# How would one calculate the Lunar liftoff thrust required for a spacecraft?

I used the thrust to weight ratio of 2.12 to determine the thrust my spacecraft needs for a lunar liftoff, Apollo Lunar Ascent Stage Thrust to Weight Ratio. Is this a proper way of determining and sizing my spacecraft based on the Thrust needed using the thrust to weight ratio of the Lunar Ascent Module?

• Lunar surfact gravity is 0.17 g. that means that a craft with a thrust to weight ratio of more than 0.17 can lift off. Is that your question? Commented Feb 19, 2019 at 20:39
• If my spacecraft weight for example is 45,000 kg. How much thrust does my engines need to produce? I know you mentioned the gravity. However does my spacecraft also need to satisfy the T/W=2.12, similar to Lunar Ascent Moduls T/W ratio of lunar module. Commented Feb 19, 2019 at 20:46
• When you say T/W, by "W", do you mean the weight on earth, or the weight on the moon?` Commented Feb 19, 2019 at 21:01
• Yes, mass*lunar gravity(1.62 m/s^2 ) Commented Feb 19, 2019 at 21:05