Need help to moon

[Qdog]

Ok guys I`ve aligned my orbit with moon`s to 0.001 degrees. Used transfer mfd-lined gray line
just ahead of yellow doetted line-fired trust prograde when solid green meets dotted green till I
match dotted oval with solid oval. Now here`s the problem-when I get this far the dotted yellow
(moon) moves way off. I don`t know if this is normalbut as I proceed the moon is way off to my
right. It doesn`t seem like I will intersect with it. Can anyone help me with this??

[Greaper]

Hello,
 The lines move on me also this seams to be irrelivent when I bring up my ENC MFD
I am very close to my target.
RSB

[Simonpro]

qdog: once you have done the burn the lines will wonder offcourse a bit. but you are *not* going to miss the moon!
As long as you ddi a good burn you'll still get there. Just timeaccelerate for a bit and bring up the orbit MFD. Select
the moon as the reference in the mfd (shft-R then type "moon") and over time you should see that your closest
approach slowly decreases.
Hope this helps,
Simon

[AphelionHellion]

Woohoo!
Thanks for the refresher Simon

I took the DGIII to the moon and landed right on the pad with plenty of fuel and air to spare (for once!)
Heh... I wonder if I still have that scenario from a few days ago saved when I got onto the pad with literally about 0.
3% fuel left in the tanks And yes, I drained the RCS tank almost totally dry, too.
It's times like these I remember why I became addicted to Orbiter in the first place!

[MattNW]

That's what I thought my first few Moon trips so I corrected more towards the Moon and found myself being chased
by the sucker. Everything will work out just wait and let it happen. A decent burn should have you almost smacking
into the Moon.

[johnc]

That's my problem ususlly, I get so close, that I smack right into it "SLAM!!!!!!"

another problem that I have is I can't figure out how to land at any specific point, say brighton beach.

any help on how to do that would be appreciated
I have the baseSync MFD if that help

Thx

Johnc

[Arkalius]

Yes, the moon being off to your right can be a little confusing, it seems you're going the wrong way. Just remember
that the Moon is moving too, and even if it's not that fast, it covers a pretty big distance in the 3 or 4 days it takes to
get there.

[AphelionHellion]

John: I've been meaning to try BaseSynch MFD but I haven't got around to it yet. The moon has no atmosphere, and is
relatively small and has relatively low gravity compared to, say, Earth (or even mars) so traveling to you rlanding site
sub-orbitally usually doesn't burn TOO much fuel.
Normally I "seat-of-the-pants" it like this:
Orbit MFD on one side, ship projection, and map MFD on the other with the base you want targetted (Brighton Beach
unless you have some add-ons).
I align orbit using orbit normal and antinormal burns until my orbit takes me right over our target base. I burn retro
until my orbit is at an altitude of perhaps 50 kilometers. Now this part depends on your ship, and may take practice to
get right, but you wait 'till you're just about right over your target, then burn retrograde like a mofo. With the DGIII
and the high end engines set you can be literally right on top of the thing and slow down fairly quickly, but with a
lesser performing ship you may have to begin your burn earlier. I burn retrogradeuntil my retrograde marker points
straight up. If you burn a bit more it'll flip and point toward the moon meaning you're now "hovering" UP. At that point
I let the ship hit apogee and begin to fall toward the surface. Depending on your altitude (I like to be about 40k up at
this point) you'll have a few minutes to decide what to do next. Normally what I do is look at my compass bug up top
to see where the base is relative to it. I rotate my heading to aim for the bug, then pitch straight down to 90 degrees
using the surface MFD. What I want to do is make sure my velocity vector is either straight down or headed toward
the target base. If not it'll just eat more fuel when we get down. I use the RCS linear thrusters to adjust the velocity
vector so it's headed a bit off of straight down, toward the target base. Then I use the level horizon autopilot and
switch the orbit MFD to Surface MFD (of course the DGIII has some really useful HUD functions on that 5 way AUX hud
that can be even better than the Surface MFD. Using hover thrusters (carefully, it's easy to hit 'em so hard you stop
dropping altogether and start back up). I keep the vertical speed below about 200 m/s. Around 10 K altitude I get it
down to below 100 m/s. Hopefully by this time I'm able to spot the base. The compas bug and external view helps
here  I use the hover thrusters to to get my Vspeed down to zero at about 4 k altitude, then turn on HoldAlt (if you
turn it on higher it pops you back up to that altitude, so bleh). Gotta make sure Hlevel is still on here, too, and lower
the gear. So now I'm in a stable hover and in view of the target base, it's just a matter of using main engines to thrust
over to the pad, retros or main to stop again (keep an eye on that prograde/velocity vector, it's a lifesaver here!!) and
hover down with RCS to a landing.

We don't need no steenking BaseSynch MFD  (well, I'm sure it's a godsend when you're low on fuel)

[AphelionHellion]

Forgive me if any of this sounds pedantic, or like I'm being a smartypants wiseass. I just like organizing my thoughts
via written word. It's therapeutic
That and I like being helpful if at all possible, particularly since I can't code or model or create any useful add-ons

[freespace2dotcom]

Ah.. Actually, I have trouble going to the moon, on say, realistic fuel. I manage to get into orbit, but that drains me of
near everything. and trying to align the planes so I can get close to the base takes the rest, leaving me with a
handful of KG of fuel (literally) Then I don't have enough "oumph" to stop that puppy when it comes time to land. and
I wind up crashing on the surface pretty hard, killing everyone.... Still though. that'd be a challenge for anybody (I
hope.. ^_^)

if anything, just be happy you can get to the moon if you can. it's just a matter of having enough fuel for me, and
finding the most super efficient way to ge there is a high priority. but I can get there... Aphellion is right in that sub
orbital flight is pretty darn cheap on the moon compared to earth. (if I overshoot my base on earth by more than
750KM, then I'd forget about landing there and just go in the wild..) however. It's still just too much to waste even on
the moon, because If you're like me, you didn't overshoot by a little, so you want to get there faster (the closer to an
actual orbit you're in, the less fuel you need to keep altitude. and you get to wishing there was an atmosphere just
so you can stop without wasting precious fuel.. heck, mars is ideal because you can stop through the atmosphere,
yet the atmosphere is thin enough that you can go at higher speeds, and still stop fuel efficiently. Mars is hands down
the friendliest planet to fly sub-orbitally wise. (for me, anyway)

[Simonpro]

Never ever ever ever *ever* align planes on LEO, the fuel usage is tremendous.
I cannot remember the exact formula for the deltav required to perform a plane change but it is something like:
dv=2v*Sin(i/2)
Where dv is delta v, v is orbital velocity and i is orbital inclination change. As you can clearly see it is much less costly
to perform your plane change burn while at a lower velocity, be this during launch or in a HEO.

I would recommend having the align mfd onscreen during launch and keeping the delta inclination to a minimum. Then
after you have performed your TLI you can null out the rest of the inclination error once you are further from the
earth.

[AphelionHellion]

Simon: That's interesting, I always assumed it was more efficient to make plane changes in a lower orbit (less total
distance traveled and all that). Come to think of it though, I think it was just a matter of efficiency with regard to TIME  
(lower orbit = faster period = less waiting for AN/DN). But then we all already knew I was impatient

So I'm sure you're right

Also one thing I always try and remember - you can't align your plane to an individual base on the moon from the
earth, so why bother even trying to be precise? You can be a few degrees off and it's no problem - after all you're
aiming for the MOON, not a little spacecraft.  You can always fine tune things once you enter lunar orbit.

Freespace: What fuel settings are you using? Are you using the DGIII? If so are you launching from the ground or
starting from orbit?

[Simonpro]

Altering inclination is more efficient in a LEO in terms of time usage, but nowhere close in terms of fuel usage. Plane
changes around the moon are fairly simple in terms of dv, however - so deltav is not nearly as important over there.

[AphelionHellion]

Simon: Makes sense. Once I went to the moon from a completely polar Earth orbit.
I was probably just lucky, but eh


Question: What is this Pegasus you keep referring to, and should we be concerned?  

[DocHoliday]

orbital flight is pretty darn cheap on the moon compared to earth. (if I overshoot my base on earth by more
than
750KM, then I'd forget about landing there and just go in the wild..) however. It's still just too much to waste even
on the moon, because If you're like me, you didn't overshoot by a little, so you want to get

Actually your straight-down technique works quite well on moon especially combined with the dg3's autoland
autopilot You just need to calculate how much time it will take you to brake to a halt, turn the dg around and burn
rubber. You will start losing altitude so you can engage the autoland feature when you feel the creeps by that time
you forward velocity should be down to manageable values

Simonpro is right. Plane changes are costly in low orbits. The least you can do is make the orbit highly elliptical and
perform the burns at apoapsis.

See Duncan Sharpe's tutorials for more indepth (but light) discussion on this.
http://www.orbitermars.co.uk/oldindex.htm the Standard orbit, Mr. Sulu!

Also check out the Mars tutorial. It might help you with the moon too. It's not up to date, but so what

[Simonpro]

Pegasus is something some people who use this forum know about, everyone esle doesnt and wont (for a few
years)

[AphelionHellion]

Is it that ship with the cargo pod and the tiny fuel tank?  
Or is that a different Pegasus?

Now I'm really curious

[Simonpro]

Thats a launch vehicle by orbital sciences. We have temporarily nicked their name untli we think of a better one

[freespace2dotcom]

DocHoliday wrote:
Actually your straight-down technique works quite well on moon especially combined with the dg3's autoland
autopilot You just need to calculate how much time it will take you to brake to a halt, turn the dg around and burn
rubber. You will start losing altitude so you can engage the autoland feature when you feel the creeps by that time
you forward velocity should be down to manageable values

Also check out the Mars tutorial. It might help you with the moon too. It's not up to date, but so what

Eh? I know how well it works, but I need to get to the base first before I can go straight down. that takes fuel to get
into the right postion, and whatnot... Fuel is too precious (in realistic settings) to make a far more elliptic orbit (to
make it worthwhile), change the plane, and then use more fuel to brake. at best, I can get over brighton beach, but
then I run out of my precious gas and crash half way to landing. of course, I still haven't tried changing my plane
while I'm still a ways away from the moon and on my transit to there... which is something I've been meaning to do,
but I'm lazy...

and I know very well about that tutorial. It's one of the few that I bother to visit every once in a while to make sure I
remember it all.

[AphelionHellion]

Simonpro: Think of more names for what?
Tell me or face the wrath of a million tiny pieces of debris!! And stuff!

[AphelionHellion]

Doc: What is this "autoland autopilot" you speak of?!?
And here I thought I knew everything there was to know about the DGIII

Freespace: Sorry to be nosey but I still wanted to know what fuel settings you were using for the DGIII (I assume this
is the ship you were using?)

I could swear I used a realistic fuel setting when I went to the moon, but then it may have been "realistic for Jupiter"  

[Simonpro]

No, you wont find out for a few years. It'll be worth the wait.

There shouldnt really be a "realistic" fuel setting to get the DG to mars, as we havnt invented engines that efficient
yet :p

[AphelionHellion]

Simon: Heh, good point. Maybe they're nuclear-powered ion engines?  

Of course it's not exactly that realistic being able to store enough O2 to supply 5 people for two years, in that little
fuselage, either
I've actually been wondering how difficult an undertaking it'd be to make the DeltaGlider bigger? Two person cockpit,
seats 8, that sort of thing. And of course adequate internal volume, at least, for all that fuel

The TX is a great start in terms of realism... If I recall correctly, the original plan for the space shuttle was for it to be
flown into LEO (or nearly so) atop a larger "mothership" much like the TX and the deltaglider. This is certainly more
efficient in terms of fuel, at least. But I guess it was too great (and too expensive) an undertaking to design TWO
totally new spacecraft when the shuttle alone is maddeningly complex. They figured solid rocket boosters and a big
fuel tank would be simpler and therefore safer... Not sure if the crew of the Challenger would agree, God rest them
But then I may be talking out my ass - mother-daughtership launches have always been tricky business, and accidents
have happened there as well. Look up the A-12 (which I guess was the CIA's flavor of the SR-71) and the project
using it to launch a hypersonic ramjet spy-drone. I read that they lost at least one plane that way...

[Simonpro]

Way too much power for current ion engines, but anything is possible i suppose

Havnt flown the TX, it looks like one of those SSTO designs and i have an inbuilt dislike of them as they never work :p

[AphelionHellion]

Simon: Well it's really not SSTO, it's TSTO (Two Stage To Orbit) :P
The TX just barely gets you up out of the atmosphere, it's not made to be an interplanetary dream machine.
Frankly it looks big and mean enough to do the job, at least by itself (I dunno about how much it could carry)