Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Engine type | Scenario | SFC in lb/(lbf·h) | SFC in g/(kN·s) | Specific impulse (s) | Effective exhaust velocity (m/s) |
| --- | --- | --- | --- | --- | --- |
| NK-33 rocket engine | Vacuum | 10.9 | 309 | 331.0 | 3240.0 |
| SSME rocket engine | Space shuttle vacuum | 7.95 | 225 | 453.0 | 4423.0 |
| Ramjet | Mach 1 | 4.5 | 127 | 800.0 | 7877.0 |
| J-58 turbojet | SR-71 at Mach 3.2 (Wet) | 1.9 | 53.8 | 1900.0 | 18587.0 |
| Rolls-Royce/Snecma Olympus 593 | Concorde Mach 2 cruise (Dry) | 1.195 | 33.8 | 3012.0 | 29553.0 |
| CF6-80C2B1F turbofan | Boeing 747-400 cruise | 0.605 | 17.1 | 5950.0 | 58400.0 |
Question:
What engine type is used in a Space Shuttle Vacuum scenario?
Answer:
SSME rocket engine