[TheBigDog]

Originally Posted by Turtle

Gotta start somewhere. Make sure when you're at RadioShack that you ask for a copy of their Master catalog.

The first thing I would replace on your vehicle is the radio. The one supplied does not have continuous (not the right technical term) control of the servos, that is to say there is no partial throttle or turning. It's all or nothing. Look for mutichannel RC systems; you can get up to 7 or 8 channels. Link below.

Went looking for a multichannel page and stumbled on some mini-gyros that interface with them. Do we need some of these? Gyro MS for HORNET - mscompositusa.com

robot parts >> SuperDroid Robots - DC Gearmotors, Gear Motors, Robot Motors

super expensive whizz-bang radio >> JR PCM10X Air MD2 4-8611A & Case

Hmmm... Interesting. The final product is going to be more of an RC car in spirit than in practice. It will have a small PC onboard that will actually control the rover and cache all of the photo's and such. It will be controlled via its wireless connection with the lander. So I will only use the RC controls until I can make it more of a remote controlled robot than a simple RC car.

Still, the warnings about the control system are duly noted. I am going to strip off the body and every other cosmetic until it is just a platform. Then I will start fitting the payload and extra batteries to it.

Got to start someplace...

Bill

[freeztar]

Originally Posted by TheBigDog

I am getting my RC base this weekend. I went window shopping for RC's weekend before last. Spent some time asking lots of questions at Hobby Lobby. Most RC engines are built for high revs and speed. I want low rev engines that are for a marathon, not for a sprint. RC technology is all about sprinting, but there are other ways to skin that cat.

I am trying to find the right platform. So far I am leaning toward this one...

RadioShack.com - Toys & Games: Radio-controlled: Air, land & sea vehicles: Hummer® H2 with Mattracks

Whadoyathink?

That looks pretty cool!

What about building a prototype rover from scratch? I know it sounds strenuous, but it could be a more accurate lunar model. Because of the relatively small scale involved, it would be fairly easy to make a basic prototype rover in one's home shop. You could use thin steel sheets and cut them to suit. A specialized drill should assist with any drilling/cutting necessary. Blowtorches can be had for around $30, making it cheap to piece together the frame. Parts can be acquired from RC cars, or whatever.

Just a thought...

[TheBigDog]

Originally Posted by freeztar

That looks pretty cool!

What about building a prototype rover from scratch? I know it sounds strenuous, but it could be a more accurate lunar model. Because of the relatively small scale involved, it would be fairly easy to make a basic prototype rover in one's home shop. You could use thin steel sheets and cut them to suit. A specialized drill should assist with any drilling/cutting necessary. Blowtorches can be had for around $30, making it cheap to piece together the frame. Parts can be acquired from RC cars, or whatever.

Just a thought...

That will be how I do the second prototype. I have never done any metal working, so it will be new for me.

Bill

[freeztar]

Originally Posted by TheBigDog

That will be how I do the second prototype. I have never done any metal working, so it will be new for me.

Bill

Cool! When that time comes, let me know. I worked in the metal shop at my college and learned a bit about working with metal. Of course, there, I had access to thousands and thousands of dollars worth of machinery, but I think something on our desired scale can be had with a few inexpensive tools. The prototype can be accomplished pretty frugally (Mythbusters style).

[Turtle]

Originally Posted by TheBigDog

Great link, freezy! It got me thinking about our own practical testing. I think that attaching a large helium balloon to simulate the lower gravity would be key. ...Bill

Make that very large. Having once done a detailed design analysis for a scale model of the dirigible USS Macon, I arrived at a minimum 12 feet just to hold enough helium for 10 pounds of lift. That put a quit end to that project.
When you do your calculation, figure in the ballons' drag on the atmosphere as an additional load on the vehicle when moving.

[freeztar]

Heh...Check this guy out:

YouTube - man flies to idaho with lawn chair and...

[Janus]

While doing a little research, I came across this treasure trove. It's a paper written on the Lunar Surveyor, including equations, charts and figures. There's a lot here that we can use in terms of making a soft landing.

http://ntrs.nasa.gov/archive/nasa/ca...1967003873.pdf

[CraigD]

Originally Posted by TheBigDog

Is there a simulator we can play with, or can someone make a simulator for the launch to landing portion of the mission?

After a bit of debugging (I messed it up when adding an “accelerate in absolute direction” that made it easy to do orbital maneuvers), my old GRAVSIM2 simulator is pretty easy to use for this sort of simulation.

Getting the navigation calculations right are another matter. Using the “absurdly simple program, then guess over and over” approach, it took me ten tries just to hit the moon. Highlights of the run:

• Earth, Moon, and vehicle included in simulation
• Launched from the equator with the moon directly overhead, stationary with respect to Earth’s surface
• Accelerated at 18.99526256728240122 m/s/s (a tad under 2 gs) for 14 minutes
• Speed (relative to Earth) at burnout: 9853 m/s
• Speed and time at roughly gravitational midpoint: 4568 m/s at 64260 s (17:51)
• Speed and time of impact: about 5197 m/s at 71459 s (19:50:58)

When I recover from arithmetic and estimating burnout, I’ll throw in a braking and soft landing. Of course, this is highly unrealistic – a literal straight shot at the moon – but good practice with the simulator.

Here’s the actual simulator run, with excessive output edited into “…”s:

XGRAVSIM2>KILL
XGRAVSIM2>1m=5.9736e24
XGRAVSIM2>2m=7.347673e22,2x=363104000,2VY=1082
XGRAVSIM2>3m=1000,3y=0,3x=6378137,3vy=463.8,3ax=18.9,3ay=1.9
XGRAVSIM2>G 60,W 1-3D,1-3V,/LF,R 13
...
1-3D=10110963.53804393164,1-3V=9853.20037049520548
XGRAVSIM2>3a=0
XGRAVSIM2>G 60,W T,1-3D,1-3V,/LF,R 1139
...
T=64200,1-3D=328284252.3030225495,1-3V=4567.737133477811109
T=64260,1-3D=328558313.3947634875,1-3V=4567.736823344273832
T=64320,1-3D=328832374.604276622,1-3V=4567.740418772634065
...
T=69240,1-3D=351349695.2461291339,1-3V=4604.198617657744043
XGRAVSIM2>w 1-3D,2-3D,/LF,2Y,2X,/LF,3Y,3X
1-3D=351349695.2461291339,2-3D=12395713.77893637084
2Y=74420638.25048965515,2X=355883582.4297479022
3Y=74326022.46185141632,3X=343488229.7545775274
XGRAVSIM2>G 60,W 1-3D,1-3V,2-3D,/LF,R 35
...
1-3D=361486917.6463077635,1-3V=5003.49996712444223,2-3D=2038797.093477211859
XGRAVSIM2>W T
T=71400
XGRAVSIM2>G 1,W 1-3D,2-3V,2-3D,/LF,R 57
...
1-3D=361779292.6153798267,2-3V=5197.00346055165639,2-3D=1742941.705005749003
XGRAVSIM2>w 2Y,2X,/LF,3Y,3X
2Y=76771307.83253212718,2X=355415534.5224972657
3Y=76513343.23597105404,3X=353691788.5858901826
XGRAVSIM2>G 1,W 1-3D,1-3V,2-3D,/LF,2Y,2X,/LF,3Y,3X,/LF,T
1-3D=361784376.2637108167,1-3V=5084.774250892037685,2-3D=1737807.322671656012
2Y=76772366.94777497613,2X=355415320.2263761398
3Y=76514362.89940020355,3X=353696771.9431575806
T=71459

Here’s the MUMPS code of XGRAVSIM1 and XGRAVSIM2 (XGRAVSIM2 is a shell for XGRAVSIM1):

N (XGRAVSIM1) S G=6.6742e-11,TI=1,T=0,I9=0 F  R "XGRAVSIM1> ",R,! Q:R="."  X XGRAVSIM1("I",(R="R":1,R="W":2,R="":3,R?1.N:4,1:0)) ;XGRAVSIM1: interactive gravity simulator
F I2=1:1:I1-1,I1+1:1:I9 S DY=B(I2,1)-Y,DX=B(I2,2)-X,D2=DY*DY+(DX*DX),D=D2**.5,A=G*B(I2,0)/D2*TI,VY=DY/D*A+VY,VX=DX/D*A+VX ;XGRAVSIM1(1): change body I1 velocity
N (XGRAVSIM1,B,B1,I9,TI,G) F I1=1:1:I9 S VY=B(I1,11),VX=B(I1,12),Y=VY*TI/2+B(I1,1),X=VX*TI/2+B(I1,2),V="" X XGRAVSIM1(1),XGRAVSIM1(4):(B(I1,20)),XGRAVSIM1(5):(B(I1,21)) S B1(I1,11)=VY,B1(I1,12)=VX ;XGRAVSIM1(2): change all velocities
N (B,B1,I9,TI) F I=1:1:I9 S B(I,1)=B(I,11)+B1(I,11)/2*TI+B(I,1),B(I,2)=B(I,12)+B1(I,12)/2*TI+B(I,2) ;XGRAVSIM1(3): change all positions
S V=VY*VY+(VX*VX)**.5,A=B(I1,20),B(I1,21)=A*VY/V,B(I1,22)=A*VX/V ;XGRAVSIM1(4): calculate acceleration
S VY=B(I1,21)*TI+VY,VX=B(I1,22)*TI+VX ;XGRAVSIM1(5): change body I1 velocity due to defined acceleration
W "Enter: . to exit; R to enter/edit objects; W to display objects;",!," a number of iterations; Return for 1 iteration and a display",! ;XGRAVSIM1("I",0)
N (B,I9) F I=1:1 W I,". M Y,X VY,VX A: " R R,! Q:R=""  S I9=I,B(I,0)=(R," "),B(I,1)=((R," ",2),","),B(I,2)=((R," ",2),",",2),B(I,11)=((R," ",3),","),B(I,12)=((R," ",3),",",2) S:(R," ",4) B(I,20)=(R," ",4) ;XGRAVSIM1("I",1)
W "T=",T,! X XGRAVSIM1("W") ;XGRAVSIM1("I",2): display
X XGRAVSIM1(2),XGRAVSIM1(3) M B=B1 s T=T+TI X XGRAVSIM1("I",2) ;XGRAVSIM1("I",3): 1 itteration, display
F I=1:1:R X XGRAVSIM1(2),XGRAVSIM1(3) M B=B1 s T=T+TI ;XGRAVSIM1("I",4): R itterations
N (B,I9) F I=1:1:I9 W I,". M Y,X VY,VX: ",B(I,0),!," ",B(I,1),",",B(I,2)," (",B(I,1)**2+(B(I,2)**2)**.5,")",!," ",B(I,11),",",B(I,12)," (",B(I,11)**2+(B(I,12)**2)**.5,")",! ;XGRAVSIM1("W"): display all
n (XGRAVSIM1,XGRAVSIM2) x XGRAVSIM2(3,1) s QF=0 f  q:QF  x XGRAVSIM2(0,0) f  s I=(XGRAVSIM2(I)) q:'I  x XGRAVSIM2(I) ;XGRAVSIM2: gravity/thrust simulator w/ cleaned-up interface
w: ! r "XGRAVSIM2>",R,! s R=(((R,">",(R,">")),";"),"'"),CC=(R,"quithelpklmyxvarwnf","QUITHELPKLMYXVARWNF"),(R,CP,CK)="" x XGRAVSIM2(0,1) ;XGRAVSIM2(0,0)
s C=(CC,","),(CC,",")="",(CC)="",CK=(CK]"":CK_",",1:"")_C,I=(C="":99,1:0) ;XGRAVSIM2(0,1): next input item
w: ! w:(R) R,! s I=99 ;XGRAVSIM2(0,2): error stop
i C="QUIT" s (I,QF)=99 ;XGRAVSIM2(1)
i C?1(1"?",1"H",1"HELP") x XGRAVSIM2(2,1) s I=99 ;XGRAVSIM2(2)
n (XGRAVSIM2) s N="" f  s N=(XGRAVSIM2(2,1,N)) q:'N  w (XGRAVSIM2(2,1,N),";"),! ;XGRAVSIM2(2,1)
Enter - KILL to clear all objects from the simulation ;XGRAVSIM2(2,1,1)
      - an object number, property, =, and a value to set its value (eg: ;XGRAVSIM2(2,1,2)
       1M=5.9736e24) ;XGRAVSIM2(2,1,3)
      - G or GO, a space, and a number of itterations to run the simulation ;XGRAVSIM2(2,1,4)
      - W or WRITE, alone, followed by an object number, or an object number ;XGRAVSIM2(2,1,5)
       and a property to to display all properties, all properties for an ;XGRAVSIM2(2,1,6)
       object, or a single property (eg: W or W 1 or W1M) ;XGRAVSIM2(2,1,7)
      - W or WRITE, 2 object numbers separated by a dash, and a property to ;XGRAVSIM2(2,1,7.1)
       display the difference in properties or a property of 2 objects (eg: ;XGRAVSIM2(2,1,7.2)
       W 1-2D) ;XGRAVSIM2(2,1,7.3)
      - One or more of the above, separated by commas. Repeated object numbers ;XGRAVSIM2(2,1,8)
       or Ws may be skipped (eg: 3A=0.1,G 60,W 3X,Y) ;XGRAVSIM2(2,1,9)
      - QUIT to exit the simulation ;XGRAVSIM2(2,1,10)
      - R or REPEAT and a number (n) to repeat the preceeding commands n times ;XGRAVSIM2(2,1,10.1)
       (eg: G 60,W 1-2D,1-2V,/LF,R 10) ;XGRAVSIM2(2,1,10.2)
Note - Object have the following required properties: M=mass, Y,X=position, ;XGRAVSIM2(2,1,11)
      VY,VX=velocity, and the following optional properties: A=acceleration (in ;XGRAVSIM2(2,1,11.1)
      direction of travel), AY,AX=acceleration ;XGRAVSIM2(2,1,11.2)
     - Pairs of objects have the following properties: D=distance, V=relative ;XGRAVSIM2(2,1,11.3)
      velocity. These cannot be set, only displayed ;XGRAVSIM2(2,1,11.4)
     - the T property is number of seconds into the simulation ;XGRAVSIM2(2,1,11.5)
     - /LF may be used as display property (eg: W /LF) to insert a newline ;XGRAVSIM2(2,1,11.6)
      into display output ;XGRAVSIM2(2,1,11.7)
i C="KILL" x XGRAVSIM2(3,1),XGRAVSIM2(0,1) ;XGRAVSIM2(3)
k B S G=6.6742e-11,TI=1,T=0,I9=0 ;XGRAVSIM2(3,1)
n (XGRAVSIM2,B,I9,CP,C,CC,CK,I)  x XGRAVSIM2(4,1) i  x XGRAVSIM2(4,2) e  x XGRAVSIM2(4,3) e  x XGRAVSIM2(4,4) e  x XGRAVSIM2(4,5) ;XGRAVSIM2(4): 9AA=999
s:CP_C?1.n1.a1"=".e&(C?1.a1"=".e) C=CP_C i C?1(1.n,1"N")1.2a1"=".e ;XGRAVSIM2(4,1)
s I1=(C?1"N":I9+1,1:+C),L1=(C?1"N".e:1,1:(I1)+1),CP=I1 i I9+1'=I1&'(B(I1))!((C,L1)'?1a) s R="invalid object "_(C,"=") x XGRAVSIM2(0,2) ;XGRAVSIM2(4,2)
s V=(C,"=",2) s:V?.n.1".".n1"E".1"-"1.3n&((V,"E",2)>-129)&((V,"E",2)<145) V=+V i (+V?1".".E:0,1:"")_+V'=V s R="invalid value "_(C,"=",2) x XGRAVSIM2(0,2) ;XGRAVSIM2(4,3)
s J=" M:0 Y:1 X:2 VY:11 VX:12 A:20,21K,22K AY:21,20K,22G AX:22,20K,21G",(J,1,(J," "_((C,L1,(C)),"=")_":")-1)="",J=(J," ") i J="" s R="invalid property "_(C,"=") x XGRAVSIM2(0,2) ;XGRAVSIM2(4,4)
x XGRAVSIM2(4,5,1),XGRAVSIM2(4,5,2),XGRAVSIM2(0,1) ;XGRAVSIM2(4,5)
s:I1>I9 I9=I1 f  s J1=(J,",") q:J1=""  s (J,",")="",(J)="",B(I1,+J1)=(J1["G":(B(I1,+J1),0),1:V) k:J1["K" B(I1,+J1) ;XGRAVSIM2(4,5,1)
f J=0,1,2,11,12 s B(I1,J)=(B(I1,J),0) ;XGRAVSIM2(4,5,2): assure required fields set
n (XGRAVSIM1,XGRAVSIM2,B,I9,C,CC,CK,I,T,TI,G) i C?1(1"G",1"GO").1(1" "1.n) x XGRAVSIM2(5,1),XGRAVSIM2(0,1) ;XGRAVSIM2(5): run n times
s K=(C," ",2) f C=1:1:(K:K,1:1) X XGRAVSIM1(2),XGRAVSIM1(3) M B=B1 s T=T+TI ;XGRAVSIM2(5,1)
n (XGRAVSIM2,B,I9,CP,C,CC,CK,I,T,TI) x XGRAVSIM2(5.9,1) i  x XGRAVSIM2(5.9,2) e  s CP="W ",V=@K,R=(:",",1:"") x XGRAVSIM2(6,2),XGRAVSIM2(0,1) ;XGRAVSIM2(5.9): write global property
s:CP?1"W ".E&(C?1a.an) C="W "_C i C?1(1"W",1"WRITE")1" "1a.an ;XGRAVSIM2(5.9,1)
s (K,KJ)=(C," ",2) x XGRAVSIM2(5.9,2,1) i   s R="invalid property "_K x XGRAVSIM2(0,2) ;XGRAVSIM2(5.9,2)
i K'?1(1"I9",1"T",1"TI",1"G") ;XGRAVSIM2(5.9,2,1):check modularized to allow add-ons
n (XGRAVSIM2,B,I9,CP,C,CC,CK,I,T,TI,G) i C?1(1"W",1"WRITE") x XGRAVSIM2(6,0),XGRAVSIM2(6,3) W ! X XGRAVSIM2(0,1) ;XGRAVSIM2(6): write (output) all
f I1=1:1:I9 x XGRAVSIM2(6,1) w ! ;XGRAVSIM2(6,0)
s R=I1 f KJ="M:0","Y:1","X:2","VY:11","VX:12","A:20:1","AY:21:1:20","AX:22:1:20" s J=(KJ,":",2),V=+(B(I1,J)),J2=(KJ,":",4) i V!'(KJ,":",3),(J2:'(B(I1,J2)),1:1) x XGRAVSIM2(6,2) s R="," ;XGRAVSIM2(6,1): write all for 1 object
n (R,KJ,V) s W=(KJ,":")_"="_V,R=(R) W:(W)+(R)+>79& ! s:R=","&' R="" s:&R R=","_R w R,W ;XGRAVSIM2(6,2): write 1 property
s R="" f KJ="G","I9","T","TI" s V=@KJ x XGRAVSIM2(6,2) s R="," ;XGRAVSIM2(6,3): global properties
n (XGRAVSIM2,B,I9,CP,C,CC,CK,I) x XGRAVSIM2(6.1,1) i  x XGRAVSIM2(6.1,2) e  s CP="W " x XGRAVSIM2(6,1),XGRAVSIM2(0,1) ;XGRAVSIM2(6.1): write (output) 1 object
s:CP_C?1(1"W",1"WRITE")1" "1.n C=CP_C i C?1(1"W",1"WRITE")1." "1.n ;XGRAVSIM2(6.1,1)
s I1=+(C," ",2) i '(B(I1)) s R="invalid object "_(C," ",2) x XGRAVSIM2(0,2) ;XGRAVSIM2(6.1,2)
n (XGRAVSIM2,B,I9,CP,C,CC,CK,I) x XGRAVSIM2(6.2,1) i  x XGRAVSIM2(6.2,2) e  x XGRAVSIM2(6.2,3) e  s R=I1,V=(B(I1,(KJ,":",2))),CP="W "_I1 x XGRAVSIM2(6,2),XGRAVSIM2(0,1) ;XGRAVSIM2(6.2): write 1 property
s:CP_C?1(1"W",1"WRITE")1" "1.n1.2a C=('C:CP,1:"W ")_C i C?1(1"W",1"WRITE")1." "1.n1.2a ;XGRAVSIM2(6.2,1)
s I1=+(C," ",2),L1=((C," "))+(I1)+2 i '(B(I1)) s R="invalid object "_(C," ",2) x XGRAVSIM2(0,2) ;XGRAVSIM2(6.2,2)
s J=" M:0 Y:1 X:2 VY:11 VX:12 A:20 AY:21 AX:22",(J,1,(J," "_(C,L1,(C))_":")-3-(C)+L1)="",KJ=(J," ") i KJ="" s R="invalid property "_(C,L1,(C)) x XGRAVSIM2(0,2) ;XGRAVSIM2(6.2,3)
n (XGRAVSIM2,B,I9,CP,C,CC,CK,I) x XGRAVSIM2(7,1) i  x XGRAVSIM2(7,2) e  x XGRAVSIM2(7,3) i  s CP="W ",R=(:",",1:"")_I1_"-"_I2 x XGRAVSIM2(6,2),XGRAVSIM2(0,1) ;XGRAVSIM2(7): W 9-9A
s:CP?1"W ".E&("W "_C?1(1"W",1"WRITE")1" "1.n1"-"1.n1.a) C="W "_C i C?1(1"W",1"WRITE")1." "1.n1"-"1.n1.a ;XGRAVSIM2(7,1)
s J=(C," ",2),I1=(J,"-"),I2=+(J,"-",2),L1=(I1)+(I2)+2,K=((C," ",2),L1,(C)) i '(B(I1))!'(B(I2)) s R="invalid object(s) "_J x XGRAVSIM2(0,2) ;XGRAVSIM2(7,2)
x XGRAVSIM2(7,3,1),XGRAVSIM2(7,3,2) e  s R="invalid property "_K x XGRAVSIM2(0,2) ;XGRAVSIM2(7,3)
s J=" M:0 Y:1 X:2 VY:11 VX:12 A:20 AY:21 AX:22",(J,1,(J," "_K_":")-(K)-2)="",KJ=(J," "),J=(KJ,":",2) i KJ]"" s V=(B(I1,J))-(B(I2,J)) ;XGRAVSIM2(7,3,1)
i KJ="" s J=" D:1,2 V:11,12",(J,1,(J," "_K_":")-(K)-2)="",KJ=(J," "),JJ=(KJ,":",2) i KJ]"" x XGRAVSIM2(7,3,2,1) s V=V**.5 ;XGRAVSIM2(7,3,2): derived property
s V=0 f N=1:1:(JJ,",") s J=(JJ,",",N),V=(B(I1,J))-(B(I2,J))**2+V ;XGRAVSIM2(7,3,2,1)
n (XGRAVSIM2,C,CC,CK,I) i C?1(1"R",1"REPEAT").1" "1.n s N=(C," ",2) s:N>0&(CK[",") CC=(CK,",",1,(CK,",")-1)_",R "_(N-1)_(CC="":"",1:","_CC),CK="" x XGRAVSIM2(0,1) ;XGRAVSIM2(8): repeatpreceeding commands
n (XGRAVSIM2,CP,C,CC,CK,I) x XGRAVSIM2(9,1) i  x XGRAVSIM2(9,2) ;XGRAVSIM2(9): display control
s:CP?1"W ".E&(C?1"/"1a.an) C="W "_C i C?1(1"W",1"WRITE")1" /"1a.an ;XGRAVSIM2(9,1)
s K=(C," ",2),N=0 f  s N=(XGRAVSIM2(9,2,N)) q:'N  x XGRAVSIM2(9,2,N) ;XGRAVSIM2(9,2)
i K="/LF" w ! x XGRAVSIM2(0,1) s N=99,CP="W " ;XGRAVSIM2(9,2,1)
s R="syntax error "_K x XGRAVSIM2(0,2) ;XGRAVSIM2(9,2,99)
n (XGRAVSIM2,T,TI,G,C,CC,CK,I) i C?1.a1"=".e x XGRAVSIM2(10,1) e  x XGRAVSIM2(4,3) e  s @K=V x XGRAVSIM2(0,1) ;XGRAVSIM2(10):
s K=(C,"=") i K'?1(1"T",1"TI",1"G") s R="invalid property "_K x XGRAVSIM2(0,2) ;XGRAVSIM2(10,1)
s R="syntax error "_C S:CK'["," R=R_"- enter ? for information" x XGRAVSIM2(0,2) ;XGRAVSIM2(99)

[CraigD]

Here’s a GRAVSIM2 run from Earth to a soft landing on the Moon. Highlights:

• Same initial setup and acceleration as post #198
• Braking maneuvers started at 71120 sec (19:45:20)
• Contact with lunar surface (radius 1738140 m) at 71877 sec (19:57:57), speed of impact .5774 m/s

Despite being an unrealistically simple approach and landing not in real time, I got disoriented by the numeric-only interface at one point and nearly had a very un-soft landing, requiring a 20 sec burst of nearly 7 g acceleration 86 seconds before landing to recover. Flying to the moon by the seat of your pants is not recommended.

With a bit of enhancement, the simulator can fairly easily be made to simulate the changing mass and acceleration of various sorts of engines, detachable stages, etc. The difficult part, IMHO, will be the actual maneuver planning. This is, after all, rocket science.

It’s a good idea, I think, for simulation and flight planning to be moved into its own thread.

Here’s the actual simulator run input and output:

XGRAVSIM2>KILL
XGRAVSIM2>1m=5.9736e24
XGRAVSIM2>2m=7.347673e22,2x=363104000,2VY=1082
XGRAVSIM2>3m=1000,3y=0,3x=6378137,3vy=463.8,3ax=18.9,3ay=1.9
XGRAVSIM2>G 840
XGRAVSIM2>3a=0,G 70160,W 2-3D,2-3V,/LF,3y,3x,/lf,2y,2x,/lf,3vy,3vx,T,/lf,2vy,2vx
2-3D=4018352.912160723276,2-3V=4880.84477377116302
3Y=76056849.32810237054,3X=351501567.821066472
2Y=76286166.22350304192,2X=355513372.1393445162
3VY=987.246123712509141,3VX=4667.367539065672407,T=71000
2VY=1059.406443596608191,2VX=-212.9437823444177196
XGRAVSIM2>3AX=-5.2,3AY=0.8,G 120,W 2-3D,2-3V,T
2-3D=3468966.786850522624,2-3V=4298.649042918377678,T=71120
XGRAVSIM2>3AX=-5.5,3AY=0.8,G 60,W 2-3D,2-3V,T
2-3D=3220563.226577619727,2-3V=3995.589635976756434,T=71180
XGRAVSIM2>3AX=-6,3AY=1,G 300,W 2-3D,2-3V,T
2-3D=2262091.758987380426,2-3V=2433.890941978567511,T=71480
XGRAVSIM2>3AX=-6,3AY=2,G 60,W 2-3D,2-3V,T
2-3D=2125460.032397658041,2-3V=2165.622023590491667,T=71540
XGRAVSIM2>3AX=-6,3AY=3,G 60,W 2-3D,2-3V,T
2-3D=2006208.686490292585,2-3V=1942.637284549943312,T=71600
XGRAVSIM2>3AX=-7,3AY=-1,G 60
XGRAVSIM2>3AX=-10,3AY=-1,G 20,W 2-3D,2-3V,T
2-3D=1878354.76411576176,2-3V=1438.680919349270181,T=71680
XGRAVSIM2>3AX=-1,3AY=0,G 90,W 2-3D,2-3V,T
2-3D=1759402.142218962198,2-3V=1478.404966868923779,T=71770
XGRAVSIM2>3AX=-60,3AY=-30,G 5,W 2-3D,2-3V,T
2-3D=1753455.271791947174,2-3V=1150.369173240297893,T=71775
XGRAVSIM2>3AX=-40,3AY=-20,G 16,W 2-3D,2-3V,T
2-3D=1744199.996590056153,2-3V=113.9763793414585941,T=71791
XGRAVSIM2>3AX=-2,3AY=-1,G 12,W 2-3D,2-3V,T
2-3D=1742860.573395611845,2-3V=110.7033367904850459,T=71803
XGRAVSIM2>3AX=-2,3AY=1,G 18,W 2-3D,2-3V,T
2-3D=1740956.097079244423,2-3V=102.2522517936831674,T=71821
XGRAVSIM2>3AX=-2,3AY=0.1,G 9,W 2-3D,2-3V,T,/LF,3y,3x,/lf,2y,2x,/lf,3vy,3vx,/lf,2vy,2vx
2-3D=1740051.322115682185,2-3V=98.816557590960772,T=71830
3Y=77185162.14364714967,3X=353595675.4437595904
2Y=77165254.66340085202,2X=355335612.8839644895
3VY=1058.505382752025005,3VX=-116.5756786778842012
2VY=1058.87795169386201,2VX=-215.3915339163591927
XGRAVSIM2>3AX=-4.2,3AY=0.01,G 2,W 2-3D,2-3V,T
2-3D=1739051.299105161486,2-3V=67.8611957345608986,T=71842
XGRAVSIM2>3AX=-4.2,3AY=-.01,G 2,W 2-3D,2-3V,T
2-3D=1738920.734458533516,2-3V=62.70440923311849295,T=71844
XGRAVSIM2>3AX=-4.2,3AY=0.01,G 16,W 2-3D,2-3V,T
2-3D=1738247.424457677522,2-3V=21.46741516641832741,T=71860
XGRAVSIM2>3AX=-4.2,3AY=-.01,G 3,W 2-3D,2-3V,T
2-3D=1738194.631761772612,2-3V=13.74525442560693845,T=71863
XGRAVSIM2>3AX=-4.2,3AY=0.025,G 3,W 2-3D,2-3V,T
2-3D=1738165.031531080911,2-3V=6.037862317153925835,T=71866
XGRAVSIM2>3AX=-2.4,3AY=0.025,G 7,W 2-3D,2-3V,T
2-3D=1738142.064306195296,2-3V=.8860642175990340415,T=71873
XGRAVSIM2>3AX=-1.65,3AY=0.05,G 3,W 2-3D,2-3V,T
2-3D=1738140.504969749505,2-3V=.7627875008360555255,T=71876
XGRAVSIM2>3AX=-1.65,3AY=0.25
2-3D=1738140.041289413922,2-3V=.577464408973213996,T=71877
3Y=77234900.9962832482,3X=353587459.8743395258
2Y=77215021.21970332187,2X=355325486.2255829981
3VY=1058.479355846239149,3VX=-215.0854855465697223
2VY=1058.847845200812658,2VX=-215.5300985684176908

[freeztar]

This is interesting, and sounds vaguely familiar:

Drawing on the technical talent of deep-space mission veterans at Caltech and NASA’s Jet Propulsion Laboratory—and the Hollywood pizazz of directors Steven Spielberg and James Cameron—dot-com billionaire Bill Gross spearheaded an ambitious plan: Equip a 220-pound primary rover with its own rocket-braking lander system, and send a pair of 5-pound scout rovers to dash around and plot the way. And not unlike Google’s integration of YouTube-ready snapshots into its new prize, the BlastOff mission was to be a grand, interactive Web event. It wasn’t just a Cameron-inspired stereoscopic video camera mounted to that main rover; millions of users would pick a landing site, name the rovers and even “push” the launch button on their computer screens at the moment of firing.

Rent-a-Rocket Rule Shift Opens Up Field for Google Lunar X Prize: Update - Popular Mechanics