Kerbal 2- Phobos Mission (Future Cubesat feasability study)

[Aghanim]

Kinda small.

[Rakaydos]

We're getting off-topic, I think. Back to topic: How likely is it that you get launched within the narrow window of the ITN?

Given a launch to gto...

Within less than a month of waiting in orbit, the moon will be in position to slingshot you to solar orbit- your delay can be any multiple of your orbital period, which can be any value between gto and lto without any additional dv.

The moons position relative to earth+sun is based on our (forced by launch provider) initial orbit, but the lunar slingshot height csn be adjusted to generate a solar orbit with a semimajor axis of one AU from most positions.

Earth/mars orbital positions can be manipulated by solar orbit course correctios... within reason, of course.

Did I miss anything?

[astropapi1]

I don't think it would happen. Maybe one day, if more than one group/lab/university decide to send 3U (or 6U) cubesats to Mars, maybe NASA could pay for a launch with all of them in a nest-like structure. If they're independent and built/controlled by different groups, at least there's a chance of getting to Mars, or even Phobos, which is an interesting target IMO.

One thing we could do, though, is design the spacecraft. Solve problems with it and improve on it until we end up with something which could actually work. We wpuldn't need to actually launch it, but making working prototypes would be a good practice.

We need to demonstrate that spaceflight isn't something only national agencies should be doing. Some guys just recovered a probe from the 70's and are bringing it back to earth (L1), those guys with the "Spaceship One" thing are making progress, Copenhagen suborbitals plan to reach 80km with their next crowd-funded rocket, weather balloon flights to near-vacuum qre something everyone can do, and there's the Google Lunar-X prize. If it wasn't because of the cost of spaceflight, it would be much more common than it is today.

Space agencies should support these kinds of projects. Instead of sending one big probe, send ten small ones. They may not be as "efficent" as sending a big one, but doing it would make kids more excited about space, which is always good.

"See mom? Those guys sent a robot to Mars! I wanna do that too when I grow up! :D"

[Aethon]

Dennis Titto says he's sending a few missions to Mars over the next few years in prep for his one way colony/reality show (lol but I hope it succeeds). Hitch a ride on one of those. Fan the PR hype for the Mars one with this mission.

http://www.mars-one.com/mission

[Rakaydos]

Assuming noone pokes any holes in my flight plan above, here's what I see being the requirements for a phobos lander.

A GTO lift at the right general time of year (For a mars intercept)

An Ion drive with at least 1500 ms of dv.

A reaction control system or reaction wheel setup to point the sat where it needs to point.

A way to identify which way the ship was pointed to start with.

At least 3 years of reliabe command and control endurance

A titanium heat shield on at least 1 quadrent.

Something that is at least notionally "science" payload.

Can anyone think of something else to add? Then we can start listing reason why each point is impossible and we dont know what we're doing... so we can start figuring out how to do it.

[N_las]

Assuming noone pokes any holes in my flight plan above, here's what I see being the requirements for a phobos lander.

A GTO lift at the right general time of year (For a mars intercept)

An Ion drive with at least 1500 ms of dv.

A reaction control system or reaction wheel setup to point the sat where it needs to point.

A way to identify which way the ship was pointed to start with.

At least 3 years of reliabe command and control endurance

A titanium heat shield on at least 1 quadrent.

Something that is at least notionally "science" payload.

Can anyone think of something else to add? Then we can start listing reason why each point is impossible and we dont know what we're doing... so we can start figuring out how to do it.

You forgot: - The budget, engineering capability and manpower of a small nation.

[Rakaydos]

You forgot: - The budget, engineering capability and manpower of a small nation.

It's a cubesat, not a colony ship... there's no room for the manpower of a small nation onboard.

Edited July 16, 2014 by Rakaydos

[Mr Shifty]

Can anyone think of something else to add? Then we can start listing reason why each point is impossible and we dont know what we're doing... so we can start figuring out how to do it.

- A reliable way of communicating with the spacecraft over a couple hundred million miles, controlling antenna direction, handling communication errors, etc

- A dedicated mission control team who can adjust trajectory deflections due to radiation pressure and other orbital instabilities continuously during transit

- A power source capable of powering the ion drive, attitude control, command and control software, communication subsystem etc.

-- If using solar panels, a way to deploy them and control their attitude during flight.

- An actual mission plan, including launch windows, trajectories, engine firing schedule, detailed aerobraking plan, etc

- A plan for Mars orbit insertion (aerocapture just ain't gonna work without a hefty heatshield; way too much energy to dissipate in way too short a time.)

- A way to land on Phobos

- Tracking for the mission to determine where the spacecraft is located in space

[Rakaydos]

- A reliable way of communicating with the spacecraft over a couple hundred million miles, controlling antenna direction, handling communication errors, etc

- A dedicated mission control team who can adjust trajectory deflections due to radiation pressure and other orbital instabilities continuously during transit

- A power source capable of powering the ion drive, attitude control, command and control software, communication subsystem etc.

-- If using solar panels, a way to deploy them and control their attitude during flight.

- An actual mission plan, including launch windows, trajectories, engine firing schedule, detailed aerobraking plan, etc

- A plan for Mars orbit insertion (aerocapture just ain't gonna work without a hefty heatshield; way too much energy to dissipate in way too short a time.)

- A way to land on Phobos

- Tracking for the mission to determine where the spacecraft is located in space

For the highlighted, I would suggest a flexible timetable over a concrete launch date- that is, a list of launch windows that can be made to work, the more the better. Ideally, you would want to build enough flex in our plans that any lift we get could be usable, even if we have to go for venus instead of mars, or some such.

I merged your first three as "commandand control capability for at least 3 years", but I appreciate the clarification.

I would argue with your comments on aerocapture, given K2's commentary- a modest heatshield should be plenty. But my assertion should be backed by better simulation and testing before we can consider this "done"

"Land on phobos" seems to break down as either a minimum TWR on an empty fuel tank or shock absorbing/lithobreaking structure. Do you have any other ideas for that?

[cpast]

"Land on phobos" seems to break down as either a minimum TWR on an empty fuel tank or shock absorbing/lithobreaking structure. Do you have any other ideas for that?

Litho*break*ing would mean you don't even need the aerocapture.

[BagelRabbit]

Assuming noone pokes any holes in my flight plan above, here's what I see being the requirements for a phobos lander.

Poking a couple of holes in this.

A GTO lift at the right general time of year (For a mars intercept)

An Ion drive with at least 1500 ms of dv.

You think you can get to Mars with 1,500 m/s of Delta-V? Come on man, this ain't KSP. To leave the Earth's SOI via trans-lunar injection takes over 3 km/s of Delta-V, more if you're using an ion drive (most of the time you're burning your ion engines at less than peak efficiency, because of the increased burn time associated with lower thrust.) Then you have to pack enough fuel to get to Mars (likely several km/s more), circularize and land on Phobos. I'm looking at a minimum of 6-7 km/s of Delta-V here.

A reaction control system or reaction wheel setup to point the sat where it needs to point.

A way to identify which way the ship was pointed to start with.

At least 3 years of reliabe command and control endurance

Let me just point out that a CubeSat is not designed to survive three years. It is not even designed to survive three years inside of Earth's Van Allen belts. You would probably have to build the electronics from scratch for them to survive the journey. Biological specimens? Fuggedaboutit. Sensitive scientific equipment? Probably not.

A titanium heat shield on at least 1 quadrent.

Something that is at least notionally "science" payload.

I find it funny that many Forum members want to go to Phobos, but that they have made almost no decisions on the scientific equipment that they will bring. Come on, guys! NASA won't accept just going to Phobos for the heck of it!

Can anyone think of something else to add? Then we can start listing reason why each point is impossible and we dont know what we're doing... so we can start figuring out how to do it.

Mr Shifty did a good job of this.

Here's what I think of the entire project. I put this on the main page, but pasting it here too... I've "bolded" the things that haven't been said yet (I think) for quick reference.

Okay, I'm sure no one will read this small diatribe, but:

KSP is absolutely a wonderful game. It depicts real-life spacecraft mechanics incredibly well, from specific impulse to orbital mechanics.

However.

Expecting to have the KSP team create and deploy a CubeSat is simply impossible.

I'm currently working on a project to independently fly a rocket to 160,000 feet with a safe recovery. This project is widely frowned upon by many as being nearly impossible, in spite of the extensive simulations. The build is currently in progress, though I likely won't attempt the launch until next year. I know what I'm talking about when I talk rockets, because I make them in real life. The excited participants in this thread have no idea what they're getting themselves into, and I'm pretty sure they will, eventually, be disappointed.

One of the main goals in this thread is to get a CubeSat to Phobos. Mind you, the propulsion method that would most likely be used, tiny xenon thrusters, are still heavily under development and aren't planned to fly for years. It would be impossible to communicate with the probe during the trip or, perhaps, even after arriving at Mars; it would be very nearly impossible to carry any traditional science instruments on the CubeSat. A rocket would have to be launched in almost precisely the correct orbital inclination to make this plan feasible. No CubeSat has survived for long enough to get to Mars. The technological hurdles that would have to be overcome are enormous, and would likely require a research and development budget far, far higher than the satellite itself would cost. This would make a crowd-funding campaign likely to not succeed, and private backers almost certainly wouldn't be willing to fund the multimillion-dollar cost.

NASA would likely be lukewarm with its support at best. It mostly, perhaps unfortunately, supports semi-professional teams aiming to do limited science in low Earth orbit. All CubeSats launched have carried extremely limited payloads. Some carry enough fuel to deorbit, others carry no fuel at all. NASA would likely be unwilling to support any project as ambitious as this one, let alone a project (and don't get me wrong here) mainly controlled by people who are in their teens and not professional aerospace engineers. They would correctly suspect that the people would be incapable of getting a craft working.

Sorry to burst the bubble of anyone involved. I want this to work just as much as anyone else, I just don't see it happening.

[Drunken Hobo]

The whole chat about Phobos put me off of the idea of any sort of KSP CubeSat. It seemed like a really neat idea; the members of the KSP community getting together to fund and build a small satellite that would orbit the Earth and maybe take a few pretty photos. A very difficult task, but completely possible.

But the talk of the Moon, Venus or even a soft landing on Phobos has quashed any enthusiasm. The project is doomed never to even begin if that's the level of thought being put into it. It may as well have been a "what if" article, rather than a serious proposal.

[Kevon87]

The whole chat about Phobos put me off of the idea of any sort of KSP CubeSat. It seemed like a really neat idea; the members of the KSP community getting together to fund and build a small satellite that would orbit the Earth and maybe take a few pretty photos. A very difficult task, but completely possible.

But the talk of the Moon, Venus or even a soft landing on Phobos has quashed any enthusiasm. The project is doomed never to even begin if that's the level of thought being put into it. It may as well have been a "what if" article, rather than a serious proposal.

Exactly! I agree.

[Rakaydos]

Poking a couple of holes in this.

You think you can get to Mars with 1,500 m/s of Delta-V? Come on man, this ain't KSP. To leave the Earth's SOI via trans-lunar injection takes over 3 km/s of Delta-V, more if you're using an ion drive (most of the time you're burning your ion engines at less than peak efficiency, because of the increased burn time associated with lower thrust.) Then you have to pack enough fuel to get to Mars (likely several km/s more), circularize and land on Phobos. I'm looking at a minimum of 6-7 km/s of Delta-V here.

Did you allow for the "free" delta V we get from launching from a GTO flight? The numbers K2 has posed suggests that it only takes another 600 or so Dv beyond GTO to reach LTO- from there, just wait a few orbits and you've got a lunar flyby. Even if the probe dies there, it's already gone furthur than any other "minor" probe has before.

But if we can put it specifically in a solar orbit with a 1 AU semimajor axis, we would have an opportunity for more. Rosetta used that very maneuver to slingshot off earth to mars- assuming we had perfect control of our probe, there's no reason we couldnt do the same, for no fuel costs at all. (or we could just practice interplanetary aerocapture off earth- it's not like a 10 lb probe will be a danger to the ground even if we fail)

If we reach mars, aerocapture or burn up, we'll still have made it there years before any manned mission, and done what even major nations havnt done.

Phobos is the cherry on top of this fortunate turn of events. If we make it through each of the previous trials, it will take a certian amount of Dv to orbit Phobos, and a certian additional amount to land. And THAT landing, planting a kerbal flag on Phobos, is something NO eartly nation has done... and we might have done it first. If all goes well.

It's not just a phobos mission. Phobos is just having contingencies for success.

Let me just point out that a CubeSat is not designed to survive three years. It is not even designed to survive three years inside of Earth's Van Allen belts. You would probably have to build the electronics from scratch for them to survive the journey. Biological specimens? Fuggedaboutit. Sensitive scientific equipment? Probably not.

This is a valid concern. It is something we will have to answer, before this topic is done. Thank you for raising it.

I find it funny that many Forum members want to go to Phobos, but that they have made almost no decisions on the scientific equipment that they will bring. Come on, guys! NASA won't accept just going to Phobos for the heck of it!

We need a ship before we can put a science payload o it. Apollo 8 didnt bring much scientific equipment to the moon besides a camera... but the photo of Earthrise is one of the most influentual images to

come out of the modern era.

Like apollo, this would be a publicity stunt, not a scientific undertaking- science comes second to showing that "we the people" can send things to other worlds... the moon, mars, perhaps even phobos.

Edited July 16, 2014 by Rakaydos

[Mr Shifty]

Apollo 9 didnt bring much scientific equipment to the moon besides a camera... but the photo of Earthrise is one of the most influentual images to

come out of the modern era.

Apollo 9 never left low-Earth orbit.

[Rakaydos]

My bad, I meant apollo 8.

[BagelRabbit]

Hi Rakaydos!

About your first point: Geosynchronous orbit would be a great place to release a CubeSat and have it reach exotic destinations. However, I don't think that any CubeSats have been released at that altitude, and I'm not sure if NASA has any plans to do so. The additional Earth flyby would require even greater precision for a craft that already is trying for pinpoint accuracy. I should remind the forum that CubeSats, in general, either have no guidance system, or a system far less precise than this mission would require. I do, however, think that you could decrease the Delta-V budget significantly by starting out in GSO. Good catch.

Your third point leaves a bit to be desired. The Apollo craft were essentially a way for America to reinforce its technological superiority over the USSR. As you said, it was a publicity stunt from the start, and a successful one at that. But while America had several good reason to go to the Moon (President Kennedy stating that the budget would be massively increased to allow for the missions; proving that America was capable of beating the Soviets at the "space race;" etc.), what good reasons do KSP players have to go to Phobos? Sure, the flight might promote KSP or even civilian science in general, but NASA doesn't really have any need for that. After the Apollo days, NASA drastically increased the number of scientific experiments that it did after Apollo, and it (arguably) hasn't done a "publicity stunt" style mission since*. So why does anyone think that they'll make the first major exception of this rule in 44 years... for our little ragtag bunch of engineers? If I was a NASA official with little knowledge of KSP, I wouldn't allow a CubeSat to be launched primarily as a publicity stunt, no matter how lofty the goals of its designers.

*While you might think that CubeSats fall under the "publicity stunt" category, they're generally considered by NASA to be a cheaper, more widely available way to do scientific experiments in space. That is the reason that they were created, and that is the direction that NASA hopes to take them in.

[Rakaydos]

GSO is out of the picture. GTO, however, is better than GSO would have been.

The Geosynch citcularization burn is a huge Dv hog that doesnt get the probe anywere. Geosynch TRANSFER orbit, however, has all the energy of getting out to geosynch, with more oberth effect at periapse. It's the periapse burn that makes Lunar transfer a viable option.

[BagelRabbit]

You're correct (I wasn't sure what GTO meant).

Everything else I said still applies though. (I'm pretty sure that NASA doesn't have plans to release satellites in GTO either.)

[Rakaydos]

You're correct (I wasn't sure what GTO meant).

Everything else I said still applies though. (I'm pretty sure that NASA doesn't have plans to release satellites in GTO either.)

Nasa releases satelites into GTO all the time. How do you think they get up to GSO in the first place? They have to make the circularization burn themselves. (well, Ok, NASA doesnt do it anymore... but my point stands, the shuttle wasnt made to reach Geostationary orbit, but it put plenty of satelites up there.)

[Creature]

*While you might think that CubeSats fall under the "publicity stunt" category, they're generally considered by NASA to be a cheaper, more widely available way to do scientific experiments in space. That is the reason that they were created, and that is the direction that NASA hopes to take them in.

Also publicly funded agencies like NASA and ESA have political reasons to promote education and collaborate with universities and schools. Not with gaming communities. And in the world of actual scientific research something like 100k dollars for a launch to space is insanely cheap. Everyday lab equipment costs tens of thousands of dollars easily, every researcher on payroll costs some tens of thousands per year and so on. CubeSats are great pilot projects for small scale proof-of-concept demonstrations or even as purely educational tools when the people gaining the knowledge are actually worth the investment. I think CubeSat is a wonderful concept and I really hope more independent parties will start making them. Sadly I too don't see this forum pulling it off unless something dramatic happens.

But like I said in the other thread too, thinking these things through is a very good educational experience and I think these threads should continue just for the fun of it.

[BagelRabbit]

Nasa releases satelites into GTO all the time. How do you think they get up to GSO in the first place? They have to make the circularization burn themselves. (well, Ok, NASA doesnt do it anymore... but my point stands, the shuttle wasnt made to reach Geostationary orbit, but it put plenty of satelites up there.)

CubeSats, rather. You know what I meant.

(sigh)

I am still fairly sure that every single other point that I have made is correct or nearly so. I am trying my best to have a scientific discussion with several variables involved, and you're focusing on a sub-variable that is not even very relevant (Replace GSO with GTO and you have what I meant).

Is this really so difficult?

[Mr Shifty]

Nasa releases satelites into GTO all the time. How do you think they get up to GSO in the first place? They have to make the circularization burn themselves. (well, Ok, NASA doesnt do it anymore... but my point stands, the shuttle wasnt made to reach Geostationary orbit, but it put plenty of satelites up there.)

Just a point of clarification: the Shuttle couldn't make it to GTO at all. It had about 300 m/s of on-orbit delta-V total for its circularization burn, orbital maneuvering, and de-orbit. It was a strictly LEO vehicle. Payload satellites destined for higher orbits used the standard Payload Assist Modules or Inertial Upper Stage modules for boost.

[Rakaydos]

You mention that a cubesat would need custom hardened eectronics if it needed the endurance we need out of it- gotcha. That's a speciaty that is not mine, however, so I'll leave that to forumers who know what it means to rad harden things.

You mention that NASA is unlikely to underwright a LEO ride, let alone a GTO ride- understood, but this topic is more foused on the design of the craft to make completing the final goal possible.

Did I miss any?

While not quite a Sifi Theory thread, it is very much a structured "what If" topic, intended as much to keep the phobos topic OUT of the main thread as any real benifit.

[Mr Shifty]

I actually think that designing a mission like this, regardless of feasibility, will be a really interesting, fun thing to do. We might even be able to present it at a conference or something. KSP is about simulation and learning and fun. We should read over the CubeSat specification, look at other mission planning documents, and start drafting our own. We could set it up on Google Drive or something as a collaborative effort.