DMSP

I am never going back to Moho.

Recommended Posts

I'd heard the horror stories about Moho, and was determined that whatever happened I was [I]not[/I] going to run out of delta-V.

[url=https://flic.kr/p/vbgELJ][img]https://farm1.staticflickr.com/402/19150568338_a8e1c6cd22_h.jpg[/img][/url]

Over 20 km/s in the orbiter there. Sure, TWR is low, but that's what clicking hold manoeuvre and watching a TV show is for.

The mission was a resounding success - after the Moho landing I had enough dV left over to detour via Gilly and Bop doing jetpack landings on both before returning to Kerbin.

Only thing that did catch me out: In 1.0.4 at least once you're closer to the Sun than about Eve's orbit your heatshield ablator will slowly vapourise :O I returned to Kerbin with basically none left. I was OK but don't count on surviving a fast aerocapture on the return from Moho!

Share this post


Link to post
Share on other sites
Solar electric for the win! If not at Moho, where else? :P

The ablator consumption is surprising though, I thought that didn't start until >500 K skin temperature. And Moho should only heat you to 400-odd K...

Share this post


Link to post
Share on other sites
Oh, since we're showing pictures - Like Rune I thought if I was going, I should plan to stay a while.

My first Moho station, with ttransfer vehicle, tug and landers:

[url=http://imgur.com/jtVpeFJ][img]http://i.imgur.com/jtVpeFJl.png[/img][/url]

Share this post


Link to post
Share on other sites
[quote name='KerikBalm']While it is close to the sun, you parts only heat up to... what... 400C? 400k?
That's well below the temperature limit of any part. There are few parts with less than a 1200C temperature limit.[/QUOTE]
There's a significant difference between temperatures near Moho apoasis and periapsis. At periapsis, temperature of your ship with no radiator will raise above 500°K and all your ablative shields will disappear (1.0.4).

By the way, at what temperature does a Kerbal boil? Edited by gogozerg

Share this post


Link to post
Share on other sites
[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][FONT="Arial"][COLOR=#000000]After telling my typical tale of first Moho mission anguish, I realized that I have never actually been back there since that first rescue mission, so I built this to send 3 Kerbals to the surfaces and back, just to put my earlier humiliation behind me:[/COLOR][/FONT]
[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][FONT="Arial"][COLOR=#000000][imgur]zCtTZ[/imgur][/COLOR][/FONT]
[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][FONT="Arial"][COLOR=#000000]It’s been a while since I put together any big rockets, and I must say things have gotten easier since then! The awesome TWR of the Mammoth and Vector engines makes lobbing massive payloads into LKO almost too easy. Anyway, The orbital maneuvering stage can push the full lander for ~6.2km/s without even jettisoning any of the side boosters, so I think I can make it there and back even without any fancy maneuvers. I will nonetheless see what I can do to make it cheaper by swinging around Eve, without looking at any of the spoilers people have posted here…. [/COLOR][/FONT]

[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT]

Share this post


Link to post
Share on other sites
In 1.04 my Moho lander was left behind as a base for future expeditions and the crew returned to the mothership on little open-seat scooters like this:

[url=https://flic.kr/p/v6vweC][img]https://farm1.staticflickr.com/536/19096688710_4db8c3dc49_b.jpg[/img][/url]

Notice that the Kerbal has a heat gauge on his tummy and his expression indicates he's not having a good time. Also, I launched in the local afternoon so when I tipped it over to the east to head for orbit, the solar panels were pointed away from the sun, which caused problems with running low on electrical charge so I had to reach orbit by a stair-step trajectory. But it did work. Yay Lifesaver tanks ;).

Share this post


Link to post
Share on other sites
[quote name='Geschosskopf']In 1.04 my Moho lander was left behind as a base for future expeditions and the crew returned to the mothership on little open-seat scooters like this:

[URL]https://farm1.staticflickr.com/536/19096688710_4db8c3dc49_b.jpg[/URL]

Notice that the Kerbal has a heat gauge on his tummy and his expression indicates he's not having a good time. Also, I launched in the local afternoon so when I tipped it over to the east to head for orbit, the solar panels were pointed away from the sun, which caused problems with running low on electrical charge so I had to reach orbit by a stair-step trajectory. But it did work. Yay Lifesaver tanks ;).[/QUOTE]

LOL that's priceless!

Share this post


Link to post
Share on other sites
On my way back to Moho again, this time for high resolution mapping (SCANsat). 38 days out...

[IMG]http://i.imgur.com/2BPhv4n.png[/IMG]

Share this post


Link to post
Share on other sites
To add to my earlier post I'll quote my self from another thread.


[COLOR=#333333]I landed on [/COLOR][COLOR=#417394]Moho[/COLOR][COLOR=#333333] last night using macollos' method and it's slicker than snot on a broom handle. Basically you leave LKO on Mohos' AN/DN. [/COLOR]

[COLOR=#333333]The first time this occurs ( IIRC the AN ) is ( Earth ) Year 1 Day 21, on or about Hour 17. Set [/COLOR][COLOR=#417394]Moho[/COLOR][COLOR=#333333] as your target and drag a dummy Kerbin escape node out to see where the AN/DN is. I combined my Kerbin escape burn with my inclination burn at a total cost of 2300 dv. At my solar periapse ( which was also Mohos' solar periapse ) I burned 1800ms retro ( as Kashua suggests. See link ) to make sure I encountered [/COLOR][COLOR=#417394]Moho[/COLOR][COLOR=#333333] on my next orbit, which lowered my solar apoapse and slowed the eventual[/COLOR][COLOR=#417394]Moho[/COLOR][COLOR=#333333] encounter down dramatically. My capture burn at [/COLOR][COLOR=#417394]Moho[/COLOR][COLOR=#333333] was around 1000ms.[/COLOR]

Share this post


Link to post
Share on other sites
[quote name='Aethon']To add to my earlier post I'll quote my self from another thread.


[COLOR=#333333]I landed on [/COLOR][COLOR=#417394]Moho[/COLOR][COLOR=#333333] last night using macollos' method and it's slicker than snot on a broom handle. Basically you leave LKO on Mohos' AN/DN. [/COLOR]

[COLOR=#333333]The first time this occurs ( IIRC the AN ) is ( Earth ) Year 1 Day 21, on or about Hour 17. Set [/COLOR][COLOR=#417394]Moho[/COLOR][COLOR=#333333] as your target and drag a dummy Kerbin escape node out to see where the AN/DN is. I combined my Kerbin escape burn with my inclination burn at a total cost of 2300 dv. At my solar periapse ( which was also Mohos' solar periapse ) I burned 1800ms retro ( as Kashua suggests. See link ) to make sure I encountered [/COLOR][COLOR=#417394]Moho[/COLOR][COLOR=#333333] on my next orbit, which lowered my solar apoapse and slowed the eventual[/COLOR][COLOR=#417394]Moho[/COLOR][COLOR=#333333] encounter down dramatically. My capture burn at [/COLOR][COLOR=#417394]Moho[/COLOR][COLOR=#333333] was around 1000ms.[/COLOR][/QUOTE]

So, 5100m/s total from LKO to LMoO. That's a bit cheaper than going by Eve, which will cost you about 5500-6100 or so depending on how elegant you are. Both methods result in capture burns of less than 2000, however, which is the important thing, so you can actually stop there before you leave Moho's tiny SOI :). Also, having both methods gives you more flexibility in when you can leave Kerbin, either when you have a transfer window to Eve or once a year when Kerbin's lined up with Moho's nodes on the Ap side. Either way, however, it's going to be a long trip, like about a year or more, due to having to make several orbits of the sun before you can meet Moho in a convenient place. So if you use life support, pack plenty of chow.

That's always the trade-off in KSP, food (and mission time which might matter for other reasons) or fuel. Reducing the need for one increases the need for the other.

Share this post


Link to post
Share on other sites
You doing well.

I had to send multiple rescue missions back when I did it. :P

[url]http://forum.kerbalspaceprogram.com/threads/30970-Colossus-Interplanetary-Ship[/url]

Share this post


Link to post
Share on other sites
So I figured I'd post my Moho mission status, I think I'm in fairly good shape so far:

Definitely had to send additional fuel so this is it, extremely long burn.

[IMG]http://i.kinja-img.com/gawker-media/image/upload/s--I-w8p9ok--/c_scale,fl_progressive,q_80,w_800/1526700490233372813.jpg[/IMG]

Getting Close

[IMG]http://i.kinja-img.com/gawker-media/image/upload/s--ep1AV6TM--/c_scale,fl_progressive,q_80,w_800/1526700490258262413.jpg[/IMG]

Closer

[IMG]http://i.kinja-img.com/gawker-media/image/upload/s--T4x4PfbO--/c_scale,fl_progressive,q_80,w_800/1526700490158634125.jpg[/IMG]

Stable orbit

[IMG]http://i.kinja-img.com/gawker-media/image/upload/s--BVR2oKRT--/c_scale,fl_progressive,q_80,w_800/1526700490085866125.jpg[/IMG]

Adjusting orbit to match exploration vehicle. Using RemoteTech, basically all of the maneuvers were in and out of contact with Kerbin so I feel like I cheated a bit using the flight computer.

[IMG]http://i.kinja-img.com/gawker-media/image/upload/s--MrLdAwE---/c_scale,fl_progressive,q_80,w_800/1526700490114882701.jpg[/IMG]

I skipped a bit but here they are docked.

[IMG]http://i.kinja-img.com/gawker-media/image/upload/s--LS8snsPN--/c_scale,fl_progressive,q_80,w_800/1526700490023187085.jpg[/IMG]

Lander/drive unit/ISRU on its way down. This took some trial and error to get the landing right but it's very similar to landing on the Mun.

[IMG]http://i.kinja-img.com/gawker-media/image/upload/s--WmsVAKAZ--/c_scale,fl_progressive,q_80,w_800/1526700489986338189.jpg[/IMG]

And Landed. I should be able to refuel and bring some ore back to the orbiter with plenty to spare and be back for more.

[IMG]http://i.kinja-img.com/gawker-media/image/upload/s--cl1v4y8L--/c_scale,fl_progressive,q_80,w_800/1526700489885085581.jpg[/IMG]

Share this post


Link to post
Share on other sites
I have been to Moho.

I did take a lot of radiators, but this was to dissipate the heat from my nuclear thermal rocket rather than because of conditions at Moho. (I don't recall having to deploy the radiators at Moho, except during a burn.)

My biggest problem with Moho is that a) as you point out, it takes a ridiculous amount of d-V to get there, and b) when you get there, it's freaking boring. Airless, monochromatic, and a landscape like Dres, only not as feature-rich or interesting.

Once things get more stable again (right now I'm having bad, bad problems with crash-to-desktop on scene change) I might load some mod like Interstellar and build a solar-powered microwave transmitter station/antimatter bottling plant in Moho orbit. Other than the intense plentiful solar energy, or to cross it off The List, I can't think of too many other reasons to go there.

Share this post


Link to post
Share on other sites
[quote name='cantab']I'd heard the horror stories about Moho, and was determined that whatever happened I was [I]not[/I] going to run out of delta-V.
Over 20 km/s in the orbiter there. Sure, TWR is low, but that's what clicking hold manoeuvre and watching a TV show is for.
[/QUOTE]
Blast it sir, that one image has invalidated my entire XenonTempest series of high dv transfer craft. Why should I bother with heavy modular engine spars docked in orbit when I can put 'em in a ring on any size 2 part that lets cubic octagonals surface-attach? 'Provisional ship with my own fuel pod system has nearly 28km/s, shattering my previous record around 17km/s, which is about what it has with just the xenon in the spine. I feel stupid now.

Share this post


Link to post
Share on other sites
[quote name='eataTREE']I have been to Moho.

I did take a lot of radiators, but this was to dissipate the heat from my nuclear thermal rocket rather than because of conditions at Moho. (I don't recall having to deploy the radiators at Moho, except during a burn.)

My biggest problem with Moho is that a) as you point out, it takes a ridiculous amount of d-V to get there, and b) when you get there, it's freaking boring. Airless, monochromatic, and a landscape like Dres, only not as feature-rich or interesting.

Once things get more stable again (right now I'm having bad, bad problems with crash-to-desktop on scene change) I might load some mod like Interstellar and build a solar-powered microwave transmitter station/antimatter bottling plant in Moho orbit. Other than the intense plentiful solar energy, or to cross it off The List, I can't think of too many other reasons to go there.[/QUOTE]

[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][FONT="Arial"][COLOR=#000000]You know how they say getting there is half the fun? Well for Moho, it’s all the fun![/COLOR][/FONT]
[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT]

Share this post


Link to post
Share on other sites
[quote name='herbal space program'][FONT=Arial][COLOR=#000000]You know how they say getting there is half the fun? Well for Moho, it’s all the fun![/COLOR][/FONT]
[/QUOTE]In my case, it was getting [I]back[/I] that was most of the fun (almost in the Dwarf Fortress sense of Fun). Like everyone who goes to Moho, I initially thought my mission was ridiculously overbudgeted for delta-V. But I ended up having to get home via a bi-elliptic transfer, as I couldn't afford a direct return shot. Fortunately I brought lots of life support.

Share this post


Link to post
Share on other sites
[quote name='Archgeek']Blast it sir, that one image has invalidated my entire XenonTempest series of high dv transfer craft. Why should I bother with heavy modular engine spars docked in orbit when I can put 'em in a ring on any size 2 part that lets cubic octagonals surface-attach? 'Provisional ship with my own fuel pod system has nearly 28km/s, shattering my previous record around 17km/s, which is about what it has with just the xenon in the spine. I feel stupid now.[/QUOTE]Well, the long "tail" on mine did make the launch a bit of a nuisance. But other than that it worked well. It's hard to see in the pic, but it goes 10 xenon tanks, decoupler, five tanks, decoupler, five tanks, letting me shed dry mass as I go to improve delta-V.

If I wanted I could possibly also have added extra engines and solars further down the tail to keep the TWR up. I don't know if ion thrust gets blocked but even if it does I should be able to provide enough clearance.

On an unrelated note, this thread's title was a missed opportunity. It should have been [I]I, am never ever ever, going back to Moho[/I]

Share this post


Link to post
Share on other sites
[quote name='eataTREE']Like everyone who goes to Moho, I initially thought my mission was ridiculously overbudgeted for delta-V.[/QUOTE]

I even refueled my nuclear propelled craft while it was on escape trajectory from Kerbin to see if I could eyeball it. That still was not enough, even after I dumped the rest and just got my lander, it still wasn't enough. And three underpowered rescue missions later I just gave up.

Share this post


Link to post
Share on other sites
[quote name='cantab']Well, the long "tail" on mine did make the launch a bit of a nuisance. But other than that it worked well. It's hard to see in the pic, but it goes 10 xenon tanks, decoupler, five tanks, decoupler, five tanks, letting me shed dry mass as I go to improve delta-V.[/QUOTE]
Heh, mine's even more out of hand -- enough xenon tanks in the spine for three giantors on either side, plus 2 1x6s orthagonal in the back to provide reasonable power in case of mis-rotation, one more tank for docking clearance, docking port (nice we can stage those now, they're like re-usable decouplers), and an insane fuel pod with 49 more tanks in 8 additional stages.

Share this post


Link to post
Share on other sites
why dont you go for it like this?
[video=youtube;tRGZPZuzVHE]https://www.youtube.com/watch?v=tRGZPZuzVHE[/video]

Share this post


Link to post
Share on other sites
[quote name='Guz']why dont you go for it like this? [/QUOTE]
While impressive, using ISRU to get away with Mammoths and have all of the TWR is Easy Mode.

I was thinking more along the lines of this thing:[spoiler=Xenon Tempest Mk2]
[IMG]https://dl.dropboxusercontent.com/u/59091477/Monstrosities/screenshot141.png[/IMG]
Seen here with fuel pod and return system already docked and the MicroTug construction runabout arbitrarily docked to one of the engine spars (some assembly required).
[/spoiler]

Though after seeing cantab's design, I might instead go with this:[spoiler=Xenon Tempest Mk3 concept]
[IMG]https://dl.dropboxusercontent.com/u/59091477/Monstrosities/screenshot142.png[/IMG]
Much simpler, better delta-v, TWR, and even part count, plus it kinda looks like the Discovery One, just with ion engines and non-radial fuel tanks.
[/spoiler]
Granted, both of those might have too much delta-v even for Moho, depending on the lander package.

I am going to miss these spoiler tags if the new forum lacks an analogue to them.

Share this post


Link to post
Share on other sites
[quote name='DMSP']So, I just finished sending out all the parts for my Moho mission.

And it sucked. 3,000 m/s Ejection burns.

Yeah I haven't been there and I already hate it.[/QUOTE]

It doesn't suck, you don't hate it... its just hard to get there, that is why you are unhappy. In real life, could you, right now, get into space? Visit the I.S.S.?

NO and NO!

Could you work for NASA that sends a probe to Pluto and takes a decade or so to see any results?

The examples I have given you are really hard.... THAT sucks.... not a game because in a game, there is always a way... its not rocket science.... is it?

:)

Share this post


Link to post
Share on other sites
[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][FONT="Arial"][COLOR=#000000]Figuring out how to get to Moho cheaply has been a fascinating problem. I’m not done yet, but I’ll post an album here when I am. So far, it’s looking like I’ll manage capture at Moho about 3.2 km/s all told from LKO. I’m not sure how much more getting to LMO will cost from there, but I imagine only a few hundred m/s. I give a more detailed explanation, with instructions that less experienced Kerbal wranglers can hopefully follow, below:[/COLOR][/FONT]

[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][FONT="Arial"][COLOR=#000000]STOP READING NOW IF YOU DON’T WANT SPOILERS. Even if you don’t end up doing the long, later, part, I think the initial approach will still save you several hundred m/s vs. ejecting straight to Moho from Kerbin, even if you do it at the nodal point as suggested upthread. [/COLOR][/FONT]
[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][FONT="Arial"][COLOR=#000000]What I found was that if you eject for Eve from near its descending node with Kerbin, with Eve at a tighter phase angle (like -25deg vs. the -57 for a standard Hohman transfer), for about 1150 m/s you can set up an encounter about 2/3 of the way around Eve’s orbit from where you eject, i.e. later than for a Hohman transfer. As it turns out, that spot is almost exactly at the ascending node between Eve and Moho, which you can easily identify by looking at the orbital map. You’ll want to launch from the KSC about halfway between sunrise and noon and shoot for an orbit that’s inclined about 22.5deg southwards from there. When you’re done, the highest latitude of that orbit should be near the sunrise terminator. When you eject retrograde from that orbit at Eve’s descending node, you end up pretty close to its orbital plane. It doesn’t have to be perfect, so long as you can place your ascending node close to the intersect with small subsequent corrections. Anyway, from that Eve encounter I was able to eject to an orbit that goes just outside of Eve’s and intersects Moho’s on the opposite side, with a tilt of only about 0.5deg relative to Moho’s. From solar Ap a few days after Eve ejection, the remaining dV to complete the plane correction for me was only around 80m/s, but maybe a better navigator could work it out to eject dead-on into Moho’s orbital plane.[/COLOR][/FONT]
[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][FONT="Arial"][COLOR=#000000]So with that maneuver you’ve already shaved off a lot of dV from the more conventional way, getting to a significantly lower orbit than direct Kerbin-Moho transfer for 500m/s less dV, and furthermore getting 6.5deg of the 7deg plane correction for free, but then it gets even more interesting. With a series of carefully calculated burns, it’s then possible to set up a succession of Moho encounters to gradually walk down a ladder of ever-lower resonant orbits. [/COLOR][/FONT]
[COLOR=#000000][FONT=Times New Roman][SIZE=3] [/SIZE][/FONT][FONT="Arial"]Since the encounter indicators at Moho are all squirrely, this required some calculation. To get my first Moho encounter, I advanced the clock from my plane change correction to the next time Moho was at the intersect point. From there, you know Moho will return to that spot at t+102.6d, 205.2d, 307.8d, etc. You then place a node right at the intersect. If you add the time to this node to the period of your initial Moho-tangent orbit, you’ll generate a similar series of return times to that spot for your ship. You then just need to do a little bit of math to figure out how much you need to change (lower if at all possible) your orbital period to make one of your return times line up with one of Moho’s. This itself will not be a resonant orbit, because your initial approach changes the calculation, but from there out you will be shooting for them. In my case, I came in on an orbit that was a little lower than 2:1 resonant with Moho’s, and I had to lower my orbital period about 12 days to get a re-encounter 3 orbits later. I then basically tugged retrograde on that maneuver node until clicking on the orbital path behind my ship indicated the right period, resultimg in a ~200m/s burn. I then advanced my ship the first 2 orbits and did an additional ~25m/s correction to set up the actual encounter using the indicators. From there, you set up your encounter to get as close to Moho’s surface as possible from the outside. For me this lowered my initial orbit almost exactly to a 5:3 resonant one, requiring me to boost only a small amount retrograde to get another encounter 3 orbits later. This in turn lowered me to somewhere above a 3:2 orbit, with yet another relatively small retrograde correction to set up the next slowing encounter. And so on down the energy shells: 5:3, 3:2, 3:4, 4:5, and finally 9:8. Lather, rinse repeat. I got too tired to continue when I reached the final 9:8 orbit last night, but I expect from the ~2000m/s speed I had at the Pe of my previous (5:4) encounter that I’ll only need to burn for maybe 600 m/s to get captured and 200-300 more to get to a low orbit. When I finally do, I’ll post the results in an album. Working this out has been just the most excellent tutorial in orbital mechanics for me, and I’m sure I can do quite a bit better than this if I work everything out just right. [/FONT][/COLOR]

Share this post


Link to post
Share on other sites
This thread is quite old. Please consider starting a new thread rather than reviving this one.

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.