Challenge Earth to Phobos with AMSO

[jjake101]

In this challenge you need to launch the Saturn V in the Apollo 11 scenario (step 1) and land on Phobos. For this you dont need to return to Earth if you think you wont have enough fuel.

For evidence you need to post a screenshot of...
- The Apollo stack (LEM, Service Module, Command Module) in Martian Orbit
- The LEM on the surface of Phobos
if you can do this...
- The command module reentering the Earths atmosphere

 

[george7378]

This isn't even slightly possible.

 

[Hlynkacg]

Is this intended as a joke?

Mars & Venus flybys are just barely feasible with Apollo hardware.

 

[asbjos]

This isn't even slightly possible.

Isn't it?

It should almost be possible to reach hyperbolic velocity with the Saturn V rocket alone. A little push by the SPS could kick you to Mars.
Then the LM with the help of the SPS engine could brake you into a Mars orbit. If you just leave 5 m/s of delta v in the LM descent stage, you could land softly on Phobos. Then, with the ascent stage on the LM you could dock with the CSM again and send you back to Earth with the last drop of propellant in the CSM.
Cruse back to Earth, and hopefully survive the re-entry.

I have not tried it and don't know if it is doable, but it seems to be a chance if you travel economically. And since he publishes the challenge, I guess that he maybe have tried it and accomplished himself?

Of course, there is no chance on Earth to have enough oxygen to do the trip, but when only watching the fuel gauge, it may be possible, so never say never.:hmm:

 

[Loru]

IMFD default target intercept trajectory on Apollo 11 launch date is bit off from Hohman transfer

*fixed picture as I uploaded wrong one.

 

[Hlynkacg]

Isn't it?

It should almost be possible to reach hyperbolic velocity with the Saturn V rocket alone. A little push by the SPS could kick you to Mars.
Then the LM with the help of the SPS engine could brake you into a Mars orbit. If you just leave 5 m/s of delta v in the LM descent stage, you could land softly on Phobos. Then, with the ascent stage on the LM you could dock with the CSM again and send you back to Earth with the last drop of propellant in the CSM.
Cruse back to Earth, and hopefully survive the re-entry.

Getting there isn't the issue. it's stopping once you get there.

You barely have the Dv required for Mars Orbital Insertion much less a soft landing and return journey. The math simply does not add up.

 

[BruceJohnJennerLawso]

Is this intended as a joke?

Mars & Venus flybys are just barely feasible with Apollo hardware.

Getting there isn't the issue. it's stopping once you get there.

You barely have the Dv required for Mars Orbital Insertion much less a soft landing and return journey. The math simply does not add up.

bah, translation is, you're unwilling to try

Hlynkacg has several very valid points on this, but if you could aerobrake the stack at least partially, it might be doable from a hard dv standpoint. The real killer would be things like consumables, hardware lifetime, etc.

jjake101, I would suggest modifying this challenge a bit. Why not give users the option of using the daedalus capsule

[ame="http://www.orbithangar.com/searchid.php?ID=5928"]http://www.orbithangar.com/searchid.php?ID=5928[/ame]

and their goal is to create a velcro rockets stack that can do the whole thing in one go. That should make for some amusing times, what with KSP-esque rockets built from ridiculous numbers of engines & boosters.

 

[rseferino]

It would be interesting to see if it works. I would do this:

1. Launch the CSM-LM to Mars.

2. Use descent stage to enter orbit and intercept Phobos (verify)

3. Discard LM descent stage

4. Using ascent stage to land on Phobos, which would be more of a docking, due to the low gravity, low fuel consumption.

5. Docking and burned ascent stage, and enter a highly elliptical orbit around Mars.

6. Eject the ascent stage and perform with CSM burned to use the Oberth effect adding the speed gained with the ascent stage elliptical orbit. (Check if it is possible to have enough speed)

7. Mid-course corrections.

8. Reentry, preferably skip reentry.

 

[Hlynkacg]

bah, translation is, you're unwilling to try

Who says I haven't?

Taking NASSP (and now AAPO) on inappropriately long journeys is a hobby of mine. Personal best was landing a CM on titan. Fact remains that you'll be flirting with hard Dv limits just to achieve Martian orbit.

---------- Post added at 22:15 ---------- Previous post was at 20:43 ----------

The combined CSM / LM stack has a total Dv of approx 3 km/s, if you burn both the SM and both LM stages to depletion. Which means that orbital insertion of the complete stack is iffy, and Earth return is simply not possible without cheating.

Just re-flew it using AAPO and my "Curiosity" flightplan, and I managed to hit Phobos with the LEM on my third try at a reasonably sedate 86 m/s but that was only achieved by abandoning the CSM.

 

[Pioneer]

Mars & Venus flybys are just barely feasible with Apollo hardware.

That's why it's a challenge. :thumbup:

 

[Hlynkacg]

That's why it's a challenge. :thumbup:

I could challenge you to hold your breath for 87,600 consecutive hours but you'd be an idiot to try.

The tyranny of the cold equations is quite clear in this case.

 

[dgatsoulis]

In most cases of a challenge in this forum the OP has actually "done it" and wants to see if the rest of us "can do it too".

I suspect that this is not the case here, but it turns out that this is a great challenge if you stretch/change a bit some of the parameters. (Not even stretch, the OP never mentioned them).

-Use the AMSO Apollo 11 step01 configuration. Pick any lauch date you want.
-Land the LEM on Phobos and leave it there (whole LEM both stages).
-Pass the CM within 1000 km from the Martian surface and land (or splashdown) back at Earth.
-5 year time limit from launch to splashdown.
-Dont kill the crew. (G force-wise)

An Earth→Mars→Earth low encounter velocity trajectory is possible if you take an orbit to get back to Earth after a low velocity/low altitude fly by at Mars.

Using the Oberth effect, the LEM has more than enough fuel for a soft touchdown on Phobos.

All the CM has to do is to sling Mars and go around he sun once before getting back to Earth.

 

[Pioneer]

I could challenge you to hold your breath for 87,600 consecutive hours but you'd be an idiot to try.

The tyranny of the cold equations is quite clear in this case.

This is just a simulator not real life. Why don't you just try it.

 

[Screamer7]

I used the Curiosity launch date.
I ended up with -173 DV after the depletion of the third stage propellant.
Then I docked with the LEM and finished the burn.
I was able to reach Mars and orbit it, but will not be able to return to Earth with my fuel reserves without cheating.

http://www.orbiter-forum.com/attachment.php?attachmentid=11719&stc=1&d=1368385592ves

 

[Hlynkacg]

This is just a simulator not real life. Why don't you just try it.

I did.

Using the apollo 11 launch date there is simply no way to get the complete stack (CSM, LM, and s-4b) into Martian orbit. Min Dv required exceeds Dv available. Using an optimised launch date makes it possible but you'll still have to bend or break rules of the challenge as originally posted to do it. (see dgatsoulis' post above mine)