Because no one else seems to want to do the statting.
The default space combat system of Traveller assumes missiles that can thrust for the better part of an hour (or several hours) on a moderate load of fuel and carry a warhead massing several kilograms at least. It isn't shocking that someone somewhere is going to strap a jury rigged (hopefully disarmed) missile to his back and try flying the damned thing. FTL and maneuver drives do not cure the human animal of the death wish gene.
Let's build a rocket pack using Special Supplement 3 Missiles in Traveller. Let's assume a human weighs 80 kg. with gear. We need an engine that can make 3 gees. Anymore will be too hard on the flyer and we need at least 1 gee to offset gravity. A discretionary burn system will cost 2900 cr. and weigh 13 kg.
Item Cost Mass
Person Free! 80
Engine 2900 cr 13
Controls 300 cr 3
Fuel (10) 1600 cr 4
Totals 4800 cr 100
First of all even though we bought a 3 gee propulsion system it was designed for a 50 kg. missile and when strapped to a heavy human the total is 100 kg. It will thrust at 1.5 gees. The fuel will last for three combat turns or 3000 seconds or 50 minutes. On anEarth sized planet (1 gee) it will thrust at 5 meters per second (.5 gees). The Striker Design charts give it a speed of 600 kph. I'd assume less since a human is not as streamlined as most spacecraft. Let's call it 200 kph. That gives it a one way range of 170 kilometers.
I'd peg the TL for this at 9. Discretionary burn missiles are normally TL 10 but I figure a human in direct control can be introduced a TL earlier. You could allow Vacc skill to be used with a rocket pack as vacc suits have a similar thruster arrangement. You could also allow a player to choose it for his character in lieu of +1 Str on personnel development if their branch is Navy, Scout, Marine, Army or Flyer or for vehicle skills. The cost at TL 9 is about 5000 cr (merchants round up). The price drops to 4500 cr at TL 10. Fuel for the packs is available on worlds of TL 9 or higher or at D or better starports.
Flying a rocket pack requires a helmet and a specialized flight suit to protect the flier's legs from the heat of the exhaust. The whole rig costs 500 cr and is equivalent to Jack armor. Weight is 3 kg but negligible when worn. Without the helmet breathing becomes difficult. Combat armor or a vacc suit can replace the flight suit.
In high speed flight (over 120 kph) the user flies with the arms held at the side and controls direction by arching or twisting the torso. At lower speeds the rocket pack can be controlled by a lever mounted on the side.
Unusual movement or maneuvers (landing on a moving ground car, crashing through a window) requires the user to roll under Dex + skill on 2d6 with modifiers by the referee for the situation. At TL 11 a Interactive Flight suit (with helmet) appears that uses tactile sensors and heads up displays as well as voice and eye motion detectors to control the rocket pack, This rig costs 2000 cr and is otherwise the same as the plain vanilla rig.
Rocket packs are often used by unarmored troops (mainly because battledress and grav belts appear about the same time). Some particularly daring Marines use them with vacc suits or combat armor to drop from orbit before drop capsules come into use. This gives a -4 to the maneuver roll and should be considered hazardous duty. Failure is usually fatal. The user has exhausted his fuel too soon or burned up in re-entry and either way takes d6 damage. Success means the user has not only landed but retains 5 minutes fuel for each point he made the roll by.