When the Americans sent their first three man crew to the moon in Apollo 11 in 1969, they sent them on top of an enormous rocket called the Saturn V, even to this day the largest, most powerful rocket ever built. It had to be, it had to carry everything to send the crew the quarter of a million miles to the moon, keep them alive for three days in orbit and on the surface, and bring them home again.
This included all of the fuel to get them there, the oxygen, food and water they would need for nine days, the vehicle that would take them down to the lunar surface and bring them back up again, and the fuel for the voyage home. All shot from the Earth in one go (no building a spaceship in Earth orbit, that would have been too complex and therefore risky).
So that worked for going to the Moon. But imagine how much more difficulty it will be for going to Mars
Instead of Quarter of a million miles, we’re talking 90 million. Instead of a three day trip to the target, six months. You’ll need a whole lot more food, water and oxygen. For that matter, you’ll need a bigger crew – try living with just two other people to talk to and work with for a year and a half. Six people, women and men, would probably be an optimal size.
Your spaceship will need to be bigger as well. You can’t expect people to live in cramped conditions for six months, they’ll need to be able to move around, and have some measure of privacy when they need it.
Getting to the Martian surface and back up will be more difficult, as Mars has more than twice the gravity than the moon, which means you’ll need more fuel. Then you’ll need to get home, which will need still more fuel.
All that fuel needs to be stored somewhere, which means a bigger rocket. The extra weight of the fuel and the bigger rocket means you need… yet more fuel. Which needs a bigger rocket to carry it and more fuel… this gets exponential in a hurry!
The all of the first serious planning for a Martian voyage, from von Von Brauns “Das Marsprojekt” to George Bush Snr’s Space Exploration Initiative in the early 80’s, were based on this mission architecture and required massive spaceships weighing thousands of tonnes being built in Earth orbit at huge orbital dockyards that would have cost hundreds of billions to build.
It’s no surprise that none of these plans ever got off the drawing board. Going to Mars this way was never more than fantastical.
Surely there had to be another way. Surely you didn’t have to take everything with you