In 3 Body Problem, the Staircase Project involves sending a probe to the San-Ti fleet to understand the enemy humans are facing.
After learning that San-Ti are watching and listening to them all the time using their Sophons, Thomas Wade resolves to send something of their own to the San-Ti fleet.
He plans to send a probe to the San-Ti fleet. Knowing that their technology is faster than that of San-Ti, he assigns Jin to figure out a way to reach San-Ti faster using the technology they have.
The plan Jin comes up with ultimately becomes the Staircase Project.
The stairs
Since the San-Ti are traveling at 1% light speed, Wade intends to reach them at the same speed or faster.
Utilizing the existing technology, Jin finds a way to send a probe at 1% light speed using the nuclear bombs that they have.
The bombs will not be placed on the probe. Instead, the probe will have minimal mass to facilitate easier acceleration.
Jin is using an old idea from Stanislav Ullam in the 1940s called “Nuclear Pulse Propulsion.”
A series of 1000 nuclear devices will be evenly spaced in distance, stretching from Earth toward the San-Ti fleet. These bombs could be put in place using existing spacecraft.
The probe will have a mass of under 1000 kilograms and be propelled by a radiation sail. Once the probe encounters the initial bomb, the bomb will explode, propelling the probe towards the next bomb. This process repeats, causing the probe to accelerate repeatedly.
If they can precisely time the detonations as the probe passes and impart 30 kilonewtons of force on the probe per explosion, the compounding rate of acceleration will mean they can reach 1.12% of light speed after 1000 explosions.
Jin compares this process to the steps on a staircase, with each bomb bringing them closer to their destination.
Complications and the person going into space
Wade doesn’t plan to send a camera into space to spy on San-Ti; he plans to send a human being on board. However, there is more than one complication in that case.
Wade and his team need 1000 bombs for Staircase, and they only get 300. They are also using a hibernation rig to ensure the person being sent on the probe will survive by the time they reach the San-Ti fleet.
However, the smallest rig they can have is over a ton. The heaviest payload it can carry is under two kilograms.
This leads Wade to decide that they won’t be sending a person to space; they will be sending the brain of a person. They need someone who is already dying and is willing to take this chance, and they find that person in Will Downing.
Wade is well aware that San-Ti won’t risk the chance of understanding humans by destroying the probe they are sending. They will have the technology to give the brain they are sending a body.
Unfortunately, on the day of launch, the probe faces a minor complication, resulting in it losing its way. Will ends up floating in space, all on his own. Ultimately, the Staircase Project ends up being a failure.
Also Read: Sophons in 3 Body Problem explained