OFMM V3 Mission Statement

[MaverickSawyer]

Around Earth, or Mars? We may need to do an "unnofficial" flight to test the Dragon's response on Mars...

---------- Post added at 17:26 ---------- Previous post was at 17:24 ----------

I'm concerned about propellants, not restart. I.e. How will the RP-1 react to 6 months on freefall on the way to Mars? How much LOX will we lose?

 

[Pipcard]

Maybe I can fly either the first or the second mission.

(as long as it doesn't involve turning on all the pertubations, or having advanced rendezvous procedures)

 

[MaverickSawyer]

Oooh, forgot about that... I'm terrible at making rendevous manuevers. Once I'm within, oh, 5 km, I'm set. But anything more that, and I'm stuck. :embarrassed:

 

[Pipcard]

When you get into an 30 deg orbit using the Falcon 9 + Dragon, the upper stage has about 800 m/s of delta-V, according to the Burn Time Calculator.

I think that's sufficient for going to the Arrow.

 

[dgatsoulis]

If you want, can you test the Dragon's EDL capabilities from a 200km orbit.

Around Earth, or Mars? We may need to do an "unnofficial" flight to test the Dragon's response on Mars...[

Sure, I can setup one scenario and try out both the manned and the cargo Dragons.
But how are they supposed to get back to Martian orbit and rendezvous with the Arrow?

 

[mojoey]

Sure, I can setup one scenario and try out both the manned and the cargo Dragons.
But how are they supposed to get back to Martian orbit and rendezvous with the Arrow?

Around Mars.

(Read the asterisk)

 

[MaverickSawyer]

*return to Earth not guaranteed. You have been warned.

Hope you bring beer!
:lol:

---------- Post added at 17:52 ---------- Previous post was at 17:47 ----------

Hmmm... Do you think we'll have space for a greenhouse? If we're setting up a base whether we like it or not, that would be a huge benefit.
We need to allocate some space for an inflatable hab as well.

 

[dgatsoulis]

I don't undestand. You want to me to test if the Dragons (just the capsules, manned/unmanned) can perform an (E)ntry (D)escent and (L)anding from a 200x200 km parking orbit around Mars, correct?

What I am asking is how the crew is supposed to get back to the Arrow. The asterisk says "return to Earth not guaranteed. You have been warned".

With no launch vehicle, it should probably say: "Death of the crew on Martian surface guaranteed. You have been warned".

 

[MaverickSawyer]

If my interpretation is correct, this is going to be the first step of building a base. It's not part of the mission, but this is how you would do it. Read Kim Stanley Robinson's Red Mars to get a feel for what we're in for.

 

[dgatsoulis]

If my interpretation is correct, this is going to be the first step of building a base. It's not part of the mission, but this is how you would do it. Read Kim Stanley Robinson's Red Mars to get a feel for what we're in for.

Thanks for the clarification.:tiphat:
Ok, will perform the EDL tests and get back to you in a while.

 

[Bloodworth]

I missed out the last 2 times. I can fly e2m (transX) and do mars landings. COunt me in.

 

[dgatsoulis]

As suspected (by garyw), the Dragons are not fit for Martian EDL. Both tests resulted in a crash on the surface with ~70 m/s vertical speed.
The main parachutes do not provide enough drag, due to the thin atmosphere.

Here is the scenario with both manned(7) and cargo Dragons on a 200x200km orbit around Mars, if anyone else wants to give it a try. (Perhaps there is a procedure for the reentry that I am not aware of? :shrug: )

The manned has a full crew of 7, fuel 15%.
The cargo has no cargo attached, fuel 15%.

BEGIN_DESC
Contains the latest simulation state.
END_DESC

BEGIN_ENVIRONMENT
  System Sol
  Date MJD 58620.820628
;58620.7984056282
END_ENVIRONMENT

BEGIN_FOCUS
  Ship Dragon_Manned
END_FOCUS

BEGIN_CAMERA
  TARGET Dragon_Cargo
  MODE Extern
  POS 7.88 -123.46 31.03
  TRACKMODE TargetRelative
  FOV 60.00
END_CAMERA

BEGIN_HUD
  TYPE Orbit
  REF Mars
END_HUD

BEGIN_MFD Left
  TYPE Orbit
  PROJ Frame
  FRAME Ecliptic
  ALT
  REF Mars
END_MFD

BEGIN_MFD Right
  TYPE Docking
  NAV 0
END_MFD

BEGIN_SHIPS
Dragon_Cargo:SpaceX\DragonC
  CFG 1 25679448.5444
  STATUS Orbiting Mars
  RPOS 494170.66 -30.91 -3555744.78
  RVEL 3421.124 -0.250 475.461
  AROT 179.97 82.34 179.97
  RCSMODE 2
  AFCMODE 7
  PRPLEVEL 0:0.15
  NAVFREQ 0 0
  CONFIG 3 1 0
  ANIM0 0 0.0000
  UCGO @@0,1,0,0,@@1,1,0,0,@@2,1,0,0,@@3,1,0,0,@@4,1,0,0,@@5,1,0,0,@@6,1,0,0,@@7,1,0,0,
  TRUNK 0
END
Dragon_Manned:SpaceX\DragonM
  STATUS Orbiting Mars
  RPOS 494170.66 -24.63 -3555744.78
  RVEL 3421.124 -0.258 475.461
  AROT 179.97 82.35 179.97
  RCSMODE 2
  AFCMODE 7
  PRPLEVEL 0:0.15
  NAVFREQ 0 0
  CONFIG 3 1 0
  ANIM0 0 0.0000
  UCGO @@0,1,0,0,@@1,1,0,0,@@2,1,0,0,@@3,1,0,0,@@4,1,0,0,@@5,1,0,0,@@6,1,0,0,@@7,1,0,0,
  TRUNK 0
  ANIM1 0 0.0000
  ANIM2 0 0.0000
  CFG 0 1 0 1 1 0 1 10483560
  PARAMS 83.9815 14.0000 1.4000 14.2000 1.0000 24240750.0000 -2500.0000
  UMMUCREW Capt-dgat-35-68-85
  UMMUCREW Sec-Jim-28-65-75
  UMMUCREW Crew-John-26-60-89
  UMMUCREW Doc-Jenna-32-65-60
  UMMUCREW Vip-jack-45-65-70
  UMMUCREW Crew-Vera-25-58-55
  UMMUCREW SEC-Paul-48-72-88
END
END_SHIPS

BEGIN_ExtMFD
END

 

[MaverickSawyer]

Huh... so the 'chutes DO deploy. That's a plus.
Did you fire the engines at max during parachute descent? I think that would make a slight difference...

 

[Pipcard]

What about this?

 

[MaverickSawyer]

:facepalm: That's right, the Dragon M and L have propulsive landing. But that doesn't solve the cargo landing issue...

 

[dgatsoulis]

Yes, I did use the engines. But I am not very familiar with glider's Dragon, that's why I posted the scenario if anyone else wants to try.

The drogue chute deployed at ~8 km, followed by the main chutes shortly after.

I loaded the Dragons only with 15% fuel, to keep them light during the reentry, but with enough fuel to use the engines. The orientation of the spacecrafts during the reentry was "heads-down", so the panel that the chutes come out of was "right side up".

 

[MaverickSawyer]

I'll take it for a spin next week.

 

[mojoey]

Were you using the 'in-orbit' engines, or the LES motors? The LES motors (as shown in the CG video above) are way more powerful.

---------- Post added at 08:47 PM ---------- Previous post was at 08:44 PM ----------

We could, use Antares if Dragon doesn't work. Else we might have to use the DG-IV.

 

[MaverickSawyer]

I think the issue now is in the fact that the Cargo Dragon doesn't have the propulsive landing system.
However, if memory serves, the crewed Dragons do have a small UCGO allotment built in (either four or six sticks out in my head) So, if the Cargo Dragon doesn't have a larger UCGO capacity, it makes no sense to run it to Mars. We could divide the landing party between two "landers" and have a slightly heavier cargo capacity (in theory), or we can now double our landing party size.

 

[garyw]

As suspected (by garyw), the Dragons are not fit for Martian EDL. Both tests resulted in a crash on the surface with ~70 m/s vertical speed.
The main parachutes do not provide enough drag, due to the thin atmosphere.

Yup, that was my concern. Thanks for the test.

Huh... so the 'chutes DO deploy. That's a plus.

No reason they shouldn't as the chutes will be triggered on either altitude or speed - probably altitude.

Did you fire the engines at max during parachute descent? I think that would make a slight difference...

I can't see that helping much at all. What you need are bigger chutes deployed earlier - somewhere around Mach 2 (with reference to Mars). The bigger the chute the more air you trap so the slower the decent.

Either that or you'll have to UCD/Glue/attach/velcro some sort of 'soft' landing thruster like used on Soyuz.