Van Allen Extended Mission Orbit Analysis 9/2014 SWG T. Sotirelis, F. Siddique JHU/APL

2 Options Option ΔV RBSPA (m/sec) Fuel Used RBSPA (kg) ΔV RBSPB (m/sec) Fuel Used RBSPB (kg) Mission EOL Estimate** Petal Separation Oct 2015 Petal Separation Oct 2016 Do nothing000011/1/ °5.7° Increase Delta Apogee by 200%* /1/ °10.9° Decrease RBSPA Perigee to 575 km /1/ °12.4° Increase Delta Apogee by 300%* /1/ °13.6° Decrease RBSPA Perigee to 575 km /1/ °15.0° 5 Analysis assumes maneuvers performed June 1, 2015 *Current delta between apogee altitudes is ~140 km **End of life (EOL) estimates are based on projecting current propellant usage forward. EOL of spacecraft due to radiation environment is predicted to be 12/1/2019 Perigee altitude reduction already book-kept in the disposal budget, does not affect estimated EOL Predicted angle between apse lines at nominal mission Q4 exit (Aug 2014) is 2.25 deg Mission lifetime can be extended by altering disposal scenario So far, a scenario adding 50 days has been found

3 200% Apse Altitude Change and Decrease Perigee Altitude by 25 km on RBSPA 3 NOTE: Due to solar/lunar perturbations, by dropping perigee altitude by 25 km, the range of perigee altitudes will drop from [555,645] km to [495,585] km Nominal Decrease Perigee Altitude by 25 km

4 Nominal Orbit Increase Delta Apogee 200% on 6/1/2015 A/B Conjunctions: Same MLT: L vs ΔL

5 Nominal Orbit Increase Delta Apogee 300% on 6/1/2015 A/B Conjunctions: Same MLT: L vs ΔL

6 Nominal Orbit Increase Delta Apogee 200% & Decrease Perigee A by 25 km on 6/1/2015 A/B Conjunctions: Same MLT: L vs ΔL

7 Nominal Orbit Increase Delta Apogee 200% on 6/1/2015 A/B Conjunctions: Same L: L vs ΔMLT

8 Nominal Orbit Increase Delta Apogee 200% & Decrease Perigee A by 25 km on 6/1/2015 A/B Conjunctions: Same L: L vs ΔMLT

9 Nominal Orbit Increase Delta Apogee 200% & Decrease Perigee A by 25 km on 6/1/2015 A/B Conj. ≥30 Minutes: Same L: L vs ΔMLT

10 Time Close Together (hours)

11 Summary  Increasing petal separation will reduce mission lifetime  Close approaches become rarer as the petals separate  Mission lifetime can be extended by altering disposal scenario  What science can be motivated by these scenarios?

12 Backup

13 Trajectory Status ( ) [Predicted] Lapping Rate Per Quadrant27-Nov-2013 Q12.44 Q22.25 Q32.52 Q42.34 Quadrant Entry/Exit DatesRBSPARBSPB Enter Q118 Aug :0013 Aug :00 Enter Q203 Feb :0026 Jan :00 Enter Q303 Jul :0028 Jun :59 Enter Q421 Dec :0012 Dec :00 Exit Q430 May :0020 May :00 13 Q1Q2 Q3Q4

14 Remaining Usable Propellant  Propellant usage based on initial usable propellant = kg. Usable propellant depicted. For total including residuals, increase by kg.  As of August 31, 2014: SCA usable = 43.97±0.72 kg. SCB usable = 43.83±0.72 kg. SCA (kg) SCB (kg) Total propellants used as of 8/31/ Reserved for Disposal19 Available for extended missions 23.5 Propellant on-board to extend current operations until ~Nov 2018