM is attached to the stage, the lander must be either not connected, or mounted upside down. That would reverse loads during launch from Earth. We could mount it right side up during launch, then reverse the lander in transit. That would reverse loads during MOI only. But then how do we attach the CM? Side mount? That would be non-axial during MOI; you don't want to risk sheering off your Earth return capsule. We could detach the DSM when the lander detaches from the stage, then use the CSM to re-attach the DSM to the stage. Risky. And that means the CM would be upside down during MOI; making acceleration couches upside down. You can't put the capsule on the bottom, because it has to be on top during launch from Earth in case of launch abort. When NASA considered Gemini for the Moon, they included a hatch between the capsule and a habitat, but that required a hatch through the heat shield. I don't think we want anything that compromises the heat shield. Arg!

I really prefer my own modern mission architecture. It's a modification of Mars Direct.

Last edited by RobertDyck (2016-04-05 11:20:08)

Tom Kalbfus · 2016-04-05 10:52:13

What's the point of this alternate history analysis? Its not like we're going to conduct a Mars mission with 1970s technology. Maybe you want to write a book such as Stephen Baxter's Voyage?

RobertDyck · 2016-04-05 10:56:39

I'm trying to tell NASA that Mars is not multiple decades in the future. We've had the technology for a long time already. Go Now!

Last edited by RobertDyck (2016-04-05 10:59:10)

Tom Kalbfus · 2016-04-05 11:35:44

RobertDyck wrote:

I'm trying to tell NASA that Mars is not multiple decades in the future. We've had the technology for a long time already. Go Now!

I think Ted Cruz is the best bet for that, there is a primary going on in Wisconsin as we speak, the last poll had Ted Cruz up by about 6 points, If he wins that, he can deny Donald Trump the 1277 delegates he needs to become the candidate, and then it will be up to the Convention. According to rule 40, only candidates who have won 8 states can appear on the ballot, and the only two candidates are Trump and Cruz. If Hillary Clinton was pro-Space, she could have used her influence with Bill Clinton, when she was First Lady from 1992 to 2000 to lobby for a manned mission to Mars during that time - she did not, and there is no evidence of her having tried. All Bill Clinton did during his administration was fly the Shuttle and build the ISS with the Russians.

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