Puppy Probe Project

Meeting on Minmus

I wanted to build a smaller Fido that would be easier to launch, with the intention of exploring planets. I needed practice with interplanetary trajectories, and it seemed better to learn with un-kerballed probes. The "Fido Pup" probe is very similar to my previous Fido (all stock 0.18 parts) but more compact. A smaller frame and a rearrangement of the RCS fuel into radial tanks for a lower center of gravity were the main differences.

To test out Fido Pup, I sent him to Minmus to meet up with the original Fido there. Fido Pup launched on the same type of rocket that Fido used. I was surprised at how easy it was to get the lander to the same spot. Minmus is actually pretty easy because you don't need lots of fuel to loiter around a long time using your RCS to nudge your ship to just the right spot. This would be much harder to do on the Mün. Below we see the Fido Pup Carrier coming in for a landing where Fido and his Carrier are waiting.

Again, the gravity is so weak and the landing site so flat that I just brought the Carrier in rather than dropping the Fido Pup.

I gave this Carrier its own probe body (two, actually, for balance), so I was able to separate it from Fido Pup and fly it off a short distance. I landed it gently on its engine nozzles (first time I'd ever done that).

But when I went back to jump the Carrier around some more, the probe bodies were dead. Ah...that whole electricity thing in 0.18. I guess I was lucky that it lasted long enough to fly it away and land.

Below, Fido meets Fido Pup on the surface of Minmus.

Here are two views for comparing the size and construction of the Fido Pup versus the original Fido.

For his first mission, Fido Pup skirted the Near Cheek of The Big Butt formation, dipped down into a valley obscurely know as The Crack, and the drove up to the top of Far Cheek. The Pup handled quite well.

Below is the view from Fido Base when Fido Pup had made it to the maximus point of Far Cheek, 8.9 km away. Fido Pup was actually over the horizon a little, so his marker doesn't appear to be at the top.

(Afterwards I did some unofficial speed trials and found that Fido Pup could make it up to 75-80 meters/second along the Minmus Flats before violently wiping out. Also, when he does wipe out, his radially-mounted RCS tanks seem to make him more vulnerable to damage than the original Fido.


Doggies Do Duna

Below is the interplanetary doggie carrier rocket for taking Fido Pup to other planets. It has two additional side tank/motor stacks, and a nuclear transfer stage. Also, the Carrier for setting Fido Pup down on the planets was reworked to make it shorter (seven half tanks instead of three regular tanks). Also, I gave the nuclear transfer stage its own probe body so that I could use that to control the rocket launch and interplanetary transfer, and NOT have to make mistakes because the upside-down probe bodies give reversed readings. The probe body is balanced by an RTG (which is heavier, so it's mounted closer in) to make sure it does not starve from lack of electricity. The same arrangement is used on the Carrier so that it can be piloted after separation from the Fido Pup after landing.

The interplanetary stage separates from the booster before heading off to Duna.

Flaming past the Mün on the way to Duna, riding a jet of atoms super-heated by fission energy release. Don't you wish WE did stuff like this in real life? It was at this point, during the lonnnnng interplanetary injection burn, that I realized that I had forgotten to add the parachutes to the Carrier that would help set the Pup down on Duna. Arrrgh. Well, no problem: Some quick work in the VAB, and a second Fido Pup (with parachutes) was boosted off to Duna a few days later to take advantage of the same launch window.

When the first Pup reached Duna, I targeted it in for an aerobraking maneuver at an altitude of 15 km. But for some reason this value changed to 13 km on the way in...and I had to do some quick turning and burning to keep from dropping into the planet instead of dropping into orbit. But I got the first Pup safely parked into orbit around Duna in time to handle the incoming second Pup.

I was careful to watch the aerobraking periapsis for the second Pup, but it did nothing strange. Successful capture into Duna orbit, and close to equatorial as desired.

I still had plenty of delta-v in the nuke stage, so I used that to stop-and-drop the lander straight in vertically. Not fuel efficient, but it made for easy targeting of the landing spot. Below, the Carrier and Pup separate from the nuke stage.

The straight down approach is rather hectic as a lot happens fast at the end, but the chutes popped out reefed and I burned hard to lose speed. The chutes don't slow you up enough for landing, but they keep you going down straight. Just don't slow down too much and start going up, or the chutes disappear.

The Carrier and Pup grounded and I separated the Carrier...but I had also cut the engines just before, so the Carrier just flopped off the top of the Fido Pup. It handily rolled to a stop upright, so I could fly it off if desired.

Fido Pup sniffs around, but the Carrier appears to be intact.

Fido Pup's mission on Duna was to see if it could navigate the terrain by going into a large crater. The Pup handled well on the long 47 km drive as long as I kept it below 15 m/s. And, wonders of wonders, I was able to use physical time warp when driving the Pup around on Duna (this had not been an option on Minmus or the Mün with Fido), so things went much faster than they would have taken otherwise (but you have to be careful not to let the speed get away from you). The Fido Pup seems to zip along with almost not friction. Below we see Fido Pup descending the steep inside wall of the crater. It was getting dark as evening approached by the time I was making the descent.

The image below shows the terrain covered by Fido Pup on the 47.2 km journey into the crater from the landing site.

Below, Fido Pup enjoys the sun setting behind the crater wall he just descended.

But... (I'm sure you're wondering) ...what about the Fido Pup that was launched without parachutes? I sent him to Ike, Duna's rather large moon. You sure get some weird orbits maneuvering around near Ike because it's so large in relation to Duna. Anyway...below, the 'chuteless Pup is leaving the nuclear stage in orbit as it prepares to descend to the airless surface of Ike.

The landing site was slanted, and when I brought the Carrier in (still attached to Fido Pup), it was firing its RCS like crazy in order to stay vertical. So I just popped it free of the Fido Pup and let it roll off the top. Fido Pup has upward-pointing RCS thrusters that the original Fido lacked that were useful in keeping it pressed down in place as the Carrier rolled off the top.

I had a hard time judging the slopes on Ike, but in the low gravity Fido Pup could handle them well. But I decided to just let the Pup roll off and settle into a low spot, which it came to after a run of 5.3 km.

The image below shows the starting and ending locations of the Pup's rollout.


Easing onto Eve

OK...This was harder than I thought it would be. I mean, which such a thick atmosphere (five times Kerbin's atmospheric density), it should be easy to land with parachutes. But the problem is that the chutes yank HARD when they pop fully open on Eve, usually pulling the chutes off of your ship (how about a slow-opening chute you Kerbal engineers?). The Eve-bound Fido Pup was the same as the Duna version except for the addition of parachutes to the Fido Pup as well as the Carrier. Also, I was really worried that the thick Evian atmosphere would really slow down the rolling speed of the Fido Pup, so I added a standard-size RCS tank to the top of the Pup to give it more fuel to fight the drag. Below we see the ship heading off for Eve.

The primary objective for this mission was improving my interplanetary targeting and aerobraking skills. Eve's dense atmosphere is very useful for aerobraking. Below we see my aerobraking maneuver over the night side of Eve as I streak toward dawn. For my initial aerobreaking from interplanetary speed, I targeted my periapsis at 75 km, which resulted in capturing the ship in an elliptical orbit with a 20,000 km apoapsis. I then altered the periapsis to 82 km and let subsequent passes through the outer atmosphere bleed off more speed each time around. After about a dozen passes the apoapsis had been reduced to 420 km and the periapsis had degraded to 77.4 km (so the braking was becoming stronger with each of these secondary passes). This could be done faster using a little lower periapsis, but I was in no hurry. (I left the nuke transfer stage in the original high elliptical orbit with its periapsis raised to 180 km so there would be no more aerobraking.)

Below we see the Fido Pup in orbit above Eve. I've always been fascinated with Eve's shining seas, so Fido Pup's mission would be to land close enough to a seashore so that it could go down and investigate the sea.

I chose to target Fido Pup to the area shown in the image below. The sea there kind of looks like the head of a happy Snoopy... if you squint at it just right. A deformed, happy Snoopy. Maybe.

As I said earlier, this landing proved harder than I expected it would be. I made several "simulated landings" before I got a successful one. Good thing those other attempts were just simulations. So here's how it goes: Come in on a shallow trajectory and pop out the Carrier's reefed chutes as soon as they'll deploy (40-something km). This starts slowing you quickly and dropping you in vertically over your target.

Then comes the tricky part. At the right moment (around 4,000 km in this case) you have to start burning the engines madly to: a) slow the ship down as slow as possible right at the altitude where the chutes will fully open, and b) lighten the fuel load of the Carrier so you can get as slow as possible. I was regretting the mass of that extra RCS tank on the Fido Pup at this point, and I was regretting having LV-909 engines on the Carrier instead of higher-thrust LV-T45 engines.

If you've timed it just right, the fuel on the Carrier will be very low (so the ship is light) as you hit main-chute opening altitude. If the the speed is low enough, about 35 m/s, the ship will survive the full-opening of the main chutes, and the speed quickly drops ro less than 4 m/s (while you are still thrusting). Drop the Pup and wait just a bit to be sure the Pup is clear (as it begins to speed up again...noooo!) before popping the Pup's chutes. But if you did it right, you get the result shown below. Truth be told, it took me five tries.

But if all the mains open without ripping loose, you are home free. Unless you targeted your ship into the drink, which I did not. The picture below shows the Pup descending safely...ummm...with the Carrier coming down right above it. Hmmm...maybe we aren't home free yet.

In the picture below, the Fido Pup is about to touch down. Don't get a false sense of security from the fact that the shadow of the Carrier's chutes is not right on top of the Pup... that's because of the angle of the lighting... the Carrier IS right over head.

So... as soon as the Fido Pup touches down and its chutes vanish, give a blast of the rear RCS thrusters to get rolling. That way you won't be under the Carrier as it lands. In the picture below, Fido Pup is exiting, stage left.

Fido Pup and the Carrier, safely on the surface of Eve. Now... Where is that sea we want to investigate?

It turned out that the thick atmosphere really was not a big problem for Fido Pup. But what WAS a big problem was the high gravity. Even a gentle slope on Eve can stop Fido Pup in his tracks. And he really steers like a cow at the higher gravity. But, happily, the objective, Eve's shining seas, are downhill from the landing site. I did have a bit of a problem with a very slight ridge line that stopped the Pup, but by rolling back and then attacking the ridge line at an angle and with a head of speed built up, I was able to top the rise and head toward the enchanting sea. Below we see Fido Pup blasting along to keep up speed.

The sea was a bit disappointing... no texture close up...just a flat plane. I wonder what this liquid is, anyway. Below, Fido Pup reaches his objective.

And... Well, there wasn't really much choice at this point, since Fido Pup's thrusters were too weak to get him back up the slope of the beach... So I sent him in for a dip.

As Fido Pup slid in far enough, we got the sound effect and frothy water effect of a splashdown. Interesting.

Fido Pup went in and just sat there with his upper parts above the surface, looking kind of desultory. I tried backing him out of the sea. No luck. I tried his vertical boost engines. Eve just laughed at this feeble attempt to fight her gravitational clutches. I was about to give up...when I decided to shove him farther out into the sea. And guess what? Fido Pups can swim. Not very fast, to be sure, and using up lots of fuel, but I could get him moving and steer him around.

And much to my surprise, I was able to ease Fido Pup back out of the sea by aiming him at a shallow angle to the shore. And, happily, he did not shake his airframe violently to get dry. But no matter how carefully I parked him, he'd always slowly roll along the beach and back down into the sea. I guess he liked it there.

The image below shows a marker at the landing location, and a harder-to-see marker at the spot 12.9 km away where Fido Pup is playing in the shining sea.