Main Topic 10: Atmospheric Interaction and Orbital End States

Aerobraking

• aerodynamic drag

• orbital energy

____________ is an orbital maneuver in which a spacecraft uses ________ from a planet’s atmosphere to reduce its _______, rather than relying entirely on onboard propulsion.

• drag force

• velocity vector

• negative work

______________

• maneuver

Aerobreaking Considerations

• This ________ opposes the spacecraft’s ________ and performs

________work.

• The _________ must be carefully controlled to prevent overheating or

  excessive structural loads. The heat load during an aerobraking pass

  can build up rapidly because: (photo)

• Exomars Trace Gas Orbiter

_______________ completes Aerobraking

• Orbital decay

  • lower altitude

  • re-entry,

  • Low Earth Orbit (LEO).

___________ is the gradual reduction of a satellite's orbit, leading to ___________ and eventual ________ primarily caused by atmospheric drag in ____________

• shape of the satellite

• 150 km

Aerodynamic drag force

• The reference area, Aref, and the drag coefficient, CD , in will depend on the exact____________.

• It is often assumed that in the absence of specific information, then CD = 1 in the very outer regions of the atmosphere in the low-density or rarefied flow, increasing to CD = 2 when approaching an orbital altitude of ____ km.

• 10-4 km/s

• 7.5 km/s

  • ISS

Consequences of orbital decay

• Typically, satellites in LEO exceeding a radial decay rate of approximately _____ km/s are considered to bein a critical state of orbital decay.

• For a satellite with Vs approximately___ km/s (similar to the ____ in LEO), a radial decay rate exceeding that threshold could see a significant orbital decay over a relatively short period.

• Mach 12

  • aerodynamic friction

• heat shield

• blunt body

  • kinetic heating

• kinetic energy

Atmospheric re -entry

• High re-entry velocities, which canexceed Mach ____, generate substantial ___________ on the spacecraft, producing heat.

• So much heat is generated during re-entry that the spacecraft must be equipped with a thermal protection system (TPS), such as a _______, to prevent it from burning up or vaporizing.

• A ________ is preferred for a re- entry shape, which causses the shock wave to stand off from the spacecraft, reducing _______ and creating high drag.

• Managing the thermal environment during re-entry is critical, as the spacecraft’s ________ must be dissipated safely.