Indifference: A Curiosity First Anniversary Tribute

[DMagic]

To commemorate the upcoming first anniversary of Curiosity’s landing on Mars I present Indifference. Curiosity’s lazier, older, (balder?) fatter relative.

I’ve been waiting for a few more updates before I do more than tinker around here and there in KSP. But seeing as how others have been launching Duna rovers to celebrate Curiosity’s landing I figured I would try something quick and dirty.

So I built myself a rover and launcher from scratch using what I call Stock++. The first + is for Engineer, because I’ll be damned if I have to sit around guessing how much delta-v a stage has (or calculate it myself, ha), or constantly play in map mode just to figure out my orbital parameters. The second + is for all of the stock parts that I’ve duplicated, or in some cases triplicated, and tweaked. These include reaction wheels, antennae, rover bodies, and a few others. I altered their parameters accordingly, so none of them are what I would consider cheats, they’re just variations on stock parts.

After a few hours building and testing my design the rocket is ready to go. And here it is on the launch pad with the rover, skycrane, and orbital relay perched on top. The rover itself is made up of about 100 parts, with another 150 or so parts for the skycrane and atmospheric entry system, then another 100 or so parts for the launch vehicle (and no struts on that, I'm surprised it didn't fall apart). The auxiliary fuel tank on the launch clamp allows for main engine startup first, followed by SRB ignition and launch clamp separation.

Once the tower is cleared the liquid boosters ignite. There is no asparagus staging or fuel cross-feed here, so the main engine cuts out fairly soon after liquid booster separation. The orbital insertion stage worked out nicely, with just enough delta-v to put the rocket in an 80km orbit.

Once the Duna transfer window opens the rocket makes one long ejection burn. Only a very small correction burn is required to setup the final encounter.

After a long trip the rocket nears Duna, as Ike orbits close by.

But now I had a dilemma. The rover is not designed to get into orbit around Duna before landing, it’s on a direct descent path. But I need the orbital relay to get into orbit before the rover begins its landing. And I obviously can’t do both at the same time. So I came up with this. A sepratron powered, spin stabilized, ejection system that boosts the relay ahead of the rover. I wish I had a recording of this, as it worked perfectly. A 5^o twist of the sepratrons was enough to spin up the probe, followed by separation of the orbiter and deployment of the solar panels.

And best of all, it worked to get the relay there ahead of the rover. Those four sepratrons gave it enough of a boost to get it to Duna with just over three hours to spare. Only a small correction was needed using the probes main engine.

After a dip into Duna’s atmosphere the probe settles into a stable 125km, equatorial orbit and deploys its antennae.

Back to Indifference now, the transfer stage makes its final burn to setup the approach path, then separates and falls towards the planet’s surface. And the rover prepares for descent.

And now the fun part begins. The heat shields protect the vulnerable wheels, while the ablative coating on the exposed sections burns off. After peak heating the parachutes are deployed. There is one regular drogue chute, and four of my custom made, 1/2 scale, Mini-Mk25 chutes, these have about 1/4 of the drag, but fully deploy a little earlier than the full size drogue chute.

With the heat shields no longer needed, they begin their two-stage decoupling process. First, the two outer sets are pulled down and out using a single sepratron motor. Then the center shield fires directly down using a pair of sepratrons.

With the Mini-Mk25's deployed Indifference begins to lose most of its horizontal velocity over the surface. The main drogue is cut loose before it fully deploys (wouldn't want to make things too easy) as the first stage skycrane prepares for active flight mode.

Around 250m above the surface the remaining drogue chutes are cut loose and the skycrane enters fully powered mode. With it's descent velocity slowed to nearly zero, the first stage skycrane separates. A probe core and reaction wheel keep the now departing skycrane stable and a small radial engine pushes it sideways. The second stage skycrane, known informally as Skycrane 8, The Ocho, then powers up to gently lower Indifference to the surface.

The Ocho carries Indifference down the rest of the way. Once safely on the ground the reaction wheel stabilized skycrane decouples and lifts off, again, pushed to the side by an auxiliary motor. It appears, unfortunately, that one wheel was slightly damaged in the landing, but thankfully I packed a wheel repair kit, otherwise known as Notepad, with the rover. And for those wondering, I'm not manually taking screenshots during the descent stage. FRAPS has a great function that automatically takes screenshots in intervals as small as one second. You can end up with a ton of pictures if you leave it on for too long (you can set a key to activate and deactivate it), but it works great for these high pressure moments when manually taking screenshots just isn't an option.

All systems appear intact, and with the damaged wheel repaired, Indifference deploys its suite of antennae. On the front you can see two steerable, high-gain antennae. On one side is the backup, low-gain antenna. And on the back we have the large mast antenna, a 2X rescale called the Communotron 116. In the picture on the right Indifference tests out its retractable drill known as the Diggatron 16, a 1.5X rescale of the Cummunotron 16 with a toggle deployment option. If you look carefully you can also see my special made, Not-Rockomax Dead Weight modules installed next to each wheel. These bring the center of mass close to the bottom and prevent rollovers.

With all systems checking out Indifference sets off to the southeast. Finding a safe spot it powers down for the night.

As the sun comes up and Ike looms overhead, Indifference sets off for another long drive. A few samples are taken from some interesting rocks along the way using the Diggatron. That may look like a strut on the lower section of the rotatable drill arm, but it's actually a sample sluice tube that carries material from the drill to the analysis cube, perched on top of the mini rover body section.

Well, well, well, what do we have here. Not so lazy after all, it seems. Spotting the mast cam of its apparently overexerted brother, Indifference probes for signs of life.

Finding nothing from the old rover, Indifference sets off for destinations unknown.

Edited August 6, 2013 by DMagic

[mellojoe]

Awesome!

I love everything about it. The name, first off, sheer genius. Absolutely brilliant, mate. The write up is well done. And the icing on the cake is the "useable" drill. Very nicely done.

10/10 would bang

[-RanZ-]

Very cool mission

[DMagic]

Thanks. Never underestimate the usefulness of a thesaurus in naming your crafts.

And yes, bangability is always one of my chief design goals. After posting the thread I realized that the Diggatron is sort of, um, sadly phallic. So I guess a bangability rating is quite appropriate.

[Diche Bach]

Very nice! I'm amazed that that rocket made it out of orbit, what with that massive overhanging payload

Edited August 5, 2013 by Diche Bach

[DMagic]

Very nice! I'm amazed that that rocket made it out of orbit, what with that massive overhanging payload

I'm kind of surprised that the rocket worked as well as it did. The whole thing is appropriately Kerbal. Because the launch clamps are only on one side the rocket leans toward the VAB before launch. And because of my multistage ignition process (the whole thing blows up if I try to ignite everything at once) the rocket just kind of slides sideways when I blow the launch clamps and ignite the SRB's. It only really starts to stabilize once the liquid boosters are ignited. Since there are no struts on the boosters they do that thing where they sort of bend out like they're about to break off, but they settle down pretty quickly. My custom made, Big Inline Reaction Wheel (with 40 torque I think) probably helped stabilize things, too.

And because there is no fuel crossfeed the central engine is dropped off very soon after the liquid boosters, so I avoid having to deal with a really long, unstable rocket for very long. Once I got past that stage everything was very stable, and the payload itself is very well strutted down.