Orbus Family (Pratt & Whitney Chemical Systems Division)
| Specification | Orbus 6 | Orbus 21S |
|---|---|---|
| Application | Inertial Upper Stage | Perigee kick motor for INTELSAT-VI comsats |
| Propellant | ||
| Thrust (max) | 23,800 lb | 59,460 lb |
| Thrust (avg) | 17180 lb | 44,700 lb |
| Burn time | 101 s | 138 s |
| Specific Impulse | 290 s | 294 s |
| Total impulse | 1,738,000 lb-s | 6,190,000 lb-s |
| Chamber Pressure | 611 psia | 669 psia |
| Weight | 6515 lb | 22,703 lb |
| Mass Fraction | 0.927 | 0.934 |
| Expansion Ratio | 47.3 | 63.2 |
Castor : GEM
