Atmospheric Reentry Disposal for Low-Altitude Spacecraft

We explored four different options for atmospheric reentry of spacecraft from a circular low Earth orbit, below 2000 km in initial altitude, within 25 years: 1) chemical propulsion maneuvers, 2) low-thrust propulsion transfer, 3)balloon(drag enhancementdevice)deployment,and4)a combinationofoptions1and3.This atmosphericreentry approach satisŽ es the recent set of NASA guidelines on the disposal of space structures. The additional required deorbitweight for each of these options is examined as a functionof the initial altitude and ballisticcoefŽ cient of the spacecraft. The results of this study show that the additionalweight required for deorbit usinga low-thrust transfer is signiŽ cantly less than the additional weight required for the other options. The balloon deployment option is competitive with the chemical propulsion option for low initial altitudes with regard to additionalrequired weight fordeorbit.The combineduse of chemicalpropulsionwith balloondeploymentresults in a lower required additional deorbit weight than for either option alone but only for cases with a small ballistic coefŽ cient (area-to-mass ratio below 0.009 m2 /kg). The Ž nal disposal strategy chosen will also depend on other factors, such as cost, simplicity, reliability, and launch vehicle weight margin. The advantages and disadvantages of each option are discussed.