Tintin and science
Reception
The magnifying glass and fire
Thaw by salt
The lightning in ball
Tintin on the Moon

Several scientists have checked the journey of the rocket in Destination Moon and Explorers on the Moon. Here is one of them, made by Charles de Granrut.

First check
Destination Moon, page 60 : a man says that the rocket is situated 800 km (497 miles) from the Earth and that the atomic motor is running. Using the relation s2 = 2ax (where s is the speed, a is the acceleration and x the position) and taking a = 20 m/s/s (chosen by making a compromise between the needed acceleration to separe the rocket from the Earth and the acceleration that human can bear), we find a speed of 5,7 km/s (3.5 miles/s). Moreover, the relation s = at (where t is the time) shows that the rocket has been travelled for 4 min 43 s.
By doing similar arithmetics, we can find the rocket's speed and the passed time at different moments :
   - Page 61 : the rocket is 1500 km (932 miles) from the Earth.
   - Explorers on the Moon, page 2 : the rocket is 4000 km (2,486 miles) from the Earth.
   - Page 3 : the Thompson learn that the rocket is 8000 km (4,972 miles) from the Earth and has a speed of 11 km/s (6.8 miles/s).
   - Page 5 : the rocket has a speed of 13 km/s (8.1 miles/s) and isn't submitted anymore to the Earth's attraction.
   - Page 13 : the speed is 45 km/s (28 miles/s).

The results can be sum up :

DistanceSpeedPassed time
800 km (497 miles)5,7 km/s (3.5 miles/s)4 min 43 s
1 500 km (932 miles)6,4 km/s (4 miles/s)6 min 40 s
4 000 km (2,486 miles)8,4 km/s (5.2 miles/s)12 min 19 s
8 000 km (4,972 miles)10,9 km/s (6.8 miles/s)19 min 14 s
12 200 km (7,582 miles)13 km/s (8.1 miles/s)25 min 7 s
166 876 km (103,714 miles)45 km/s (28 miles/s)1 h 49 min 17 s

Conclusions
   - At 8000 km (4,972 miles), the professor Calculus round the passed time to a half-hour. The calculated speed (6.77 miles/s) correspond to the announced speed (6.84 miles/s), because we haven't considered the loss of rocket's weight (loss of fuel).
   - Little mistake at 12 200 km (7,582 miles) : the rocket is submitted to the earth attraction (it will always, even on the Moon). The right thing is, that with a speed of 13 km/s (8.1 miles/s), the rocket passed the needed speed not to fall in direction of Earth if the motor was ctopped.
   - By finishing the operations, we find that the point where the rocket turn over is situated 188 100 km (116,905 miles) from the Earth (with a speed of 47,4 km/s = 29.5 miles/s). The passed time is then 2 h 47 s. Considerating that this point is the middle of the journey, and that the rest of the travel is so long as the first part, the travel to Moon would last 4 h 1 min 34 s. Very good : the Apollo missions needed 4 days !

Second check
We can do an other calcul, made by Roland Lehoucq and Robert Mochkovitch. Published in Mais où est donc le temple du Soleil ? (Where is the Temple of Sun ?, Flammarion, 2003), it gives the following results :

DistanceSpeedPassed time
8000 km (4,972 miles)11 km/s (6.8 miles/s)30 min
10 000 km (6,215 miles)12,66 km/s (7.9 miles/s)32 min 49 s
10 447 km (6,493 miles)13 km/s (8.1 miles/s)33 min 24 s>
12 007 (7,462 miles)13 km/s (8.1 miles/s)35 min 24 s>
16 348 km (10,160 miles)15,94 km/s (9.9 miles/s)40 min 24 s
25 914 km (16,106 miles)15,94 km/s (9.9 miles/s)50 min 24 s
116 171 km (72,201 miles)45 km/s (28 miles/s)1 h 39 min 46 s>
196 579 km (122,175 miles)60,02 km/s (37.3 miles/s)2 h 5 min 17 s)
240 000 km (149,161 miles)52,45 km/s (32.6 miles/s)2 h 18 min 9 s
326 200 km (202,735 miles)32,55 km/s (20.2 miles/s)2 h 51 min 57 s
370 200 km (230,081 miles)14,01 km/s (8.71 miles/s)3 h 23 min 28 s
375 200 km (233,188 miles)9,9 km/s (6.2 miles/s)3 h 30 min 26 s
376 200 km (233,810 miles)03 h 33 min 48 s