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The Tintin Challenge


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I'm sure most of us are at least partially familiar with the Tintin comics and one of Hergé's best storylines, Destination Moon and Explorers on the Moon.

The_Adventures_of_Tintin_-_16_-_Destinat

In the comic, Tintin et al. ride to the moon and back on a nuclear-powered single-stage rocket. The comic was written in 1950, well before we had a good idea of what orbital launch vehicles would actually look like, but Hergé did his best to make the launch vehicle as accurate as possible to the imaginations of the time. The rocket was a tailsitter, launching and landing vertically on three fixed landing legs (which apparently also contained auxiliary fuel tanks) and used two inline main engines: a chemical rocket engine with a whopping amount of thrust (enough to make the crew black out during ascent) as well as a nuclear rocket engine for the transfer to the Moon. The chemical rocket engine may have been annular, since it appeared to fire through the same aperture as the nuclear engine. It had three fixed RCS thrusters near the base as well:

xg8sE2t.png

(There's some discrepancy between the French and English versions of the comic; in the French version the rocket's nuclear engine is a brachistochrone which fires continuously at a noticeable acceleration, completing the trip in a matter of hours, while in the English version the trip takes about as long as you would expect from a standard Hohmann transfer, but for our purposes we'll go with the English version because it's the only one that's realistic for KSP.)

The chemical rocket had enough throttle range for a gentle moon landing, and its crew hatch was low, with a ladder that reached all the way to the surface:

61VzkEr-BPL._SY291_BO1,204,203,200_QL40_

The rocket had prodigious payload capacity, even able to bring along a "Moon tank" for exploring:

$_12.JPG?set_id=880000500F

In the Earth-Moon system, the dV for such a trip is prohibitively high -- in excess of 18 km/s, not even counting the huge braking burns you'd need to re-enter and land from cislunar space without a heat shield. You would need an open-cycle gas-core nuclear thermal rocket with a LOX afterburner to even hope for that kind of thrust and efficiency. But in the Kerbin-Mun system, it's within the realm of possibility. On Kerbin, a pure-chemical SSTO powered by a Mammoth, Mastodons, or Vectors can reach orbit (about 3.4 km/s with gravity and aerodynamic drag losses) with a payload fraction (payload/mf) of ~48% or so, and getting from LKO to the surface of the Mun and back to Kerbin entry interface is under 2.7 km/s. With the LV-N's 800 seconds of specific impulse, you only need about 30% of your mass-in-orbit to get over 2.7 km/s, so if you can fit the dry mass of LV-Ns, LF tanks, a crew capsule, auxiliary structure, and landing propellant into the remaining 18%, you're golden.

Of course, the challenge is pulling it off. Can you?

The Tintin Challenge

Your mission, should you choose to accept it, is simple. Take Jeb (and whoever you want to accompany him) on a round-trip from the surface of Kerbin to the surface of the Mun and back. You must use a single-stage rocket which takes off and lands vertically on a single axis. You must use a stock vehicle (no, don't use the Tintin mod) and you cannot use propellers, airbreathing engines, or ion engines. NO EXCEPTIONS -- chemical rockets and nuclear rockets only. If you need some sort of ground infrastructure to help support the vehicle at launch, that's fine, but the rocket needs to be able to land by itself.

Part clipping is fine -- in particular, you'll probably want to clip your engines together to help ensure a single thrust axis -- but don't abuse it too much. The Tintin rocket may have had comically undersized propellant tanks, but if you do this in KSP then it's just going to become a question of whose computer can handle the highest part count, which is a much less interesting challenge. You can pick any launch site you want and you can use drag-avoidance tricks.

Scoring

As usual, there are scoring rules:

  • The Basics. Getting Jeb from Kerbin to Mun to Kerbin in one piece: 200 points.
  • Keeping Company. Sending additional Kerbals along for the ride: 10 points per Kerbal, up to a max of 10 Kerbals total.
  • Form and Function. The rocket lands on three fixed landing legs: 30 points.
  • It's the Climb. Kerbals climb down to the surface of the Mun and back up on a ladder from the main body of the rocket: 15 points.
  • Rock Solid. The main engines are fixed with no gimbal and all pointing is provided by RCS: 35 points.
  • Reaction Control. All RCS is clustered at the base of the rocket, near the engines: 10 points.
  • Blackout. The rocket exceeds 5 gees during launch: 40 points.
  • Nukular. Use only nuclear engines for the Mun landing: 30 points.
  • Combat. The main body of the rocket has the traditional ogive bullet shape of the V2 and the original Tintin rocket.
  • Wheelie. Bring a deployable "Mun tank" with three seats to the Mun: 60 points.

 This challenge has razor-thin margins so I don't think anyone will be able to score all the points. But I'm excited to see what you can come up with!

Edited by sevenperforce
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12 hours ago, sevenperforce said:

I'm sure most of us are at least partially familiar with the Tintin comics and one of Hergé's best storylines, Destination Moon and Explorers on the Moon.

The_Adventures_of_Tintin_-_16_-_Destinat

In the comic, Tintin et al. ride to the moon and back on a nuclear-powered single-stage rocket. The comic was written in 1950, well before we had a good idea of what orbital launch vehicles would actually look like, but Hergé did his best to make the launch vehicle as accurate as possible to the imaginations of the time. The rocket was a tailsitter, launching and landing vertically on three fixed landing legs (which apparently also contained auxiliary fuel tanks) and used two inline main engines: a chemical rocket engine with a whopping amount of thrust (enough to make the crew black out during ascent) as well as a nuclear rocket engine for the transfer to the Moon. The chemical rocket engine may have been annular, since it appeared to fire through the same aperture as the nuclear engine. It had three fixed RCS thrusters near the base as well:

xg8sE2t.png

(There's some discrepancy between the French and English versions of the comic; in the French version the rocket's nuclear engine is a brachistochrone which fires continuously at a noticeable acceleration, completing the trip in a matter of hours, while in the English version the trip takes about as long as you would expect from a standard Hohmann transfer, but for our purposes we'll go with the English version because it's the only one that's realistic for KSP.)

The chemical rocket had enough throttle range for a gentle moon landing, and its crew hatch was low, with a ladder that reached all the way to the surface:

61VzkEr-BPL._SY291_BO1,204,203,200_QL40_

The rocket had prodigious payload capacity, even able to bring along a "Moon tank" for exploring:

$_12.JPG?set_id=880000500F

In the Earth-Moon system, the dV for such a trip is prohibitively high -- in excess of 18 km/s, not even counting the huge braking burns you'd need to re-enter and land from cislunar space without a heat shield. You would need an open-cycle gas-core nuclear thermal rocket with a LOX afterburner to even hope for that kind of thrust and efficiency. But in the Kerbin-Mun system, it's within the realm of possibility. On Kerbin, a pure-chemical SSTO powered by a Mammoth, Mastodons, or Vectors can reach orbit (about 3.4 km/s with gravity and aerodynamic drag losses) with a payload fraction (payload/mf) of ~48% or so, and getting from LKO to the surface of the Mun and back to Kerbin entry interface is under 2.7 km/s. With the LV-N's 800 seconds of specific impulse, you only need about 30% of your mass-in-orbit to get over 2.7 km/s, so if you can fit the dry mass of LV-Ns, LF tanks, a crew capsule, auxiliary structure, and landing propellant into the remaining 18%, you're golden.

Of course, the challenge is pulling it off. Can you?

The Tintin Challenge

Your mission, should you choose to accept it, is simple. Take Jeb (and whoever you want to accompany him) on a round-trip from the surface of Kerbin to the surface of the Mun and back. You must use a single-stage rocket which takes off and lands vertically on a single axis. You must use a stock vehicle (no, don't use the Tintin mod) and you cannot use propellers, airbreathing engines, or ion engines. NO EXCEPTIONS -- chemical rockets and nuclear rockets only. If you need some sort of ground infrastructure to help support the vehicle at launch, that's fine, but the rocket needs to be able to land by itself.

Part clipping is fine -- in particular, you'll probably want to clip your engines together to help ensure a single thrust axis -- but don't abuse it too much. The Tintin rocket may have had comically undersized propellant tanks, but if you do this in KSP then it's just going to become a question of whose computer can handle the highest part count, which is a much less interesting challenge. You can pick any launch site you want and you can use drag-avoidance tricks.

Scoring

As usual, there are scoring rules:

  • The Basics. Getting Jeb from Kerbin to Mun to Kerbin in one piece: 200 points.
  • Keeping Company. Sending additional Kerbals along for the ride: 10 points per Kerbal, up to a max of 10 Kerbals total.
  • Form and Function. The rocket lands on three fixed landing legs: 30 points.
  • It's the Climb. Kerbals climb down to the surface of the Mun and back up on a ladder from the main body of the rocket: 15 points.
  • Rock Solid. The main engines are fixed with no gimbal and all pointing is provided by RCS: 35 points.
  • Reaction Control. All RCS is clustered at the base of the rocket, near the engines: 10 points.
  • Blackout. The rocket exceeds 5 gees during launch: 40 points.
  • Nukular. Use only nuclear engines for the Mun landing: 30 points.
  • Combat. The main body of the rocket has the traditional ogive bullet shape of the V2 and the original Tintin rocket.
  • Wheelie. Bring a deployable "Mun tank" with three seats to the Mun: 60 points.

 This challenge has razor-thin margins so I don't think anyone will be able to score all the points. But I'm excited to see what you can come up with!

I'll look into doing it for my Kerbol Konquest Series.

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  • 1 month later...
On 11/30/2021 at 5:56 PM, sevenperforce said:

On Kerbin, a pure-chemical SSTO powered by a Mammoth, Mastodons, or Vectors can reach orbit (about 3.4 km/s with gravity and aerodynamic drag losses) with a payload fraction (payload/mf) of ~48% or so

How are you getting 48% payload fraction? I don't think you can even get close to 48%.

With a properly drag optimised rocket you can get into low Kerbin orbit for 2800 m/s, and sometimes even lower if TWR is sufficiently high.

Suppose delta-v is 2800 m/s = g * isp * ln(mass ratio). Vector isp goes from 295 to 315 and with a properly drag optimized rocket you'll be mainly burning lower in the atmosphere so we can assume isp of about 305 on average. This means mass ratio = e^(2800 / 9.81 / 305) = 2.549, so your craft's mass in orbit can be at most 0.392 of your mass on the ground. This means 0.608 of your mass must be liquid fuel and oxidizer for just the ascent. LFO tanks have a mass ratio of 9:1 which means that 0.684 of your craft must be LFO tanks, which leaves 0.316 of your rocket to be payload, fairing, engines, control systems, crew, etc.

I've found that a Vector surface TWR of 1.5 is close to optimal for rocket SSTO craft. A Vector has 93.6 tons of thrust at sea level, which means a rocket mass of 62.4 tons. This would imply that the rocket has 42.68 tons of rocket fuel tanks and 19.72 tons of other stuff. Subtract four tons for the Vector engine and you get 15.72 tons of usable payload. This would imply payload fraction of 25.2%. Note that this figure is calculated based on an extremely low delta-v ascent as well as zero mass for a fairing, fins, or anything else you may need. In reality, payload fraction will probably be even less than 25%.

The good news is that 25% is probably enough to do a Mun mission and return on nuclear engines, but fitting in all the extras might be difficult...

Edited by camacju
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Okay, here's my submission. I didn't tick all the score objectives as I was going for a small and light craft.

kxx0FYI.png

Craft in VAB. One Vector, two Nervs. You can see the three landing legs and the three RCS ports. Also the mild part clipping.

Spoiler

AXf3eqH.png

On pad

n9Ir1Dj.png

Launch on just the Vector. I turn on the Nervs at 10 km - they're actually more efficient than the Vector from about 2.5 km altitude but I don't want to waste their 800 second isp.

bAuqTcA.png

Tops out at 3.5 G

4v45SWc.png

Continue to orbit on just Nerv power and fairing body lift

rZpthOH.png

Circularizing

Db2rb8K.png

In orbit, with more than enough delta-v left to go to Mun and back

Wi74wjB.png

Mun transfer

fDXzqln.png

Combination Mun capture burn and deorbit burn. Inefficient but I had fuel to spare.

ZEujjd0.png

Landing burn

7VZWX3g.png

Landed on Mun!

TTEoCur.png

Breaking Ground hydraulics are used to deploy the tank

Spoiler

gjCXQnU.png

Climbing down the ladder

3ZSqUe8.png

Flag!

srvkmqn.png

Driving

MPGDcRW.png

Takeoff

hMa5fYT.png

Circularization

V18Opkq.png

Mun orbit

IuU6QIG.png

Mun ejection

acVCGsy.png

Aerobraking

A51d9Ey.png

Aerobraking further, I burn off my remaining fuel here to save mass

zwqd08o.png

Chutes deployed

1gHw1Zl.png

Landed

I believe my score is:
200 for completion
30 for landing legs
15 for ladder
10 for RCS placement
30 for only using nuke for Mun landing
60 for tank

Total: 345 points

 

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Modded section please? I could do the french version with mods

On 11/30/2021 at 8:56 PM, sevenperforce said:

I'm sure most of us are at least partially familiar with the Tintin comics and one of Hergé's best storylines, Destination Moon and Explorers on the Moon.

The_Adventures_of_Tintin_-_16_-_Destinat

In the comic, Tintin et al. ride to the moon and back on a nuclear-powered single-stage rocket. The comic was written in 1950, well before we had a good idea of what orbital launch vehicles would actually look like, but Hergé did his best to make the launch vehicle as accurate as possible to the imaginations of the time. The rocket was a tailsitter, launching and landing vertically on three fixed landing legs (which apparently also contained auxiliary fuel tanks) and used two inline main engines: a chemical rocket engine with a whopping amount of thrust (enough to make the crew black out during ascent) as well as a nuclear rocket engine for the transfer to the Moon. The chemical rocket engine may have been annular, since it appeared to fire through the same aperture as the nuclear engine. It had three fixed RCS thrusters near the base as well:

xg8sE2t.png

(There's some discrepancy between the French and English versions of the comic; in the French version the rocket's nuclear engine is a brachistochrone which fires continuously at a noticeable acceleration, completing the trip in a matter of hours, while in the English version the trip takes about as long as you would expect from a standard Hohmann transfer, but for our purposes we'll go with the English version because it's the only one that's realistic for KSP.)

The chemical rocket had enough throttle range for a gentle moon landing, and its crew hatch was low, with a ladder that reached all the way to the surface:

61VzkEr-BPL._SY291_BO1,204,203,200_QL40_

The rocket had prodigious payload capacity, even able to bring along a "Moon tank" for exploring:

$_12.JPG?set_id=880000500F

In the Earth-Moon system, the dV for such a trip is prohibitively high -- in excess of 18 km/s, not even counting the huge braking burns you'd need to re-enter and land from cislunar space without a heat shield. You would need an open-cycle gas-core nuclear thermal rocket with a LOX afterburner to even hope for that kind of thrust and efficiency. But in the Kerbin-Mun system, it's within the realm of possibility. On Kerbin, a pure-chemical SSTO powered by a Mammoth, Mastodons, or Vectors can reach orbit (about 3.4 km/s with gravity and aerodynamic drag losses) with a payload fraction (payload/mf) of ~48% or so, and getting from LKO to the surface of the Mun and back to Kerbin entry interface is under 2.7 km/s. With the LV-N's 800 seconds of specific impulse, you only need about 30% of your mass-in-orbit to get over 2.7 km/s, so if you can fit the dry mass of LV-Ns, LF tanks, a crew capsule, auxiliary structure, and landing propellant into the remaining 18%, you're golden.

Of course, the challenge is pulling it off. Can you?

The Tintin Challenge

Your mission, should you choose to accept it, is simple. Take Jeb (and whoever you want to accompany him) on a round-trip from the surface of Kerbin to the surface of the Mun and back. You must use a single-stage rocket which takes off and lands vertically on a single axis. You must use a stock vehicle (no, don't use the Tintin mod) and you cannot use propellers, airbreathing engines, or ion engines. NO EXCEPTIONS -- chemical rockets and nuclear rockets only. If you need some sort of ground infrastructure to help support the vehicle at launch, that's fine, but the rocket needs to be able to land by itself.

Part clipping is fine -- in particular, you'll probably want to clip your engines together to help ensure a single thrust axis -- but don't abuse it too much. The Tintin rocket may have had comically undersized propellant tanks, but if you do this in KSP then it's just going to become a question of whose computer can handle the highest part count, which is a much less interesting challenge. You can pick any launch site you want and you can use drag-avoidance tricks.

Scoring

As usual, there are scoring rules:

  • The Basics. Getting Jeb from Kerbin to Mun to Kerbin in one piece: 200 points.
  • Keeping Company. Sending additional Kerbals along for the ride: 10 points per Kerbal, up to a max of 10 Kerbals total.
  • Form and Function. The rocket lands on three fixed landing legs: 30 points.
  • It's the Climb. Kerbals climb down to the surface of the Mun and back up on a ladder from the main body of the rocket: 15 points.
  • Rock Solid. The main engines are fixed with no gimbal and all pointing is provided by RCS: 35 points.
  • Reaction Control. All RCS is clustered at the base of the rocket, near the engines: 10 points.
  • Blackout. The rocket exceeds 5 gees during launch: 40 points.
  • Nukular. Use only nuclear engines for the Mun landing: 30 points.
  • Combat. The main body of the rocket has the traditional ogive bullet shape of the V2 and the original Tintin rocket.
  • Wheelie. Bring a deployable "Mun tank" with three seats to the Mun: 60 points.

 This challenge has razor-thin margins so I don't think anyone will be able to score all the points. But I'm excited to see what you can come up with!

 

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