Mission Objectives

• Demonstrate drag-free and attitude control in spacecraft with two proof masses
• Test feasibility of laser interferometry at the level of accuracy envisaged for LISA
• Test endurance of the different instruments and hardware in the space environment

Mission Name

LISA Pathfinder is the proper name of SMART-2. (SMART is the abbreviation for Small Missions for Advanced Research and Technology.)  The name indicates the original mission objective: to pave the way for the joint ESA-NASA LISA mission.

Spacecraft

LISA Pathfinder is comprised of the science spacecraft and a separable propulsion module. The science spacecraft contains the two main instruments LTP and DRS, and is covered with one single fixed solar array. The mass of the science spacecraft after arrival at the operational orbit is 420 kg.

Instruments

The science spacecraft carries two test packages:

• LISA Technology Package (LTP)
  The LTP will contain two identical proof masses in the form of 46 mm cubes, each suspended in its own vacuum can. They perform a double role of acting as mirrors for the interferometer and as inertial references for the drag-free control system.
• Disturbance Reduction System (DRS)
  The DRS is a NASA-supplied system comprising two clusters of Colloidal micropulsion thrusters and an electronic unit containing a computer with associated drag-free control software.

Orbit

LISA Pathfinder will be launched into a slightly elliptical parking orbit. From there, it will use its own propulsion module to progressively expand its Earth orbit and reach the final operational orbit: a halo orbit around the first Sun-Earth Lagrange point (this is the same position in space as the ESA-NASA SOHO mission). After the last transfer burn is performed, and the health of the science spacecraft is ascertained, the propulsion module will be jettisoned.

Operations Centre

The mission control centre is situated at ESOC in Darmstadt, Germany. The science and technology operations will be coordinated from ESTEC in Noordwijk, the Netherlands.